Validation of POSSUM scoring systems for audit of major hepatectomy

Abstract

Background: The aim of the study was to validate the use of Physiological and Operative Severity Score in the enumeration of Mortality and morbidity (POSSUM) and Portsmouth (P) POSSUM scoring systems to predict postoperative mortality in a group of Chinese patients who had a major hepatectomy for hepatocellular carcinoma. Methods: A retrospective analysis was performed on data collected prospectively over a 6-year interval from January 1997 to December 2002. The mortality risks were calculated using both the POSSUM and the P-POSSUM equations. Results: Two hundred and fifty-nine patients underwent major hepatectomy; there were 17 (6-6 per cent) postoperative deaths. Of 32 preoperative and intraoperative variables studied, age, smoking habit, serum creatinine concentration, American Society of Anesthesiologists grade, and physiological and operative severity scores were found to be significant factors predicting mortality. On multivariate analysis only the physiological and operative severity scores were independent variables. The POSSUM system overpredicred mortality risk (14-2 per cent) and there was a significant lack of fit in these patients (X2 = 14.1, 3 d.f., P = 0.003). The mortality rate predicted by P-POSSUM was 4.2 per cent and showed no significant lack of fit (x2 = 7.6, 3 d.f., P = 0.055), indicating that it predicted outcome effectively. A new logistic equation was derived from the present patient data set that requires testing prospectively. Conclusion: P-POSSUM significantly predicted outcome in Chinese patients who had major hepatectomy for hepatocellular carcinoma. A modified disease-specific equation requires further testing.