THE IMPORTANCE OF SEVERITY OF ILLNESS ADJUSTMENT IN PREDICTING ADVERSE OUTCOMES IN THE MEDICARE POPULATION

The importance of using risk-adjusted mortality rates to measure quali ty of care is well-established. However, mortality rates may be an ins ensitive measure of quality for surgical patients since death is a rel atively rare outcome. This study used Medicare files to identify, thro ugh chart abstraction, clinical postoperative complications of four su rgical procedures (n = 8126) that could serve as measures of quality. Disease-specific severity of illness models using a moderate number of clinical variables and admission MedisGroups score models computed fr om approximately 250 clinical variables were compared in predicting po stoperative adverse events. Initial differences between the two models disappeared upon cross-validation. Validated R-squareds and C statist ics from model using half the data were generally positive, suggesting that these models had real, although modest, predictive power. We hav e shown that severity of illness on admission plays a role in predicti ng adverse events of surgery. Risk-adjusted outcomes may potentially b e useful in screening for quality shortfalls.