Impact of drug interactions with direct oral anticoagulants on mortality in elderly with atrial fibrillation during the COVID-19 pandemic

OBJECTIVE: To evaluate the effect of drug interactions with chronic direct oral anticoagulants (DOAC) on mortality in older atrial fibrillation (AF) patients during the Coronavirus disease 2019(COVID-19) pandemic. METHODS: We followed a total of 601 elderly patients (65 years of age) from the NOEL-Drug Registry cohort who were referred to a tertiary outpatient clinic between 9 March 2020 and 1 March 2021. We recorded clinical characteristics and medications for the last 3 months. In addition, all drug interactions were identified using Lexicomp®. Finally, we recorded retrospectively all death events, COVID-19 diagnosis, and relevant deaths from the database at the end of the study. According to logistic regression, we performed propensity score (PS) matching to reduce potential bias. Factors associated with total mortality in the 12 months were analyzed using multivariable Cox proportion hazard analysis. RESULTS: The mean age [standard deviation (SD)] was 74.5 (±6.9), and the male/female ratio was 337/264. The prevalence of total mortality was 16.9% (n = 102). A total of 4472 drugs were analyzed for DOAC interaction. 81.8% of older AF patients were not at risk in terms of potential interaction. In the Cox proportional hazard model after PS-matching, previous DOAC use with class X interaction was associated with significantly higher mortality risk (adjusted hazard ratio: 2.745, 95% confidence interval: 1.465–5.172, p = 0.004). CONCLUSIONS: Our study showed that while most co-medications do not have significant interactions with DOACs, few serious drug interactions contribute to mortality in elderly patients with AF during the pandemic.