Dialysis unit and patient characteristics associated with reuse practices and mortality: 1989-1993

The diverse patient and dialysis unit characteristics in the United States pose challenges for assessing the safety and efficacy of reuse practices. A 10% random sample of period-prevalent hemodialysis patients from units practicing conventional dialysis (<25% of patients with high- efficiency/highflux dialysis) were analyzed. The data included 13,926 patient observations in 1989-1990 and 20,422 in 1991-1993. Centers for Disease Control and Prevention and Health Care Financing Administration facility survey Medicare data were analyzed with a Cox regression model, evaluating the risk of reuse compared with no reuse and adjusting for comorbidity, unit characteristics, and profit status. In 1989-1990, freestanding and hospital- based units that did not reuse dialyzers were not significantly different from each other in mortality rates. In 1991-1993, however, no-reuse, freestanding, for-profit units had higher risks (relative risk [RR] = 1.23, P = 0.003) compared with no-reuse, hospital-based, nonprofit units. No-reuse, hospital-based, for-profit units, in contrast, were associated with a lower mortality risk (RR = 0.70, P = 0.0001). An isolated higher risk associated with peracetic acid manual reuse in freestanding units (1989-1990) was identified in for-profit units only. In the 1991-1993 period, an increased mortality risk was noted in hospital-based, nonprofit units practicing formaldehyde automatic reuse, and in freestanding, for-profit units using glutaraldehyde, which accounted for <5% of all units. All other interactions of reuse germicide and technique were not different from no-reuse. The varying mortality rates identified in both no-reuse and reuse units using conventional dialysis suggest that other factors, such as dialysis therapy and anemia correction (both known predictors of patient survival), have a greater influence on U.S. mortality than reuse germicides and techniques.