Validation of the American College of Surgeons Risk Calculator for preoperative risk stratification

Abstract

Objective Various risk prediction models are available to stratify patients before non-cardiac surgery and pave the way for anticipative and preventive measures. The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) Surgical Risk Calculator is an extensive tool that predicts the risk for major adverse cardiovascular events (MACE) and other perioperative outcomes. This study validated the calculator in a Filipino population and compared its predictive ability with the more widely used Revised Cardiac Risk Index (RCRI). Methods The study included 424 patients referred for preoperative stratification before non-cardiac surgery in St Luke's Medical Center Quezon City. The development of all-cause mortality, morbidity, pneumonia, cardiac events, venous thromboembolism, urinary tract infection, renal failure and return to operating room were observed. The discriminative ability of the ACS NSQIP to predict these outcomes was evaluated using the area under the receiver operating characteristic curve (AUC) while calibration was measured using the Brier score. The AUC of the ACS NSQIP was compared with that of the RCRI. Results The ACS NSQIP Surgical Risk Calculator had excellent predictive ability for MACE and was comparable with the RCRI (AUC 0.93 vs 0.93). It also had acceptable predictive ability for pneumonia (AUC 0.93), all-cause mortality (AUC 0.89) and morbidity (AUC 0.88). It had poor to fair predictive ability for renal failure, return to operating room, surgical site infection, urinary tract infection and venous thromboembolism. Calibration was excellent for all-cause mortality, morbidity, pneumonia, venous thromboembolism and renal failure. Conclusion The ACS NSQIP Surgical Risk Calculator is a valid tool for predicting MACE and other important perioperative outcomes among Filipinos.