Appendix A

Data sources

The USRDS maintains a stand-alone database with data on diagnoses and demographic characteristics of ESRD patients, along with biochemical data, dialysis claims, and information on treatment and payor histories, hospitalization events, deaths, physician/supplier services, and providers.

REMIS/REBUS/PMMIS DATABASE

The major source of ESRD patient information for the USRDS is the CMS (formerly HCFA) Renal Beneficiary and Utilization System (REBUS), adopted in 1995 as the On-Line Transaction Processing system from the previous Program Management and Medical Information System (PMMIS) database. The REBUS/PMMIS database contains demographic, diagnosis, and treatment history information for all Medicare beneficiaries with ESRD. The database has also been expanded to include non-Medicare patients, as discussed later in this appendix. Having advanced its database technology, CMS migrated the REBUS database into an Oracle relational database in the fall of 2003, including all patients who were alive and had ESRD as of January 1, 1995, or incident after this date. This database is known as the Renal Management Information System (REMIS).

CMS regularly updates the REMIS/REBUS/PMMIS database, using the Medicare Enrollment Database (EDB), Medicare inpatient and outpatient claims, the United Network for Organ Sharing (OPTN) transplant database, ESRD Medical Evidence forms (2728) provided by the ESRD networks, and ESRD Death Notification forms (2746) obtained from renal providers, as well as the Standard Information Management System (SIMS) database of the ESRD networks. CMS has also established data integrity rules to ensure accurate identification of patients in the SIMS and CMS databases. Each ESRD patient (old and new) will now be identified with a unique patient identification number common to both databases, ensuring that data on all patients are consistently managed over time.

CMS MEDICARE ENROLLMENT DATABASE

CMS’s Enrollment Database (EDB) is the designated repository of all Medicare beneficiary enrollment and entitlement data, and provides current and historical information on residence, Medicare as secondary payor (MSP) and employee group health plan (EGHP) status, and Health Insurance Claim/Beneficiary Identification Code (HIC/BIC) cross-referencing.

ESRD MEDICAL EVIDENCE FORM (CMS 2728)

The ESRD Medical Evidence Form is used as the official form for registering individual patients at the onset of ESRD. This form must be submitted by dialysis or transplant providers within 45 days of ESRD initiation. The CMS, USRDS, and renal research communities rely on this form to ascertain basic patient demographic attributes, primary cause of renal failure, major comorbidities, and biochemical test results at the time of ESRD initiation.

The third major revision of the Medical Evidence Form was released in May, 2005. This latest revision was intended to remedy several shortcomings found in the 1995 form and its earlier version. Key additions target pre-ESRD care and vascular access use, and additional new fields collect information on HbA1c and lipid testing, on the frequency of hemodialysis sessions, and on whether patients are informed of their transplant options. This new form will help federal and private researchers gain better insights into the health and care of ESRD patients prior to their entry into the program.

CMS PAID CLAIMS RECORDS

Inpatient transplant and outpatient dialysis claims records are used to identify new ESRD patients for whom no Medical Evidence form has been filed. These patients, primarily non-Medicare patients, or beneficiaries who develop ESRD while already on Medicare because of age or disability, will eventually be entered into the REMIS/REBUS/PMMIS—and hence the USRDS—database through the claims records. For patients without Medical Evidence forms these claims are the only reliable information from which to determine first ESRD service dates. These paid claims records are, however, only a supplement to, rather than a replacement of, other sources of information on incidence and prevalence.

The problem of timely identification has lessened since the revision of the Medical Evidence form in April 1995, and the amended ESRD entitlement policy that now requires the form to be submitted for all ESRD patients regardless of insurance and eligibility status.

It is important to note that some Medicare-eligible patients may not have bills submitted to and paid by Medicare, including MSP patients covered by private insurance, HMOs, Medicaid, or the Department of Veterans Affairs (DVA).

OPTN TRANSPLANT DATABASE

In the early 1980s CMS began collecting data on all Medicare kidney transplants. In 1988, the United Network of Organ Sharing (now OPTN) was created to provide a national system for allocating donor organs and to maintain a registry on transplantation. OPTN also began collecting data on all transplants. These two efforts were consolidated in 1994, and OPTN became the single source of data on transplant donors and recipients.

The CMS and OPTN transplant data files overlap for 1988–1993, and some patients with Medical Evidence (ME) forms indicating transplant as the initial modality are not included in either file. To resolve conflicts among the three sources, the USRDS has adopted the following procedure:

• OPTN transplants are accepted into the database.
• CMS transplants before 1988 are accepted.
• CMS transplants from 1988 to 1993 are accepted if there is no OPTN transplant record for that patient within 30 days of the CMS transplant.
• Transplants indicated on ME forms are accepted if there is no previously accepted record of a transplant for that patient within 30 days of the date listed on the ME form.

CMS STANDARD ANALYTICAL FILES (SAFs)

These files contain billing data from final action claims, submitted by Medicare beneficiaries, in which all adjustments have been resolved.

For inpatient/outpatient institutional claims we use the following data: inpatient, 100 percent SAF; outpatient, 100 percent SAF; home health agency (HHA), 100 percent SAF; hospice, 100 percent SAF; and skilled nursing facility (SNF), 100 percent SAF. For physician/supplier claims, we use: physician/supplier, 100 percent SAF; and durable medical equipment (DME), 100 percent SAF.

CMS SAFs are updated each quarter through June of the next year, when the annual files are finalized. Datasets for the current year are created six months into the year and updated quarterly until finalized at 18 months, after which they are not updated to include late arriving claims. Annual files are thus approximately 98 percent complete. The USRDS 2007 ADR includes all claims up to December 31, 2005. Patient-specific demographic and diagnosis information, however, includes data as recent as October, 2006.

STANDARD INFORMATION MANAGEMENT SYSTEM (SIMS) DATABASE (ESRD NETWORKS)

The USRDS continues to collaborate with CMS and the ESRD networks to address data tracking issues relating to non-Medicare ESRD patients. Past ADRs have documented the lack of consistent Medicare claims data among these patients. Working solely with data from the Medical Evidence form, the USRDS could establish the first ESRD service date for them, but could not generate a more detailed treatment history. With the integration of the SIMS event data into the USRDS database, however, we can now address issues in the non-Medicare ESRD population such as the large and growing number of lost-to-follow-up patients, and look as well at patients for whom there previously were no data on initial modality or death. This data integration is detailed in the section on data management and preparation.

CMS DIALYSIS FACILITY COMPARE DATA

The USRDS uses the CMS Dialysis Facility Compare data to define chain and ownership information for each renal facility. Prior to the 2003 ADR, similar data were extracted from the Independent Renal Facility Cost Report (CMS 265-94).

ESRD CLINICAL PERFORMANCE MEASURES PROJECT

CMS developed its ESRD Clinical Performance Measures Project (CPM, formerly the ESRD Core Indicators Project) to collect information on the quality of care provided to dialysis patients. The data originate from data collection forms completed by staff at primary care facilities, and focus on dialysis adequacy measures, anemia management, and vascular access. Additional clinical parameters such as albumin are available as well. These data have been collected annually since 1994, using a random sample of adult (age 18 and older) patients alive and on dialysis at the end of each calendar year; on average, roughly 8,500 adult in-center hemodialysis patients and 1,500 peritoneal dialysis patients are surveyed each year. Data collection for all hemodialysis patients age 12–17 was begun in 2000. In 2002 it was expanded to all in-center hemodialysis patients younger than 18, and in 2005 to all peritoneal dialysis patients of this age. The USRDS Coordinating Center, in collaboration with CMS, is now making these ESRD CPM data available to the general research community.

MINIMUM DATA SET

The CMS Minimum Data Set (MDS) contains data on ESRD patients in long-term care facilities. Since June 22, 1998, CMS has required nursing homes participating in Medicare and/or Medicaid programs to supply MDS information, which is collected by staff at the nursing homes and reported to CMS through the Nursing Home Resident Assessment and Care Screening form.

NATIONAL HEALTH & NUTRITION EXAMINATION SURVEY (NHANES)

NHANES is a series of health examination surveys conducted by the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC). Begun in 1960, NHANES is designed to monitor the health and nutritional status of the non-institutionalized civilian population in the United States. NHANES III was conducted in two phases between 1988 and 1994. In 1999, NHANES became a continuous annual survey to allow annual estimates, with release of public-use data files every two years. Both NHANES III and NHANES 1999–2004 were nationally representative cross-sectional surveys and used a complex, stratified, multistage probability cluster sampling design that included selection of primary sampling units (counties), household segments within the counties, and sample persons from selected households. Survey participants were interviewed in their homes and/or received standardized medical examinations in mobile examination centers. Both surveys over-sampled African Americans, Mexican Americans, and individuals age 60 or older to improve the estimates for these subgroups.

ANNUAL FACILITY SURVEY (AFS)

Independent ESRD patient counts are available not only from the CMS ESRD database, but also from CMS’s Annual Facility Survey (CMS 2744), which all dialysis units must complete at the end of each year. The AFS reports counts of patients being treated at the end of the year, new ESRD patients starting treatment during the year, and patients dying during the year. Both Medicare and non-Medicare end-of-year patients are counted. While AFS files do not carry patient-specific demographic and diagnosis data, they provide independent patient counts used to complement the CMS patient-specific records. Starting with the 2005 AFS, CMS stopped its effort in posting data from these surveys on the web. For the 2007 ADR, the USRDS has extracted the relevant data directly from the SIMS database.

CDC SURVEILLANCE

The CDC used its National Surveillance of Dialysis-Associated Diseases to collect data from U.S. dialysis facilities on patient and staff counts, membrane types, reuse practices, water treatment, therapy, vascular access use, antibiotic use, hepatitis vaccination and conversion rates, and the incidence of HIV, AIDS, and tuberculosis. No data are patient-specific. The CDC did not conduct a survey in 1998, and terminated this program after 2002.

UNITED STATES CENSUS

In rate calculations throughout this year’s ADR we use data from the 2000 U.S. Census, and also incorporate CDC population estimates by race. Our methods are described on page 291.

Data management & preparation  

Our main computer system is based on a VMS cluster running Alpha EV6 processors. We currently maintain three nodes in the cluster: two 4-CPU 16-GB systems, and the other a dual CPU with 4-GB of memory. Through the HP Advanced Server System, we map VMS directories to network shares accessible to Windows clients as mapped network drives. The Alpha EV6s are one-GB CPUs and are connected to an 16 terabytes of RAID-5 (Redundant Array of Independent Disks, level 5) disk farms, all managed by five interconnecting high-speed disk controllers.

We use SAS database management system and development tools as our core database technology platform; this differs from the Oracle RDBMS system used by the previous contractor only in physical data allocation and management. All information in the earlier system was integrated into the new database, and its continuity and completeness are maintained.

DATA LOADING & CLEANING

Data files come to the USRDS in IBM 3490 and 3490e cartridges/CD-ROMs with EBCDIC, ASCII, or SAS formats. Once loaded, files are converted into SAS data sets for processing, and a series of data verification steps is completed to ensure data quality and integrity before updating the USRDS database.

DATABASE UPDATES

For this ADR, patient demographic and diagnosis data are updated through October, 2006, and Medicare inpatient/outpatient and physician/supplier claims through December 31, 2005.

ESRD PATIENT DETERMINATION

A person is identified as having ESRD when a physician certifies the disease on the CMS Medical Evidence (ME) form, or when there is other evidence of chronic dialysis or a kidney transplant. Patients with acute kidney failure who are on dialysis for days or weeks, but who then recover kidney function, are excluded from the database if their Medical Evidence forms have not been submitted. Patients who die soon after kidney failure without receiving dialysis are sometimes missed.

