Prognostic Stratification in Acute Renal Failure

We read with interest the article by Chertow et al 1 on prognostic stratification of patients with severe acute renal failure. We agree with them that APACHE (Acute Physiology and Chronic Health Evaluation) II criteria are not satisfactory for the prediction of outcome in patients with acute renal failure requiring dialysis. There are several possible explanations for this, not least of which is the inclusion of the serum creatinine concentration as a positive predictor of mortality. The findings of both a study from our hospital (St Thomas Hospital, London, England) 2 and that of Chertow and colleagues show the reverse to be true. However, whereas Chertow and colleagues attributed this to the association between muscle wasting and serum creatinine levels, 1 the study at our hospital 2 suggested a different explanation, namely, that in acute renal failure the serum creatinine concentration principally reflects the length of time that has elapsed