Lower gastrointestinal bleeding in patients with coronary artery disease on antithrombotics and subsequent mortality risk

BACKGROUND: Lower gastrointestinal bleeding (LGIB) is a common complication for patients with coronary artery disease (CAD) due to the use of antithrombotic medications. Limited data exist describing which patients are at increased risk for mortality. AIM: This study aims to (i) determine whether patients on dual antiplatelet therapy (DAPT) or triple therapy are at higher risk of 90-day and 6-month mortality compared with patients on aspirin alone and (ii) evaluate risk factors for mortality in patients with CAD on antithrombotics hospitalized with LGIB. METHODS: We conducted a retrospective cohort study of patients hospitalized with LGIB and CAD while on aspirin at a single academic medical center from 2007 to 2015. Patients were identified using a validated, machine-learning algorithm and classified by use of aspirin, DAPT, or triple therapy. Univariate and multivariate Cox proportional hazards were used to determine mortality associated risk factors. RESULTS: Seven hundred sixteen patients were identified with LGIB and CAD. Four hundred seventy-two (65.9%) patients were on aspirin monotherapy, 179 (25%) on aspirin and thienopyridine (DAPT), and 65 (9.1%) on aspirin, thienopyridine, and systemic anticoagulant (triple therapy). On univariate analysis, triple therapy use was associated with increased risk of 90-day (hazard ratio [HR] 3.12, 95% confidence interval [CI] 1.52-5.92, P = 0.003) and 6-month (HR 2.46, 95%CI 1.29-4.35, P = 0.008) mortality. Holding anticoagulation was associated with higher mortality at 90 days (HR 2.30, 95%CI 1.27-4.07, P = 0.007). On multivariate analysis, after adjusting for confounding variables, the use of triple therapy remained associated with higher 90-day mortality (HR 3.23, 95%CI 1.56-6.16, P = 0.003). CONCLUSION: Triple therapy is associated with mortality at 90 days and at 6 months post discharge.