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 the week of all-cause, cardiovascular, and noncardiovascular mortality with day-of-week coded 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, and compared mortality on each day to the 7-day average. Patients on a Monday-Wednesday-Friday (MWF) schedule had elevated all-cause mortality on Mondays, and those on a Tuesday-Thursday-Saturday (TTS) schedule had increased risk of mortality on Tuesdays in all three regions. The association between day-of-week mortality and schedule was generally stronger for cardiovascular than noncardiovascular mortality, and was most pronounced in the United States. Unexpectedly, Japanese patients on a MWF schedule had a higher risk of noncardiovascular 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.