Dialysis outcomes and analysis of practice patterns suggests the dialysis schedule affects day-of-week mortality

The risk of death for hemodialysis patients is thought to be highest on the days following the longest interval without dialysis (usually Mondays and Tuesdays); however, existing results are inconclusive. To clarify this we analyzed Dialysis Outcomes and Practice Patterns Study (DOPPS) data of 22,163 hemodialysis patients from the United States, Europe and Japan. Our study focused on the association between dialysis schedule and day-of-week of all-cause, cardiovascular and non-cardiovascular mortality with day-of-week coding as a time-dependent covariate. The models were adjusted for dialysis schedule, age, country, DOPPS Phase I or II, and other demographic and clinical covariates comparing mortality on each day to the 7-day average. Patients on a Monday-Wednesday-Friday (MFW) schedule had elevated all-cause mortality on Monday, and those on a Tuesday-Thursday-Saturday (TTS) schedule increased risk of mortality on Tuesday in all 3 regions. The association between day-of-week mortality and schedule was generally stronger for cardiovascular than non-cardiovascular mortality, and most pronounced in the United States. Unexpectedly, Japanese patients on a MWF schedule had a higher risk of non-cardiovascular mortality on Fridays, and European patients on a TTS schedule experienced an elevated cardiovascular mortality on Saturdays. Thus, future studies are needed to evaluate the influence of practice patterns on schedule-specific mortality and factors that could modulate this effect.