The ESRD First Service Date (FSD) is the single most important data element in the USRDS database, and each patient must, at a minimum, have a valid FSD. This date is used to determine the incident year of each new patient and the first year in which the patient is counted as prevalent. The date 90 days after the FSD is used as the starting point for most survival analyses.

The FSD is derived by taking the earliest of the date of the start of dialysis for chronic kidney failure, as reported on the ME form; the date of a kidney transplant, as reported on a CMS or OPTN transplant form, an ME form, or a hospital inpatient claim; or the date of the first Medicare dialysis claim. Most FSDs are obtained from the ME form. In the absence of this form, the date of the first Medicare dialysis claim or transplant usually supplies the FSD. In the few cases in which the date of the earliest dialysis claim precedes the first dialysis date reported on the ME form, the earliest claim date is used as the FSD. However, starting with the 2007 ADR, a patient entering into the ESRD program after December 31, 1994 will have his/her FSD defined solely by the regular dialysis start date or the preemptive transplant date, whichever is earliest, on the Medical Evidence form. This new method of determining the FSD has been introduced in this ADR so as to align more closely to the methods used by CMS. After years of careful monitoring and repeated comparative analyses of the traditional USRDS method to the new ME method, the USRDS believes it is time to begin applying the ME method to incident patients entering into the ESRD program on or after January 1, 1995.

MEDICARE & NON-MEDICARE (‘ZZ’) PATIENTS

Beneficiaries are enrolled in Medicare based on criteria defined in Title XVIII of the Social Security Act of 1965, and in subsequent amendments to the act. A person in one of these four categories is eligible to apply for Medicare: age 65 and over, disabled, ESRD program, and Railroad Retirement Board (RRB).

Most ESRD patients are eligible to apply for Medicare as their primary insurance payor. Some, however, are not immediately eligible for Medicare coverage because of their employment status and insurance benefits. These patients are usually covered by Employer Group Health Plans (EGHPs), must wait 30–33 months before becoming eligible to have Medicare as their primary payor, and are therefore not in the EDB database during the waiting period. Some of these patients, particularly new patients since 1995, have FSDs established by Medical Evidence forms, but have no dialysis claims or hospitalization events in the CMS claims database. In the REBUS/PMMIS database all non-Medicare ESRD patients are assigned a code of ‘ZZ’ in the two-character Beneficiary Identification Code field. CMS does not generally include these patients in the datasets released to researchers.

The USRDS recognizes that ‘ZZ’ patients are true ESRD patients, and should therefore be included in patient counts for incidence, prevalence, and treatment modality. Calculations of standardized mortality ratios (SMRs), standardized hospitalization ratios (SHRs), and standardized transplantation ratios (STRs), however, should not include these patients because of the small number of claims available in the first 30–33 months after their first ESRD service. Furthermore, it may not be possible to link ‘ZZ’ patients to their ESRD Death Notification forms (CMS 2746) or the OPTN transplant data, or to determine comorbidity or inpatient/outpatient and physician/supplier services. Because such data are limited, event rates that include these patients must be assessed with caution.

We continue to include ‘ZZ’ patients in the mortality rate calculations of the ADR. We are collaborating with CMS and other interested researchers to establish a consistent approach to managing the data for these patients. USRDS, in working with CMS, have been able to resolve most of the ‘ZZ’ patients since the release of ESRD Patient Database, REMIS, in the fall of 2003. According to the most recent assessment performed during the production of 2007 ADR, we have determined that at least 99 percent of ‘ZZ’ patients have been resolved due to significant advancements in the REMIS/REBUS database system over the past five years.

LOST-TO-Follow-up METHODOLOGY

The USRDS uses all available data to create a treatment history for each patient in the database, including all modality events, their duration, and the renal providers involved in each patient’s care.

Gaps frequently exist in the billing data upon which modality periods are based. The USRDS assumes that a modality continues until death or the next modality-determining event. A patient with a functioning transplant is assumed to maintain it unless a transplant failure or death notification is encountered in the data. In the absence of a death notification, dialysis claims, or other confirmation of a continuing modality, a dialysis modality, in contrast, is assumed to continue for only 365 days from the date of the last claim. After this period the patient is declared lost-to-follow-up until the occurrence of a dialysis claim or transplant event.

Because Medicare may be the secondary payor for up to the first 30–33 months of ESRD, delaying the submission of Medicare dialysis claims, lost-to-follow-up categorization cannot begin until the end of the third year after the start of ESRD service. This “first three-year rule” is particularly important for non-Medicare patients, who may be followed for up to three years with limited event or mortality data. These patients would contribute dialysis or transplant days to the denominator of rate calculations, but only questionable event data to the numerator. In comparison to the two-year rule used in the 2001 ADR, this three-year rule significantly reduces the number of lost-to-follow-up patients in the prevalent population.

A number of events can result in a lack of dialysis data and eventual reclassification of a patient as lost-to-follow-up:

• The patient may have recovered renal function (RRF) and no longer have ESRD. This event must occur within first 180 days of FSD, and the RRF period must persist for at least 90 days.
• The patient may have left the country.
• The patient may receive dialysis covered by a payor other than Medicare, or have received a transplant not paid for by Medicare or reported to OPTN.
• The patient may be enrolled in a Medicare HMO, so that Medicare dialysis claims are not generated even though the patient is eligible for Medicare coverage.
• The patient’s death may not have been reported to the Social Security Administration or to CMS.

INTEGRATION OF THE USRDS, SIMS, & REMIS DATABASES

We continue working to reconcile ESRD patients in the SIMS, REMIS, and USRDS databases. We have analyzed each database for duplicate records, consolidated these records, and integrated the databases. These integrated data were then re-analyzed for duplicates, which were themselves consolidated. This consolidation of patients is an ongoing collaborative effort between the ESRD Networks, CMS, and the USRDS.

Patient treatment histories compiled by the USRDS rely on Medicare dialysis billing records, which contain no information on dialysis therapy or modality changes in non-Medicare patients. Beginning with the 2003 ADR, we incorporate treatment-specific information from the ESRD Networks’ SIMS event database to improve the tracking of these patients in the USRDS database, and of patients who are considered lost-to-follow-up. The consolidation efforts from database integration among USRDS, SIMS, and REMIS continue to pay dividends in reducing the number of lost-to-follow-up patients—10,763 in 2002 (2007 ADR), for example compared to 24,726 in 2002 (2004 ADR).

We continue to take a conservative approach to incorporating SIMS Event History data into the USRDS treatment history; as we learn more about the data, we may expand this approach. We currently make the following updates on an annual basis:

The USRDS database is updated with mortality data from the SIMS event database.

The database is updated for each incident patient whose initial modality is listed as “unknown dialysis,” and for whom the SIMS database lists a known dialytic modality within 90 days of the established first ESRD service date.

Data on non-Medicare “lost-to-follow-up” patients are substituted with treatment information when found in the SIMS database.

Starting with this ADR, we have introduced the recovered renal function (RRF) event in the modality sequence, which in turn will directly reduce the lost-to-follow-up episodes within the prevalent population. Presently, an RRF event is established in the USRDS database only if such an event occurs within the first 180 days of FSD and lasts for at least 90 days. This definition is much more conservative than that in the SIMS event database.

60-DAY STABLE MODALITY RULE: TREATMENT HISTORY

This rule requires that a modality continue for at least 60 days before it is considered a primary or switched modality. It is used to construct a patient’s modality sequence, or treatment history, so that incident and prevalent patients are known to have stable and established modalities. Starting with the 2003 ADR, all descriptive data in the incident, prevalent, and modality sections are based on incident and prevalent cohorts produced from the modality sequence without using this rule. In analyses of patient outcomes such as hospitalization and mortality, in contrast, this rule is applied.

90-DAY RULE: OUTCOMES ANALYSES

This rule defines each patient’s start date, for data analyses, as day 91 of ESRD. Allowing outcomes to be compared among all ESRD patients at a stable and logical point in time, it is used primarily to calculate survival rates and compare outcomes by modality at several points in time. Use of the rule overcomes the difficulties of examining data from the first three months of ESRD service (an unstable time for new patients as renal providers try to determine the best treatment modality), and from in-center hemodialysis patients younger than 65 and not disabled, who cannot bill Medicare for their dialysis treatments and hospitalizations until 90 days after the first ESRD service date. Patients on peritoneal dialysis or home dialysis, or with transplant as the first modality, can bill immediately.

SERUM ALBUMIN DATA

The Medical Evidence form reports a patient’s albumin level along with the test’s lower limit, which indicates the testing method. There are currently two methods in use: bromcresol purple and bromcresol green, with lower limits of 3.2 and 3.5 g/dl, respectively.

While producing the 2004 ADR we uncovered severe problems in data quality related to albumin information on the ME form. We found that, from 1995 to 2003, almost 50 percent of forms contained lower limit values equal to “zero,” while another 25 percent reported values other than the expected 3.2 and 3.5 g/dl. Only 25 percent (n=173,000) of incident patients had legitimate lower limit values for determining normal serum albumin. Further analyses have shown that these patients are a representative cohort sample, with a similar demographic distributions by age, gender, race, and cause of ESRD to that of the overall ESRD population. For all figures in the 2005 and later ADRs which present data on serum albumin from the ME form, we have therefore included only those incident patients with both an albumin lower limit of 3.2 or 3.5 g/dl and an albumin value.

Database definitions  

MODALITIES

The Coordinating Center and the ESRD group at CMS have worked extensively on methods of categorizing patients by ESRD modality. While the Medical Evidence form is the primary source of data on modality at ESRD initiation, the modality it indicates may be temporary, as patients often change to a new one within the first 90 days, and it can be difficult to track modality during this time. Patients age 65 and older have Medicare claims in the first 90 days; these claims contain revenue codes that designate modality. Patients younger than 65 who are in employer group health plans or Medicare risk programs, however, have no such claims. Modality may thus not be determined until Medicare becomes the primary payor at day 91 or, for EGHP patients, at 30–33 months after the first ESRD service date. These limitations influence our ability to determine a patient’s exact modality at any one point in time.

Of particular concern are patients categorized as having an unstable modality (i.e. on a modality for fewer than 60 consecutive days) in the first 90 days, and who are therefore not recognized as being hemodialysis or peritoneal dialysis patients. These patients tend to have higher death and hospitalization rates, and unless they are identified and assigned to modalities, interpretations of modality-specific outcomes should be viewed with caution. These patients are included in the “all ESRD” category, which provides a more complete view of mortality and hospitalization with the least biasing of the data.

As mentioned earlier, a new modality/event—recovered renal function (RRF)—has been introduced in the 2007 ADR. RRF can only be established if it occurs within first 180 days of FSD and the RRF period persists for at least 90 days. The RRF modality (i.e. event) is similar to the lost-to-follow-up event in that patients with an RRF event will not be included in the prevalent populations for outcomes analyses. However, as with the lost-to-follow-up events, we have kept them in the modality sequence so that subsequent renal failure episodes can be closely tracked in a timely manner.

Individual analyses categorize modalities in different ways; these are defined in the methods sections for each chapter.

PAYORS

Information on payors is obtained from the CMS Medicare Enrollment Database (EDB). We also examine Medicare outpatient claims to identify patients for whom the EDB does not indicate Medicare as primary payor (MPP), but who have at least three consecutive months of dialysis treatment covered by Medicare; these patients are also designated as having MPP coverage. From these two data sources we construct a payor sequence file to provide payor history, and, starting with the 2003 ADR, we use this file to identify Medicare eligibility status and other payors.

