Importance  

Antibiotic therapy is effective and safe for uncomplicated acute appendicitis in adults, but randomized clinical trial results exceeding 5 years are missing.

Objective  

To determine the 10-year appendicitis recurrence and appendectomy rate in patients with uncomplicated appendicitis treated with antibiotics.

Design, Setting, and Participants  

Ten-year observational follow-up of patients in the Appendicitis Acuta (APPAC) multicenter randomized clinical trial comparing appendectomy with antibiotics at 6 Finnish hospitals from November 2009 to June 2012, where 530 patients (aged 18-60 years) with uncomplicated acute appendicitis diagnosed by computed tomography were randomly assigned to appendectomy (n = 273) or antibiotics (n = 257). Last follow-up was April 29, 2024. This current analysis focused on assessing the 10-year appendicitis recurrence rate among patients assigned to antibiotics.

Interventions  

Open appendectomy vs antibiotics with intravenous ertapenem sodium (1 g/d) for 3 days followed by 7 days of oral levofloxacin (500 mg once daily) and metronidazole (500 mg 3 times/d).

Main Outcomes and Measures  

Prespecified 10-year secondary end points included late (after 1 year) appendectomy and appendicitis recurrence rate after antibiotics and complications. Post hoc outcomes included the detection of possible appendiceal tumors among patients in the antibiotic group undergoing appendectomy or with an intact appendix using magnetic resonance imaging. Additional post hoc outcomes were quality of life and patient satisfaction.

Results  

At 10-year follow-up, 253/257 patients (98.4%) randomized to receive antibiotics (median age, 33 years; 102 [40.3%] female) were assessed for appendicitis recurrence, with a true appendicitis recurrence rate (appendicitis at histopathology) of 37.8% (95% CI, 31.6%-44.1% [87/230]) and a cumulative appendectomy rate of 44.3% (95% CI, 38.2%-50.4% [112/253]). Overall, the 10-year cumulative complication rate in the group randomized to appendectomy was 27.4% (95% CI, 21.6%-33.3% [62/226]) and 8.5% (95% CI, 4.8%-12.1% [19/224]) in the group randomized to receive antibiotics (P < .001). There was no observed significant difference in quality of life between antibiotics and appendectomy (387/530; median health index value, 1.0 [95% CI, 1.0-1.0] for both groups; P = .18).

Conclusions and relevance  

Among patients initially treated with antibiotics for uncomplicated acute appendicitis, the rate of recurrence and appendectomy at 10-year follow-up supports the use of antibiotics as an option for uncomplicated acute appendicitis in adult patients.