UC research finds slightly lower mortality risk in female dialysis patients

Women have a two percent lower risk of dying at one year after dialysis initiation than men, according to new research from the University of Cincinnati (UC). The study, “Temporal Trends in Incident Mortality in Dialysis Patients: Focus on Sex and Racial Disparities,” published online in American Journal of Nephrology, finds that one-year mortality rates among patients with end-stage kidney disease (ESKD) have decreased steadily during a recent 10-year period for both men and women. The study also showed that white patients with ESKD have higher mortality as compared to blacks, Hispanics, Asians and Native Americans.. 

Each year in the United States, over a half million patients receive dialysis, and approximately 100,000 new patients start dialysis. Dialysis patients experience high morbidity and average mortality of 20 percent at one year.

The study, using data from the United States Renal Data System (USRDS) with linked data from Medicare parts A and P, examines a national cohort of 944,650 adult patients who initiated dialysis. It finds that, from 2005 to 2014, mortality rates decreased across both sexes and all races.

“Given that women and racial minorities constitute substantial portions of the incident and prevalent ESKD population in the United States, our study focused on the association of sex and race on clinical outcomes in patients with ESKD,” says Silvi Shah, MD, assistant professor, Division of Nephrology, Kidney CARE Program at the UC College of Medicine, and lead author of the study. “This research is unique in that it takes into account pre-dialysis health status, as well as examining trends in mortality for these subgroups.”

The study shows that while women experienced a survival advantage over men in 2005, by 2014, it was reversed to a survival advantage for men.

“While women survive longer than men in the general population, this survival advantage is lost once women start dialysis,” says Shah. “This raises the question of why women don’t sustain this survival advantage once they initiate dialysis. While the reasons are not clear, we speculate several factors, including the pre-dialysis health status and post-dialysis care, may contribute to the narrowing of this gap in women.”

The study also shows that white patients with ESKD have higher mortality rates compared to blacks, Hispanics, Asians and Native Americans. Additionally, white patients with incident ESRD experienced the lowest reduction in both unadjusted (23 percent) and adjusted (16 percent) one-year mortality rates from 2005 to 2014.

“Dialysis care, including one-year mortality, continues to be under a microscope for quality and payment for performance by Medicare,” says Charuhas Thakar, MD, professor and director, Division of Nephrology Kidney CARE Program, and one of the study co-authors. “It is important that we leverage the advantage of large linked data sets like the USRDS to learn about how pre-dialysis health status and disparities continue to impact post-dialysis care.”

“When a patient initiates dialysis, we seldom recognize the impact of sex and race on long term outcomes,” Shah says. “Our results emphasize the need for sex and race-specific treatment strategies that could require multi-level changes to chronic kidney disease care. Since dialysis initiation is a life-changing event, this transition of care may need to be customized based on sex and race.”

The other co-authors in the study include Anthony Leonard, PhD, research associate professor in the Department of Family and Community Medicine, Karthikeyan Meganathan and Annette Christianson, research associates in the Department of Biomedical Informatics all in the UC College of Medicine.