title: Risk of Major Abdominal Surgery in an Asian Population-based Crohn's Disease Cohort.
abstract: BACKGROUND
  Crohn's disease (CD) is increasing in incidence and prevalence in Asia, but there is a paucity of population-based studies on risk factors for surgery in Asian patients with CD. This will be useful to identify patients who may benefit from top-down treatment. This study describes the rates of abdominal surgery and identifies associated risk factors in Singaporean patients with CD.
  
  
  METHODS
  This was a retrospective observational study. The medical records of Singaporeans diagnosed with CD from 1970 to 2013 were reviewed from 8 different hospitals in Singapore. The cumulative probability of CD-related abdominal surgery was estimated using the Kaplan-Meier method. The logistic regression model was used to assess associations between independent risk factors and surgery.
  
  
  RESULTS
  The cohort of 430 Singaporean patients with CD included 63.5% Chinese, 11.9% Malay, and 24.7% Indians, with a male to female ratio of 1.6; median follow-up was 7.3 years (range, 2.9-13.0 yr) and median age at diagnosis 30.5 years (range, 19.5-43.7 yr). One hundred twelve patients (26.0%) required major abdominal surgery: the cumulative risk of surgery was 14.9% at 90 days, 21.2% at 5 years, 28.8% at 10 years, 38.3% at 20 years, and 50.6% at 30 years from diagnosis. Of the surgical patients, 75.0% were Chinese, 10.7% Malays, and 14.3% Indians; 21.4% underwent surgery for inflammatory disease, 40.2% for stricturing disease, and 38.4% for penetrating disease. Age at diagnosis (A2 17-40 yr, OR: 2.75, 95% confidence interval [CI], 1.14-7.76), ileal disease (L1 location, OR: 2.35, 95% CI, 1.14-5.0), stricturing (B2 OR: 6.09, 95% CI, 3.20-11.8), and penetrating behavior (B3 OR: 21.6, 95% CI, 9.0-58.8) were independent risk factors for CD-related abdominal surgery. Indian patients were less likely to require surgery (OR: 0.40, 95% CI, 0.19-0.78).
  
  
  CONCLUSIONS
  Age at diagnosis, L1 location, B2, and B3 disease behavior are independent risk factors for abdominal surgery. Interestingly, despite a higher prevalence of CD in Indians, a smaller proportion of Indian patients required surgery. These findings suggest that both environmental and genetic factors contribute to the risk of surgery in Asian patients with CD.
authors.affiliation: *Duke-NUS Graduate Medical School, Singapore; †Department of Gastroenterology and Hepatology, Singapore General Hospital, Singapore; ‡Department of Gastroenterology and Hepatology, Tan Tock Seng Hospital, Singapore; §Department of Gastroenterology and Hepatology, Changi General Hospital, Singapore; ‖Division of Gastroenterology and Hepatology, University Medicine Cluster, National University Health System, Singapore; ¶Gastroenterology Service, Paediatric Medicine, KK Women's and Children's Hospital, Singapore; **Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Khoo Teck Puat-National University Children's Medical Institute, National University Health System, Singapore; ††Department of Gastroenterology and Hepatology, Khoo Teck Puat Hospital, Singapore; and ‡‡Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Pandey
authors.forename: Ennaliza
authors.initials: E
authors.lastname: Salazar
authors.forename: Christopher S C
authors.initials: CS
authors.lastname: Kong
authors.forename: Wee Chian
authors.initials: WC
authors.lastname: Lim
authors.forename: Jeannie
authors.initials: J
authors.lastname: Ong
authors.forename: David E H
authors.initials: DE
authors.lastname: Ong
authors.forename: Christina
authors.initials: C
authors.lastname: Ong
authors.forename: Marion
authors.initials: M
authors.lastname: Aw
authors.forename: Eric
authors.initials: E
authors.lastname: Wee
authors.forename: Sai Wei
authors.initials: SW
authors.lastname: Chuah
authors.forename: Valerie
authors.initials: V
authors.lastname: Tan
authors.forename: Wei Lin
authors.initials: WL
authors.lastname: Tay
authors.forename: Nivedita
authors.initials: N
authors.lastname: Nadkarni
authors.forename: Khoon Lin
authors.initials: KL
authors.lastname: Ling
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000328:Adult; D000367:Age Factors; D044466:Asian People; D003251:Constriction, Pathologic / Q000601:surgery*; D003424:Crohn Disease / Q000150:complications* / Q000601:surgery*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012846:Singapore; D055815:Young Adult