The role of renal function in outcome-prediction models

General clinical scoring systems are relatively recently developed statistical tools available to clinicians for purposes including comparison of outcome data, evaluation of new therapies, quality assurance, and evaluation of resource utilization. As statistical devices, they are valid when applied to patient groups, not individual prognostication. The most well known general systems are the APACHE (Acute Physiology and Chronic Health Evaluation), SAPS (Simplified Acute Physiology System), and MPM (Mortality Prediction Model). Each of these systems has considered renal dysfunction as a contributor to mortality and, as the systems have matured, have given increasing importance to the presence of renal failure as a predictor of mortality. Cardiac surgery patients make up a large part of many critical-care physicians' practice, but are not presently considered in any of the general scoring systems. In addition, the outcome for these patients is well known to be significantly affected by the presence of renal failure. Specific scoring systems have been developed that evaluate cardiac surgery patients in much the same fashion as do the general scoring systems.