title: Male gender is a risk factor for recurrent appendicitis following nonoperative treatment.
abstract: 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.
authors.affiliation: Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Wan-Ching
authors.initials: WC
authors.lastname: Lien
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Lee
authors.forename: Hsiu-Po
authors.initials: HP
authors.lastname: Wang
authors.forename: Yi-Chu
authors.initials: YC
authors.lastname: Chen
authors.forename: Kao-Lang
authors.initials: KL
authors.lastname: Liu
authors.forename: Chien-Jen
authors.initials: CJ
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001064:Appendicitis / Q000453:epidemiology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012737:Sex Factors; D055815:Young Adult