Acute Renal Failure Trial Network (ATN) Study

Primary Hypothesis: An intensive management strategy for renal support in critically ill patients with acute renal failure decreases mortality as compared to less intensive (conventionally recommended) management strategies for renal replacement therapy.

Secondary Hypotheses: An intensive management strategy for renal support in critically ill patients with acute renal failure will shorten the duration of ARF, decrease the incidence and duration of non-renal complications and is cost-effective as compared to less intensive (conventionally recommended) management strategies for renal replacement therapy.

Primary Outcomes: 60-day all-cause mortality.

Secondary Outcomes: All-cause hospital mortality; 1-year all cause mortality; recovery of renal function; duration of renal support (dialysis-free days); ICU and hospital length of stay (ICU-and hospital-free days); non-renal organ system failures (organ-failure-free days); and discharge to "home" not on dialysis.

Study Abstract: The optimal management of renal replacement therapy (RRT) in acute renal failure (ARF) is uncertain. The VA/NIH Acute Renal Failure Trial Network (ATN Study) is designed to test the hypothesis that a strategy of intensive renal support will decrease mortality in critically ill patients with ARF as compared to less intensive (conventionally recommended) management. In this multicenter, prospective trial, patients with ARF due to acute tubular necrosis will be randomized equally to intensive or conventional management strategies for RRT.

In both arms, RRT will be initiated using the same criteria. Hemodynamically stable patients (SOFA cardiovascular score: 0-2) will receive intermittent hemodialysis (IHD) while hemodynamically unstable patients (SOFA cardiovascular score: 3-4) will be treated with continuous venovenous hemodiafiltration (CVVHDF) or sustained low-efficiency hemodialysis (SLED). Patients will convert between modalities of therapy as hemodynamic status changes over time. The intensity of therapy in IHD and SLED will vary between groups based on treatment frequency; with treatments provided 6-times per week in the intensive management strategy arm and 3-times per week in the conventional management strategy arm. In CVVHDF, intensity of therapy will vary based on effluent flow rate with a prescribed flow rate of 35 mL/kg/hour in the intensive management strategy arm and 20 mL/kg/hour in the conventional management strategy arm.

Protocol therapy will be continued until renal function recovers or until day 28. The primary study end-point will be 60-day all-cause mortality. Other end-points will include hospital and 1-year mortality, recovery of renal function, duration of renal support, ICU and hospital length of stay, hospital discharge off of dialysis and development/recovery of non-renal organ failure. An economic analysis will be performed to assess the costs and relative cost effectiveness of the two strategies.

The planned total enrollment of 1164 patients at 27 institutions over 44 months was selected to provide a power of 0.90 to detect a reduction in mortality from 55% to 45% with alpha=0.05 assuming a dropout/loss-to-follow-up rate of 10%.

Study enrollment began in November 2003 and closed after 44 months on July 2, 2007. Total enrollment was 1124 subjects. Fewer than 3% of subjects withdrew from protocol therapy. Follow-up for the primary study endpoint (60-day all-cause mortality) concluded on August 31, 2007; one-year follow-up will conclude in July 2008.