2011 USRDS Annual Data Report
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Chapter Five

Mortality

Sections this chapter: 

Introduction

Assessing mortality in the ESRD population is a unique challenge, in that two sources of death records are available to the USRDS Coordinating Center (CC). Universal reporting to CMS of ESRD patient deaths is required as a condition of coverage for dialysis units and transplant centers. Since all ESRD patients have Social Security numbers, the CC can also link these patients to the National Death Index files, updated every quarter and in the public domain. The USRDS was formerly able to report deaths only from day 90 of treatment, as Medicare did not cover services for those younger than 65; now, however, the comprehensive tracking of all ESRD patient deaths allows the USRDS to identify all deaths occurring after the first outpatient dialysis session.

Between 1993 and 2003 there was little improvement in first-year death rates in the ESRD population. Between 2004 and 2008, however, these rates fell more than 10 percent. And over similar intervals, second- to fifth-year death rates decreased 1214 percent. Month-by-month mortality rates in the first year of hemodialysis have shown similar improvements, overall and for mortality due to cardiovascular disease and infection. Mortality due to other causes, in contrast, has increased since 1998, a finding which requires further investigation. Still striking are the high rates of all-cause mortality in the early months of therapy.

Rates of mortality in the prevalent population have also declined nearly 25 percent over the last two decades, and 19 percent since 1999.

Despite these improvements, however, only 50 percent of dialysis patients, and 82 percent of those who receive a preemptive transplant, are still alive three years after the start of ESRD therapy numbers that help illustrate the extreme vulnerability of these patients when compared to the general population. Among dialysis patients age 65 and older, for example, mortality is twice as high as for patients in the general population who have diabetes, cancer, congestive heart failure, CVA/TIA, or AMI.

Patients with kidney disease are clearly at a high risk of death and, as shown in the hospitalization data, have very high event rates as well. Thrice-weekly treatment may be inadequate for addressing the critical problems of persistent fluid overload, hypertension, left ventricular hypertrophy, and recurrent vascular access infections and complications. Recent publication of the Frequent Hemodialysis Trial (NEJM Nov 2010), comparing treatment of three days per week to that of six days, demonstrated significant reductions in left ventricular hypertrophy and hyperphosphatemia among patients receiving more frequent therapy. Mortality comparisons still need to be considered, as do questions of how more frequent sessions might be implemented across the country. In the meantime, there should be a focus on improving care and outcomes through medication interventions and reductions in the use of dialysis catheters, with their high rates of associated complications.

Figure 5.1 Adjusted all-cause mortality rates (from day 90), by modality & year of treatment (see page 386 for analytical methods. Incident ESRD patients. Adj: age/gender/race/primary diagnosis; ref: incident ESRD patients, 2005.)

Mortality and Survival Top

Figure 5.2 Adjusted all-cause mortality in the ESRD & general populations, by age, 2009 (see page 386 for analytical methods. Prevalent ESRD & general Medicare (non-ESRD) patients. Adj: gender/race; ref: Medicare patients, 2009.)

Adjusted rates of all-cause mortality are 6.57.4 times greater for dialysis patients than for individuals in the general population. For renal transplant patients, rates approach those of the general population, yet remain 1.11.6 times higher. Rates rise by age, reaching 274 per 1,000 patient years at risk for ESRD patients age 65 and older, and 313 for dialysis patients of the same age.

Figure 5.3 Adjusted all-cause & cause specific mortality (from day one) in the first year of hemodialysis (see page 386 for analytical methods. Incident hemodialysis patients. Adj: age/gender/race/primary diagnosis; ref: incident hemodialysis patients, 2005.)

In the first year of hemodialysis, all-cause mortality and mortality due to cardiovascular disease or to other causes peak in month two following initiation, then fall. For incident hemodialysis patients in 2008, for example, all-cause mortality reached 442 deaths per 1,000 patient year at risk in month two, then fell to 213 in month 12. For the same population, cardiovascular mortality peaked at 166, and decreased to 85. Mortality due to infection peaks in months 23.

Figurer 5.4 Adjusted all-cause mortality rates in prevalent hemodialysis patients, by vintage (see page 386 for analytical methods. Period prevalent hemodialysis patients. Adj: age/gender/race/primary diagnosis; ref: dialysis patients, 2005.)