The construction of this file is similar to that of the treatment history file. Payor status is maintained for each ESRD patient from the first ESRD service date until death or the end of the study period. Payor data are used to categorize a patient as MPP, Medicare as secondary payor, Medicare+Choice, Medicaid, or a combination of payors. With this approach, the USRDS is now able to apply payor status information in all outcome analyses using the “as-treated” model (see the discussion of Chapter Eleven).

PRIMARY CAUSE OF RENAL FAILURE

Information on the primary cause of renal failure is obtained directly from the Medical Evidence form. For the ADR we use eight categories, with ICD-9-CM codes as follows:

• diabetes: 250.00 and 250.01
• hypertension: 403.9, 440.1, and 593.81
• glomerulonephritis: 580.0, 580.4, 582.0, 582.1, 582.9, 583.1, 583.2, 583.4, and 583.81
• cystic kidney: 753.13, 753.14, and 753.16
• other urologic: 223.0, 223.9, 590.0, 592.0, 592.9, and 599.6
• other cause: all other ICD-9-CM codes covered in the list of primary causes on the Medical Evidence form, with the exception of 799.9
• unknown cause: 799.9 and ICD-9-CM codes not covered in the list of primary causes on the Medical Evidence form
• missing cause: no ICD-9-CM code listed

RACE & ETHNICITY

Data on patient race and ethnicity are obtained from the ME form, the CMS Medicare Enrollment Database, and the REMIS/REBUS identification file. Because they are addressed in separate questions on the Medical Evidence form, racial and ethnic categories can overlap.

Patient ethnicity became a required field on the 1995 revised ME form; because data for 1995 are incomplete, information on Hispanic patients is presented starting in 1996. The non-Hispanic category includes all non-Hispanics and patients with unknown ethnicity.

Because of the small number of ESRD patients of some races, as well as the construction of the U.S. census data, we concentrate on white, African American, Native American (includes Alaskan Native), and Asian (includes Pacific Islander) populations. Data on patients of other races will be presented as their numbers increase.

EGHP COHORT

EGHP data in this year’s ADR are derived, as mentioned above, from Medstat MarketScan databases. To examine the demographic segment not represented by Medicare, we use enrollment information to construct yearly cohorts of enrollees younger than 65. To ensure that we select enrollees with the potential to generate claims evidence appropriate to the demands of analytical methods, rules for inclusion also include 12 months of continuous coverage in a fee-for-service plan with no more than a 40-day gap between plan changes, and, for medication analyses, continuous prescription drug coverage. Comorbidities are identified using claims. Patients with at least one inpatient claim or at least two outpatient claims during the period of interest and with a diagnosis code of a particular comorbidity are identified as having that comorbidity.

ESRD COHORT IN THE EGHP POPULATION

Since the Medstat database does not provide data that allow patients to be identified, we are unable to link it directly to the USRDS ESRD registry. To identify ESRD patients, we therefore use a process similar to that used in the registry. Transplant patients are identified by evidence of a kidney transplant procedure or an adverse graft event, and chronic dialysis patients by evidence of continuous history of dialysis therapy, with at least three consecutive months of dialysis service and with dialysis service claims in at least 70 percent of treatment months. Treatment months are defined by the period from the first dialysis claim to the earliest of kidney transplant, death, or end of enrollment. Both inpatient and outpatient claims are evaluated for evidence of dialysis service history.

The first ESRD service date is set to the earliest of the first dialysis service date or the transplant date. If neither is available, the start of enrollment is used. Incidence is defined by a first ESRD service date at least 60 days after the start of enrollment.

Précis  

For Figure p.1 we identify chronic kidney disease (CKD), congestive heart failure (CHF), and diabetes in patients from the 5 percent Medicare sample using methods described for Chapter One; these methods are also used to determine diabetic status and CHF in the ESRD population. Costs for the “cost year” are determined for the entire calendar year for patients who have fee-for-service coverage and Medicare as primary payor. Because this analysis combines the ESRD cohort with the 5 percent Medicare sample, ESRD patients in the 5 percent sample are excluded. Dual enrollment is determined from the payor sequence, based on the state buy-in code.

Methods for the portion of Table p.a that addresses Medicare spending are addressed in the discussion of Chapter Eleven.

Trends in quality of care

Vascular access use in Figure p.11 represents data from 1999–2005 ESRD CPM reports on the current access used at the last dialysis session. The methods for Figure p.12 are the same as those used for Figure hp.13 in the HP2010 chapter.

Figure p.13 includes prevalent hemodialysis patients who are in both the USRDS and ESRD CPM databases, and the access represents the current access according to the ESRD CPM data; complication rates are calculated as the number of events (from Medicare claims) divided by the time at risk, which is censored at death, change in modality, change in payment status, or the placement of a different type of access. Vascular access codes are listed in the methods for Chapter Eleven.

Figure p.14 includes prevalent hemodialysis patients in the ESRD CPM database with at least one valid URR measurement. For each patient, we calculate a mean URR measurement from all measurements available, then the percentage of patients whose mean URR is in each category. Figure p.15 includes prevalent peritoneal dialysis patients in the ESRD CPM database with at least one valid Kt/V measurement. For each patient, we calculate a mean Kt/V measurement from all those available, then the percentage of patients whose mean Kt/V is in each category.

Figure p.16 presents the distribution of patients by mean hemoglobin group on a monthly basis, in which each month contains all patients with at least one valid EPO claim during the month. The hemoglobin is calculated as the reported hematocrit value divided by three. Figure p.17 shows the mean hemoglobin, by month, for prevalent dialysis patients with EPO claims, along with the monthly EPO dose per week for patients with 20 or fewer administrations per month. The mean EPO dose is adjusted in the same way used in Chapter Five, with a patient’s time at risk including only those days in which he or she is not in an inpatient hospital setting.

For Figure p.18, an archived PMMIS quarterly dialysis record is used to track transfusions in ESRD patients in years prior to 1991. The percentage of hemodialysis patients receiving transfusions is calculated as the number of patients receiving at least one transfusion in a given quarter divided by the number of hemodialysis patients with at least one dialysis record in that quarter. Since the archived data are current only to the third quarter of 1995, we emulate this method, using Medicare claims generated by ESRD facilities, to update the trend.

The method and cohort used for Figure p.19, on diabetic care in prevalent patients, are the same as those used for Figures 5.20, 5.24, and 5.28.

hospitalization & mortality

Hospitalization data are shown in Figures p.20–22. Included patients have Medicare as a primary payor and are residents of the 50 states and the District of Columbia; residents of Puerto Rico and the Territories are also included in Figures p.20 and p.22, but are excluded from the maps in Figure p.21. Patients with AIDS as a primary or secondary cause of death are excluded, as are patients with missing age or gender information.

Figure p.20 shows one-year probabilities of hospitalization, death, and a combined endpoint of hospitalization or death. The cohort includes 2000–2004 incident dialysis patients age 20 and older. Patients are followed from day 91 of ESRD until the event or censoring. For death, patients are censored at loss to follow-up, transplant, December 31, 2005, or at one year. For first hospitalization, patients are censored at the above and also at death, end of Medicare primary payor status, and three days prior to transplant rather than the transplant date (to avoid counting the transplant hospitalization). Also, for the combined endpoint, censoring follows that for first hospitalization, except that death is an event rather than a censoring criterion. Patients with a bridge hospitalization that spans day 91 are excluded from the hospitalization and combined endpoint analyses. Event probabilities are computed from the Cox model using the model-based adjustment method, described in the statistical methods section, adjusting for age, gender, race, and primary ESRD diagnosis. The reference cohort consists of all included 2000–2004 incident patients.

Figures p.21–22 show total admission rates and the percent change in admission rates for period prevalent ESRD patients. Methods generally follow those described for the prevalent patient cohorts in Chapter Six and Reference Section G. In Figure p.22, rates are adjusted for age, gender, race, and primary diagnosis using the model-based adjustment method. The reference cohort includes period prevalent ESRD patients, 2005. Principal ICD-9-CM diagnosis codes for cardiovascular and infectious hospitalizations are listed in the discussion of Figures 6.5–6. Vascular access hospitalizations are those defined as “pure” inpatient vascular access events, as described for Table G.11.

Figure p.23 illustrates trends in mortality rates by patient vintage for period prevalent dialysis patients alive on renal replacement therapy on January 1, with a first service date at least 90 days prior to the beginning of the year, and reaching day 91 of ESRD treatment during the year. Patients with unknown age or gender, or of a race other than white, African American, Native American, or Asian, are excluded. Patients are followed from January 1 until death, transplantation, or the end of the year, and all-cause mortality rates are adjusted for age, gender, race, and primary diagnosis using generalized mixed models. The reference population consists of 2001 prevalent dialysis patients, and adjusted mortalities across vintages are comparable.

Figure p.24 presents adjusted first-, second-third, and fourth-fifth-year mortality rates, by modality, for incident ESRD patients. Patients are followed from day 91 until death or December 31, 2005. Dialysis patients are also censored at transplant. Rates are computed from the Cox model using the model-based adjustment method, described later in this appendix, and adjusted for age, gender, race, and primary cause of ESRD. The reference population consists of 1996 incident ESRD patients, and these rates are comparable across modalities.

Figure p.25 illustrates five-year survival by first modality. Populations for the 1991–1995 and 1996–2000 cohorts include incident patients on hemodialysis or peritoneal dialysis on the first ESRD service date, and patients receiving their first renal transplant in a calendar year. All cohorts include both Medicare and non-Medicare patients living in the 50 states, the District of Columbia, Puerto Rico, and the Territories, and exclude those with unknown age, gender, or primary diagnosis, as well as those with a listed age greater than 110; in the dialysis cohort, patients who die or are transplanted in the first 90 days are also excluded. Dialysis patients are followed from day 91 until death, transplantation, or the end of 2005, while transplant patients are followed from the first transplant date until death or the end of 2005. Survival probabilities are adjusted for age, gender, race, and primary diagnosis. The reference population consists of 1996 incident ESRD patients, and adjusted probabilities can be compared across modalities.

ESRD expenditures

Methods used for Figures p.26–34 and Table p.b are described in the text for Chapter Eleven and in the figure captions.

CKD populations & expenditures

In Figures p.35–42, CKD, CHF, and diabetes are determined using methods from Chapter One. The population for the 5 percent Medicare data is limited to those with fee-for-service coverage and Medicare as primary payor.

Emerging issues  

Figure ei.1 illustrates adjusted first-year mortality rates, by modality, for incident dialysis patients. The study cohort includes hemodialysis and peritoneal dialysis patients with a first service date between January 1, 1996, and December 31, 2004, who live in the 50 states, the District of Columbia, Puerto Rico, and the Territories, and excludes those with unknown age, gender, or primary diagnosis, as well as those with a listed age greater than 110. Patients are followed from the first service date up to one year. The intent-to-treat method is used, and patients are censored at transplant or kidney recovery. Rates are computed from the Cox model. Variables for the basic adjustment include age, gender, race, and primary cause of ESRD, and those for the composite adjustment include hemoglobin, BMI, eGFR, and comorbidities, obtained from the Medical Evidence form. The reference population consists of incident hemodialysis and peritoneal dialysis patients, 1996, and adjusted probabilities can be compared across modalities.

Figures ei.2–3 display rates of intravenous vitamin D and iron administration from 1992 to 2005 among period prevalent dialysis patients. For each calendar year, the cohort consists of patients who initiate ESRD therapy at least 90 prior to the start of the year and are receiving dialysis on December 31 of the previous year. All patients survive, continue dialysis, and carry Medicare as primary payor (with physician/supplier coverage) during the ensuing year. In Figure e.2, Calcijex is indicated by HCPCS codes J0635–J0636; Hectorol by HCPCS J1270; and Zemplar by HCPCS J2500–J2501. In Figure e.3, Ferrlecit is indicated by HCPCS codes J2915–J2916; INFeD by HCPCS J1750, J1760, J1770, J1780; and Venofer by HCPCS J1755–J1756.

