Abstract
BACKGROUND: Postoperative intra-abdominal abscesses (IAA) remain a significant complication after laparoscopic appendectomy for acute appendicitis. This study investigates the roles of the 5-item modified Frailty Index (mFI-5) and Inflammatory Burden Index (IBI) in predicting IAA risk. METHODS: This retrospective study analyzed elderly patients who underwent laparoscopic appendectomy from 2015 to 2025. Patients were assessed for frailty using mFI-5 and systemic inflammation using IBI. We collected demographic, clinical, and laboratory data, and univariate and multivariate logistic regression were performed to identify risk factors for IAA. A nomogram was developed based on significant variables from the multivariate analysis by R. RESULTS: A total of 428 patients were included, with 43 (10.0%) developing IAA. Multivariate analysis revealed that perforated appendicitis (OR: 2.950, 95% CI: 1.210-7.197, P = 0.017), higher mFI-5 scores (OR: 3.370, 95% CI: 1.956-5.806, P < 0.001), and elevated IBI values (OR: 1.104, 95% CI: 1.027-1.186, P = 0.007) were independently associated with IAA. The nomogram, developed from these factors, showed good discriminatory ability with an AUC of 0.776. CONCLUSIONS: Perforated appendicitis, mFI-5 and IBI are reliable predictors of IAA in elderly patients after laparoscopic appendectomy. The nomogram incorporating these factors can effectively guide clinical decision-making and identify high-risk patients.