Through the 1980s, patients newer to dialysis had higher mortality rates than those on treatment for five years or more. This trend began to change in the early 1990s, and in 2009 the rate of 230 per 1,000 patient years in patients on therapy for five or more years was 16 percent higher than the rate of 198 in patients treated with hemodialysis for less than two years.

Table 5.a Adjusted survival probabilities, from day one, in the incident ESRD population (see page 386 for analytical methods. Incident ESRD patients. Adj: age/gender/race/primary diagnosis; ref: incident hemodialysis patients, 2005.)

While six- and twelve-month survival probabilities have remained stable since 1996 in the hemodialysis population, they have improved for both peritoneal dialysis and transplant patients. Five-year survival, in contrast, has improved across modalities from 0.29 to 0.34 for hemodialysis, from 0.29 to 0.4 for peritoneal dialysis, and from 0.65 to 0.73 for transplant.

In the 2004 incident cohort, survival over the first five years of therapy is consistently highest in the transplant population and among younger patients, African Americans (compared to whites), and patients with a primary diagnosis of glomerulonephritis (compared to patients with diabetes or hypertension).

Mortality in the General and ESRD Populations Top

Table 5.b Unadjusted & adjusted mortality rates in the ESRD & general Medicare populations, age 65 & older (per 1,000 patient years at risk) (see page 386 for analytical methods. January 1 point prevalent ESRD & general Medicare patients age 65 & older. Adj: age/gender/race/comorbidity; ref: ESRD patients, 2005.)

Since 1995, unadjusted mortality among prevalent ESRD patients has fallen 20.7 percent, to 254 deaths per 1,000 patient years. Mortality adjusted for age, gender, race, and comorbidity (defined in the previous year), however, has fallen nearly 26 percent, to 281. In the dialysis population, the unadjusted rate has fallen 13 percent, to 292, while the adjusted rate is now 21.3 percent lower than in 1996, reaching 304 in 2009.

Figure 5.5 Geographic variations in unadjusted mortality rates (per 1,000 patient years) in the ESRD & general Medicare populations, by HSA, 2009 (see page 386 for analytical methods. Prevalent ESRD & general Medicare (non-ESRD) patients, 2009; unadjusted.)

In the ESRD population, the highest unadjusted mortality rates show a distinct geographic pattern, spanning an area from Oklahoma and northward into areas of New England, and average 187 deaths per 1,000 patient years in the upper quintile. Deaths in general Medicare patients with cancer are highest in areas of the upper Midwest and the Ohio Valley, averaging 126 in the upper quintile, while rates for patients with cardiovascular disease are highest in the upper tier of the country and in Alaska, averaging 98.5 in the upper quintile. Mortality rates in patients with diabetes are highest in the upper Midwest and in portions of New England, Louisiana, and Alaska, averaging 72.7 in the upper quintile.

Figure 5.6 Adjusted all-cause mortality rates in the ESRD & general populations (age 65 & older), by age & gender, 2009 (see page 386 for analytical methods.January 1 point prevalent ESRD & general Medicare patients age 65 & older. Adj: age/gender/race/comorbidity; ref: 2009 ESRD patients.)

Figure 5.7 Adjusted all-cause mortality rates in the ESRD & general populations (age 65 & older), by race & gender, 2009 (see page 386 for analytical methods. January 1 point prevalent ESRD & general Medicare patients age 65 & older. Adj: age/gender/race/comorbidity; ref: 2009 ESRD patients.)

Adjusted rates of mortality in the prevalent ESRD population age 65 and older rise, not surprisingly, by age, are commonly greater in men than in women, and are 1.82.6 times greater for dialysis patients than for those with a transplant. In the transplant population, rates among patients age 6579 are lower than rates of mortality among patients with cancer in the general Medicare population.

By race, the contrast in mortality rates between dialysis and transplant patients is even more pronounced. Rates among white and African American women on dialysis, for example, are 3.3 and 2.4 times greater than those seen in their counterparts with a transplant. For African American transplant patients of both genders, mortality is most often lower than that among patients with cancer, diabetes, congestive heart failure, CVA/TIA, or acute myocardial infarction in the general population.