Comparative study of left colonic Peritonitis Severity Score and Mannheim Peritonitis Index

Background: Prognostic evaluation of patients with left colonic perforation is useful in predicting mortality. The aims of this prospective study were to determine the prognostic value of the left colonic Peritonitis Severity Score (PSS) and to compare it with the Mannheim Peritonitis Index (MPI). Methods: One-hundred and fifty-six patients underwent emergency operation for distal colonic peritonitis. The PSS and MPI were calculated for each patient. The Spearman rank correlation coefficient was used to measure the association between the two scores. The predictive power of the two scoring systems and their differences were studied using the area under the receiver-operator characteristic (ROC) curve. Results: Forty-one patients died (26.3 per cent). The relationship between scores and mortality was statistically significant for each scoring system (P<0.001). The Spearman rank correlation coefficient for the correlation between the MPI and PSS was 0.55 (P<0.001). There was no difference between areas under the ROC curves for the two systems. Conclusion: The PSS and MPI are both well validated scoring systems for left colonic peritonitis. Their routine use might allow stratification of patients according to mortality risk.