CAUSE OF ACUTE TUBULAR-NECROSIS AFFECTS ITS PROGNOSIS

Background: Acute tubular necrosis (ATN) is the most common type of ac ute renal failure in hospitalized patients and is associated with a hi gh morbidity and mortality. The cause of ATN can be divided into nephr otoxic, ischemic, or mixed. Objective: To test the hypothesis that the cause of ATN affects its clinical outcome. Methods: The study compare s clinical outcomes of patients enrolled in the placebo arm of a multi center, randomized, double-blinded, placebo-controlled trial of anarit ide (Auriculin, synthetic atrial natriuretic peptide, Scios, Mountain View, Calif) in patients with well defined ATN. Patients were divided prospectively into groups according to the cause of ATN: pure nephroto xic, pure ischemic, or mixed nephrotoxic and ischemic. Outcomes of int erest were dialysis-free survival and all-cause mortality on day 14 an d day 21. The causal groups were compared with respect to the prevalen ce of several comorbidities suspected of affecting the clinical outcom es. Results: Mortality was 10% in the nephrotoxic group and 30% in the ischemic group on day 21. Dialysis-free survival was 66% in the nephr otoxic group and 41% in the ischemic group on day 21. Outcomes in the mixed and ischemic groups were similar. Compared with the nephrotoxic group, there was a significantly higher prevalence of cardiogenic shoc k, hypotension, sepsis, and respiratory failure and a tendency toward a higher prevalence of acute hepatic dysfunction in the ischemic group . Diabetes mellitus was more prevalent in the nephrotoxic group. Among patients with ischemic ATN, dialysis-free survival improved significa ntly and mortality tended to decline with advancing age, Conclusions: Among patients with ATN, those in whom renal ischemia was causative ha d significantly higher mortality and lower dialysis-free survival than those whose ATN was purely nephrotoxic in origin. ?his difference in clinical outcomes was associated with a higher prevalence of serious c omorbidities in the ischemic ATN group. Advancing age was associated w ith improved dialysis-free survival and a tendency toward reduced mort ality in patients with ischemic ATN.