Greater hemodialysis exposure (“quotidian hemodialysis”) has different mortality associations by patient age group

Abstract

Abstract Background Worldwide, most people requiring kidney replacement therapy receive hemodialysis (HD) three times per week. Greater HD time and/or frequency may improve survival, but implementation requires understanding potential benefits across the range of patients. Methods Using data from the Australia and New Zealand Dialysis and Transplant Registry we assessed whether quotidian HD (defined as > 3 sessions per week and/or > 5 hours per session) was associated with reduced mortality in adult patients. The primary outcome all-cause mortality was analyzed by a time-varying Cox proportional hazards model with quotidian HD the exposure of interest. Results Of 24 138 people who received HD between 2011 and 2019, 2 632 (10.9%) received Quotidian HD at some stage. These patients were younger, more likely male and more likely to receive HD at home. Overall, quotidian versus standard HD was associated with decreased risk for all-cause mortality (crude hazard ratio (HR) 0.50, 95% confidence interval 0.45–0.56) but an interaction between quotidian HD and age was identified (P = 0.005). Stratified by age groups and splitting follow-up time where proportional hazards were violated, the corresponding HR compared to standard HD was 2.43 (1.56–3.79) for people aged > 75 years in the first year of quotidian HD, 1.52 (0.89- 2.58) for 1–3 years, and 0.95 (0.51–1.78) for ≥ 3 years. There was no significant survival advantage in younger people. Conclusions Although Quotidian HD conferred survival benefit in crude analyses, people aged ≥ 75 years had greater mortality with Quotidian HD than Standard HD. Mortality benefit in younger people was attenuated when adjusted for known confounders.