The preoperative risk tool SURPAS accurately predicts outcomes in emergency surgery

The Surgical Risk Preoperative Assessment System (SURPAS) uses eight variables to accurately predict postoperative complications but has not been sufficiently studied in emergency surgery. We evaluated SURPAS in emergency surgery, comparing it to the Emergency Surgery Score (ESS). SURPAS and ESS estimates of 30-day mortality and overall morbidity were calculated for emergency operations in the 2009–2018 ACS-NSQIP database and compared using observed-to-expected plots and rates, c-indices, and Brier scores. Cases with incomplete data were excluded. In 205,318 emergency patients, SURPAS underestimated (8.1%; 35.9%) while ESS overestimated (10.1%; 43.8%) observed mortality and morbidity (8.9%; 38.8%). Each showed good calibration on observed-to-expected plots. SURPAS had better c-indices (0.855 vs 0.848 mortality; 0.802 vs 0.755 morbidity), while the Brier score was better for ESS for mortality (0.0666 vs. 0.0684) and for SURPAS for morbidity (0.1772 vs. 0.1950). SURPAS accurately predicted mortality and morbidity in emergency surgery using eight predictor variables. •SURPAS accurately estimated mortality and morbidity in emergency surgery.•SURPAS and the Emergency Surgery Score produced comparable predictions.•With only 8 input variables (vs 22 in ESS), SURPAS is applicable to nearly all cases.