Erythropoietin (EPO) dose information and hemoglobin values (calculated from hematocrit values) for Figures ei.4–8 are obtained from the EPO claims data.

The cohort for Figures ei.4–8 includes incident dialysis patients age 65 and older, 1995–2004, with Medicare as primary payor, and receiving EPO during the first six months after incidence. Patients who die or are transplanted in the first six months are excluded, as are patients who have missing initial hemoglobin values or a hemoglobin value over 11 g/dl. Patients are censored at a missing hemoglobin value. Cumulative probabilities are calculated using Kaplan-Meier method.

Figure ei.6 illustrates the time to return to a hemoglobin above 12 g/dl in patients who exceed 12, 12.5+, 13+, 13.5+, and 14+ g/dl. The average time above 12 g/dl is calculated using the Kaplan-Meier method. Figure ei.8 illustrates the EPO dose used to achieve particular hemoglobin levels. For patients hitting 11+ g/dl in month 2, for example, the average dose is the mean dose in months 1 and 2. EPO doses in this figure are adjusted for inpatient days.

Figure ei.12 characterizes the number of comorbidities during the two years prior to ESRD initiation. Included ESRD patients are at least 67 years old, have a first ESRD service date between January 1, 1995, and December 31, 2005, have Medicare inpatient/outpatient and physician/supplier coverage for the complete two-year period prior to initiation, and have at least one claim in the two-year period prior to initiation. Comorbidities are identified from claims in the two years prior to initiation.

Figures ei.13–14 characterize hospital days and admissions during the two years prior to ESRD initiation. Included ESRD patients are at least 67 years old, have a first ESRD service date between January 1, 1995, and December 31, 2005, and have Medicare inpatient/outpatient and physician/supplier coverage for the complete two-year period prior to initiation. Methods for counting hospital days and admissions follow those described for Reference Section G later in this appendix.

Figures ei.15–17 and Table ei.a characterize the number of comorbidities during the two years prior to ESRD initiation. Included ESRD patients are at least 67 years old, have a first ESRD service date between January 1, 1995, and December 31, 2005, have Medicare inpatient/outpatient and physician/supplier coverage for the complete two-year period prior to initiation, and have at least one claim in this period. Comorbidities are identified from claims during the two years prior to initiation. Estimated GFR information for Figures ei.9–10 and Table ei.a, and laboratory information in the table, come from the Medical Evidence form; age is calculated at ESRD initiation. Adjustments for Figure ei.10 are standardized to the 1995 data using general linear model-based adjustments.

Figure ei.18 includes incident hemodialysis patients who are in both the USRDS and ESRD CPM databases, and whose day 91 begins prior to October 1 of the incident year. The access represents the access being used on day 90 according to the CPM data.

Figures ei.19–22 and Table ei.b include incident hemodialysis patients, 1995–2005, age 67 and older at initiation. Catheter placements are determined from physician/supplier claims prior to initiation, and from any inpatient hospital stays for acute dialysis initiation that indicate a catheter was placed during that stay. Acute dialysis initiation is determined from inpatient hospital stays at initiation with a primary procedure code of hemodialysis (ICD-9-CM 39.95), an admission source of “Emergency Room,” and an admission type of either “urgent” or “emergency.” Those dialyzing with catheters at initiation are those who a) have only a catheter placement claim and not a fistula/graft placement claim prior to initiation, or b) have both types of placement claims but either the fistula/graft placement is less than one month prior to initiation or the catheter placement is more recent. Comorbidities in Figure ei.22 and Table ei.b are identified from claims.

Table ei.c and Figures ei.23–26 present monthly mortality rates in dialysis patients. The study cohort includes dialysis patients with a first service date between January 1, 1993, and December 31, 2004, who reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories. Patients with unknown age, gender, or primary diagnosis are excluded, as are those with a listed age greater than 110. Patients are followed from the first service date up to one year, and are censored at transplant or recovery of kidney function. Overall adjusted mortality rates are adjusted for age, gender, race and primary diagnosis, and adjusted mortality rates for one of the four variables are adjusted for the remaining three. The reference population consists of 1993 incident dialysis patients, and adjusted mortality rates can be compared across years.

Figure ei.27 illustrates adjusted first-year mortality rates, by modality, for dialysis patients. The study cohort is constructed with the method used in Figure ei.1. Patients are followed from the first service date up to one year. The intent-to-treat method is used, and patients are censored at transplant or recovery of kidney function. Unadjusted mortality rates are calculated using the Kaplan-Meier method, while adjusted mortality rates use the model-based method based on a Cox model, as described in the section on statistical methods. Adjusted rates are adjusted for age, gender, race, primary diagnosis, comorbidity, eGFR, BMI, and hemoglobin. The reference population consists of incident hemodialysis and peritoneal dialysis patients, 1996, and adjusted probabilities can be compared across modalities.

The Cox model is used to obtain the hazard ratios in Table ei.d. The study cohort includes incident hemodialysis and peritoneal dialysis patients, 1996–2004, who reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories. Patients with unknown age, gender, or primary diagnosis are excluded, as are those with a listed age greater than 110. Patients are followed from the first service date up to one year. The intent-to-treat method is used, and patients are censored at transplant or recovery of kidney function.

Healthy People 2010  

Targets come directly or are estimated from published HP2010 objectives on chronic kidney disease and immunizations.

Objective 4.1: Incident rates in Figures hp.2–3, hp.4 (first graph), and hp.26, and in Table hp.a, are calculated using the methods described for Chapter Two. Rates of diabetes in the general population (second graph in Figure hp.4) are obtained from the CDC’s Behavioral Risk Factor Surveillance System, at www.cdc.gov/brfss.

Objective 4.2: The study cohort includes period prevalent ESRD patients, 1991–2005. Cause-specific cardiovascular mortality is defined using CMS codes 27, 31, and 32 (congestive heart failure), 26 (atherosclerotic heart disease), 02 and 23 (myocardial infarction), and 01, 04, 25, 28–30, and 36–37 (other cardiovascular disease). Age is calculated for point prevalent patients as of January 1, and for incident patients as of the first ESRD service date. We exclude patients with unknown age, gender, or race, and those with an age calculated to be less than zero. Rates are estimated as the number of patients who die from cardiovascular disease in each year per 1,000 patient years at risk.

Objective 4.3: Table hp.c and figure hp.8 use data from the newest version of the Medical Evidence form for patients initiating ESRD on hemodialysis. Information on pre-ESRD care is obtained directly from the Medical Evidence form. The cohort for Figures hp.9–10 includes incident ESRD patients, age 67 and older at initiation; pre-ESRD nephrologist care is identified through at least one physician/supplier claim with a physician specialty code of “nephrologist.” Albumin tests are identified from Medicare claims during the two-year period prior to ESRD.

Objective 4.4: For Figures hp.12–13, the calculation of placement rates follows methods used in Chapter Five. For Table hp.d (ESRD CPM year 2005) and Figures hp.11 and hp.29 (ESRD CPM years 1999–2005), data are obtained from the CMS ESRD Clinical Performance Measures (CPM) Project. Patients included in these two figures and the table are those whose date of dialysis initiation, according to the CPM data, occurs in the same year as the data collection, and the access type represents the access used during the last quarter of the year. To obtain consistent information on race and ethnicity, patients included in the CPM dataset are matched to those in the ESRD database using UID numbers.

Objective 4.5: The cohort for Figures hp.14–15 and Table hp.e includes patients younger than 70 in 1991–2003. Percentages are calculated as the number of patients placed on the deceased donor organ wait list or receiving a deceased donor transplant within one year of initiating ESRD therapy, divided by the number of patients without a living donor available (i.e., patients receiving a living donor transplant are excluded), and are estimated using the Kaplan-Meier method. Note that this method differs from those used in previous ADRs, which showed the percent of point prevalent dialysis patients on the wait list as of December 31 of the given year.

Objective 4.6: The study cohort here includes patients from 1991–2002 who are younger than 70 at ESRD certification. Patients are followed for three years, from ESRD certification until the first of death, transplant, or censoring at three years post-transplant. Percentages are calculated using the Kaplan-Meier methodology.

Objective 4.7: For Figures hp.18–20 and hp.32, and for Table hp.g, incident rates of ESRD due to diabetes are calculated using the methods described for Chapter Two.

Objective 4.8: Methods and codes used to determine rates of glycosylated hemoglobin (HbA1c) testing and eye exams are taken from HEDIS 2002 specifications (HEDIS 2002, an NCQA program, is used to monitor the performance of managed health care plans), and are described in the methods for Chapter One along with those for lipid testing. The general Medicare population includes patients diagnosed with CKD and diabetes in each year, continuously enrolled in the Medicare inpatient/outpatient and physician/supplier program during the whole year, and age 65 or older at the beginning of the year. Testing is tracked during each year. Patients are excluded if they are enrolled in a managed care program (HMO), acquire Medicare as secondary payor, are diagnosed with ESRD during the year, have a missing date of birth, or do not live in the 50 states, the District of Columbia, Puerto Rico, or the Territories. Racial and ethnic categories are mutually exclusive. For HbA1c testing, tests are at least 30 days apart. Methods of defining CKD and diabetes are described in Chapter One.

Figure hp.21 shows all ACE-I/ARB use for diabetic CKD patients in the Medicare population. We use Cost and Use data from the Medicare Current Beneficiary Survey (MCBS)—a national, continuous, multipurpose survey of older, disabled, and institutionalized beneficiaries—to measure cost in Medicare patients age 65 and older. To ensure that we obtain information on all therapy received by each person during each study year, included patients are continuously enrolled in the Medicare inpatient/outpatient and physician/supplier program during the entire year, survive until the end of the year, have a completed survey, are not enrolled in a managed care organization, and do not have ESRD; they also reside in the 50 states or the District of Columbia and are community-dwelling respondents. Comorbidities, including CKD and diabetes, are defined from the claims, using the same method used with the 5 percent data. Drug use information is obtained from the MCBS Cost and Use data file “Prescribed Medicine Events,” and SUDAAN (Research Triangle Institute, Research Triangle Park, NC) is used to analyze all data.

Objective 14.29: The cohort for influenza vaccinations includes all ESRD patients initiating therapy at least 90 days prior to September 1 of each year and alive on December 31. For pneumococcal pneumonia vaccinations, cohorts include all ESRD patients initiating therapy at least 90 days before January 1 of the graphed time period and alive on December 31. Patients not residing in the 50 states, the District of Columbia, Puerto Rico, or the Territories are omitted from the study, as are those who have a missing date of birth, who have ESRD for fewer than 90 days prior to the start of the reporting interval, or who are lost-to-follow-up during the study period. Influenza vaccinations are tracked between September 1 and December 31 of each year, while pneumococcal pneumonia vaccinations are tracked during the time periods graphed. Patients in both analyses have Medicare inpatient/outpatient and physician/supplier coverage during the study periods. All ages are calculated at the end of the graphed time period. Influenza vaccinations are identified by CPT codes 90724, 90657, 90658, 90659, and 90660, and HCPCS code G0008; pneumococcal vaccinations are identified through CPT codes 90669 and 90731, and HCPCS codes J6065 and G0008.

