A comparison of POSSUM, P-POSSUM and colorectal POSSUM for the prediction of postoperative mortality in patients undergoing colorectal resection

Purpose: POSSUM (Physiologic and Operative Severity Score for enUmeration of Morbidity & Mortality) and P-POSSUM have been validated as scoring tools for the prediction of postoperative complications in general surgical patients. More recently a colorectal-specific POSSUM has been developed for mortality prediction. This study was designed to evaluate and compare the accuracy for mortality prediction of POSSUM, P-POSSUM, and colorectal POSSUM after major and complex major colorectal procedures. Methods: The relationship between the observed and expected morbidity and mortality was examined in 347 consecutive patients (321 elective, 26 urgent) undergoing a major or complex major colorectal resection using POSSUM, P-POSSUM, and Colorectal POSSUM. The accuracy of using these scoring tools to predict mortality was assessed using Receiver Operator Characteristic curve analysis. Results: A total of 347 consecutive patients (median age, 69 (range, 34-92) years) were assessed. Seventy-one patients (20.5 percent) suffered a postoperative complication and 15 patients (4.3 percent) died. The observed: expected POSSUM ratio for morbidity was 0.71 and mortality 0.68. The area under curve from Receiver Operator Characteristic curve analysis for POSSUM was 0.752. The observed:expected mortality ratio for P-POSSUM was 0.71, and the area under curve from Receiver Operator Characteristic curve analysis was 0.749. The observed:expected mortality ratio for colorectal POSSUM was 0.75, and the area under the curve from Receiver Operator Characteristic curve analysis was 0.781. Conclusions: Colorectal POSSUM provides comparable prediction of mortality risk after colorectal resection compared with POSSUM and P-POSSUM.