Adherence to dabigatran therapy and longitudinal patient outcomes: Insights from the Veterans Health Administration

Abstract

Background Dabigatran is a novel oral anti-coagulant (NOAC) that reduces risk of stroke in patients with non-valvular atrial fibrillation (NVAF). It does not require routine monitoring with laboratory testing which may have an adverse impact on adherence. We aimed to describe adherence to dabigatran in the first year after initiation and assess the association between non-adherence to dabigatran and clinical outcomes in a large integrated healthcare system. Methods We studied a national cohort of 5,376 patients with NVAF, initiated on dabigatran between October-2010 and September-2012 at all Veterans Affairs hospitals. Adherence to dabigatran was calculated as proportion of days covered (PDC) and association between PDC and outcomes was assessed using standard regression techniques. Results Mean age of the study cohort was 71.3 ± 9.7 years; 98.3% were men and mean CHADS2 score was 2.4 ± 1.2 (mean CHA2DS2VASc score 3.2 ± 1.4). Median PDC was 94% (IQR 76%-100%; mean PDC 84% ± 22%) over a median follow-up of 244 days (IQR 140-351). A total of 1,494 (27.8%) patients had a PDC <80% and were classified as non-adherent. After multivariable adjustment, lower adherence was associated with increased risk for combined all-cause mortality and stroke (HR 1.13, 95% CI 1.07–1.19 per 10% decrease in PDC). Adherence to dabigatran was not associated with non-fatal bleeding or myocardial infarction. Conclusions In the year after initiation, adherence to dabigatran for a majority of patients is very good. However, 28% of patients in our cohort had poor adherence. Furthermore, lower adherence to dabigatran was associated with increased adverse outcomes. Concerted efforts are needed to optimize adherence to NOACs.

Current Status and Outcomes of Direct Oral Anticoagulant Use in Real-World Atrial Fibrillation Patients ― Fushimi AF Registry ―

“…25 In contrast, a US Veterans Affairs cohort had good adherence to dabigatran (72%), but poor adherence to dabigatran was associated with increased adverse outcome. 26 In patients with CHA2DS2-VASc score ≥2, poorer adherence was associated with higher stroke risk and a relatively small decrease in bleeding risk. 27 OAC adherence is often suboptimal in real-world clinical practice, and may be associated with poor clinical outcome.…”

Therapy persistence in newly diagnosed non-valvular atrial fibrillation treated with warfarin or NOAC

“…Unfortunately, information from large randomised controlled studies (4,18) cannot provide a reliable indication of levels of persistence that might be anticipated in real world practice. Some studies, largely from pharmacy or health system administrative data and all limited to a single NOAC have attempted to estimate persistence and in some studies to determine whether that NOAC drug showed improved persistence compared with VKA (19)(20)(21)(22)(23)(24). To address this important question of OAC persistence in real-world practice following the approval of NOACs, we conducted a cohort study in the UK general practice of patients with a first diagnosis of AF, comparing VKA with NOAC persistence, i. e. the probability of continuing on OAC treatment at one year after the initiation of therapy.…”

The Use of Electronic Personal Health Records to Improve Medication Adherence and Patient Engagement: A Randomized Study of Non-valvular Atrial Fibrillation Patients

“…9 One study from the US Veteran's Administration hospital system database analyzed dabigatran adherence, finding that 28% of patients were non-adherent, and that lower adherence was associated with an increased risk for combined all-cause mortality and stroke. 10 Another study found that anticoagulant clinic patients were more likely to have medication possession ratio (MPR) values of Z80% (considered to be good adherence) on dabigatran at the end of a three-month period than the usual care group. 11 In spite of existing dabigatran research, adherence for this new anticoagulant agent varies among studies and remains sparsely documented.…”