Chronic kidney disease / Chapter One  

CKD populations & costs

According to a previously validated method for using Medicare claims to identify diabetic patients, a patient is diabetic if, within a one-year observation period, he or she has an ICD-9-CM diagnosis code of diabetes on one or more inpatient/outpatient institutional claims (inpatient hospitalization, skilled nursing facility, or home health agency), or two or more institutional claims (outpatient) or physician/supplier claims. Using this methodology, we identify CKD patients with or without diabetes or CHF in each calendar year. Codes used to identify patients are as follows: CHF, 398.91, 422.xx, 425.x, 428.xx, 402.x1, 404.x1, 404.x3, V42.1; CKD, 016.0, 095.4, 189.0, 189.9, 223.0, 236.91, 250.4, 271.4, 274.1, 283.11, 403.x1, 404.x2, 404.x3, 440.1, 442.1, 447.3, 572.4, 580–588, 591, 642.1, 646.2, 753.12–753.17, 753.19, 753.2, and 794.4; anemia, 280–285; and diabetes, 250, 357.2, 362.0x, and 366.41. Individuals are classified as dually-enrolled based on the State buy-in codes found in the 5 percent denominator file, and must be dually-enrolled for the entire study period to be so classified.

predictors of CKD in the NHANES population

Figures 1.1 and 1.5–7 and Table 1.b present data from the NHANES III and NHANES 1999–2004 populations. Pregnant and menstruating female subjects are not excluded. Microalbuminuria is defined by the ratio of urinary albumin to urinary creatinine (albumin/creatinine ratio, or ACR). Participants age 19 or younger are excluded from the analyses. The eGFR is estimated separately for NHANES III, NHANES 1999–2000, NHANES 2001–2002, and NHANES 2003–2004, using the MDRD method based on the adjusted creatinine value. Participants with a valid ACR are classified as having a positive microalbuminuria if this value is not less than 30 mg/g. Hypertension and diabetes are self-reported comorbidities identified through the survey’s medical history questionnaires. As per the recommendations from NHANES (http://www.cdc.gov/nchs/nhanes.htm) serum creatinine values are standardized as follows:

• NHANES III: standardized creatinine = 0.960 * reported creatinine – 0.184
• NHANES 1999-2000: standardized creatinine = 1.013 * reported creatinine + 0.147
• NHANES 2001–2002 and 2003–2004: standardized creatinine = reported creatinine

The formula used to estimate GFR is as follows (Levey et al., 2006): estimated GFR = 175 * (standardized serum creatinine in mg/dl)-1.154 * age-0.203 * (0.742 if female) * (1.212 if black).

Figure 1.1 uses two methods of estimating CKD prevalence. One method defines Stage 4–5 CKD as eGFR < 30, Stage 3 as 30 ≤ eGFR < 60, Stage 2 as ACR ≥ 30 and 60 ≤ eGFR ≤ 89, and Stage 1 as ACR ≥ 30 and eGFR ≥ 90. The other adjusts for the non-gender-specific persistence of albuminuria (Coresh et al.), with Stage 4–5 as eGFR<30, Stage 3 CKD as 30 ≤ eGFR < 60, Stage 2 as PCT(ACR ≥ 300 | 60 ≤ eGFR ≤ 89) * PCT(60 ≤ eGFR ≤ 89) + 0.75 * PCT(30 ≤ ACR ≤ 299 | 60 ≤ eGFR ≤ 89) * PCT(60 ≤ eGFR ≤ 89), Stage 1 as PCT(ACR ≥ 300 | eGFR ≥ 90) * PCT(eGFR ≥ 90) + 0.509 * PCT(30 ≤ ACR ≤ 300 | eGFR ≥ 90) * PCT(eGFR ≥ 90). Table 1.b and Figures 1.5–7 show the percentage of patients with eGFR < 60, ACR ≥ 30, or (eGFR < 60 or ACR ≥ 30). In Figure 1.8, eGFR < 60 and ACR ≥ 30 are used as the standard to detect individual metabolic abnormalities.

Sensitivity and specificity in Figure 1.8 are from NHANES 1999–2004, with the exception of data on parathyroid hormone, which are from NHANES 2003–2004. The following thresholds were used: potassium > 4.62 mmol/l, hemoglobin < 12.01 g/dl, bicarbonate < 19.70 mmol/l, phosphorus > 4.54 mg/dl, and PTH > 83.76 pg/ml.

disease burden & care

Figures 1.9–10 include non-ESRD patients from the 5 percent general Medicare sample, 2005, who are alive and Medicare eligible for the entire year. Comorbidities (including CKD) are identified from claims during 2005. Dually-enrolled patients include patients identified as such at any time during 2005.

Figures 1.11–12 and 1.14 compare the cumulative probabilities of CKD preventive care in general Medicare and dually-enrolled (with both Medicare and Medicaid coverage) patients, using the Kaplan-Meier estimation method.

For influenza vaccinations in Figure 1.11, the prevalent Medicare cohort includes patients entering Medicare before January 1, 2004, alive and remaining in the program through August 31, 2005, and diagnosed with CKD during 2004. For pneumococcal vaccinations, the cohort includes patients entering Medicare before January 1, 2003, remaining alive and in the program though December 31, 2003, and diagnosed with CKD during 2003. Patients enrolled in an HMO, with Medicare as secondary payor, or diagnosed with ESRD during 2004 (for pneumococcal vaccinations, during 2003) are excluded, as are patients not residing in the 50 states, the District of Columbia, Puerto Rico, or the Territories. The first influenza vaccination is tracked between September 1 and December 31, 2005. The first pneumococcal vaccination is tracked during 2004 and 2005. Methodologies and codes used to define CKD and diabetes are described under “CKD populations and costs.”

The prevalent Medicare cohort for Figure 1.12 includes patients entering Medicare before January 1, 2004, alive and age 66 or older on December 31, 2004, and with CKD diagnosed during 2004. Patients enrolled in an HMO, with Medicare as secondary payor, or diagnosed with ESRD during the year are excluded, as are patients who do not reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories. For glycosylated hemoglobin testing and eye examinations, patients are also diagnosed with diabetes in 2004. Methodologies and codes used to define CKD and diabetes are described under “CKD populations and costs.”

CKD preventive care includes diabetic HbA1c testing, microalbuminuria or proteinuria testing, lipid testing, parathyroid hormone testing, calcium and phosphorus testing, and diabetic eye examinations. Except for diabetic HbA1c testing, the first testing is tracked in 2005. For HbA1c testing, the probability is for two or more tests, so the second testing is tracked in 2005 and tests are 30 days apart.

For all testing and vaccinations, patients are censored at the end of the plan, the end of 2005, the onset of ESRD, and death.

Figure 1.14 shows trends in the probability of preventive care. Methods and codes are similar to those for Figures 1.11–12.

hospitalization rates in CKD & non-CKD patients

Figures 1.15 and 1.17–20 show adjusted all-cause and cause-specific hospitalization admission rates, by the presence of diabetes and CHF, for general Medicare and dually-eligible patients, 1993–2005, with and without CKD. The prevalent Medicare cohort includes patients age 66 or older who are continuously enrolled in the Medicare inpatient/outpatient and physician/supplier program, who are not enrolled in HMO during the one-year entry period, and who reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories. The dually-enrolled patients are included under the same criteria, except that they are also enrolled in the Medicaid program at any time during the one-year entry period. Patients diagnosed with ESRD before or during the entry period are omitted from the study. The period at risk for the hospitalization analysis is a maximum of one year, from January 1 until the earliest of death, end of Medicare inpatient/outpatient and physician/supplier coverage, or December 31 of the year.

The same methodology described for Figure 1.1 is used to define patients with CKD, diabetes, or CHF. Principle ICD-9-CM diagnosis codes used to define cause-specific inpatient hospitalization categories are as follows: CHF, 398.91, 422, 425, 428, 402.x1, 404.x1, and 404.x3; ASHD, 410–414; pneumonia, 480–486 and 487.0; and bacteremia/septicemia, 038–038.9 and 790.7. An admission for a hospitalization spanning the start of the analysis period is excluded from the total admissions for that period. All overlapping and certain consecutive hospitalizations are combined using the methods described for Chapter Six.

Admission rates are adjusted for age, gender, and race, using the direct adjustment method (described in the section on statistical methods), with the 2005 Medicare cohort used as the reference group.

Figure 1.16 displays geographic variations in unadjusted all-cause admission rates for general Medicare CKD and non-CKD patients in 2005. The cohort includes general Medicare patient age 66 or older, enrolled in the Medicare inpatient/outpatient and physician/supplier program, and with no HMO coverage during 2004. Patients diagnosed with ESRD before January 1, 2005, and those who do not reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories, are omitted from the study. CKD is identified from 2004 using the same methodology in Figure 1.1. Follow-up begins on January 1, 2005, and continues until death, the last day of Medicare coverage, or December 31, 2005.

Table 1.c show the adjusted odds ratios for hospitalization and death following an influenza vaccination for 2005 CKD patients. The cohort includes general Medicare CKD patients age 66 or older on January 1, 2005, enrolled in the Medicare inpatient/outpatient and physician/supplier program, and with no HMO coverage during 2004. Patients diagnosed with ESRD before January 1, 2005, are omitted. The period from January 1, 2004, to August 31, 2004, is used as an entry period to characterize comorbidities and hospitalization days. Influenza vaccinations are identified from September 1, 2004, to December 31, 2004, and outcomes are assessed in the first three months of 2005. Cause-specific hospitalizations are determined from principle ICD-9-CM diagnosis codes on Medicare inpatient claims, including influenza/pneumonia (ICD-9-CM, 480-487), bacteremia/viremia/septicemia (038, 790.7, 790.8), and respiratory infection (472–474.0, 475–477.9, 478.22–478.24, 480–491, 494, 510–511, 513.0, and 518.6). Logistic models are used to estimate the odd ratios, adjusting for influenza vaccination, age, race, gender, comorbidity, and hospital days.

acute kidney injury

For Figures 1.21–28, hospitalization for acute kidney injury (AKI) is identified through the 584 ICD-9-CM code appearing on Medicare inpatient claims as any diagnosis code (except in Figure 1.27), and the methodology to identify CKD is essentially the same as that for in Figure 1.1, with the exception of the use of the 584 ICD-9-CM code. Patients who do not reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories are omitted from the analysis.

Figures 1.21 display the demographic characteristics of patients suffering AKI, using the general Medicare population. The two cohorts consist of 1993–1995 and 2003–2005 patients. Patients with an AKI hospitalization are identified from inpatient claims any time during those period. For both cohorts, patients with ESRD diagnosed before the AKI hospitalization admission are omitted. For patients with multiple AKI hospitalizations through the years, the first one in the time frame is counted. Dually-enrolled patients are those also enrolled in Medicaid program at the time of the AKI hospitalization.

Figure 1.22 presents hospital admission rates for AKI in the general Medicare population, 1993–2005, with and without CKD. The study cohort consists of patients continuously enrolled in the Medicare inpatient/outpatient and physician/supplier program and with no HMO coverage during the one-year entry period. Patients diagnosed with ESRD before or during the entry period are omitted from the study. A one-year entry period is used to define patients with CKD, and the event is defined as the first AKI hospitalization. Patients are followed from January 1 of the year until the earliest of AKI hospitalization, ESRD, death, end of Medicare inpatient/outpatient and physician/supplier coverage, or the end of the year. Patients with hospitalizations for AKI overlapping the start date of the follow-up period are excluded from the analysis. AKI hospitalization rates are adjusted for age, race, and gender using the direct adjustment methods, with the 2005 general Medicare cohort as the reference group.

Figure 1.23 shows the percentage of general Medicare patients hospitalized for AKI who see a nephrologist in hospital, 1993–2005. The study cohort includes patients with an AKI hospitalization during the year, continuously enrolled in the Medicare inpatient/outpatient and physician/supplier program, and with no HMO coverage in the one-year entry period before the first AKI hospitalization. The one-year entry period is used to define CKD, and the percentage of patients who see a nephrologist at least once during the first AKI hospitalization period is calculated by year. Physician type is determined from physician/supplier claims during the hospitalization period.

