title: Pre-colectomy appendectomy and risk for Crohn's disease in patients with ileal pouch-anal anastomosis.
abstract: BACKGROUND
  A subset of patients with a pre-operative diagnosis of ulcerative colitis can develop Crohn's disease (CD) of the pouch after restorative proctocolectomy. While appendectomy has been implicated to be associated with an increased risk for CD, its impact on the development of de novo CD of the pouch in patients' ileal pouch-anal anastomosis (IPAA) has not been studied. The aims of the study were to assess the prevalence of CD of the pouch in patients with pre-colectomy appendectomy and to investigate the impact of appendectomy on the development of de novo CD of the pouch.
  
  
  METHODS
  All eligible patients with restorative proctocolectomy and IPAA for IBD who had available information on pre-colectomy appendectomy were studied. Demographic and clinical characteristics were evaluated. Cox regression analysis was performed.
  
  
  RESULTS
  The study included 434 patients (44.9 % male) with a mean age of 45.2 ± 4.4 years and follow-up of 4.6 ± 2.3 years. Forty patients (9.2 %) had had appendectomy prior to colectomy. Appendectomy was not shown to be associated with CD of the pouch or its phenotypes in both univariable and multivariable analyses. In the Cox model, independent risk factors associated with CD of the pouch were active smoking (hazard ratio [HR] =1.58; 95 % confidence interval [CI], 1.03-2.43) and family history of CD (HR=1.82; 95 % CI, 0.99-3.32).
  
  
  CONCLUSIONS
  While this study has shown no association between previous appendectomy and the development of CD of pouch, active smoking was an independent risk factor for development of CD of the pouch.
authors.affiliation: Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China.
authors.forename: Zhaoxiu
authors.initials: Z
authors.lastname: Liu
authors.forename: Haiyan
authors.initials: H
authors.lastname: Lu
authors.forename: Ravi P
authors.initials: RP
authors.lastname: Kiran
authors.forename: Runzhou
authors.initials: R
authors.lastname: Ni
authors.forename: Feza H
authors.initials: FH
authors.lastname: Remzi
authors.forename: Bo
authors.initials: B
authors.lastname: Shen
mesh_terms: D000328:Adult; D001062:Appendectomy; D003093:Colitis, Ulcerative / Q000150:complications / Q000601:surgery*; D039021:Colonic Pouches / Q000473:pathology*; D003424:Crohn Disease / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000453:epidemiology; D015995:Prevalence; D016737:Proctocolectomy, Restorative; D016016:Proportional Hazards Models; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects