2008 USRDS Annual Data Report
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Introduction

Funding & chapter contributors
Production of this ADR was solely funded through NIH contract HHSN 267 2007 15002C / NO1-DK-7-5002 with the Minneapolis Medical Research Foundation (MMRF). Most contributors to this report are employed by MMRF, with many of the physician investigators being employed by MMRF’s parent organization, Hennepin Faculty Associates. MMRF has enacted conflict of interest (COI) policies and practices governing the conduct of research within the USRDS and other research not related to the USRDS. In addition to internal controls, USRDS work is overseen by NIDDK Project Officers, the USRDS Steering Committee, and the USRDS External Advisory Committee.

Listed below are those who contributed to this volume of the ADR. Unless otherwise noted in parentheses, the contributor’s employer was MMRF or its parent organization, Hennepin Faculty Associates.

Directors & co-investigators Allan Collins, MD, FACP; USRDS Director (entire ADR). Robert Foley, MB, MSc, USRDS Deputy Director (entire ADR). David Gilbertson, PhD (entire ADR). Charles Herzog, MD (Chapter 3). Anne Murray, MD, MSc (Chapter 3) Jon Snyder, PhD (entire ADR).

USRDS staff • Administrative staff Beth Forrest, BBA. ADR production Edward Constantini, MA (entire ADR). Susan Everson, PhD (entire ADR). Biostatisticians. Haifeng Guo, MS (Précis, Chapters 3, 4). Qi Li, MS (Chapter 2). Shuling Li, MS (Chapter 3). Suying Li, PhD (Chapter 5). Yi Peng, MS (Chapter 2). Tricia Roberts, MS (Précis, Chapter 3). Craig Solid, MS (entire ADR). Changchun Wang, MS (Précis, Chapters 1, 4). Eric Weinhandl, MS (Chapter 2). David Zaun, MS (Chapter 4). Information systems & software development for all chapters, with additional work as follows: Cheryl Arko, BA. Shu-Cheng Chen, MS. Frederick Dalleska, MS. Frank Daniels, BS. James Ebben, BS (Chapter 5). Eric Frazier, BS. Christopher Hanzlik, BS. Roger Johnson. C Daniel Sheets, BS. Xinyue Wang, BA/BS.

Disclosures for potential conflicts of interest
Allan Collins, MD, FACP Consultant/honoraria: AMAG Pharmaceuticals, Amgen, Baxter, NxStage. Robert Foley, MB, MSc Consultant/honoraria: 21st Services, Affymax, Amgen, Luitpold Pharmaceuticals. David Gilbertson, PhD Consultant/honoraria: AMAG Pharmaceuticals, Amgen. Charles Herzog, MD Consultant/honoraria: Amgen, CorMedix, Genzyme. Trustee: RoFAR. Equity ownership: Cambridge Heart. Shuling Li, MS Consultant/honoraria: AMAG Pharmaceuticals. Jiannong Liu, PhD Consultant/honoraria: AMAG Pharmaceuticals. Anne Murray, MD, MSc Equity ownership: Medtronic, NxStage. Jon Snyder, PhD Equity ownership: Amgen. Wendy St. Peter, PharmD, BCPS Consultant/honoraria: Abbott. • Also, MMRF as an institution has separate contracts to conduct other, independent research with 21st Services, Abbott, AMAG Pharmaceuticals, Amgen, Baxter, Bristol-Myers Squibb, Fresenius, Centers for Disease Control and Prevention, Genzyme, Merck/Schering-Plough, National Institute on Aging / National Institutes of Health, National Kidney Foundation, NxStage, Roche, and Sigma-Tau.

This 20th annual report of the United States Renal Data System is produced by the USRDS Coordinating Center, operated under NIH contract HHSN 267 2007 15002C / NO1-DK-7-5002 by the Minneapolis Medical Research Foundation.

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Suggested citation for this report
U.S. Renal Data System, USRDS 2008 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2008. Publications based upon USRDS data reported here or supplied upon request must include this citation and the following notice: The data reported here have been supplied by the United States Renal Data System (USRDS). The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy or interpretation of the U.S. government.

