Comparison of Drug Switching and Discontinuation Rates in Patients with Nonvalvular Atrial Fibrillation Treated with Direct Oral Anticoagulants in the United States

Abstract

IntroductionContinuous usage of direct oral anticoagulants (DOACs) among nonvalvular atrial fibrillation (NVAF) patients is essential to maintain stroke prevention. We examined switching and discontinuation rates for the three most frequently initiated DOACs in NVAF patients in the USA.MethodsPatients who initiated apixaban, rivaroxaban, or dabigatran (index event/date) were identified from the Pharmetrics Plus claims database (Jan 1, 2013–Sep 30, 2016, includes patients with commercial and Medicare coverage) and grouped into cohorts by index DOAC. Patients were required to have a diagnosis of NVAF and continuous health plan enrollment for 12 months prior to the index date (baseline period) and at least 3 months during the follow-up period. Drug switching rates to any other DOAC or warfarin and index DOAC discontinuation rate were evaluated separately with descriptive statistics, Kaplan–Meier analysis, and multivariable Cox regression analysis.ResultsOf the NVAF study population (n = 41,864), 37% initiated apixaban (n = 15,352; mean age 62 years), 51% initiated rivaroxaban (n = 21,250; mean age 61 years), and 13% initiated dabigatran (n = 5262; mean age 61 years). During the follow-up period, the unadjusted drug switching rates of patients treated with apixaban, rivaroxaban, and dabigatran were 3.6%, 6.3%, and 11.1%, respectively (p < 0.001 across the three cohorts); while the index DOAC discontinuation rates were 52.8%, 60.3%, and 62.9%, respectively (p < 0.001). After we controlled for differences in patient characteristics, patients treated with rivaroxaban (HR 1.8; 95% CI 1.6–2.0; p < 0.001) and dabigatran (HR 3.4; 95% CI 3.0–3.8, p < 0.001) had a significantly greater likelihood for drug switching than patients treated with apixaban. Also, both rivaroxaban (HR 1.1; 95% CI 1.1–1.2, p < 0.001) and dabigatran (HR 1.3; 95% CI 1.2–1.3, p < 0.001) treated patients were more likely to discontinue treatment.ConclusionIn the real-world setting, patients with NVAF newly treated with apixaban were less likely to switch or discontinue treatment compared to patients treated with rivaroxaban or dabigatran.FundingPfizer and Bristol-Myers Squibb.

Switching to Another Oral Anticoagulant and Drug Discontinuation Among Elderly Patients With Nonvalvular Atrial Fibrillation Treated With Different Direct Oral Anticoagulants

“…21 However, the data on the prescribing pattern of apixaban complement our other findings in that we have observed before that of the DOACs, apixaban is generally prescribed to older patients with greater comorbidity and higher stroke and bleeding risks. 11,21,22 Among the elderly patients with NVAF in the current study who were prescribed DOACs, after adjusting for the differences in patient characteristics, those treated with rivaroxaban and dabigatran had a 2-fold and nearly a 4-fold higher risk, respectively, to switch to another OAC than patients treated with apixaban. The relative risks of switching to another OAC are consistent with that of our previous study of younger patients with NVAF, although the unadjusted rates of switching among the elderly study population were numerically higher.…”

“…The relative risks of switching to another OAC are consistent with that of our previous study of younger patients with NVAF, although the unadjusted rates of switching among the elderly study population were numerically higher. 21 For elderly patients treated either with apixaban or rivaroxaban, warfarin was the most frequent OAC switched to, while of those treated with dabigatran, the most frequent OAC switched to was apixaban. In addition to which DOAC was initiated, the regression analysis indicated that the risk for switching to another OAC may have been influenced by the geographic region of care and having significant comorbidity (CCI ≥5).…”

Discontinuation of non-Vitamin K antagonist oral anticoagulants in patients with non-valvular atrial fibrillation: a population-based cohort study using primary care data from The Health Improvement Network in the UK

“…Studies from other European countries have reported either highly comparable,32 notably higher17 or lower15 18 1-year NOAC discontinuation rates based on a 30-day treatment gap,18 60-day treatment gap17 32 or other definition of discontinuation,15 with differences possibly attributable to differences in study size, design and/or composition of the study population (eg, the inclusion of OAC-naïve users only). One-year NOAC discontinuation rates among patient populations with NVAF reported from claims database studies in USA have been substantially higher,21 33 yet are consistent with a trend of higher discontinuation for dabigatran compared with rivaroxaban or apixaban,13 15 17 21 22 32 33 and of rates lowest for apixaban in most,13 15 17 21 33 although not all,22 studies. Most other studies on NOAC discontinuation have reported rates over shorter time periods 34…”

“…These findings suggest good tolerability and confidence in this class of medication in the UK. Comparable NOAC switching rates have been reported in two large US claims database studies,14 33 while in another large US administrative database among 34 022 OAC-naïve patients with NVAF, nearly 20% switched medication 36. Switching rates among other European NVAF cohorts starting NOAC therapy have been notably higher.…”

Geriatric Conditions and Prescription of Vitamin K Antagonists vs. Direct Oral Anticoagulants Among Older Patients With Atrial Fibrillation: SAGE-AF

“…Prior studies have shown that geriatric conditions, including cognitive impairment, frailty, and depression, are associated with a higher odds of not being prescribed OAC despite being eligible (40, 41); however, few studies have examined relations between geriatric conditions and type of OAC selected (42, 43). We hypothesized that older, frailer participants affected by a greater burden of geriatric conditions would be prescribed VKA, since these conditions are associated with renal impairment, polypharmacy, and other age-related factors that affect DOAC treatment.…”