Figure 1.24 describes the type of physician seen after an AKI hospitalization discharge. Patients with an AKI hospitalization are identified from the 2004 general Medicare population. The follow-up period extends up to one year after the first AKI hospitalization discharge. Patients diagnosed ESRD before or during the AKI hospitalization are excluded. Physician type is determined from the outpatient physician/supplier claims during the follow-up period. Physician types are categorized into five groups: nephrology, internal medicine, cardiology, general practice, and family practice. The percentage for a specific type is interpreted as the percentage of patients seeing that type of physician at least once, following AKI hospitalization, in the one-year follow-up period.

Figure 1.25 presents the probability of receiving a test for microalbumin following an AKI hospitalization. A study period of January 1, 2000, to December 31, 2002, is used to identify general Medicare patients with an AKI hospitalization any time during the time frame. Patients who do not survive the AKI hospitalization or who develop ESRD before or during the AKI hospitalization are excluded. The follow-up period extends up to three years after the first AKI hospitalization discharge until the earliest of death, ESRD diagnosis, or the end of Medicare inpatient/outpatient and physician/supplier coverage. Microalbumin testing is determined from physician/supplier inpatient/outpatient claims, using CPT codes 82042, 82043, and 82044. Based on the physician seen most frequently during the follow-up period, patients are categorized into two groups: nephrologist versus non-nephrologist. We use the Kaplan-Meier method to investigate the cumulative unadjusted probability of receiving a test for microalbumin at each month during the follow-up period.

Figure 1.26 shows the probability of patients receiving follow-up testing post-discharge for AKI. Testing includes HbA1c tests and eye examinations (diabetics only), lipid testing, and influenza vaccinations. For the first three, patients with AKI are identified from the general Medicare population in 2004, and are followed from the AKI discharge up to one year. Diabetic status is determined from the one-year entry period before the AKI hospitalization. For influenza vaccinations, patients with AKI are identified in March through August, 2004, and followed from September through December, 2004. Codes for testing are as follows: HbA1c tests, CPT 83036 (at least two tests, each 30 days apart); eye examinations: taken directly from HEDIS 2003 specifications; influenza vaccinations: CPT codes 90724, 90657, 90658, 90659, and 90660, and HCPCS G0008; and lipid testing: CPT codes 80061, 82465, 83715–83721, and 84478. Patients are categorized into two groups based on whether they see nephrologist in the follow-up period after AKI discharge. Patients are censored at death, ESRD diagnoses, and the end of Medicare inpatient/outpatient and physician/supplier coverage. The Kaplan-Meier method is used to present the cumulative unadjusted probability of testing at three-month intervals during the one-year follow-up period.

Figure 1.27 display the pattern of ESRD development and death in Medicare patients with an AKI hospitalization. The study cohort is the same as that used in Figure 1.25. Patients are followed up to three years after the first AKI hospitalization discharge until the earliest of death, ESRD diagnosis, or December 31, 2005. A one-year entry period before the first AKI hospitalization discharge date is used to define CKD. Rates for ESRD development or death in each three-month interval are estimated by the Poisson model, adjusted for baseline age, race, and gender.

Figure 1.28 shows the cumulative probability of dialysis or CKD following discharge for AKI. The study cohort is the same as that used in Figure 1.25, except that patients with prior CKD before AKI hospitalization are omitted. Hospitalization for AKI is identified through the 584 ICD-9-CM code, appearing on Medicare inpatient claims, by two methods, 1) as a primary diagnosis code, and 2) as a secondary diagnosis code (not a primary diagnosis code). Patients are followed up to three years after the first AKI hospitalization discharge until the earliest of death, ESRD diagnosis, end of Medicare inpatient/outpatient and physician/supplier coverage, or December 31, 2005. Dialysis service is defined by ESRD. The Kaplan-Meier method is used to investigate the cumulative unadjusted probability of receiving dialysis service or having ESRD at each month during the follow-up period.

comparison of care in CKD patients

Figures 1.29–32 show the differences in preventive care of CKD patients and pre-ESRD patients by insurance status. For Figure 1.29, the general Medicare population includes patients entering Medicare before January 1, 2005, alive and age 67 or older on December 31, 2005, and with CKD and diabetes diagnosed during 2005. The pre-ESRD population includes 2005 incident patients age 67 or older at initiation, and with diabetes one year prior to start of ESRD. Cohorts in Figures 1.30–31 are similar, except that patients are diagnosed with both CKD and anemia for Figure 1.30, and with CKD for Figure 1.31. Testing is tracked during 2005 for the general Medicare population, and one year prior to the start of ESRD for the pre-ESRD population.

In Figure 1.32 the general Medicare population is the same as that used for Figure 1.31, but testing is tracked between September 1 and December 31, 2005. The pre-ESRD population includes ESRD patients initiating therapy between January 1 and August 31, 2005, and age 67 or older at initiation. Testing is tracked between September 1 and December 31, 2004. For all cohorts, patients enrolled in an HMO, with Medicare as secondary payor, or diagnosed with ESRD during the year (for the pre-ESRD population, in the year prior) are excluded, as are patients who do not reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories. Methodologies and codes used to define CKD, diabetes, and anemia are described above. Age is calculated on December 31, 2005.

Methods and codes used to determine rates of glycosylated hemoglobin (HbA1c) testing and eye examinations are taken from HEDIS 2002 specifications. Codes used to identify testing are as follows: diabetic HbA1c testing, CPT code 83036 (claims made within 30 days of the last claim for each patient are excluded, and at least two HbA1c claims must be counted); microalbuminuria or proteinuria, CPT codes 82042, 82043, and 82044; lipid testing, CPT codes 80061, 82465, 83715–83721, and 84478; parathyroid hormone, CPT code 83970; calcium and phosphorous, CPT codes 80069, 80073, 82310, 82315, 82320, 82325, 82330, and 84100; diabetic eye exams, CPT codes 92002, 92004, 92012, 92014, 92018, 92019, 92225, 92226, 92230, 92235, 92240, 92250, 92260, 92287, 67101, 67105, 67107, 67108, 67110, 67112, 67141, 67145, 67208, 67210, 67218, 67227, and 67228, ICD-9-CM procedure codes 14.1–14.5, 14.9, 95.02, 95.03, 95.04, 95.11, 95.12, and 95.16, and ICD-9-CM diagnosis code V80.2; influenza vaccinations, CPT codes 90724, 90657, 90658, 90659, and 90660, and HCPCS code G0008; pneumococcal vaccinations, CPT codes 90669 and 90732, and HCPCS codes J6065 and G0009; ESA use, revenue code 0634, 0635, value code 68, and HCPCS codes Q0136, Q0137, Q4054–Q4055, Q9920–Q9940, and J0880.

Figures 1.33 and 1.34 use the same cohorts as Figures 1.31 and 1.30, respectively. Patients are identified as seeing a nephrologist if they have a physician/supplier claim with a physician specialty code of 39. For pre-ESRD patients these claims are searched during the one-year period prior to dialysis initiation; for general Medicare patients these claims are searched during 2005.

Table 1.d shows the adjusted relative risks for ESRD, death, or both. The cohort includes general Medicare patients entering Medicare before January 1, 2004, alive and age 66 or older on December 31, with CKD, anemia, and diabetes diagnosed during 2004. Patients enrolled in an HMO, with Medicare as secondary payor, or diagnosed with ESRD during 2004 are excluded. Also excluded are patients not residing in the 50 states, the District of Columbia, Puerto Rico, or the Territories. Preventive testing and ESA use are tracked during 2004. Data on HbA1c testing include two or more tests at least 30 days apart. Patients are then followed during 2005 for ESRD, death, or both. For ESRD, patients are censored at death; for death, patients are censored at ESRD. A proportional hazards model is used to obtain the relative risks. Covariates include age, gender, race, two or more HbA1c tests, microalbuminuria or proteinuria testing, lipid testing, PTH testing, calcium and phosphorus testing, eye examinations, influenza vaccinations, and ESA use. Reference groups are age 65–69 at the beginning of 2004, male, white, no corresponding preventive testing, and no ESA use.

Figures 1.35–36 include incident hemodialysis patients in 1996–2005, age 67 or older at initiation. Nephrology claims prior to initiation include all physician/supplier claims in the two years prior to initiation with a physician specialty code of “nephrologist.” Fistulas in Figure 1.36 are also obtained from physician/supplier claims during the two-year period. A subset of this cohort, including only those initiating in 2003, is used for Figure 1.37. Figures 1.38 and 1.40 include patients incident in 2004, and use Medicare claims after initiation to identify complications and infections.

Figure 1.39 shows the percent of patients with at least one hospitalization during three-month intervals from 24 months prior to six months after ESRD initiation. We include Medicare ESRD patients at least 67 years old with a first ESRD service date between January 1, 2004, and June 30, 2005. Included patients have Medicare coverage (inpatient/outpatient and physician/supplier) in the two-year period prior to initiation. Principal ICD-9-CM diagnosis codes for cardiovascular and infectious hospitalizations are listed in the discussion of Figure 6.6. Vascular access hospitalizations are those defined as “pure” inpatient vascular access events, as described for Table G.11.

Incidence & prevalence / Chapter Two / Reference Sections A & B  

Here and throughout the ADR, the USRDS generally reports point prevalence—the type of prevalence used throughout most of the book—as of December 31, while period prevalence is reported for a calendar year. Annual period prevalent data thus consist both of patients who have the disease at the end of the year and those who have the disease during the year and die before the year’s end. Because the USRDS treats successful transplantation as a therapy rather than as a “recovery” from ESRD, patients with a functioning transplant are counted as prevalent patients.

Because data are available only for patients whose ESRD therapy is reported to CMS, patients who die of ESRD before receiving treatment or whose therapy is not reported to CMS are not included in the database. We therefore qualify the terms incidence and prevalence as incidence and prevalence of reported ESRD. Some ESRD registries use the term “acceptance into ESRD therapy.” We believe, however, that “incidence of reported ESRD therapy” is more precise, because “acceptance” implies that remaining patients are rejected, when they may simply not be identified as ESRD cases or may not be reported to CMS.

Beginning with the 1992 ADR, lost-to-follow-up patients are not included in the point prevalent counts; they are, however, reported in Table B.1 of the Reference Tables.

reference section A

The Reference Tables present parallel sets of counts and rates for incidence (Section A) and December 31 point prevalence (Section B). Section B also presents annual period prevalent counts and counts of lost-to-follow-up patients.

Because the U.S. population figures (shown in Reference Section M) used in the ADR include only residents of the 50 states and the District of Columbia, tables also focus on patients from these areas. Exceptions are Tables A.1, A.a, A.6, A.8, A.10, and A.c, all of which present data specific to patients in Puerto Rico and the Territories, or include these patients in the patient population. Age is computed as of the beginning of ESRD therapy.

reference section B

With the exception of Tables B.1, B.6, B.8, and B.10, these tables focus on patients residing in the 50 states and the District of Columbia. Age is calculated as of December 31.

Patient characteristics / Chapter Three / Reference Section C  

Data used here are obtained from the Medical Evidence form, completed at the dialysis unit for each new ESRD patient treated at that unit and sent to CMS through the ESRD networks. This form establishes Medicare eligibility for individuals previously not Medicare beneficiaries, reclassifies previously eligible Medicare beneficiaries as ESRD patients, and provides demographic and diagnostic information on all new ESRD patients.

