title: Risk factors for gastrointestinal bleeding: a hospital-based case-control study.
abstract: OBJECTIVE
  Gastrointestinal (GI) bleeding is a frequent serious adverse drug reaction, potentially causing hospital admission and death. We investigated risk factors for a first-time GI bleeding leading to hospital admission with a focus on drugs and drug-drug interactions (DDIs).
  
  
  METHODS
  We conducted a hospital-based case-control study at the Kantonsspital Winterthur, encompassing 74 patients with a first-time GI bleeding in the year 2005 and 148 controls, matched to cases on age, sex and calendar time.
  
  
  RESULTS
  Multivariate models including various drugs and comorbidities revealed a significant risk for GI bleeding for treatment with nonsteroidal antiinflammatory drugs (NSAIDs) (odds ratio [OR] 8.6, 95% confidence interval [CI] 3.1-23) and thrombocyte aggregation inhibitors (OR 2.2, 95% CI 1.1-4.6). Anticoagulation alone in the therapeutic international normal ratio (INR) range was not associated with bleedings (OR 0.9, 95% CI 0.4-2.3), but INR values > or = 4 were associated with an increased bleeding risk (OR 13, 95% CI 1.2-150). DDI models yielded increased risk estimates for combined use of NSAID and glucocorticoids (OR 20, 95% CI 1.6-257), and for combined use of oral anticoagulants and NSAIDs (8 cases, 0 controls, crude OR approx. 20).
  
  
  CONCLUSIONS
  The findings of this small hospital-based case-control analysis suggest that a first-time GI bleeding is associated with INR values above the therapeutic range, but not with well-controlled oral anticoagulation in the absence of other risk factors such as DDIs. The combinations of glucocorticoids or oral anticoagulants with NSAIDs carry a high risk for GI bleeding.
authors.affiliation: Hospital Pharmacy, Kantonsspital Winterthur / University Children's Hospital Zurich, Switzerland.
authors.forename: Priska
authors.initials: P
authors.lastname: Vonbach
authors.forename: Rahel
authors.initials: R
authors.lastname: Reich
authors.forename: Friedrich
authors.initials: F
authors.lastname: Möll
authors.forename: Stephan
authors.initials: S
authors.lastname: Krähenbühl
authors.forename: Peter E
authors.initials: PE
authors.lastname: Ballmer
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Meier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use; D000925:Anticoagulants / Q000008:administration & dosage; D016022:Case-Control Studies; D004347:Drug Interactions; D005260:Female; D005765:Gastrointestinal Agents / Q000009:adverse effects / Q000627:therapeutic use; D006471:Gastrointestinal Hemorrhage / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000925:Anticoagulants; D005765:Gastrointestinal Agents