Abstract P541: Trends in Initiation of Anticoagulation for Atrial Fibrillation in the Early Months of the COVID-19 Pandemic

Introduction: Oral anticoagulation (OAC) is the treatment of choice to prevent stroke in patients with atrial fibrillation (AF). We evaluated changes in OAC initiation in newly diagnosed AF after the onset of the COVID-19 pandemic. Hypothesis: We hypothesized that individuals newly diagnosed with AF in the early months of the COVID-19 pandemic would be less likely to initiate OAC than those with incident AF before the pandemic. Methods: We selected individuals with incident AF in 01/01/2016 - 09/30/2021 from Optum’s de-identified Clinformatics® Data Mart Database. AF was defined by having ICD-9 code 427.31 or ICD-10 codes I48.0, I48.1, I48.2, or I48.91 at the first or second diagnosis field. For every 30-day period. We measured the proportion of individuals newly diagnosed with AF initiated OAC within 30 or 180 days of diagnosis. As secondary outcomes, we evaluated the initiation of warfarin and of direct oral anticoagulants (DOACs) individually. We constructed interrupted time series analyses to examine changes in the level and trend of OAC initiation following the onset of the COVID-19 pandemic, defined by the date of the World Health Organization declaration (3/11/2020). Results: The study sample included 573,524 individuals (age 73± 11 years, 48% female sex, 85% Medicare beneficiaries). Although initiation of OAC and DOAC increased in 01/01/2016-09/30/2021 (Figure), there were no significant changes associated with the onset of pandemic (all P>0.05). Rates of warfarin initiation decreased over time, from 9.7% in year 2016 to 1.9% in year 2021. Conclusion: There were no significant changes in the initiation of OAC immediately after the onset of the COVID-19 pandemic among patients newly diagnosed with AF during this time.