LAUSR

Data were collected prospectively from all patients undergoing LA between 2006 and 2019. Demographics and surgical outcomes were analyzed. Complicated appendicitis was defined as a gangrenous or perforated appendix, and severe peritonitis as the presence of pus in ≥ 2 abdominal quadrants. Postoperative IAA was confirmed by CT scan in all cases. The series was randomly divided into a training cohort (70%) and an internal validation cohort (30%). A logistic regression model with 13 potential risk factors for IAA was performed in the training cohort. A nomogram including all statistically significant risk factors was created based on a proportionally conversion of each regression coefficient in the multivariate logistic regression to a 0 to 100-point scale. The low-, intermediate-, and high-risk estimated groups were created by stratifying the cohort in percentiles (< 80th percentile, between the 80th and 95th percentile, and > 95th percentile, respectively). The performance of the model was then evaluated in the validation cohort with a receiver operating characteristic (ROC) curve and its associated sensitivity, specificity, and area under the curve (AUC). All statistical analyses were done using the R software version 4.0.1. A p value < 0.05 was considered statistically significant.