Survival by time of day of hemodialysis in an elderly cohort

Context Patients with end-stage renal disease (ESRD) typically undergo hemodialysis (HD) during the morning or afternoon, with time of treatment generally based on space availability or patient preference. No studies have investigated variation in patient survival as a function of the time of day when they receive dialysis. Objective To investigate the association of elderly patients' HD treatment shift with their continued survival, controlling for well-established HD-related mortality risk factors. Design, Setting, and Participants An 11-year follow-up cohort study conducted among 242 ESRD patients aged 60 years or older who underwent HD at 58 dialysis facilities in Georgia either during a morning shift (n=167) or an afternoon shift (n=75) and who completed baseline (1998) and follow-up (1991) interviews. Main Outcome Measure Mortality from all causes occurring through July 7, 1999, as verified by death-certificate reviews, and compared by morning- vs afternoon-shift HD. Results Morning-shift HD patients survived significantly longer than afternoon-shift patients (median survival, 941 days vs 470 days; P<.001), A Cox proportional hazards model indicated that the morning shift was protective (relative risk, 0.71; 95% confidence interval, 0.53-0.95) independent of age, race, sex, body mass index, functional status, diabetic ESRD, cardiovascular comorbidity, weekly hours of dialysis, and months of dialysis. Conclusions Possible explanations for differential survival in association with morning vs afternoon dialysis include salutary effects of sleep in the morning or less efficient biochemical exchange during afternoon dialysis. Results from this cohort study may warrant prospective observational studies and randomized clinical trials that systematically alter the time of day at which HD is administered.