Does biocompatibility of dialysis membranes affect survival in patients with acute renal failure?

Introduction

During hemodialysis, contact between blood and dialysis membranes leads to complement and neutrophil activation. This effect is known as bioincompatibility and is most pronounced with older, less expensive, cellulose-based membranes. However, there is considerable controversy as to whether synthetic (more biocompatible) dialysis membranes improve survival in patients with acute renal failure (ARF) compared to cellulose-based membranes. Numerous trials have been conducted but have yielded conflicting results. Although the discordant results of existing studies could be explained by the varying degrees of biocompati-bility among the different membranes used, these studies were also of low statistical power. Thus we sought to determine whether combining results from all published trials would provide a better estimate of the effect of membrane on survival in ARF.

Methods

Studies were identified through a Medline search, authors' files and bibliographies of review articles. Studies were included if they were done prospectively, compared synthetic and cellulose-based membranes, and specified mortality rates for each group. Results were expressed as the cumulative odds ratio (OR) of survival over time where a P < 0.05 was considered significant. The entire sample was then analyzed for homogeneity using a Mantel–Haenszel (M–H) test, the OR recalculated using the weights from the M–H test and final M–H combined odds ratio determined.

Results

Eight prospective studies were included (n = 857) and an improvement in survival with biocompatible membrane was demonstrated (OR = 1.37, 95% CI = 1.03–1.84, P = 0.03).

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Conclusion

Use of biocompatible membranes for dialysis in ARF is associated with improved patient survival compared to the use of bioincompatible dialysis membranes.