Comparison of Surgical Risk Score, POSSUM and p-POSSUM in higher-risk surgical patients

Background: Much current interest is focused on the use of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and the Portsmouth predictor equation (p-POSSUM) for risk-adjusted surgical audit. The Surgical Risk Score (SRS) has been shown to offer an equivalent accuracy, but was validated using a cohort that contained a high proportion of low-risk patients. The aim of this study was to compare the accuracy of mortality prediction using SRS with that of POSSUM and p-POSSUM in a cohort of higher-risk patients. Methods: Some 949 consecutive patients undergoing inpatient surgical procedures in a district general hospital under the care of a single surgeon were analysed. Results: The observed 30-day mortality rate was 8.4 per cent. Mean mortality rates predicted using SRS, POSSUM and p-POSSUM scores were 5.9, 12.6 and 7.3 per cent respectively. No significant difference was observed in the area under the receiver-operator characteristic curves for the three methods. Conclusion: The SRS accurately predicted mortality in higher-risk surgical patients. The accuracy of prediction equalled that of POSSUM and p-POSSUM.