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

Abstract

ObjectiveTo 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.MethodsThis 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).ResultsOverall, 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, p<0.05). MMAS-8-adherent patients reported higher treatment satisfaction; total DASS score was significantly lower among MMAS-8-adherent than MMAS-8-nonadherent patients (37.3 vs 42.9, respectively, p<0.001).ConclusionUsing claims-based or patient-reported methods to measure OAC adherence may lead to different results when assessing impact on health care costs and satisfaction with anticoagulation medication. These results underscore the importance of considering both claims-based and patient-reported measures when evaluating treatment adherence in real-world settings.

Satisfaction of Patients with Nonvitamin K Anticoagulants Compared to Vitamin K Antagonists: a Systematic Review and Meta-analysis

“…With respect to the DASS scale, since only two studies were included, 48,50 we did not perform meta-analysis. Individual data reported in these studies showed a statistically significant decrease favoring NOAC in all the DASS scale domains (total, limitations, burdens, and psychological impact).…”

Reducing Stroke Risk in Atrial Fibrillation: Adherence to Guidelines Has Improved, but Patient Persistence with Anticoagulant Therapy Remains Suboptimal

“…Different methods can provide vastly differing results when calculating adherence and persistence rates. In a study using the USA HealthCore Integrated Research Database (n=675) adherence at 12-months was 48% using prescription refill data, and only 37% when measured using self-report (the eight-item Morisky Medication Adherence Scale [MMAS-8]) 75). This could suggest that although people were filling their prescription they may not have actually taken all the doses 76).…”

A mixed methodology, non-interventional study to evaluate the use of direct oral anticoagulants in UK clinical practice for patients with a first stroke associated with non-valvular atrial fibrillation: study protocol

“…Therefore, a sample size of 150 patients in Group 2 distributed evenly between patients initiated on apixaban, edoxaban and rivaroxaban is considered feasible. A sample size of 50 patients treated with each of the anti-FXa DOACs is considered sufficient to give reliable estimates of patient adherence based on scores from a previously published study of DOAC adherence [24]. For a sample of 50 patients with a mean adherence score of 7.2 and a standard deviation of 1.2, the lower and upper confidence limits are expected to be between 6.9 and 7.5, indicating the sample size is sufficient to provide a reliable estimate of mean adherence score.…”