Before 1995, units were required to file the Medical Evidence form only for Medicare-eligible patients. With the adoption of a revised form in 1995, however, providers are now required to complete the form for all new ESRD patients, regardless of their Medicare eligibility. The 1995 revision also introduced new fields for comorbid conditions, employment status, race, ethnicity, and biochemical data at the start of ESRD therapy.

This form is the only source of information about the cause of a patient’s ESRD. Because the list of diseases has been revised, the USRDS stores the codes from each version so that detail is not lost through trying to convert one set of codes to the other.

A new revision of the Medical Evidence form was released in the spring of 2005, introducing new fields related to comorbidity, laboratory test values, pre-ESRD care, and vascular access.

Figures 3.12–14 include incident hemodialysis patients. Figure 3.13 uses the hemoglobin and/or hematocrit value from the Medical Evidence form, while Figures 3.12 and 3.14 use EPO claims and therefore only include patients who have valid EPO claims during each of the first four months after dialysis initiation. Patients are linked to altitude data on a county level based on their county of residence.

Treatment modalities / Chapter Four / Reference Section D  

Chapter Four and the associated reference tables describe the treatment modalities of all known ESRD patients, both Medicare and non-Medicare, who are not classified as lost-to-follow-up or having recovered renal function (RRF). The RRF event, introduced in this 2007 ADR, is defined as an event that occurs within the first 180 days of the ESRD initiation and lasts for at least 90 days. This definition is much more conservative than that used in the SIMS event database. Unless noted otherwise, incident and point prevalent cohorts without the 60-day stable modality rule are used in the analyses.

Treatment modalities are defined here as follows:

• center hemodialysis: hemodialysis treatment received at a dialysis center
• center self-hemodialysis: hemodialysis administered by the patient at a dialysis center; a category usually combined with center hemodialysis
• home hemodialysis: hemodialysis administered by the patient at home; cannot always be reliably identified in the database
• CAPD: continuous ambulatory peritoneal dialysis; usually combined with CCPD
• CCPD: continuous cycling peritoneal dialysis; usually combined with CAPD
• other peritoneal dialysis: primarily intermittent peritoneal dialysis (IPD), a small category except among very young children; usually combined with unknown dialysis and uncertain dialysis to form an other/unknown dialysis category
• uncertain dialysis: a period in which the dialysis type is unknown or multiple modalities occur but none last 60 days; usually combined with other peritoneal dialysis (IPD) and unknown dialysis to form an other/unknown dialysis category
• unknown dialysis: a period in which the dialysis modality is not known (e.g. when dialysis sessions are performed in a hospital); usually combined with other peritoneal dialysis (IPD) and uncertain dialysis to form an other/unknown dialysis category
• renal transplantation: a functioning graft from either a living donor (a blood relative or other living person) or a cadaveric donor
• death: a category not appearing in the year-end modality tables, which report only living patients, but used as an outcome (e.g. in tables showing living patients followed for a period of time for their modality treatment history)

Modality and provider characteristics are presented in Figures 4.7–12. For a description of the provider data used in these figures, please see the discussion of Chapter Ten. All provider-related figures include only dialysis patients.

Reference Section D is divided into three sections. The first, Tables D.1–11 and D.15–16, provides counts and percentages—by demographics, geographic location, and treatment modality—of incident and prevalent patients alive at the end of each year. Age is computed as of the start of ESRD for incident patients, and as of December 31 for point prevalent patients.

Table D.12 shows modality at 90 days and two years after first service for all incident Medicare patients beginning renal replacement therapy from 2001 to 2003. The 90-day rule is used to exclude patients who die during the first 90 days of ESRD, and age is computed as of the first ESRD service date.

The third section, Tables D.13–14, presents counts of prevalent patients alive at the end of each year, by ESRD exposure time and modality. Table D.13 shows counts by the number of years of ESRD, while Table D.14 presents counts by the number of years on the end-of-year treatment modality. For the duration of ESRD exposure, zero should be read as less than one year, one as at least one full year but less than two, and so on.

Clinical care & preventive health / Chapter Five  

In Figure 5.1, for both Kt/V measurements, 2004 ESRD CPM data are used to calculate a mean Kt/V value for each patient from the 1–3 values present for each, and the percent of patients with a mean Kt/V over a certain threshold is determined. For prevalent hemodialysis patients in 2005, each patient’s URR is obtained from the G-modifier attached to CPT code 90999, with a revenue code of 821 or 825. Each measurement is categorized into one of five ranges, and the median URR is calculated; for patients whose median lies between two ranges, we assign a weight of 0.5 to each. Information on new hemodialysis patients with an arteriovenous fistula as the first access is calculated as described for Figure hp.11. Hemoglobin levels are calculated for EPO-treated, 2005 prevalent hemodialysis patients, using available EPO claims during the year. EPO claims with a dose per administration of less than 500 or greater than 80,000 units, or with a hematocrit value less than 10 or greater than 50, are omitted. For each patient a yearly mean hemoglobin is calculated as the mean of all hematocrit values divided by three. Data on albumin are obtained for incident hemodialysis patients in 2005 who have a valid value on their Medical Evidence form; those with a lower limit equal to zero are omitted.

anemia treatment

The methods for Figures 5.2–3 are described in the discussion of Figures p.16–17. Figures 5.4–6 include data from all incident dialysis patients with an EPO claim in the first 30 days of ESRD therapy, and at least one EPO claim during each of the following six months. EPO claims with a dose per administration of less than 500 units or more than 80,000 units are omitted, as are those with an average dose per day (calculated as the total EPO units on the claim divided by the number of days spanned by the claim) of less than 100 units or greater than 10,000 units. For 2005, patients are incident prior to June 1, to allow them to have six months of EPO and/or iron claims after their incident date. For graphs by starting hemoglobin, patients are included only if they have a hematocrit listed on the Medical Evidence form, and their starting hemoglobin is determined from this value. In Figure 5.4, a mean hemoglobin is calculated for each patient from claims during the month, and the average of these values is then calculated for each month. For Figure 5.5, the mean EPO dose per week is adjusted by only including days during a month in which a patient is not in an inpatient hospital setting, so that the mean EPO dose represents outpatient dosing only. And for Figure 5.6, an average monthly iron dose is calculated for each patient during the first six months of dialysis.

Methods for Figures 5.7–12 are described in the captions.

overshooting of target hemoglobin levels:

Cumulative probabilities in this section are calculated using the Kaplan-Meier method, and patients are censored at a missing hemoglobin value.

The cohort for Figures 5.13 and 5.15 includes incident dialysis patients with a first service date between July 1, 2004, and June 30, 2005, with Medicare as primary payor, and receiving EPO during the first six months after incidence. Patients who die or are transplanted in the first six months are excluded. The cohort for Figure 5.14 includes point prevalent dialysis patients, 2004, with a valid hemoglobin value in each of the first six months.

Figures 5.16 includes incident dialysis patients with a first service date between July 1, 2004, and June 30, 2005, with Medicare as primary payor, receiving EPO or DPO, and with at least one hemoglobin value less than 11 g/dl during the first six months after incidence. Patients who die or are transplanted in the first six months are excluded. Figure 5.17 includes hemodialysis patients age 20 and older in the USRDS and ESRD CPM databases. Only patients with at least one hemoglobin value of 11–12 g/dl in the CPM period and with EPO treatment during the first six months after the CPM period are included. Patients are followed from the CPM period up to six months.

Figure 5.18 includes point prevalent dialysis patients, 2004, with Medicare as primary payor on January 1, 2004, receiving EPO, and with at least one hemoglobin value less than 11 g/dl during the first six months after January 1, 2004.

diabetic preventive care

Figures 5.19–34 present data on diabetic preventive care in patients age 18–75. ESRD patients without Medicare inpatient/outpatient and physician/supplier coverage during the entire study period are omitted from these analyses, as are those who do not reside in the 50 states, the District of Columbia, Puerto Rico, or the Territories; who have a missing date of birth; who do not survive the entire reporting period; who have ESRD for fewer than 90 days prior to the start of the reporting interval; or who are lost-to-follow-up during the study period. Patients who reside in the District of Columbia, Puerto Rico, and the Territories are also omitted from the maps. Age is generally calculated at the end of the study period.

Methods and codes used to determine rates of diabetic glycosylated hemoglobin (HbA1c) testing, lipid testing, and eye exam are described in the methods for Chapter One. Patients are defined as having diabetes either through medical claims (one inpatient/outpatient, two physician/supplier, two outpatient, or one physician/supplier and one outpatient), or through a listing of diabetes on the Medical Evidence form as the primary cause of ESRD or as a comorbid condition. ICD-9-CM diagnosis codes used to define diabetes are described in the methods for Chapter One.

Figures 5.19, 5.23, 5.27, and 5.31 show rates of diabetic preventive care in 2005; Figures 5.21, 5.25, and 5.29 show the amount of diabetic testing by modality; and Figures 5.22, 5.26, 5.30, and 5.34 compare rates in dialysis and transplant patients. The population for these figures includes ESRD patients initiating therapy at least 90 days prior to January 1, 2004, alive on December 31, 2004, and with diabetes defined in 2004. Rates include patients receiving at least four HbA1c tests, at least two lipid tests, at least one eye exam, or, for comprehensive diabetic monitoring in Figures 5.31 and 5.34, all of the above during 2005.

Figures 5.20, 5.24, and 5.28 show the number of tests by year, Figure 5.32 shows overall trends, and Figure 5.33 shows trends by modality. The cohort for those figures includes patients starting therapy at least 90 days prior to January 1 of the first year of each study period and with diabetes in the first year. Diabetic HbA1c and lipid testing, and eye examinations, are tracked in the second year of each period. HbA1c, lipid testing, and eye examination claims made within 30 days of the last claim for each patient are excluded. In Figures 5.32 and 5.33, “comprehensive” diabetic monitoring means at least four HbA1c tests, at least two lipid tests, and at least one eye examination.

preventive care

Figures 5.35–38 show rates of lipid testing for ESRD patients. Cohorts for Figures 5.35 and 5.37–38 are 2005 ESRD patients initiating therapy at least 90 days before January 1, 2005, with Medicare inpatient/outpatient and physician/supplier coverage at initiation, and alive and remaining in the program through December 31. For Figure 5.35, patients residing in Puerto Rico and the Territories are excluded. The cohort for Figure 5.36 includes ESRD patients initiating therapy at least 90 days before January 1 of each year, with Medicare inpatient/outpatient and physician/supplier coverage at initiation, and alive and remaining in the program through December 31. For all figures, testing is tracked during each year, and tests are at least 30 days apart.

Figures 5.39–44 show rates of influenza, pneumococcal pneumonia, and hepatitis B vaccinations for prevalent ESRD patients by modality, age, race/ethnicity, and time period. Cohorts for Figures 5.39–42 are the same as those described for Objective 14.29 in the HP2010 chapter, while the cohorts for Figures 5.43–44 are the same as those for Figures 5.36 and 5.35, respectively. Patients who reside in Puerto Rico and the Territories are omitted from the maps. Age is generally calculated at the end of the study period. Hepatitis B vaccinations are identified through CPT codes 90636, 90740, 90743–90744, 90748, 90731, and 90723.

vascular access in prevalent patients

Figures 5.45–51 include prevalent hemodialysis patients who are in both the USRDS and ESRD CPM databases, and whose day 91 begins prior to October 1 of the prevalent year. The access represents the current access being used according to the CPM data. Claims are then searched during the following calendar year for events and complications. Figure 5.51 includes incident peritoneal dialysis patients from the USRDS database. For Figures 5.48–51, complication rates are calculated as the number of events (from Medicare claims) divided by the time at risk, which is censored at death, change in modality, change in payment status, or the placement of a different type of access. Vascular access codes are listed in the methods for Chapter Eleven.

