Male gender is a risk factor for recurrent appendicitis following nonoperative treatment.

Background: This prospective study investigates recurrence rates and identifies predictive factors for recurrence following successful nonoperative treatment in adult patients with acute appendicitis.

Methods: Between January 2003 and December 2009, adult patients with acute appendicitis who received successful nonoperative management were enrolled. Cumulative recurrence rates were calculated using the Kaplan-Meier method. Recurrence-free curves were compared using with the log-rank test. Cox regression models were employed to identify parameters that significantly and independently predict recurrence.

Results: During the study period, 128 patients were enrolled. The median follow-up period was 12 months (range=1-90 months). Twenty (16%) patients developed recurrent appendicitis during follow-up. Twenty-one (16%) patients underwent interval appendectomy (IA). There was no significant difference between nonperforated (NPA) and perforated appendicitis (PA) groups with respect to recurrence rates (16% at the 9th month). Moreover, male gender was significantly associated with recurrence (HR 3.45; 95% CI, 1.15-10.39). Analytical results remained significant after excluding IA patients.

Conclusions: Since the recurrence rate is similar between NPA and PA, nonoperative treatment can be used for PA patients. Roughly 20% of the adult patients selected for nonoperative treatment experienced recurrence. Males were more susceptible than females to recurrent appendicitis.