In Volume Two of the 2008 Annual Data Report: information on USRDS services & data requests, a glossary, the USRDS Agreement for Release of Data, the USRDS International Data Collection Form, copies of CMS forms 2728, 2746, & 2744, & photo credits.

PDF files of the 2008 Annual Data Report & the Researcher’s Guide PowerPoint slide files of all figures in the ADR, & Excel files of the data underlying the graphs Excel files of the Reference Tables, including supplemental hospitalization & mortality tables with calculations per 1,000 patients, & Medicare-only tables RenDER, our online query application for accessing USRDS data An online application for requesting data from the USRDS on our website, www.usrds.org.

This is the twentieth annual report of the United States Renal Data System, and the first to dedicate a separate volume to chronic kidney disease (CKD). In this volume we define the disease burden in the prevalent population, and look at cardiovascular and other comorbidities, rates of adverse events, preventive care, prescription medication therapy, care delivered in the transition to end-stage renal disease (ESRD), and the cost to Medicare and employer group health plans. In Volume Two we go on to provide information on the size and impact of the ESRD population — the traditional focus of the USRDS — presenting an overview of the ESRD program, along with detailed data on incidence, prevalence, comorbidity of new ESRD patients, severity of disease, clinical care, hospitalization and mortality rates, pediatric patients, renal transplantation, the provider delivery system, and the economics of the ESRD program.

We approach this volume from the perspective that the implications of CKD were under-appreciated prior to February, 2002, when a new CKD classification staging system was proposed. The five-stage system was developed using population-level data from the National Health and Nutrition Examination Survey (NHANES), coordinated by the National Center for Health Statistics at the Centers for Disease Control and Prevention. The system’s conceptual model was based on those being developed for populations at risk for diabetes and hypertension, two well-known diseases that damage the kidney as well as other organ systems. The model characterizes progressive stages of CKD, from early evidence of kidney damage — such as albumin in the urine — to overt reductions in the filtering capacity of the kidney, defined by estimation of the glomerular filtration rate.

There are many issues related to defining the level of urine albumin that indicates “true disease” in the kidney during the early stages of CKD, as compared to a normal reduction in kidney filtering capacity, particularly in the elderly. The USRDS and others will continue to investigate these issues in both the clinical and public health arenas, but already there is important information available on the impact of CKD, information based not only on biochemical data, but on the disease as defined within the Medicare and health plan datasets.

In the Précis we summarize important points from throughout this volume, highlighting NHANES data on disease burden, comorbidity, and treatment and control of hypertension and cardiovascular risk factors, as well as data from the recognized CKD populations within the Medicare and employer group health plan (EGHP) systems. Data using reported diagnosis codes underestimate the true disease burden, but provide insight into how healthcare providers report on services given to this high-risk population. We look here at hospitalization rates, as well as at the effect on these rates of the complex relationship among CKD, diabetes, and congestive heart failure. Since the CKD population carries a heavy burden of cardiovascular disease, and has high rates of cardiovascular and infectious events, primary and secondary treatment of these complications provide important perspectives on quality of and access to care. Data on angiotensin converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) show their frequent use in the diabetes population to treat CKD, to reduce its progression, and to lower rates of cardiovascular events. Use in the non-diabetic CKD population is about half that among diabetics — a major concern in terms of access to care for the prevention of adverse events. Data on the economic impact of the CKD population complete the Précis.

Chapter One begins with prevalent estimates of the CKD population developed from the NHANES cohorts, demonstrating the population’s size and complexity. We present information on the type and degree of biochemical abnormalities, including disorders related to potassium levels, anemia, bicarbonate levels, and bone and mineral disease. We also look at the degree of iron deficiency, as anemia is a common complication of CKD, yet may be exacerbated by poor nutrition and blood loss. Data on the prevalence of CKD in association with other comorbid conditions demonstrate the interactive nature of CKD, diabetes, and cardiovascular disease. Because defining target groups for CKD detection and intervention is an important public health approach for addressing CKD, we present data on risk factors, along with a classification tree analysis showing that the target populations for detection should be patients age 60 and older and those with self-reported diabetes or hypertension. We conclude with data showing that management of risk factors such as hypertension and cardiovascular disease in CKD patients is characterized by poor control of blood pressure and lipid levels, and with information on the use of prescription medications.

