COVID-19 and Anticoagulation for Atrial Fibrillation: An Analysis of US Nationwide Pharmacy Claims Data.

Background Adherence to oral anticoagulation (OAC) is critical for stroke prevention in atrial fibrillation. However, the COVID-19 pandemic may have disrupted access to such therapy. We hypothesized that our analysis of a US nationally representative pharmacy claims database would identify increased incidence of lapses in OAC refills during the COVID-19 pandemic. Methods and Results We identified individuals with atrial fibrillation prescribed OAC in 2018. We used pharmacy dispensing records to determine the incidence of 7-day OAC gaps and 15-day excess supply for each 30-day interval from January 1, 2019 to July 8, 2020. We constructed interrupted time series analyses to test changes in gaps and supply around the pandemic declaration by the World Health Organization (March 11, 2020), and whether such changes differed by medication (warfarin or direct OAC), prescription payment type, or prescriber specialty. We identified 1 301 074 individuals (47.5% women; 54% age ≥75 years). Immediately following the COVID-19 pandemic declaration, we observed a 14% decrease in 7-day OAC gaps and 56% increase in 15-day excess supply (both P <0.001). The increase in 15-day excess supply was more marked for direct OAC (69% increase) than warfarin users (35%; P <0.001); Medicare beneficiaries (62%) than those with commercial insurance (43%; P <0.001); and those prescribed OAC by a cardiologist (64%) rather than a primary care provider (48%; P <0.001). Conclusions Our analysis of nationwide claims data demonstrated increased OAC possession after the onset of the COVID-19 pandemic. Our findings may have been driven by waivers of early refill limits and patients' tendency to stockpile medications in the first weeks of the pandemic.