The effects of acute renal failure on long-term renal function

The relationship between acute renal failure (ARF) and long-term renal function remains unknown. We therefore undertook a study of patients at the Baltimore VA Hospital to examine the effects of a bout of acute renal injury on long-term renal function. We retrospectively reviewed the relationship between serum creatinine and time of observation for 6058 individuals who had values greater than 1.4 mg/dL in any two consecutive years. Individuals were stratified according to total years of observation with a minimum of two years. Severity of acute renal injury was divided into mild, moderate, and severe with elevations in baseline creatinine of < 50%, 50-300% and > 300% respectively. Sporadic elevations in creatinine were evident in 8-15% of the population. There were a total of 1328 episodes of acute renal failure in 916 patients that were suitable for analysis. Mild ARF on a substrate of normal or mildly abnormal renal function resolved without long-term sequelae. Moderate and severe ARF occurred more frequently on a background of reduced renal function but baseline function was retained in at least 60% of patients. We conclude that ARF is more frequent in patients with chronic kidney disease but it is not invariably associated with an accelerated course to end-stage renal disease or death. Overall, the majority of ARF events resolved without adverse long-term effects suggesting appropriate management in the majority of instances.