Sex Disparity in Cause-Specific and All-Cause Mortality Among Incident Dialysis Patients

Abstract

RATIONALE & OBJECTIVE: Early mortality rates of female patients receiving dialysis have been, at times, observed to be higher than rates among male patients. The differences in cause-specific mortality between male and female incident dialysis patients with kidney failure are not well understood and were the focus of this study.STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Incident patients who had initiated dialysis in Australia and New Zealand in 1998-2018. EXPOSURE: Sex. OUTCOMES: Cause-specific and all-cause mortality while receiving dialysis, censored for kidney transplant. ANALYTICAL APPROACH: Adjusted cause-specific proportional hazards models, focusing on the first 5 years following initiation of dialysis. RESULTS: Among 53,414 patients (20,876 [39%] female) followed for a median period of 2.8 (IQR, 1.3-5.2) years, 27,137 (51%) died, with the predominant cause of death attributed to cardiovascular disease (18%), followed by dialysis withdrawal (16%). Compared with male patients, female patients were more likely to die in the first 5 years after dialysis initiation (adjusted hazard ratio [AHR], 1.08 [95% CI, 1.05-1.11]). Even though female patients experienced a lower risk of cardiovascular disease-related mortality (AHR, 0.93 [95% CI, 0.89-0.98]) than male patients, they experienced a greater risk of infection-related (AHR, 1.20 [95% CI, 1.10-1.32]) and dialysis withdrawal-related (AHR, 1.19 [95% CI, 1.13-1.26]) mortality. LIMITATIONS: Possibility of residual and unmeasured confounders. CONCLUSIONS: Compared with male patients, female patients had a higher risk of all-cause mortality in the first 5 years after dialysis initiation, a difference driven by higher rates of mortality from infections and dialysis withdrawals. These findings may inform the study of sex differences in mortality in other geographic settings.