Renal recovery from acute tubular necrosis requiring renal replacement therapy: a prospective study in critically ill patients

Background. Data on the incidence of end-stage renal disease (ESRD) resulting from irreversible acute tubular necrosis (ATN) are controversial. This prospective cohort study was designed to assess the need for short- and long-term dialysis in critically ill patients with severe ATN and to define risk factors for lack of renal recovery. Methods. 433 consecutive patients with clinically diagnosed severe ATN necessitating renal replacement therapy were enrolled. Eight patients were excluded because renal biopsy revealed another cause of acute renal failure. None of the remaining 425 patients had pre-existing chronic renal insufficiency. Primary outcome criteria were recovery of renal function at discharge and ESRD status at 1 year follow-up. Results. The overall in-hospital mortality of the cohort was 47%. At discharge, 57% of the 226 surviving patients had normal renal function, 33% had mild to moderate renal failure (serum creatinine: 1.3-3 mg/dl) and 10% had severe renal failure (serum creatinine: 3-6 mg/dl). Multivariate analysis showed that neither patient characteristics (age, gender, comorbid conditions), severity of illness (APACHE III, number of failed organs) nor mode and duration of renal replacement therapy were related to recovery of renal function. After 1 year, 76 of the surviving patients had died and in one patient chronic renal failure had progressed to ESRD. Conclusions. If critically ill patients with normal renal function prior to the renal insults survive the precipitating cause of ATN, the overwhelming majority will recover sufficient renal function.