Validation of the use of Possum0 and P- Possum0 score in perforation peritonitis in Indian population

Abstract

Background: The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model, its Portsmouth (P-POSSUM) modification are two surgical risk scoring systems used extensively to predict post-operative morbidity and mortality in general surgery. The aim was to undertake the study of validity of these models in Indian patients undergoing exploratory laparotomy for perforation peritonitis. Patients and Methods: A prospective study was performed, in which a total of 103 patients undergoing exploratory laparotomy for perforation peritonitis were included during the period of November 2011 to October 2013. The morbidity and mortality risks were calculated using the POSSUM and P-POSSUM. Results: Around 44/103 patients developed complications (total morbidity rate of 42.72%) in post-operative period; this was compared with POSSUM predicted morbidity. There was no statistical difference between observed and predicted morbidity (χ 2 = 45.607; df = 1; observed/expected ratio (O:E) = 0.82; P value = 0.000). Ten patients died (total mortality rate of 9.7%). The P-POSSUM expected mortality rate was compared. There was no statistical difference between the observed and P-POSSUM predicted mortality rates (χ 2 = 17.444, df = 1; P value = 0.000). However, P-POSSUM overpredicts mortality in our study (O:E = 0.25; P value = 0.000). Conclusion: POSSUM and P-POSSUM appear to be good and valid indices for use in risk prediction of morbidity and mortality, respectively (surgical outcome in perforation peritonitis) in the Indian population. We found that POSSUM accurately predicts morbidity but P-POSSUM is not able to predict mortality accurately.