Risk of lower and upper gastrointestinal bleeding, transfusions, and hospitalizations with complex antithrombotic therapy in elderly patients.

BACKGROUND Complex antithrombotic therapy (CAT) prescribed to elderly patients increases the risk of gastrointestinal bleeding. We quantified upper (UGIE) and lower gastrointestinal (LGIE) events, transfusions, and hospitalizations in a national cohort of elderly veterans prescribed CAT. METHODS AND RESULTS Veterans ≥60 years of age prescribed anticoagulant-antiplatelet, aspirin (ASA)-antiplatelet, ASA-anticoagulant, or triple therapy (ie, TRIP, anticoagulant-antiplatelet-ASA) were identified from the national pharmacy database (October 1, 2002 to September 30, 2008). Prescription-fill data were linked to Veteran Affairs and Medicare encounter files, each person-day of follow-up was assessed for CAT exposure, and outcomes were defined by using diagnostic code algorithms derived following chart abstraction. Incidence density ratios (compared with the reference category of no CAT) and survival analysis was conducted. Among 78,133 veterans (98.6% white; mean age, 72.3 [standard deviation 7.7]), 64% were prescribed ASA-antiplatelet and anticoagulant-antiplatelet and 6% were prescribed TRIP. The incidence of UGIE was 20.1/1000 patient-years, and the incidence of LGIE was 70.1/1000 patient-years. ASA-anticoagulant and TRIP were associated with the highest incidence of transfusion and hospitalization. A 40% to 60% increased risk of UGIE was observed with all strategies. LGIE was 30% higher with anticoagulant-antiplatelet, and transfusion increased with ASA-anticoagulant (hazard ratio, 6.1; 95% confidence interval, 5.2-7.1) and TRIP (hazard ratio, 5.0; 95% confidence interval, 4.2-5.8). Increased risk of hospitalization was noted with all strategies. The number needed to harm for UGIE or LGIE ranged from 52 to 65 and 15 to 23, respectively. The number needed to harm for hospitalization was 39 (anticoagulant-antiplatelet), 34 (ASA-anticoagulant), 67 (ASA-antiplatelet), and 45 (TRIP) patients. CONCLUSIONS Among elderly patients, CAT-related LGIE and UGIE are clinically relevant risks resulting in increased hospitalizations and transfusions.