Impact of Social Determinants of Health on Primary Adherence of Oral Anticoagulants Among Patients with Newly Diagnosed Atrial Fibrillation

Introduction: Oral anticoagulants (OAC) reduce the risk of stroke among patients with atrial fibrillation (AF). However, adherence remains suboptimal. We focused on primary nonadherence to OAC and its associations with patient characteristics-specifically social determinants of health collected in electronic health records (EHR).

Methods: This retrospective cohort study used EHR data linked to prescription fill data from a large, integrated Midwestern community healthcare system. Adult patients with an incident AF diagnosis from 2020 to 2021 and a first OAC prescription (index visit) were included. Primary nonadherence was defined as failure to fill an initial OAC prescription within 30 days. Outcomes included 1-year all-cause mortality, first stroke, and first bleed after first OAC prescription. Multivariable logistic regression models evaluated the likelihood of primary nonadherence, and multivariable Cox proportional hazard models evaluated the association between primary nonadherence with outcomes.

Results: Among 8679 patients, 46% were female, 82% were non-Hispanic white, and the mean age was 71.3 ± 12.1 years. Twenty-one percent were primary nonadherent. The odds of primary nonadherence were greater among patients who were non-Hispanic Black, older (≥ 75 years), male, lacking commercial insurance, not employed/retired, and referred to social work; similar results were observed for secondary nonadherence. Primary nonadherence was associated with an increased risk of all-cause mortality (hazard ratio, 1.69; 95% confidence interval, 1.42-2.01).

Conclusion: These results reveal disparities in primary nonadherence among patients with a new AF diagnosis. There is a need to develop and test interventions for primary nonadherence that are implemented in disadvantaged patients, among whom nonadherence is highest.