Forni and colleagues contend that the association between serum creatinine concentration and in-hospital mortality may be related to the duration or severity of underlying disease rather than to muscle wasting or malnutrition. We agree that this is a plausible alternative explanation.
Regarding the overall poor prognosis for patients with acute renal failure requiring dialysis, we congratulate the St Thomas group, whose mortality rate is below that reported by other investigators, particularly in recent years.1 It would be important to learn about the timing and intensity of dialysis provided to these patients, as well as other supportive therapies, such as hyperalimentation, to see if other investigators could match their results.
The main purpose of our study was to identify an extremely high-risk subgroup with little chance of inhospital survival. In our experience, patients who underwent mechanical ventilation, with malignancy and/or nonrespiratory organ system failure, incurred an in-hospital mortality rate well