Shorter dialysis times are associated with higher mortality among incident hemodialysis patients.
There is an association between hemodialysis session length and mortality independent of the effects of session duration on urea clearance. However, previous studies did not consider changes in session length over time nor did they control for the influence of time-dependent confounding. Using data from a national cohort of 8552 incident patients on thrice-weekly, in-center hemodialysis, we applied marginal structural analysis to determine the association between session length and mortality. Exposure was based on prescribed session length with the outcome being death from any cause. On the 31st day after initiating dialysis, the patients were considered at-risk and remained so until death, censoring, or completion of 1 year on dialysis. On primary marginal structural analysis, session lengths <4 h were associated with a 42% increase in mortality. Sensitivity analyses showed a dose-response relationship between session duration and mortality, and a consistency of findings across prespecified subgroups. Our study suggests that shorter hemodialysis sessions are associated with higher mortality when marginal structural analysis was used to adjust for time-dependent confounding. Further studies are needed to confirm these findings and determine causality.
Brunelli
Steven M
SM
Renal Division, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. sbrunelli@partners.org
Chertow
Glenn M
GM
Ankers
Elizabeth D
ED
Lowrie
Edmund G
EG
Thadhani
Ravi
R
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology