Comparison of comorbidity indices for prediction of morbidity and mortality after major surgical procedures

Background Assessing perioperative risk is essential for surgical decision-making. Our study compares the accuracy of comorbidity indices to predict morbidity and mortality. Methods Analyzing the National Surgical Quality Improvement Program, 16 major procedures were identified and American Society of Anesthesiologists (ASA), Charlson Comorbidity Index and modified Frailty Index were calculated. We fit models with each comorbidity index for prediction of morbidity, mortality, and prolonged length of stay (pLOS). Decision Curve Analysis determined the effectiveness of each model. Results Of 650,437 patients, 11.7%, 6.0%, 17.0% and 0.75% experienced any, major complication, pLOS, and mortality, respectively. Each index was an independent predictor of morbidity, mortality, and pLOS (p < 0.05). While the indices performed similarly for morbidity and pLOS, ASA demonstrated greater net benefit for threshold probabilities of 1–5% for mortality. Conclusions Models including readily available factors (age, sex) already provide a robust estimation of perioperative morbidity and mortality, even without considering comorbidity indices. All comorbidity indices show similar accuracy for prediction of morbidity and pLOS, while ASA, the score easiest to calculate, performs best in prediction of mortality.