Chapter Two addresses CKD in the Medicare and EGHP data. These datasets contain considerable detail about services and complications, but generally include no biochemical data. We discuss the case definitions used here, and provide perspective on them through comparisons with the NHANES data. New ICD-9-CM diagnosis codes for CKD were introduced in the fall of 2005; we analyze their use in 2006. The Ingenix i3 dataset includes considerable biochemical data along with information on service use, allowing us to compare CKD as identified from the diagnosis codes to that defined through serum creatinine and urine albumin tests, and thus to address the utility and weaknesses of each approach.

In Chapter Three we present data on morbidity and mortality, demonstrating the high rates of hospitalization in CKD compared to non-CKD patients. Complication rates appear to be declining in the recognized population, but this likely represents increased reporting of CKD on the claims, which identify patients with less severe illness. Improved adjustments to these populations will be developed for the 2009 ADR. Regardless of the trends in rates, however, the recognized CKD population has high rates of hospitalization for congestive heart failure, and for other cardiovascular and infectious events. Mortality rates are high, particularly in those whose CKD is accompanied by diabetes and congestive heart failure. Given these high event and death rates, the use of diagnostic tests and interventions for cardiovascular disease is lower than expected.

In Chapter Four we first present information on the likelihood that CKD patients will die or advance to ESRD, showing that death is the dominant outcome — far exceeding the likelihood of reaching ESRD. We next examine the care of patients who do advance to ESRD, looking at the first recognition of CKD in the reported services, and at the degree of progression of cardiovascular and infectious complications. Recognition of CKD, even in those who reach ESRD, is slow, and referral is generally late. Use of diagnostic tests to track the degree of kidney failure progression and the risk factors for cardiovascular disease is also low, and differs in the Medicare and EGHP populations. This chapter also presents information on the use of recommended prescription drugs in those known to reach ESRD, including ACE-Is/ARBs, beta blockers, antihypertensive drugs, and medications to treat anemia and address bone and mineral disorders. We conclude with information on vascular access placement before and in the six months after ESRD, showing the high use of catheters, along with increasing attempts at simple fistula placement and falling rates of arteriovenous graft use.

This new volume concludes with data on the expenditures associated with the CKD population. As we show in Chapter Five, costs have grown in both the Medicare and EGHP systems, in part reflecting the interaction of CKD with diabetes and congestive heart failure. Data on expenditures during the transition to ESRD show high costs for the younger EGHP population as compared to the older patients covered by Medicare. And, finally, we compare differences in actuarial expenditures and predicted payment models used by Medicare, showing that the new Medicare HCC payment system does a better job predicting expenditures than do the simple models that adjust for age, gender, and disability. We describe the clear economic impact of recognized CKD on the healthcare system — and discuss how the impact may be even greater than shown, given that case definitions under-count the actual disease burden of the NHANES population estimates.

As in past Annual Data Reports, we provide detailed analytical methods in the appendix. The USRDS Coordinating Center will be developing reference tables for CKD in the future, as well as new cohort definitions to better describe this and other high-risk populations. Since this is the first ADR to fully address CKD as well as ESRD, we will work closely with the Project Officers, review committees, public health officials, and researchers to more completely characterize the patients in this population, their complications, their care, and their associated costs to the Medicare and other health systems. When it becomes available, we will also incorporate Medicare Part D prescription drug information into the CKD and ESRD volumes to examine access to care along with safety and efficacy of treatment.

Information about the USRDS website, the Researcher’s Guide, the USRDS database, and administrative oversight of the USRDS is presented in the introduction to Volume Two.

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