United States Renal Data System public health surveillance of chronic kidney disease and end-stage renal disease

Abstract

The United States Renal Data System (USRDS) began in 1989 through US Congressional authorization under National Institutes of Health competitive contracting. Its history includes five contract periods, two of 5 years, two of 7.5 years, and the fifth, awarded in February 2014, of 5 years. Over these 25 years, USRDS reporting transitioned from basic incidence and prevalence of end-stage renal disease (ESRD), modalities, and overall survival, as well as focused special studies on dialysis, in the first two contract periods to a comprehensive assessment of aspects of care that affect morbidity and mortality in the second two periods. Beginning in 1999, the Minneapolis Medical Research Foundation investigative team transformed the USRDS into a total care reporting system including disease severity, hospitalizations, pediatric populations, prescription drug use, and chronic kidney disease and the transition to ESRD. Areas of focus included issues related to death rates in the first 4 months of treatment, sudden cardiac death, ischemic and valvular heart disease, congestive heart failure, atrial fibrillation, and infectious complications (particularly related to dialysis catheters) in hemodialysis and peritoneal dialysis patients; the burden of congestive heart failure and infectious complications in pediatric dialysis and transplant populations; and morbidity and access to care. The team documented a plateau and decline in incidence rates, a 28% decline in death rates since 2001, and changes under the 2011 Prospective Payment System with expanded bundled payments for each dialysis treatment. The team reported on Bayesian methods to calculate mortality ratios, which reduce the challenges of traditional methods, and introduced objectives under the Health People 2010 and 2020 national health care goals for kidney disease.

The United States Renal Data System (USRDS), established in 1989, is the largest and most comprehensive national end-stage renal disease (ESRD) and chronic kidney disease surveillance system. It has operated for 25 years under competitive contracting with the National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Division of Kidney, Urologic, and Hematologic Diseases. In its first 10 years, the USRDS Coordinating Center developed standard techniques for calculating incidence and prevalence of treated ESRD, and reported on treatment modalities and basic mortality outcomes in the dialysis and transplant populations. The USRDS focus changed in the third and fourth contract periods toward assessment of cause-specific morbidity and mortality by organ system, thereby expanding the domain of care assessment beyond dialysis therapy delivery.

MORBIDITY AND MORTALITY

Death rates among dialysis patients have been falling 2–3% per year since 2001 (28% reduction), and in 2012 reached a level comparable to rates reported in 1982 (Figure 1), despite other data showing increased complexity of the population after 1983. Over time, causes of death shifted from acute myocardial infarction to heart failure and sudden death (Figure 2), in many ways paralleling changes in mortality in the general population. Acute myocardial infarction as a cause of death decreased in the dialysis, transplant, and general populations.

Figure 1.

Trends in prevalent dialysis death rates. pt-years, patient-years.

Figure 2.

Causes of death in incident dialysis patients, 2009–2011, first 180 days.⁵

Although few clinical trials in the dialysis population have shown any benefit of techniques such as increasing the amount of dialysis therapy delivered three times per week or use of high-flux versus lower-flux membranes, the recent Frequent Hemodialysis Network trial showed for the first time that dialysis delivered 6 days per week provided substantial benefit.¹ In the Adequacy of Dialysis Mexico trial, more therapy for peritoneal dialysis patients also did not show a benefit beyond a minimum weekly therapy.² These findings led the USRDS to conduct detailed assessments of the broad range of care delivery for heart failure, ischemic heart disease, and valvular heart disease and compare outcomes between prosthetic and porcine valves. Revascularization procedures using surgical interventions with internal mammary artery grafting, versus stent placement, appeared to be best for dialysis patients, as for the general population.

Medication use changed markedly from reports on the incident and prevalent populations in the 1993–1994 and 1996–1997 Dialysis Morbidity and Mortality Studies^{3, 4} to full assessment of prescription medications under the expanded Medicare prescription drug benefit, Medicare Part D.⁵ Use of statin drugs increased from less than 10% of dialysis patients in the 1990s to 50% from 2007 to 2011.³ Use of beta blockers, also less than 10% in the 1990s, increased to 65% overall and to 75% in dialysis patients with prior acute myocardial infarction.⁵ In dialysis patients with heart failure, use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers increased fourfold form 50 to 60% in the current era. Along with these changes, use of dialysis catheters also declined under the Centers for Medicare and Medicaid Fistula First program. These changes were associated with substantial decreases in death rates in the prevalent population since 2001 (Figure 1).⁶

Infectious complications presented serious problems (Figure 3); highlighting these in detail over many years helped bring back the Centers for Disease Prevention and Control's dialysis unit infection control surveys, which had stopped in 2002. Additional organ-specific assessments centered on infectious complications related to use of dialysis catheters and their event rates. Placement rates for catheters, fistulas, and grafts were tracked through physician service claims. Catheter and graft placements decreased markedly through 2011 (Figure 4).

