Development and validation of a new scoring system to discriminate between uncomplicated and complicated appendicitis.

A scoring system to discriminate between uncomplicated and complicated appendicitis is beneficial to determine the optimal treatment for acute appendicitis. We developed a scoring system to discriminate between uncomplicated and complicated appendicitis and assessed the clinical usefulness of the scoring system using external validation. A total of 299 patients with acute appendicitis were retrospectively reviewed. One hundred and ninety-nine patients were assigned to the model development group, while the other 100 patients were assigned to an external validation group. A scoring system for complicated appendicitis was created using a final multivariate logistic regression model with six independent predictors. The area under the receiver operating characteristic curve of the scoring system was 0.882 (95% confidence interval: 0.835-0.929). The cutoff point of the scoring system was 12, and the sensitivity and specificity were 82.9% and 86.2%, respectively. In the external validation group, the area under the receiver operating characteristic curve of the scoring system was 0.868 (95% confidence interval 0.794-0.942), and there was no significant difference between the groups in the area under the receiver operating characteristic curve (P = 0.750). Our newly developed scoring system may contribute to prompt determination of the optimal treatment for acute appendicitis.