title: Appendectomy does not decrease the risk of future colectomy in UC: results from a large cohort and meta-analysis.
abstract: Early appendectomy is inversely associated with the development of UC. However, the impact of appendectomy on the clinical course of UC is controversial, generally favouring a milder disease course. We aim to describe the effect appendectomy has on the disease course of UC with focus on the timing of appendectomy in relation to UC diagnosis.
  
  
  
  Using the National Institute of Diabetes and Digestive and Kidney Diseases Inflammatory Bowel Disease Genetics Consortium database of patients with UC, the risk of colectomy was compared between patients who did and did not undergo appendectomy. In addition, we performed a meta-analysis of studies that examined the association between appendectomy and colectomy.
  
  
  
  2980 patients with UC were initially included. 111 (4.4%) patients with UC had an appendectomy; of which 63 were performed prior to UC diagnosis and 48 after diagnosis. In multivariable analysis, appendectomy performed at any time was an independent risk factor for colectomy (OR 1.9, 95% CI 1.1 to 3.1), with appendectomy performed after UC diagnosis most strongly associated with colectomy (OR 2.2, 95% CI 1.1 to 4.5). An updated meta-analysis showed appendectomy performed either prior to or after UC diagnosis had no effect on colectomy rates.
  
  
  
  Appendectomy performed at any time in relation to UC diagnosis was not associated with a decrease in severity of disease. In fact, appendectomy after UC diagnosis may be associated with a higher risk of colectomy. These findings question the proposed use of appendectomy as treatment for UC.
authors.affiliation: Division of Gastroenterology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Parian
authors.affiliation: Division of Gastroenterology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.|Division of Gastroenterology & Hepatology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Berkeley
authors.initials: B
authors.lastname: Limketkai
authors.affiliation: Division of Gastroenterology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Joyce
authors.initials: J
authors.lastname: Koh
authors.affiliation: Division of Gastroenterology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Brant
authors.affiliation: Division of Gastroenterology, McGill University, Montreal, Québec, Canada.
authors.forename: Alain
authors.initials: A
authors.lastname: Bitton
authors.affiliation: Division of Gastroenterology, Mount Sinai Hospital, New York, New York, USA.
authors.forename: Judy H
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Duerr
authors.affiliation: Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Dermot P
authors.initials: DP
authors.lastname: McGovern
authors.affiliation: Division of Digestive Disease, Yale School of Medicine, New Haven, Connecticut, USA.
authors.forename: Deborah D
authors.initials: DD
authors.lastname: Proctor
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Miguel D
authors.initials: MD
authors.lastname: Regueiro
authors.affiliation: Division of Medicine, Université de Montréal, Montreal, Québec, Canada.
authors.forename: John D
authors.initials: JD
authors.lastname: Rioux
authors.affiliation: Department of Health Studies, University of Chicago, Chicago, Illinois, USA.
authors.forename: Phil
authors.initials: P
authors.lastname: Schumm
authors.affiliation: Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Kent D
authors.initials: KD
authors.lastname: Taylor
authors.affiliation: Division of Gastroenterology, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Silverberg
authors.affiliation: Division of Gastroenterology, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: A Hillary
authors.initials: AH
authors.lastname: Steinhart
authors.affiliation: Division of Gastroenterology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Ruben
authors.initials: R
authors.lastname: Hernaez
authors.affiliation: Division of Gastroenterology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Lazarev
mesh_terms: D000293:Adolescent; D000328:Adult; D001062:Appendectomy / Q000706:statistics & numerical data*; D003082:Colectomy / Q000706:statistics & numerical data*; D003093:Colitis, Ulcerative / Q000175:diagnosis / Q000601:surgery*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking; D013997:Time Factors; D055815:Young Adult
keywords: APPENDIX; COLORECTAL SURGERY; INFLAMMATORY BOWEL DISEASE; ULCERATIVE COLITIS