Outpatient Non-operative Management of Uncomplicated Acute Appendicitis: A Non-inferiority Study.

ABSTRACT

INTRODUCTION: Non-operative management (NOM) of uncomplicated acute appendicitis is a well-established alternative to upfront surgery. The administration of intravenous broad-spectrum antibiotics is usually performed in hospital, and only one study described outpatient NOM. The aim of this multicentre retrospective non-inferiority study was to evaluate both safety and non-inferiority of outpatient compared to inpatient NOM in uncomplicated acute appendicitis. METHODS: The study included 668 consecutive patients with uncomplicated acute appendicitis. Patients were treated according to the surgeon's preference 364 upfront appendectomy, 157 inpatient NOM (inNOM), and 147 outpatient NOM (outNOM). The primary endpoint was the 30-day appendectomy rate, with a non-inferiority limit of 5%. Secondary endpoints were negative appendectomy rate, 30-day unplanned emergency department (ED) visits, and length of stay. RESULTS: 30-day appendectomies were 16 (10.9%) in the outNOM group and 23 (14.6%) in the inNOM group (p = 0.327). OutNOM was non-inferior to inNOM with a risk difference of-3.80% 97.5% CI (- 12.57; 4.97). No difference was found between inNOM and outNOM groups for the number of complicated appendicitis (3 vs. 5) and negative appendectomy (1 vs. 0). Twenty-six (17.7%) outNOM patients required an unplanned ED visit after a median of 1 (1-4) days. In the outNOM group, the mean cumulative in-hospital stay was 0.89 (1.94) days compared with 3.94 (2.17) days in the inNOM group (p < 0.001). CONCLUSIONS: Outpatient NOM was non-inferior to inpatient NOM with regard to the 30-day appendectomy rate, while a shorter hospital stay was found in the outNOM group. Further, studies are required to confirm these findings.