Association of Young versus Elderly Maintenance Hemodialysis Patients with Mortality: A Multicenter Retrospective Cohort Study in China

Background End-stage renal disease patients with maintenance hemodialysis have high-mortality risk. The association of different age of hemodialysis patients with mortality remains uncertain in China. This study aimed to assess the survival outcomes and risk factors affecting mortality between young and elderly patients with maintenance hemodialysis.Methods The multicenter retrospective cohort study enrolled adult patients undergoing maintenance hemodialysis from 24 hemodialysis centers in China between January 1, 2008, and September 30, 2015. The patients were assigned to young and elderly group according to age on the initiation of the hemodialysis. The primary outcome was all-cause mortality of patients. Survival outcomes of patients was performed using a Kaplan-Meier survival analysis. Multivariate cox proportional hazards regression models were implemented to identify risk factors affecting all-cause mortality of patients with maintenance hemodialysis.Results A total of enrolled 1601 patients undergoing maintenance hemodialysis, including 642 young patients and 959 elderly patients. The mean follow-up duration was 48.17 ± 25.59 months, the all-cause mortality was 64 (9.97%) in young group and 255 (26.59%) in elderly group, the hazard ratio [HR] of elderly patients relative to young patients, 1.699 (95% confidence interval [95% CI], 1.482 to 1.949, P＜0.001). The Kaplan-Meier survival curve showed that overall cumulative survival was lower in elderly group than young group (Log Rank tests = 63.31, P＜ 0.001). Multivariate cox regression analysis revealed that the cardiovascular disease (HR, 1.544; 95% CI, 1.103 to 2.161; P = 0.011), cerebrovascular disease (HR, 2.158; 95% CI, 1.309 to 3.557; P = 0.003), lower serum albumin (HR, 1.404; 95% CI, 1.001 to 1.968; P = 0.049), Charlson comorbidity index (CCI) scores with 4-5 (HR, 4.910; 95% CI, 2.327 to 10.357; P＜ 0.001), CCI scores with ≥6 (HR, 9.596; 95% CI, 4.807 to 19.158; P＜ 0.001) were the risk factors associated all-cause mortality of patients.Conclusions The elderly patients undergoing maintenance hemodialysis showed lower survival and higher mortality than young patients in China. Cardiovascular disease, cerebrovascular disease, serum albumin, CCI scores were the risk factors for all-cause mortality of young and elderly patients with maintenance hemodialysis.