Validation of the American College of Surgeons risk calculator for thoracic surgery

<bold>Introduction:</bold> Advances in medicine and surgical techniques make it possible to operate on selected elderly, comorbid patients, where a risk assessment is essential. <bold>Aim:</bold> We aim to validate the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk calculator specifically for thoracic surgery. <bold>Methods:</bold> 283 consecutive patients who underwent thoracic surgery at our center were included. Considering “severe complication” as the most important outcome, we compared the predicted risk scores with the observed incidence of 30-day morbidity and mortality. We calculated the area under the receiver operating characteristic curve (AUROC) with 95% confidence intervals (CI) for each outcome and Brier score to check the calibration and complication odds ratios above vs. below average risk in all score outcomes with the number of occurred events. <bold>Results:</bold> For “serious complication” AUROC was 59% and events were equal in patients with risk score above and below average, p=1.0. AUROC was 67% for “any complication” and 58% for “return to OR”, expressing no useful prediction. The Brier score and odds ratios were low for all outcomes. Dyspnoea, ASA, COPD, and BMI as single, postoperative risk predictors significantly improved the basic model, consisting of the logit of the risk calculator alone. Therefore, the calculator alone did not perform as well as these single variables did. <bold>Conclusion:</bold> The ACS NSQIP risk calculator exhibited low sensitivity, specificity, and low AUROC for postoperative 30-day morbidity and mortality in our study cohort. Therefore, it cannot be considered as valid risk estimation tool for thoracic surgery.