Association of dialyzer reuse with hospitalization and survival rates among US hemodialysis patients: Do comorbidities matter?

The objective of this study was to determine whether the associations betwe en reuse of hemodialyzers and higher rates of death and hospitalization per sist after adjustment for comorbidity. This was a nonconcurrent cohort stud y of survival and hospitalization rates among 1491 U.S. chronic hemodialysi s patients beginning treatment in 1986 and 1987. The impact of dialyzer reu se was compared across three survival models: an unadjusted model, a "base" model adjusted only for demographics and renal diagnosis, and an "augmente d" model additionally adjusted for comorbidities. We found that reuse of di alyzers was associated with a similarly higher rate of death in analyses un adjusted for confounders (relative risk [RR] 1.25, 95% confidence interval [CI] 0.97-1.61), adjusted for demographics and renal diagnosis (RR 1.16, 95 % CI 0.96-1.41), and analyses additionally adjusted for comorbidities (RR = 1.25, CI, 1.03, 1.52). Reusing dialysers was also associated with a greate r rate of hospitalization that was stable regardless of adjustment procedur es. We conclude that higher rates of death and hospitalization associated w ith dialyzer reuse persist regardless of adjustment for demographic charact eristics or baseline comorbidities. These findings amplify concerns that th ere exists elevated morbidity among hemodialysis patients treated in facili ties that reuse hemodialyzers. Although the association we observed was not confounded by comorbidity, a cause-and-effect relationship between dialyze r reuse and morbidity could not be proved because of the inability to contr ol for aspects of care other than dialyzer reuse. J CLIN EPIDEMIOL 52;3:209 -217, 1999. (C) Elsevier Science Inc.