Comparison and prospective evaluation of in-hospital post operative moratlity in patients undergoing major surgery using possum and p- possum scoring system

Background: POSSUM AND P-POSSUM are two well known scoring systems for the evaluation of mortality and morbidity. It uses both preoperative and intra operative parameters of the patient for calculation of the score. Mortality rate alone cannot be used to compare the outcome of surgery between units or institutions. These scores can be used for the prediction of mortality and also for surgical audit, thus help in improvisation of our skill and proper documentation of patient details. Materials and Methods: This study was conducted in a tertiary care hospital in 300 patients above the age of 12 years from 2016 to June 2018, undergoing major surgery. This is a prospective observational study. Results: POSSUM and P-POSSUM had cut off of 42.3% and 22.3% respectively from ROC curve, above which proved equally good in predicting mortality. Overall mortality was 13.7%, of which 9.6% was from emergency. Both scores accurately predicted mortality in 81% of total patients. The discriminative ability to predict mortality was excellent. The area under the ROC curve (AUC), for POSSUM with 95% CI = 0.879 [0.810 – 0.938], P-value<0.001; P-POSSUM: AUC with 95% CI = 0.852 [0.795 – 0.928], P-value<0.001. O/E ratio for mortality was 0.32, 0.57, 0.5 respectively for POSSUM score and 0.28, 0.61, 0.57 respectively for P-POSSUM, in <60, 60-70, >70 year age group. Conclusion: Both POSSUM and P-POSSUM can be used as tool for prediction of mortality. But both POSSUM and P-POSSUM slightly over predicted the mortality in younger and low risk age group. Patients with higher scores can be given special attention, thus may help to bring down the mortality to some extent. They can be good tool for surgical audit as well.