title: Natural history of bleeding risk in colonic diverticulosis patients: a long-term colonoscopy-based cohort study.
abstract: BACKGROUND
  The natural history of bleeding risk from colonic diverticulosis remains unclear.
  
  
  OBJECTIVE
  To identify the incidence of bleeding in colonic diverticulosis patients and associated risk factors.
  
  
  METHODS
  A cohort of 1514 patients with colonoscopy-confirmed asymptomatic diverticulosis was selected between 2001 and 2013. Age, sex and location of colonic diverticulosis (right or left side, or bilateral) were assessed. The endpoint was a bleeding event, and data were censored at the time of last colonoscopy. The cumulative and overall incidences of bleeding were estimated using the Kaplan-Meier and person-years methods. The Cox proportional hazards model was used to estimate age- and sex-adjusted hazard ratios (aHRs).
  
  
  RESULTS
  The median follow-up period was 46 months. Bleeding events occurred in 35 patients, and the median time-to-event interval was 50 months. Kaplan-Meier analysis showed that the cumulative incidence of diverticular bleeding was 0.21% at 12 months, 2.2% at 60 months and 9.5% at 120 months. By the person-years method, the overall incidence rate of bleeding was 0.46 per 1000 patient-years. On multivariate analysis, age ≥70 (aHR. 3.7) and bilateral diverticulosis (aHR, 2.4) were significant risk factors for bleeding.
  
  
  CONCLUSIONS
  This long-term follow-up study demonstrated that the cumulative incidence of bleeding from diverticulosis was approximately 2% at 5 years and 10% at 10 years, and the overall incidence was 0.46 per 1000 patient-years. Bilateral diverticulosis increased the risk of bleeding.
authors.affiliation: Department of Gastroenterology and Hepatology, National Center for Global Health and Medicine, Tokyo, Japan; Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Niikura
authors.forename: N
authors.initials: N
authors.lastname: Nagata
authors.forename: T
authors.initials: T
authors.lastname: Shimbo
authors.forename: T
authors.initials: T
authors.lastname: Aoki
authors.forename: A
authors.initials: A
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Hirata
authors.forename: K
authors.initials: K
authors.lastname: Sekine
authors.forename: H
authors.initials: H
authors.lastname: Okubo
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
authors.forename: C
authors.initials: C
authors.lastname: Yokoi
authors.forename: M
authors.initials: M
authors.lastname: Mizokami
authors.forename: M
authors.initials: M
authors.lastname: Yanase
authors.forename: J
authors.initials: J
authors.lastname: Akiyama
authors.forename: K
authors.initials: K
authors.lastname: Koike
authors.forename: N
authors.initials: N
authors.lastname: Uemura
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003113:Colonoscopy / Q000379:methods*; D043963:Diverticulosis, Colonic / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D006471:Gastrointestinal Hemorrhage / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors