Comparative Audit: The Trouble with Possum

Abstract

The Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM) has been proposed for use in comparative audit between surgeons and between hospitals. To assess its feasibility, POSSUM scoring was attempted on admission in all patients under the care of two consultant surgeons over a six-month period. Scores were awarded only if all investigations necessary for POSSUM were performed; investigations unnecessary for effective treatment were not performed. 815 patient discharges were recorded over the six-month period, with 521 patients undergoing operative procedures. Of those undergoing an operation, scores could be allocated in only 155 (30%). Scoring systems such as POSSUM are procedure-based, thereby excluding those who do not undergo an operation. However, most of our operative cases were also excluded. Full POSSUM scoring will often require additional investigations. POSSUM is unlikely to be of use in the wider setting of comparative audit.