Three-year outcome of severe acute tubular necrosis: a prospective study of critically ill patients

Introduction

Severe acute tubular necrosis (ATN) in critically ill patients is associated with considerable morbidity, mortality and use of health resources. Its precise long-term outcomes, however, have not been well described. The objectives of this observational study were to establish long-term survival and renal recovery for severe ATN in a well-defined population.

Methods

Four hundred and twenty-five critically ill patients with hospital-acquired ATN necessitating renal replacement therapy (RRT) during 1992 and 2001 were followed up for 3 years. RRT was either intermittent hemodialysis or continuous RRT. No patient had chronic renal dysfunction prior to ARF. Patients were classified according to the cause of ATN as surgical or medical. ATN was categorized as ischemic, septic or nephrotoxic. Patient characteristics were documented at commencement of RRT. Major outcomes (survival and renal status) were determined at discharge and after 1 and 3 years of follow-up.

Results

The study population was characterized by high age (mean 65 years), excess comorbidity and by extensive organ failure (mean 2.4 failed organs). The overall inhospital, 1-year and 3-year case fatality rates were 47%, 65% and 71%, respectively. All survivors had renal functional recovery without further need of RRT at discharge and only 0.6% progressed to end-stage renal disease after 1 year. After 3 years, 2% of the survivors needed chronic RRT.

Conclusion

In contrast to the poor inhospital prognosis of critically ill patients with severe ATN, the overwhelming majority of surviving patients become independent from renal replacement therapy. In patients without pre-existing renal dysfunction, severe chronic renal failure is unusual and the persistent need for maintenance hemodialysis is rare.