Kidney Failure Survival Improving in United States

Veronica Hackethal, MD

December 18, 2017

Mortality among people with kidney failure in the United States decreased significantly between 1995 and 2013, according to a study published online December 14 in the Clinical Journal of the American Society of Nephrology.

The study is the first to evaluate the risk for death related to kidney failure across all ages, and found that it decreased regardless of age, as well as in people receiving dialysis and those with a kidney transplant.

"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. This is important given the huge investment of resources in caring for these patients; we have shown that these investments have made a difference," first author Bethany Foster, MD, from Montreal Children's Hospital, Quebec, Canada, said in a news release.

However, kidney failure still carries a very high risk for death, and the authors stress continued efforts to improve outcomes for these patients.

"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, Dr Foster added. "Everyone needs to think about organ donation and sign their organ donor cards."

Although other studies have suggested that death from kidney failure has decreased over time, mortality in the general population has also decreased. That raises the question of whether improved survival in kidney failure merely reflects the overall decrease in mortality in the general population. To tease out the issue, the researchers looked at changes in risk for early death among Americans with kidney failure over and above mortality risk in the general population.

The study included 1,938,148 children and adults who started dialysis or received a kidney transplant between 1995 and 2013. Data came from the US Renal Data System, which includes almost all people diagnosed with kidney failure in the United States. Using mortality rates from the Centers for Disease Control and Prevention, the investigators calculated change in excess risk for death related to kidney failure during periods of 5 years.

Change in the risk for early death from kidney failure varied with age, but all ages experienced significantly improved mortality. For each 5-year increment, the risk for death from kidney failure decreased by 27% among those aged 0 to 14 years (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.69 - 0.77), and by 12% among those aged 65 years or older (HR, 0.88; 95% CI, 0.88 - 0.88).

Death related to kidney failure also declined significantly in patients receiving dialysis and in those with a functioning kidney transplant (both P < .001). The youngest patients with functioning kidney transplants showed the largest relative improvements in mortality caused by kidney failure. The oldest patients showed the largest absolute decreases in kidney failure-related mortality.

The only age group that did not show significant improvements in relative survival were patients aged 15 to 24 years between 1995 and 2006 (relative excess risk, 0.95; 95% CI, 0.88 - 1.02), regardless of whether they were receiving dialysis or had a functioning transplant.

These results were expected, according to Dr Foster, because this age group carries increased risk for poor health outcomes. Adolescents and young adults sometimes have difficulty adhering to treatment, and transitioning from pediatric to adult providers can negatively affect continuity of care.

"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," Dr Foster said in a press release. "This may be because healthcare professionals became more sensitized to these problems in the early 2000s and have changed the way they care for these young people."

In a linked editorial, Kirsten Johansen, MD, from San Francisco VA Medical Center in California, writes that the study raises more questions than it answers, and should serve to start the conversation rather than serving as the final say about improving mortality in kidney failure.

Although the study cannot determine why mortality rates in kidney failure have improved, both Dr Johansen and Dr Foster speculate the combined effect of multiple care advances may have contributed, including improvements in dialysis, new medications, increased access to kidney transplant, and uptake of clinical practice guidelines.

However, Dr Foster advises restrained optimism. Mortality in the United States as a whole showed a slight uptick in 2016, and data from 2013 to 2015 suggest that mortality in people with kidney failure may have stabilized, or even slightly increased.

"I do not recommend complacency or all-out self-congratulation because if we do not fully understand why the improvement occurred, it is not clear that we will be able to continue to improve or to prevent future increases in mortality," she concluded.

"The analyses by Foster et al. provide a framework for future studies that are needed to examine which changes in practice patterns and clinical care may be important contributors to changes in mortality in the [end stage renal disease] population."

The authors have disclosed no relevant financial relationships.

CJASN. Published online December 14, 2017. Article abstract

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