Figure 3.

Change in adjusted all-cause and cause-specific hospitalization rates, by modality. CV, cardiovascular; ESRD, end-stage renal disease.⁵

Figure 4.

Catheter, fistula, and graft insertions, 1991–2011.¹⁶

Prior studies on death risk after infectious complication⁷ contributed to these findings. Infectious hospitalizations were not reduced to the extent that mortality was. Rates of infectious hospitalizations increased in hemodialysis patients during the time of highest dialysis catheter use, but failed to decline once catheter use declined. This is a source of major concern. Infectious hospitalization rates for peritoneal dialysis patients did not change (Figure 5). This lack of progress needs greater attention to reduce infectious complications.

Figure 5.

Adjusted rates of hospital admissions, by modality and diagnostic code type: infection.⁵

Each Annual Data Report presented data on morbidity and treatment, including the changes in anemia treatment due to clinical trials showing adverse cardiovascular events when hemoglobin levels were targeted to above 12 g/dl (Figure 6).

Figure 6.

Mean monthly hemoglobin and mean epoetin alfa (EPO) dose per week: hemodialysis patients.⁵

GRAPHIC LAYOUT OF THE ANNUAL DATA REPORT

These findings were shown in a graphic format that the USRDS developed to advance the presentation of data describing the ESRD population and public health surveillance to the public, Congressional committees, the National Institutes of Health, the Centers for Medicare and Medicaid Services, the White House, and nephrologists and dialysis providers.

The USRDS Coordinating Center developed the graphic full-color layout in 2000 under the third contract, awarded to the University of Minnesota and Minneapolis Medical Research Foundation investigators. The concept was modeled after the Dartmouth Atlas of Health Care,⁸ the Centers for Disease Control and Prevention Atlas of Mortality,⁹ and the National Cancer Institute's Atlas of Cancer Mortality.¹⁰ The atlas of ESRD was developed in a spread format much like a poster presentation with targeted areas such as incidence by specific diseases or types of hospitalization. The design employed a thematic metaphor from the art and literary world to evoke the human elements of disease, hope, and philosophical aspects of the human spirit. The first atlas developed the technique of mapping data on a national level to demonstrate the wide geographic variation in care and outcomes.¹¹ The most recent incidence rate map is shown in Figure 7, demonstrating clear patterns across the country.

Figure 7.

Geographic variation in adjusted incident rates of end-stage renal disease (ESRD) per million population, 2011, by Health Service Area (HSA).¹⁵

Geographic display brought a new dimension to the understanding of disease location and of areas to target, such as the Ohio River basin and the Mississippi River area, in which ESRD incidence rates are high even after adjustment for age, sex, race, cause of kidney failure, and Hispanic ethnicity. Past high rates of poverty and air and water pollution in these regions may partially explain the concentration. Regardless of the causes, focused attention to these areas with early detection programs for kidney disease among those with diabetes and hypertension may be needed.^{12, 13, 14}

Additional graphic formats were developed to show the disease burden in the Medicare population and the associated expenditures to policy makers in Congress and to the public (Figure 8).¹⁵

Figure 8.

Distribution of general (fee-for-service) Medicare patients and costs for chronic kidney disease (CKD),⁵ congestive heart failure (CHF), diabetes (DM), and end-stage renal disease (ESRD), 2011.

The most recent reports incorporated colors and fonts that were typical of the era being presented through thematic metaphor, such as the 2009 focus on the science, art, and humanity of da Vinci (Figure 9) or the 2013 focus on navigation as a metaphor for understanding how disease unfolds and is treated in the kidney disease population (Figure 10). These presentations combined the arts and the depth of the human experience with detailed data on kidney disease and how it plays out in the population under treatment.

Figure 9.

United States Renal Data System Annual Data Report cover image, 2009.¹⁷

Figure 10.

United States Renal Data System Annual Data Report cover image, 2013.⁵

SUMMARY

The USRDS has evolved over the last 25 years to advance the reporting of morbidity and mortality in the kidney disease population and to point out areas where care may be improved. The fifth contract is under the direction of a new team of investigators from the University of Michigan, who took over the 5-year contract in February 2014. The USRDS under the Minneapolis Medical Research Foundation team over the prior fourteen and a half years advanced the reporting to cover the full spectrum of disease present in the kidney disease population and documented marked improvements in care and outcomes, which have changed the lives of many patients. The reduction in death rates is an important milestone for patients and providers. The USRDS has advanced the public understanding of this vulnerable population.

AJC has provided consultation to Amgen, Relypsa, NxStage and Bayer, received lecture fees from Hospira, and grant support from Amgen and National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Disease. The remaining authors declared no competing interests.