Women typically live 5 years longer than men, and in most countries, that survival advantage extends beyond age 65. Little evidence exists regarding whether this survival advantage is present among women with advanced chronic disease, such as stage 5 chronic kidney disease (CKD) or kidney failure.
Christian Chan, PhD, and colleagues conducted a population-based cohort study designed to examine differences by sex in mortality and treatment with kidney replacement therapy, including dialysis and transplantation, among adults aged 18 years and older with incident stage 5 CKD. “The study highlights the urgent need to better understand and address inequities in kidney failure management,” co-author Ping Liu, PhD, told Nephrology Times.
The primary outcome of interest was all-cause death. Secondary outcomes included 5-year probability of receiving maintenance dialysis and probability of kidney transplant. The researchers used multistate models, stratified by age and the presence of diabetes or cardiovascular disease, to estimate the 5-year probabilities for the outcomes for patients with incident stage 5 CKD.
Using linked administrative, laboratory, and provincial kidney program data from Alberta, Canada, the researchers identified 7,506 individuals with newly documented stage 5 CKD. Of those, 54.9% (n=4,121) were male (median age, 70 years), and 45.1% (n=3,385) were female (median age, 74 years). The groups were similar in baseline estimated glomerular filtration rate and qualifying period by sex. Female participants met criteria for stage 5 CKD at older ages than male participants (age at first documentation of stage 5 CKD: 74 years vs 70 years, respectively).
Follow-up continued for a median of 7.9 years. During the follow-up period, female patients had greater excess mortality (compared with the general population) than male patients, particularly at younger ages. Standard mortality ratios among those 20 to 44 years of age were 47.5 for females and 12.0 for males. The gap narrowed with age; standardized mortality rates for women 65 to 74 years of age were 14.1 compared with 8.5 for male patients. Patterns of female to male mortality rates were consistent: the female survival advantage in the general population was diminished in stage 5 CKD and reversed in younger ages.
Female patients younger than 65 years were substantially less likely to receive a kidney transplant; females aged 65 or older were less likely to receive dialysis or a transplant.
“Our study reveals important sex-based differences in survival among adults with newly developed stage 5 chronic kidney disease. Notably, the typical female survival advantage was absent or even reversed after development of stage 5 CKD,” Dr. Liu explained.
“These findings suggest that inequities in access to kidney transplantation and differences in decision-making between dialysis and conservative kidney management may contribute to poorer survival among female individuals, even within a universal healthcare system,” she continued. The authors concluded that the results highlight a need for more research regarding the biological, structural, and societal factors influencing sex differences in treatment decision and survival.