Sex and Cause-Specific Mortality among US Adults Receiving Maintenance Dialysis: A National U.S. Cohort Study 2000-2021.

Abstract

Background: We examined sex differences in cause-specific mortality among men and women receiving maintenance dialysis and examined potential effect modification by age and race.

Methods: We identified all adults aged ≥ 18 years initiating dialysis between 2000 and 2020 from the United States Renal Data System (n=2.16 million; 43.3% women). Cause-specific mortality (i.e., cardiovascular (CVD), withdrawal, infection, cancer) was defined from the Centers for Medicare and Medicaid Death Notification Form. All individuals were followed from dialysis start date until death date, transplant, 10-years, or end of follow-up (December 31, 2021), whichever occurred first. Multivariable Cox proportional hazards models assessed the association between sex and 10-year cause-specific mortality, adjusting for demographic, clinical, and socioeconomic factors overall and stratified by age and race.

Results: Overall, 832,259 men (67.9%) and 658,043 women (70.4%) died receiving maintenance dialysis with median survival times of 2.69 (IQR,1.17-5.19) and 2.72 (IQR, 1.16-5.21) years, respectively. CVD was the leading cause of death (38.6% women; 40.2% men), followed by withdrawal (11.1% women; 9.6% men) and infections (9.8% women; 8.6% men). Overall, women had a 9% (adjusted Hazard Ratio: 1.09 [95%CI 1.08-1.11]) and 15% (1.15 [1.14-1.17]) higher likelihood of infection, and withdrawal -related mortality compared with men, respectively. Conversely, women had a 7% (0.93 [0.92-0.94]) and 10% (0.90 [0.87-0.92]) lower likelihood of CVD and cancer-related mortality, respectively, compared with men. By age, younger women (vs. men) aged 18-44 years had higher likelihood of excess mortality across all specific causes (including a 40% increased risk of withdrawal compared to men of the same age), while older women (vs. men) aged >75 years had a lower likelihood. By race, non-Hispanic Black women (vs. men) had higher mortality across all specific causes, but for all other races, sex differences were similar to the overall population.

Conclusions: A sex-specific approach that incorporates intersectionality of both age and race in the management of complications among dialysis patients may be recommended to mitigate excess mortality risks.