Morbidity & mortality / Chapter Six / Reference Sections G, H, & I  

hospitalization

Methods used for the prevalent patient hospitalization figures in this chapter generally echo those used for the tables in Reference Section G (described below). Inclusion and exclusion criteria are generally the same, as are the methods for counting hospital admissions and days, and defining the follow-up time at risk. One difference is the exclusion in Reference Section G of patients of races that are unknown or other than white, African American, Native American, or Asian; these patients are included in the Chapter Six figures, except where data are presented by race.

Inpatient institutional claims are used for the analyses, and methods for cleaning claims follow those described for Section G. Adjusted rates are calculated using the model-based adjustment method on the observed category-specific rates. This method is described further in the discussion of Section G, and in the statistical methods section later in this appendix.

Figure 6.2 presents adjusted rates of total hospital admissions and days per patient year. Prevalent ESRD patients are included, with the 2005 ESRD cohort used as the reference. Methods for rates in Figures 6.2–3 follow those described for Reference Section G. In Figure 6.3, methods are similar to those described for Figure p.22 in the Précis, with admissions for pneumonia, bacteremia/septicemia, and cellulitis in Figure 6.3 replacing the categories of all-cause, infection, and cardiovascular disease in p.22. Principal ICD-9-CM diagnosis codes are used to identify cause-specific admissions: pneumonia, 480–486 and 487.0; bacteremia/septicemia, 038.0–038.9 and 790.7; and cellulitis, 682. Vascular access hospitalizations are “pure” inpatient vascular access events, as described for Table G.11 later in this appendix. Due to new vascular access codes for peritoneal dialysis patients in 1998, vascular access hospitalizations are shown for hemodialysis patients only.

Figure 6.4 presents unadjusted rates for period prevalent ESRD patients in 2005 by HSA and state. (Rates for peritoneal dialysis and transplant patients are presented by state rather than by HSA due to few patients and events in many HSAs.) Maps by HSA are smoothed using the Bayesian method.

Figure 6.5 shows adjusted admission rates for principal diagnoses for prevalent ESRD patients. Principal ICD-9-CM codes for pneumonia, bacteremia/septicemia, and cellulitis are listed above for Figure 6.3. Other principal ICD-9-CM codes are as follows: for vascular access infection (hemodialysis patients only), 996.62; and for peritonitis (peritoneal dialysis patients only), 567.

Figure 6.6 presents the percent change in adjusted hospital admission rates for period prevalent dialysis patients, 1995–2005. Values presented for all patients are adjusted for age, gender, race, and primary diagnosis, while rates presented by one of these factors are adjusted for the remaining three. As noted in the caption, these adjustments for different factors mean that rates across the individual graphs are not directly comparable. We use the model-based adjustment method here, with 2005 dialysis patients as the reference cohort. Vascular access hospitalizations (hemodialysis patients only) are “pure” inpatient vascular access events, as described later for Table G.11. The cardiovascular category consists of codes 276.6, 394–398.99, 401–405, 410–420, 421.9, 422.90, 422.99, 423–438, and 440–459, while infection is indicated by codes 001–139, 254.1, 320–326, 331.81, 372–372.39, 373.0–373.2, 382–382.4, 383.0, 386.33, 386.35, 388.60, 390–393, 421–421.1, 422.0, 422.91–422.93, 460–466, 472–474.0, 475–476.1, 478.21–478.24, 478.29, 480–490, 491.1, 494, 510–511, 513.0, 518.6, 519.01, 522.5, 522.7, 527.3, 528.3, 540–542, 566–567.9, 569.5, 572–572.1, 573.1–573.3, 575–575.12, 590–590.9, 595–595.4, 597–597.89, 598, 599.0, 601–601.9, 604–604.9, 607.1, 607.2, 608.0, 608.4, 611.0, 614–616.1, 616.3–616.4, 616.8, 670, 680–686.9, 706.0, 711–711.9, 730–730.3, 730.8–730.9, 790.7–790.8, 996.60–996.69, 997.62, 998.5, and 999.3.

Tables 6.a–c present adjusted hospital admission rates by vintage for adult (age 20 and older) period prevalent ESRD patients in 1995 and 2005. Patient vintage is calculated as the time from the first ESRD service date to the first of the year for prevalent patients, or as less than one year for incident patients. Rates in the “all” row are adjusted for age, gender, race, and primary ESRD diagnosis, while rates presented by one factor are adjusted for the other three.

Figures 6.7–9 show rates by age, adjusted for gender, race, and primary diagnosis using the model-based adjustment method. These figures include period prevalent dialysis patients age 20 and older, with the 2005 dialysis cohort as the reference. Figure 6.7 presents adjusted rates of cause-specific hospital admissions per patient year. The categories for cardiovascular disease and infection are defined by the codes listed for Figure 6.6; the infection codes for Figure 6.7, however, exclude those due to internal device. The principal ICD-9-CM diagnosis codes used for infection due to internal device (related to a vascular access device or peritoneal dialysis catheter) are 996.62 and 996.68.

Figure 6.8 shows adjusted event rates for inpatient coronary revascularization. Patients are followed until the first coronary revascularization event, and are censored at the earliest of death, three days prior to transplant, or the end of the calendar year. Events are identified from inpatient and physician/supplier claims occurring within a hospital stay. The following ICD-9-CM procedure and CPT codes are used to identify events: angioplasty, procedure codes 00.66, 36.01, 36.02, and 36.05, and CPT codes 92982, 92984, 92995, and 92996; coronary stents, procedure code 36.06 and CPT codes 92980–92981; and bypass, procedure codes 36.1x and CPT codes 33510–33523, 33533–33536.

Figure 6.9 displays adjusted vascular access placement rates for period prevalent adult hemodialysis patients. These are not hospital admission rates, but procedure rates for vascular access placements in an inpatient setting. Vascular access placements are obtained from CPT codes on physician/supplier claims, and are restricted to those occurring in the hospital (during an inpatient stay or emergency room visit). Categories include the following CPT codes: catheters, 36488–36491, 36533, 36555–36558, 36565, 36800, and 76937; fistulas, 36818–36821 and 36825; and grafts, 36830. The category for all vascular access placements includes all of the above CPT codes. Methods are also used to exclude vascular access used for purposes other than dialysis. Rates for catheter and all vascular access placements exclude patients with specific chemotherapy or parenteral nutrition claims during the year. inpatient/outpatient institutional, physician/supplier, and durable medical equipment claims indicate chemotherapy (CPT codes 96408, 96410, and 96412) or parenteral nutrition (CPT codes B4164–B5200, B9004, B9006, and B9999). Also, catheter placements with CPT codes 36488–36491, 36533, 36555–36558, 36565, and 76937 are included only if they are accompanied by an ICD-9-CM line-level diagnosis code or claim-level principal diagnosis code related to dialysis or renal failure (250, 403, 580–589, 593, 996.1, 996.62, 996.73, V45.1, or V56).

Figures 6.10–11 display geographic variations in cause-specific admission rates by state. Codes used to identify cardiovascular and infectious admissions are listed in the discussion of Figure 6.6, and vascular access admissions represent “pure” inpatient vascular access events as later described for Table G.11. Inpatient catheter placement rates in Figure 6.11 follow the methods described for Figure 6.9, except that rates by state here are unadjusted.

mortality

Patient cohorts for all mortality figures here include both Medicare and non–Medicare patients living in the 50 states, the District of Columbia, Puerto Rico, and the Territories.

Figure 6.1 shows trends in mortality rates by modality for incident ESRD patients, 1980–2004. The population groups include all-ESRD, hemodialysis, CAPD/CCPD, and first transplant (known deceased and living donors only). Adjusted first-, second-, third-, fourth-, and fifth-year mortality rates for incident cohorts—including all-ESRD, hemodialysis, CAPD/CCPD, and first transplant patients—are computed from the Cox model using the model-based adjustment method, described later in this appendix. Mortality rates for all patients are adjusted for age, gender, race, and primary diagnosis. The reference population for adjusted rates consists of 1996 incident ESRD patients.

Figure 6.12 shows all-cause mortality by age for 2005 prevalent ESRD, dialysis, transplant, and general Medicare patients. General Medicare patients are non-ESRD patients with at least one month of Medicare eligibility in 2005; they are followed from the first day of the first month with Medicare eligibility until death or December 31, 2005. ESRD patients are followed from January 1 until December 31, 2005. All-cause mortality rates by age are calculated using generalized mixed models, and are adjusted for gender and race. Medicare patients from 2005 are used as the reference cohort.

Figure 6.13 presents unadjusted all-cause mortality, by HSA, for 2005 prevalent ESRD, dialysis, transplant, and general Medicare patients. The populations are those used in Figure 6.12, except that general Medicare patients are age 65 and older.

Table 6.d shows expected remaining lifetimes for dialysis patients, renal transplant patients, and the general U.S. population. For period prevalent ESRD patients in 2005, expected lifetimes are calculated using the death rates from the mixed model with 16 age groups, assuming constant survival and mortality within each age group. Patient inclusion and exclusion criteria are those used in Tables H.4.4 and H.28.4, and the method for calculating expected remaining lifetimes is described in the section on statistical methods at the end of this appendix. Data for the general population are obtained from the CDC’s National Vital Statistics Reports.

Figure 6.14 illustrates trends in mortality rates by patient vintage for period prevalent dialysis patients alive on renal replacement therapy on January 1, with a first service date at least 90 days prior to the beginning of the year, and reaching day 91 of ESRD treatment during the year. Patients with unknown age or gender, or of a race other than white, African American, Native American, or Asian are excluded. Patients are followed from January 1 until death, transplantation, or the end of the year, and all-cause mortality rates are adjusted for age, gender, race, and primary diagnosis using generalized mixed models. The reference population consists of 2001 prevalent dialysis patients, and adjusted mortalities across vintages are comparable.

Figures 6.15 and 6.17 show all-cause mortality and survival rates for general Medicare and ESRD patients with cardiovascular disease, malignancy, and septicemia. Figure 6.15 presents annual mortality rates for the 2005 general Medicare and ESRD populations, while Figure 6.17 shows one- and five-year survival rates for 1992–2004 general Medicare, dialysis, and transplant patients. Using Medicare claims in a calendar year, diseases are identified through the appearance of ICD-9-CM codes at least once in inpatient/outpatient claims or at least twice in outpatient or physician/supplier claims. The ICD-9-CM codes are 390.xx–398.xx, 402.xx, 404.xx, and 410.xx–429.xx for heart disease; 140.xx–208.xx for malignancy, and 038 for septicemia. Mortality rates in Figure 6.15 are calculated using generalized mixed models, and are adjusted for gender and race. Survival rates in Figure 6.17 are calculated using Cox regressions, and are adjusted for age, gender, and race. In both figures, 2005 general Medicare patients are used as the reference cohort

Figure 6.16 presents five-year survival by modality for 1991–1995 and 1996–2000 incident patients, with modality defined on the first ESRD service date. Transplant is defined as the first transplant in the incident year. Patients with unknown age, gender, or primary diagnosis, and those with a listed age greater than 110, are excluded, as are dialysis patients who die or receive a transplant in the first 90 days. Dialysis patients are followed from day 91 until death, transplantation, or the end of 2005, while transplant patients are followed from the first transplant date until death or the end of 2005. All probabilities are adjusted for age, gender, and race; overall probabilities are also adjusted for primary diagnosis. As in the 2003–2006 ADRs, the reference population consists of 1996 incident ESRD patients, and adjusted probabilities are comparable across modalities.

Figures 6.18–22 display adjusted all-cause and cause-specific mortality in in