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School of Pharmacy


Pharmaceutical Systems and Policy


Purpose This study aims to evaluate the associations between switching from warfarin to non-vitamin K oral anticoagulants (NOACs), exposure to potential drug-drug interactions (DDIs), and major bleeding events in working-age adults with atrial fibrillation (AF). Methods We conducted a retrospective cohort study using the claims database of commercially insured working-age adults with AF from 2010 to 2015. Switchers were defined as patients who switched from warfarin to NOAC; non-switchers were defined as those who remained on warfarin. We developed novel methods to calculate the number and proportion of days with potential DDIs with NOAC/warfarin. Multivariate logistic regressions were utilized to evaluate the associations between switching to NOACs, exposure to potential DDIs, and major bleeding events. Results Among a total of 4126 patients with AF, we found a significantly lower number of potential DDIs and the average proportion of days with potential DDIs in switchers than non-switchers. The number of potential DDIs (AOR 1.14, 95% CI 1.02–1.27) and the HAS-BLED score (AOR 1.64, 95% CI 1.48–1.82) were significantly and positively associated with the likelihood of a major bleeding event. The proportion of days with potential DDIs was also significantly and positively associated with risk for bleeding (AOR 1.42, 95% CI 1.03, 1.96). We did not find significant associations between switching to NOACs and major bleeding events. Conclusions The number and duration of potential DDIs and patients’ comorbidity burden are important factors to consider in the management of bleeding risk in working-age AF adults who take oral anticoagulants.

Source Citation

Feng X, Sambamoorthi U, Innes K, et al. Predictors of Major Bleeding Among Working-Age Adults with Atrial Fibrillation: Evaluating the Effects of Potential Drug-drug Interactions and Switching from Warfarin to Non-vitamin K Oral Anticoagulants. Cardiovascular Drugs and Therapy. 2018;32(6):591-600. doi:10.1007/s10557-018-6825-7