Cohort Study: Higher serious bleeding rates linked to diltiazem in elderly atrial fibrillation patients on anticoagulation

Study Design and Population:
This retrospective cohort study analyzed data from 204,155 Medicare beneficiaries aged 65 years or older diagnosed with atrial fibrillation. The study focused on new users of the anticoagulants apixaban or rivaroxaban who commenced treatment with either diltiazem or metoprolol between January 2012 and November 2020, with follow-up extending up to 365 days.

Main Findings:
Patients treated with diltiazem exhibited a significantly increased risk of serious bleeding, including bleeding-related hospitalization and death, compared to those treated with metoprolol. The hazard ratio (HR) for serious bleeding events was 1.21, with a rate difference (RD) of 10.6 per 1000 person-years. Notably, the risk escalated with diltiazem doses exceeding 120 mg/day, indicating a dose-response relationship. Secondary outcomes, such as ischemic stroke or systemic embolism, did not show significant differences between the treatment groups.

Implications for Practice:
The findings suggest that in older adults with atrial fibrillation treated with apixaban or rivaroxaban, diltiazem increases the risk of serious bleeding, especially at higher doses. These results underscore the importance of cautious medication management and might influence clinical decisions regarding the choice of ventricular rate control in this population.

Reference (link to abstract – $ for full-text):

Ray, W. A., Chung, C. P., Stein, C. M., et al. (2024). Serious Bleeding in Patients With Atrial Fibrillation Using Diltiazem With Apixaban or Rivaroxaban. JAMA, Published online April 15, 2024. doi:10.1001/jama.2024.3867