SP652
DIALYSIS SCHEDULE AND DAY-OF-WEEK MORTALITY IN A NATIONAL DIALYSIS COHORT

INTRODUCTION AND AIMS: In the United States (US), maintenance hemodialysis is typically prescribed as thrice-weekly treatments with two one-day and one two-day intervals between sessions. Given their impaired ability to excrete electrolytes, fluid, and uremic solutes, hemodialysis patients may have limited reserve to tolerate deviations in metabolic and volume status associated with the long two-day interdialytic interval.

METHODS: We examined patients receiving hemodialysis from a large national dialysis organization in the US from 2007-2011 who were on a stable thrice-weekly hemodialysis schedule. We compared all-cause mortality by day-of-week among patients receiving hemodialysis on a Monday-Wednesday-Friday (MWF) vs. Tuesday-Thursday-Saturday (TTS) schedule.

RESULTS: Among 105,120 patients who met eligibility criteria, 61,152 and 43,968 patients received hemodialysis on a MWF vs. TTS schedule (Table). In the overall cohort, the mean±SD age was 64 ± 15 years, among whom 43% were female, 30% were African-American, 16% were Hispanic, and 53% had diabetes mellitus. Among patients receiving hemodialysis on a MWF schedule, the highest proportion of deaths was observed on the day after the long two-day interdialytic interval, followed by hemodialysis days after the one-day interval: 23.7%, 14.7%, and 15.4% deaths on Mondays, Wednesdays, and Fridays, respectively (Figure). A similar pattern was observed among patients receiving hemodialysis on a TTS schedule, such that the highest proportion of deaths was observed on the day after the long two-day interval, followed by hemodialysis days after the one-day interval: 22.3%, 16.2%, and 15.9%, respectively.

CONCLUSIONS: Among patients receiving hemodialysis on a stable thrice-weekly schedule, the greatest proportion of deaths occurred on Mondays and Tuesdays after the long two-day interval. Further studies are needed to determine the factors implicated in the intensified mortality of the long interdialytic interval, including the excess accumulation of fluid, potassium, and/or uremic toxins, their removal with dialysis, and/or a weekend “lag” effect (i.e., reduced access to medical care or deferring medical services during the weekend).

SP652 Figure 1

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SP652 Figure 2

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