Mortality risk by hemodialyzer reuse practice and dialyzer membrane characteristics: Results from the USRDS dialysis morbidity and mortality study

Hemodialyzer reuse is commonly practiced in the United States. Recent studi es have raised concerns about the mortality risk associated with certain re use practices. We evaluated adjusted mortality risk during 1- to 2-year fol low-up in a representative sample of 12,791 chronic hemodialysis patients t reated in 1,394 dialysis facilities from 1994 through 1995. Medical record abstraction provided data on reuse practice, use of bleach, dialyzer membra ne, dialysis dose, and patient characteristics and comorbidity. Mortality r isk was analyzed by bootstrapped Cox models by (1) no reuse versus reuse, ( 2) reuse agent, and (3) dialyzer membrane with and without the use of bleac h, while considering dialysis and patient factors. The relative risk (RR) f or mortality did not differ for patients in reuse versus no-reuse units (RR = 0.96; 95% confidence interval [CI], 0.86 to 1.08; P > 0.50), and similar results were found with different levels of adjustment and subgroups (RR = 1.01 to 1.05; 95% CI, lower bound > 0.90, upper bound < 1.19 each; each P > 0.40). The RR for peracetic acid mixture versus formalin varied significa ntly by membrane type and use of bleach during reprocessing, achieving bord erline significance for synthetic membranes. Among synthetic membranes, mor tality was greater with low-flux than high-flux membranes (RR = 1.24; 95% C I, 1.02 to 1.52; P = 0.04) and without than with bleach during reprocessing (RR = 1.24; 95% CI, 1.01 to 1.48; P = 0.04), Among all membranes, mortalit y was lowest for patients treated with high-flux synthetic membranes (RR = 0.82; 95% CI, 0.72 to 0.93; P = 0.002). Although mortality was not greater in reuse than no-reuse units overall, differences may exist in mortality ri sk by reuse agent. Use of high-flux synthetic membrane dialyzers was associ ated with lower mortality risk, particularly when exposed to bleach. Cleara nce of larger molecules may have a role. (C) 2001 by the National Kidney Fo undation, Inc.