Abstract 10015: Predictors of Primary Non-Adherence in Patients With Nonvalvular Atrial Fibrillation Prescribed Oral Anticoagulants in the US

Abstract

Introduction: Primary non-adherence (PMN) is defined as the failure to fill an initial prescription for a medication or an appropriate alternative. This study assessed the rates and predictors of PMN among patients with non-valvular atrial fibrillation (NVAF) who were newly prescribed an oral anticoagulant (OAC). Methods: A retrospective database analysis of linked claims and electronic health record data was conducted using the Optum ® Market Clarity Dataset. Adult NVAF patients with a first written prescription for an OAC (apixaban, rivaroxaban, dabigatran, or warfarin) from 1/2016-6/2019 were identified (date of first prescription = index date). Patients had a 1-year pre-index period to describe baseline characteristics and a 6-month post-index period to assess rates of PMN, defined as having a written OAC prescription but not having a paid claim for any OAC within 30 days following the index date. Sensitivity analyses explored 60-, 90- and 180-day PMN thresholds. Logistic regression models were used to examine predictors of PMN. Results: The study sample comprised 20,393 patients (mean [SD] age 70.5 [11.3], 59.3% male, 90.0% Caucasian, 53.9% with Medicare only, 30.9% Commercial only, 54.5% in the Midwest). Apixaban (55.4%) was the most commonly prescribed OAC. The overall OAC 30-day PMN rate was 28.4%. Compared to warfarin, direct oral anticoagulants were associated with significantly higher odds of PMN (Figure 1). A CHA2DS2-VASc score of ≥3, Commercial insurance, and African American race were also associated with higher odds of PMN. Sensitivity analyses revealed decreasing PMN over time with a 180-day PMN rate of 17.0%. Conclusions: More than a quarter of patients experienced PMN within 30 days of an initial written OAC prescription; however, this rate decreases over a 180-day period, suggesting a delay in fills. Understanding the factors associated with no fills or delayed fills is warranted to guide interventions for improving OAC treatment rates in NVAF.