Abstract MP07: Are Gaps In Anticoagulation Due To Under-prescribing Or Prescriptions Not Being Filled: An Administrative Health Claims Analysis

Introduction: Previous studies evaluating factors associated with the underuse of oral anticoagulation (OAC) in patients with atrial fibrillation (AF) relied foremost on claims data, which only contains information on prescription fills but not prescriptions written. Thus it remains unclear to the extent to which OAC underuse is due to providers not prescribing OAC versus patients not filling the medication prescribed. Methods: We used Optum’s De-identified Integrated Claims-EHR data, which combined adjudicated claims data with EHR for 24 million patients across the US. We identified patients newly diagnosed with AF between January 2013 and June 2017. The electronic health records (EHR) allowed us to observe the prescriptions ordered by providers, while the claims data provided prescription fill records by patients. We evaluated patient-, provider-, and health plan-related factors associated with under-prescribing of OAC and under-filling after OAC prescribed. Multivariable logistic regression models were constructed to determine factors associated with under-prescribing and under-filling. Results: Of the 6,141 individuals in the study cohort, 51% were not prescribed OAC within six months of their AF diagnosis. Of the 2,956 patients who were prescribed, 19% did not fill it at the pharmacy. ( Figure ) In the final adjusted model, younger age, location (Northeast and South), a low CHA2DS2-VAS score, and a high HAS-BLED score were associated with a lower likelihood of being prescribed OAC. Among patients who were prescribed, Medicare enrollment (OR and 95% CI: 2.2 [1.3, 3.7]) and having a direct oral anticoagulant prescription (OR and 95% CI: 1.5 [1.2, 1.9]) were associated with lower likelihood of filling the prescription. Conclusion: The underuse of OAC among newly diagnosed patients with AF is largely driven by under-prescribing. Our findings support the development of strategies that target improving prescription orders for the underuse of OAC by millions of patients with AF.