CKD Prevalence Stable, but Higher in Older Adults, Report Says

The US prevalence of end stage renal disease (ESRD) continues to increase, but the rate of new cases may be leveling off. Meanwhile, mortality among patients on dialysis or with a kidney transplant continues to decline. Those are among the key findings of the recently released 2014 US Renal Data System Annual Data Report.

The report also finds that the prevalence of chronic kidney disease (CKD) has remained relatively stable, but continues to increase in the Medicare population. The 2014 report on the “state of kidney disease” in the United States was released by the US Renal Data System (USRDS) Coordinating Center, based at the University of Michigan in partnership with Arbor Research Collaborative for Health. Rajiv Saran, MD, is director of the USRDS Coordinating Center and associate director of the University of Michigan’s Epidemiology and Cost Center.

CKD remains stable, but higher in older adults

The USRDS is a national data system that collects, analyzes, and distributes information on kidney disease trends. Based on data from the National Health and Nutrition Examination Survey (NHANES), the report suggests an overall CKD prevalence of 13.6 percent.

Saran noted that while CKD prevalence was “certainly stable” during the periods 1999–2004 and 2007–2012, it was about 30 percent higher than in the 1988–1994 NHANES cohort.

“It’s 13.6%, which is a pretty high prevalence,” he said in an interview. “Let’s say conservatively even if it’s 12% … that is still higher than the prevalence of diabetes in the general population. That fact is not well-recognized.”

Medicare data suggest an ongoing increase in CKD among Americans aged 65 years or older. In 2012, the most recent year for which data were available, the prevalence of recognized CKD in the Medicare population was 10.4 percent.

That is consistent with recent evidence suggesting that age may be the single strongest risk factor for CKD. “When we look at the risk factors for CKD, we look at diabetes, we look at hypertension, we look at BMI/obesity, the one thing that sticks out and has the highest odds ratio in terms of the strength of that relationship is age,” Saran said. The growing body of evidence on CKD and age has “practical implications for screening, prevention, risk stratification, and treatment,” according to the USRDS report. “Another point I’d like to make is, the prevalence of urine testing leaves a lot to be desired,” Saran added. “Even in the Medicare data, only about 40 percent of diabetics are receiving the urine test. So it tells you that there’s still lots of room for improvement, even among those that have clear-cut, known risk factors.”

Although care patterns are difficult to assess, data suggest that while 91 percent of Medicare patients with CKD see a primary care physician and 62 percent see a cardiologist within a year of diagnosis, only 31 percent see a nephrologist. For patients with stage 3 to 5 CKD, the rate of nephrologist care increases to 55 percent.

All-cause mortality continues to decline among Medicare patients with CKD. But these patients remain at much higher risk of death than those without CKD, a risk that is “multiplied” for CKD patients with cardiovascular disease or diabetes. Cardiovascular morbidity remains very high among Medicare patients with CKD—about 70 percent, compared to 35 percent in patients without CKD.

The report also highlights the ongoing, age-related increase in hospitalizations for acute kidney injury (AKI)—a diagnosis associated with declines in both renal and functional status. Less than 20 percent of patients see a nephrologist within one year of AKI hospitalization, even though more than 90 percent undergo follow-up serum creatinine testing.

Continued declines in ESRD incidence

For the third consecutive year, new cases of ESRD declined, with 114,813 new cases in 2012. In that year, the adjusted incidence rate was 353 per million per year—the lowest since 1997.

The population prevalence of ESRD continued to increase, although there were encouraging signs that the rate of growth may be slowing. “[T]he percentage increase in 2011 and 2012 was the lowest recorded over the last three decades,” according to the USRDS report. At the end of 2012, there were a total of 636,905 dialysis and transplant patients receiving treatment for ESRD.

Analysis of Healthy People 2020 goals showed that about one-third of patients see a nephrologist at least one year before the start of renal replacement therapy. Nearly all mortality targets have been met, including promising trends in overall and cardiovascular mortality among dialysis and transplant patients.

Clinical indicators of hemodialysis care are also improving—nearly 80 percent of patients now have an ateriovenous fistula or graft during the first year. Mean hemoglobin levels have declined, reflecting changes in erythropoietin use. Although mortality rates continue to decline, they are up to eight times higher than for matched Medicare patients without ESRD.

Transplantation rates have decreased, while the percentage of dialysis patients wait-listed continues to increase. In 2012, nearly 29,000 patients were added to transplant waiting lists. For those who do receive a transplant, one-year survival rates are excellent: 96 percent for deceased donor transplant recipients, and 99 percent for living donor transplant recipients.

The incidence of pediatric ESRD remained stable, with 1161 cases in 2012. At the end of that year, nearly three-fourths of children with ESRD had a functioning kidney transplant.

The slow but steady decline in ESRD is encouraging news, Saran said. ”But the question is what’s causing [it] and can we accelerate that?” Noting that more in-depth studies are planned, he speculatesd on some possible reasons.

Increased recognition of CKD. “Certainly by claims, we notice that there is greater recognition of CKD in the health systems, by providers,” Saran said. He said near-universal eGFR reporting has been an important contributor to the increased recognition of CKD. “There’s better care of CKD, and there’s better detection and care of upstream CKD risk factors such as diabetes and hypertension,” Saran said. “So there may be a slower progression of CKD overall. Over time, perhaps, CKD in general is progressing slower, so people are not reaching ESRD as quickly as they used to in different settings.”

Changes in risk factors. Saran also noted improvement in risk factor profiles nationwide, including stabilization of obesity rates and reduction in cardiovascular mortality.

Starting dialysis later. “In recent years there has been some evidence that earlier start to dialysis is not that advantageous, as some physicians had long believed,” said Saran. So it could be that nephrologists may be starting dialysis “a little bit later.” If so, “that could somewhat artificially lower the incidence of ESRD.”

What can nephrologists do to keep that trend going? “Raising awareness, raising the ante for upstream CKD, earlier stages of CKD, and improving the recognition, awareness, management, continuing to harp on the importance of recognizing CKD earlier and earlier . . . . should be the mantra to be followed communitywide,” Saran said. “The other thing is lifestyle factors. I’m going really upstream now. As a community, nephrologists have to be more and more in favor of practicing lifestyle medicine. They need to be part of that. They can’t take care of all the CKD that there is, so I think they have to advise, guide, and work with their primary and other colleagues.