Effect of Frequent Dialysis on Renal Recovery: Results From the Acute Renal Failure Trial Network Study

INTRODUCTION: The optimal frequency of intermittent hemodialysis (IHD) in the treatment of acute kidney injury (AKI) remains unclear. Increasing the frequency of IHD, while offering the possible advantage of reduced ultrafiltration requirement and less hemodynamic instability per session, amplifies patient contact with an extracorporeal circuit with possible deleterious cardiovascular and immunological consequences. A recent study suggested that intensive renal replacement therapy (RRT) is associated with a decrease in urine output during AKI. We hypothesized that increased frequency of IHD may be associated with delayed renal recovery. METHODS: This is a post hoc analysis of the Acute Renal Failure Trial Network (ATN) study. The ATN study was a large randomized multicenter trial of intensive versus less-intensive RRT in critically ill patients with AKI. This study used either continuous RRT or IHD, depending on the hemodynamic status of the patient. Of 1124 patients, 246 were treated solely with IHD during the study period and were included in this analysis. The participants were randomized to receive IHD 3 days per week (L-IntRRT) or 6 days per week (IntRRT). The primary outcome of interest was renal recovery at day 28. RESULTS: L-IntRRT was associated with higher number of RRT-free days through day 28 than IntRRT (mean difference 2.5 days; 95% confidence interval [CI]: −4.79 to −0.27 days; P = 0.028). The likelihood for renal recovery at day 28 was lower in the IntRRT group (OR: 0.49; 95% CI: 0.28–0.87; P = 0.016). CONCLUSION: In hemodynamically stable patients with AKI, intensifying the frequency of IHD from 3 to 6 days per week may be associated with impaired renal recovery.