Scoring Systems for Outcome Prediction of Patients with Perforation Peritonitis

Peritonitis continues to be one of the major infectious problems confronting a surgeon. Mannheim Peritonitis Index (MPI), Physiological and Operative Severity Score for en Umeration of Mortality (POSSUM) and Morbidity and sepsis score of Stoner and Elebute have been devised for risk assessment and for prediction of postoperative outcome.

The aim of this study was to find the accuracy of these scores in predicting outcome in terms of mortality in patients undergoing exploratory laprotomy for perforation peritonitis.

The prospective study was carried out in 100 diagnosed cases of perforation at our centre in a single unit over a period of 21 months from December 2012 to August 2014. Study was conducted on all cases of peritonitis albeit primary, tertiary, iatrogenic and those with age less than 12 years were excluded from the study. All the relevant data were collected and three scores were computed from one set of data from the patient. The main outcome measure was survival of the patient. The Receiver Operator Characteristics (ROC) curves were obtained for the three scores. Area Under the Curves (AUC) was calculated. Sensitivity and specificity were calculated at a cut off point obtained from the ROC curves.

POSSUM had an AUC of 0.99, sepsis score had an AUC of 0.98 and MPI had an AUC of 0.95. The cut off point score of 51 for POSSUM had an accuracy of 93.8 and positive predictive value of 70.5, the score of 29 for MPI had an accuracy of 82.8 and positive predictive value of 46 and the score of 22 for sepsis score had an accuracy of 95.9 and positive predictive value of 86.67.

POSSUM score was found to be superior in prediction of mortality as compared to sepsis score of Stoner and Elebute and MPI. POSSUM and MPI over predicted mortality in some cases. None of these scores are strictly preoperative.