Benefit of continuous renal replacement therapy in subgroups of acutely ill patients: a retrospective analysis.

AIMS: Acute renal failure in the intensive care setting is common and impacts on patient's outcome. Continuous hemodialysis or hemofiltration offers theoretical benefit for patients with acute renal failure, but the clinical benefit has not been demonstrated in randomized trials. ICU patients with acute renal failure are a heterogeneous population and we hypothesize that patients with increased illness severity would benefit from continuous renal replacement therapy. METHODS: From a comprehensive ICU database, we identified patients with acute renal failure exposed to continuous or intermittent renal replacement therapy. We a priori identified a subgroup of patients with multiple organ dysfunction syndrome, then used survival analysis to assess the effect of dialysis modality in the overall acute renal failure population and in the subgroup with increased illness severity. RESULTS: We identified 66 patients treated with intermittent and 36 patients treated with continuous renal replacement therapy. Patients with severe illness were preferentially selected for treatment with continuous dialysis (p = 0.01). Overall, there was no significant difference in survival between patients treated with intermittent or continuous dialysis. The relative risk of in-hospital mortality was significantly decreased in patients with multiple organ dysfunction syndrome (relative risk = 0.42+/-0.22, p = 0.027) treated with continuous therapy as compared with intermittent therapy. Among the survivors, continuous dialysis did not appear to hasten the return of renal function. CONCLUSIONS: This retrospective study suggests that continuous dialysis may be beneficial in a subgroup of ICU patients with multiple organ dysfunction syndrome or severe sepsis. Further randomized trials of dialysis modality should, if possible, concentrate on this population.