title: Thromboprophylaxis is associated with reduced post-hospitalization venous thromboembolic events in patients with inflammatory bowel diseases.
abstract: OBJECTIVE
  Patients with inflammatory bowel diseases (IBDs) have increased risk for venous thromboembolism (VTE); those who require hospitalization have particularly high risk. Few hospitalized patients with IBD receive thromboprophylaxis. We analyzed the frequency of VTE after IBD-related hospitalization, risk factors for post-hospitalization VTE, and the efficacy of prophylaxis in preventing post-hospitalization VTE.
  
  
  METHODS
  In a retrospective study, we analyzed data from a multi-institutional cohort of patients with Crohn's disease or ulcerative colitis and at least 1 IBD-related hospitalization. Our primary outcome was a VTE event. All patients contributed person-time from the date of the index hospitalization to development of VTE, subsequent hospitalization, or end of follow-up. Our main predictor variable was pharmacologic thromboprophylaxis. Cox proportional hazard models adjusting for potential confounders were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  From a cohort of 2788 patients with at least 1 IBD-related hospitalization, 62 patients developed VTE after discharge (2%). Incidences of VTE at 30, 60, 90, and 180 days after the index hospitalization were 3.7/1000, 4.1/1000, 5.4/1000, and 9.4/1000 person-days, respectively. Pharmacologic thromboprophylaxis during the index hospital stay was associated with a significantly lower risk of post-hospitalization VTE (HR, 0.46; 95% CI, 0.22-0.97). Increased numbers of comorbidities (HR, 1.30; 95% CI, 1.16-1.47) and need for corticosteroids before hospitalization (HR, 1.71; 95% CI, 1.02-2.87) were also independently associated with risk of VTE. Length of hospitalization or surgery during index hospitalization was not associated with post-hospitalization VTE.
  
  
  CONCLUSIONS
  Pharmacologic thromboprophylaxis during IBD-related hospitalization is associated with reduced risk of post-hospitalization VTE.
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts. Electronic address: aananthakrishnan@partners.org.
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.affiliation: Research IS and Computing, Partners HealthCare, Charlestown, Massachusetts.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cagan
authors.affiliation: Research IS and Computing, Partners HealthCare, Charlestown, Massachusetts.
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Gainer
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Su-Chun
authors.initials: SC
authors.lastname: Cheng
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Tianxi
authors.initials: T
authors.lastname: Cai
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Scoville
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Gauree G
authors.initials: GG
authors.lastname: Konijeti
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts.
authors.forename: Peter
authors.initials: P
authors.lastname: Szolovits
authors.affiliation: Harvard Medical School, Boston, Massachusetts; Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Stanley Y
authors.initials: SY
authors.lastname: Shaw
authors.affiliation: i2b2 National Center for Biomedical Computing, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Susanne
authors.initials: S
authors.lastname: Churchill
authors.affiliation: Harvard Medical School, Boston, Massachusetts; Division of Rheumatology, Allergy and Immunology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Elizabeth W
authors.initials: EW
authors.lastname: Karlson
authors.affiliation: Harvard Medical School, Boston, Massachusetts; Research IS and Computing, Partners HealthCare, Charlestown, Massachusetts; Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Shawn N
authors.initials: SN
authors.lastname: Murphy
authors.affiliation: Harvard Medical School, Boston, Massachusetts; i2b2 National Center for Biomedical Computing, Brigham and Women's Hospital, Boston, Massachusetts; Children's Hospital Boston, Boston, Massachusetts.
authors.forename: Isaac
authors.initials: I
authors.lastname: Kohane
authors.affiliation: Harvard Medical School, Boston, Massachusetts; Division of Rheumatology, Allergy and Immunology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Katherine P
authors.initials: KP
authors.lastname: Liao
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013923:Thromboembolism / Q000453:epidemiology* / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants
keywords: CD; Clot; UC; Vascular; Vein