Individuals with end stage renal disease (ESRD) have a very high risk of premature death, but a new analysis indicates that their excess risk of all-cause mortality—over and above the risk in the general population—decreased significantly between 1995 and 2013 in the United States. The findings, which come from a study appearing in an upcoming issue of the Clinical Journal of the American Society of Nephrology, are encouraging and suggest that efforts to improve care for patients with kidney failure have resulted in improved survival.
Although registry data indicate that survival of patients with ESRD has improved in recent decades, general population survival has also benefited from public health efforts (such as smoking prevention) and medical advances (such as improved cardiovascular interventions).
To see if the longer life expectancy observed in ESRD registries simply reflects improved general population survival, a team led by Bethany Foster, MD, MSCE, of Montreal Children’s Hospital and the Research Institute of the McGill University Health Centre, and Benjamin Laskin, MD, of The Children’s Hospital of Philadelphia, applied time-dependent relative survival modeling to examine changes over time in the excess risk of death in persons with ESRD. Excess risk was defined as the mortality risk in the ESRD population minus the expected risk in the age-, sex-, race-, and calendar-year matched general population.
In the analysis of information from the United States Renal Data System (USRDS) on almost 2 million children and adults diagnosed with ESRD from 1995 to 2013, the change over any 5-year interval in the excess risk of ESRD-related death varied by age, with decreases from 12% for ≥65 year olds to 27% for 0 to 14 year olds. Decreases in excess mortality over time were observed for all ages and both during treatment with dialysis and during time with a functioning kidney transplant, with the largest relative improvements observed for the youngest individuals with a functioning kidney transplant. Absolute decreases in excess ESRD-related mortality were greatest for the oldest patients.
“We showed that all age groups have had significant improvements in mortality risk over the past 22 years. Some of the improvements were due to improved access to kidney transplantation and to longer survival of kidney transplants, but there were also improvements that can only be attributed to improvements in the care provided to people treated with dialysis and to those with kidney transplants,” said Foster. “This is important given the huge investment of resources in caring for these patients; we have shown that these investments have made a difference.”
Foster noted that the investigators expected to find decreased mortality rates for all age groups except those in late adolescence and early young adulthood. “We expected this for several reasons. First, this age group often has difficulty adhering to the recommended treatments. Therefore, it was possible that they would not experience the same benefits from therapies as other age groups,” she said. “Second, there may be a breakdown in the continuity of care when young people are transferred from a pediatric health care facility to an adult care facility that contribute to poorer outcomes. We discovered that young people in this age group had no improvements in mortality risk between 1995 and 2006 (unlike all other age groups), but started to have significant improvements after 2006. This may be because health care professionals became more sensitized to these problems in the early 2000s and have changed the way they care for these young people.”
Although individuals with ESRD still have much higher risks of early death than people in the general population, it appears that the gap is gradually closing. “Things are getting better for all age groups. But one of the best ways to improve health in people with kidney failure is for them to get a kidney transplant, and the limited supply of suitable organs is still a major impediment to more progress in outcomes for people with kidney failure, Foster said. “Everyone needs to think about organ donation and sign their organ donor cards.”
In an accompanying editorial, Kirsten Johansen, MD, of the University of California, San Francisco, noted that the study raises more questions than it answers, and it should provide a framework for future studies that are needed to examine which changes in practice patterns and clinical care may contribute to changes in mortality rates in patients with ESRD. “Analyses of differences in outcomes over time and across geographic regions are powerful tools we can apply to gain an understanding of the impact of changes or variations in practices on survival,” she wrote. She also stressed the need to fully understand why the improvement occurred so that improvements can continue and future increases in mortality can be prevented. Newer data from 2013 to 2015 showed that the mortality rate among patients with ESRD stabilized or even increased, and the mortality rate in the United States as a whole has demonstrated a similar uptick.
According to the most recent data by the USRDS, adjusted mortality rates in 2015 for ESRD, dialysis, and transplant patients were 136, 166, and 29, per 1000 patient-years. Five-year survival rose from 36% in 2002 to 42% in 2010 among hemodialysis patients, from 42% to 52% among peritoneal dialysis patients, from 69% to 76% among deceased donor transplant patients, and from 77% to 88% among living donor transplant patients. Johansen noted that despite increases in life expectancy in recent years, patients with ESRD have lower 5-year survival rates than patients with cancer.
Study co-authors include Mark Mitsnefes, MD, Xun Zhang, PhD, and Mourad Dahhou, MSc.
The article, entitled “Changes in Excess Mortality from End-Stage Renal Disease in the United States from 1995-2013,” and the editorial, entitled “Life Expectancy Gains for Patients with ESRD,” are online at http://cjasn.asnjournals.org/.
