Sex Differences in Mortality and Receipt of Kidney Replacement Therapy Among Adults With Stage 5 Chronic Kidney Disease.

Importance: Female individuals typically outlive male individuals in the general population. Whether this survival advantage persists among adults with stage 5 chronic kidney disease (CKD) is unknown. Objective: To examine sex differences in mortality and treatment with kidney replacement therapy (KRT; including dialysis and transplant) among adults with incident stage 5 CKD. Design, Setting, and Participants: This population-based cohort study used linked administrative and kidney care program data from Alberta, Canada. Adults 18 years and older with incident non-KRT-dependent stage 5 CKD were identified between April 2005 and March 2019 and observed from study entry until death, out-migration, or March 2021. Data were analyzed from January to August 2025. Main Outcomes and Measures: Sex-specific, age-stratified standardized mortality ratios were calculated using general population mortality data. Five-year probabilities of all-cause death, receipt of maintenance dialysis, and kidney transplant were estimated in incident stage 5 CKD cases using multistate models, stratified by age and presence of diabetes or cardiovascular disease. Results: Among 7506 cohort members, 4121 (54.9%) were male (median [IQR] age, 70 [58-80] years), and 3385 (45.1%) were female (median [IQR] age, 74 [61-83] years). The median (IQR) follow-up was 7.9 (4.7-11.5) years. Compared with the general population, female individuals experienced greater excess mortality than male individuals, particularly at younger ages (eg, among adults younger than 55 years: standardized mortality ratio, 40.9 [95% CI, 34.6-47.3] in female individuals vs 15.9 [95% CI, 13.5-18.2] in male individuals); this difference narrowed with increasing age. Within the stage 5 CKD cohort, 5-year all-cause mortality risks were higher in younger female individuals than male individuals (younger than 55 years: 20.7% vs 14.6%) and similar between sexes at older ages. Irrespective of comorbidity, female individuals younger than 65 years were substantially less likely to receive a kidney transplant, and female individuals 65 years and older were less likely to receive dialysis or a transplant. Conclusions and Relevance: In this cohort study using data from a universal health care system, across all ages, the female survival advantage observed in the general population was absent or even reversed after developing stage 5 CKD. Fewer female individuals transitioned to KRT treatment, independent of their comorbidities. Younger female individuals experienced the greatest survival disadvantage and were less likely to receive a transplant. These findings suggest that differences in treatment decision-making or inequities in access to KRT may contribute to poorer outcomes in female individuals, especially at younger ages. Further investigations are warranted to understand the potential underlying structural, social, and biological mechanisms.