Comparison of claims vs patient-reported adherence measures and associated outcomes among patients with nonvalvular atrial fibrillation using oral anticoagulant therapy

To compare oral anticoagulant (OAC) adherence among patients with nonvalvular atrial fibrillation (NVAF) using patient-reported and claims-based measures, and to evaluate the effect of OAC adherence on health care costs and patient satisfaction with OAC therapy. This was a hybrid US observational study consisting of a longitudinal cohort survey followed by linkage and analysis of respondents' administrative claims data. Patients with NVAF receiving warfarin, dabigatran, rivaroxaban, or apixaban completed an initial survey and follow-up surveys at 4, 8, and 12 months. Patient-reported adherence was measured at each survey by Morisky Medication Adherence Scale (MMAS-8) and pharmacy claims-determined adherence by the proportion of days covered (PDC) for the 12-month period following the initial survey date; adherence was defined as MMAS-8 score =8 and PDC ≥80%. Patient satisfaction with OAC therapy was assessed by the Duke Anticoagulation Satisfaction Scale (DASS). Overall, 675 patients completed at least the initial survey (warfarin, n=271; dabigatran, n=266; rivaroxaban, n=128; apixaban, n=10). Fewer than half (47.9%) were PDC adherent, 37.2% were MMAS-8 adherent, and 19.4% were adherent by both measures. Total medical costs of PDC-adherent patients were significantly lower vs PDC-nonadherent patients (US$640 vs $993 per-patient per-month, respectively,