Predictive factors for recurrent acute appendicitis after conservative treatment.

Introduction: Conservative treatment of acute appendicitis is gaining popularity, and identifying patients with a higher risk of recurrence is becoming increasingly important. Previous studies have suggested that older age, male sex, diabetes, appendicolith and abscess formation may be contributing factors, however, results from the adult population are inconsistent.

Aim: This study aims to identify predictive factors for recurrent appendicitis after conservative treatment.

Methods: This retrospective study included patients with conservatively treated acute appendicitis at Skåne University Hospital, Sweden during 2012-2019. Information on patient demographics at index admission and follow-up data were retrieved from medical charts and radiologic images. Uni -and multivariable logistic regression analysis were performed using Stata Statistical Software.

Results: In total, 379 patients with conservatively treated acute appendicitis were identified, of which 78 (20.6%) had recurrence. All patients were followed-up for a minimum of 41 months after the first diagnosis of acute appendicitis unless appendectomy after successful conservative treatment or death occurred during follow-up. The median time to recurrence was 6.5 (1-17.8) months. After multivariable logistic regression analysis, external appendix diameter >10 mm [OR 2.4 (CI 1.37-4.21), p = .002] and intra-abdominal abscess [OR 2.05 (CI 1.18-3.56), p = .011] on computed tomography were significant independent risk factors for recurrent appendicitis. Appendicolith was not associated with an increased risk of recurrence.

Conclusion: This study suggests abscess formation and appendix distension of >10 mm to be potential risk factors for recurrent acute appendicitis after initial successful conservative treatment.