Risk factors associated with gastrointestinal bleeding in patients with cardiovascular disease (INTERBLEED): a case control study

AIMS: This study aimed to identify and quantify the importance of risk factors for gastrointestinal (GI) bleeding in patients with CV disease. METHODS: We conducted a case-control study in 9 countries in Asia, America, Europe, and Australia. Cases were patients with CV disease with GI bleeding. Controls were patients with CV without a history of GI bleeding. All participants completed a baseline standardized assessment. We calculated adjusted odds ratios (ORs) and average population attributable fractions (aPAFs) with 95% confidence intervals (CIs). RESULTS: Between September 2015 and December 2022, we enrolled 2,519 cases and 2,202 controls. Independent risk factors for GI bleeding were age (age 71+: OR 4.16, 95% CI 3.48-4.97; age 61-70: OR 1.69, 95% CI 1.39-2.04; age ≤60 as reference), underweight (OR 3.38, 95% CI 2.24-5.10; aPAF 1.6%, 95% CI 1.0-2.0%), current smoker (OR 1.31; 95% CI 1.09-1.58; aPAF 1.5%, 95% CI 0.6-2.5); chronic kidney disease (OR 1.86, 95% CI 1.62-2.14; aPAF 8.8%, 95% CI 7.0-9.6%), prior stroke (OR 1.56, 95% CI 1.30-1.88, aPAF 2.6%, 95% CI 1.2-4.0%), glucocorticoids (OR 1.71, 95% CI 1.34-2.16, aPAF 1.8%, 95% CI 1.3-2.9%), NSAIDs or COX-2 inhibitors (OR 1.82, 95% CI 1.45-2.29; aPAF 2.2%, 95% CI 1.3-3.0%), liver disease (OR 3.68, 95% CI 2.77-4.89; aPAF 3.5%, 95% CI 2.8-4.2%), peptic ulcer disease (OR 3.38, 95% CI 2.66-4.31; aPAF 4.8%, 95% CI 3.8-5.7%), diverticular disease (OR 1.81, 95% CI 1.46-2.24; aPAF 2.8%, 1.9-3.6%) and antithrombotic therapy within 6 months (aPAF 7.6%, 95% CI 4.3-12.8%). Overall aPAF adjusted for age, sex and region was 37.3% (95% CI 33.0-42.2%). CONCLUSION: Potentially modifiable risk factors are associated with only about one third of the aPAF for GI bleeding.