Risk factors for gastrointestinal bleeding: a hospital-based case-control study.

QUESTIONS UNDER STUDY/PRINCIPLES: 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).

CONCLUSION

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.