Evaluating the Initiation of Novel Oral Anticoagulants in Medicare Beneficiaries

Abstract

BACKGROUND As alternatives to warfarin, 2 novel oral anticoagulants (NOACs), dabigatran and rivaroxaban, were approved in 2010 and 2011 to prevent stroke and other thromboembolic events in patients with atrial fibrillation. It is unclear how patient characteristics are associated with the initiation of anticoagulants. OBJECTIVE To evaluate how patient demographics, clinical characteristics, types of insurance, and patient out-of-pocket spending affect the initiation of warfarin and 2 NOACs—dabigatran and rivaroxaban. METHODS We used pharmacy claims data from a 5% random sample of Medicare beneficiaries to identify patients who were newly diagnosed with atrial fibrillation between October 1, 2010, and October 31, 2012, and who were prescribed an oral anticoagulant within 60 days of diagnosis. We identified key predictors of initiation of NOACs using a multinomial logistic regression model with generalized logit link. RESULTS Patients who were black and who had a history of acute myocardial infarction, stroke or transient ischemic attack, chronic kidney disease, or congestive heart failure were significantly associated with lower odds of receiving NOACs compared with warfarin. Age greater than 65 years, a history of hypertension, and use of nonsteroidal anti-inflammatory drugs were positively associated with the initiation of NOACs. Rivaroxaban was most likely to be initiated among women, followed by warfarin and dabigatran. Individuals receiving a low-income subsidy were more likely to initiate warfarin than NOACs, even though they paid little copayment. Individuals with supplemental Part D drug coverage, such as national Programs for All-Inclusive Care for the Elderly or employer-sponsored plans, were more likely to initiate NOACs compared with warfarin. CONCLUSIONS We found that race, sex, type of Part D plans, and some clinical conditions were associated with the initiation of NOACs relative to warfarin. But patient demographic and clinical characteristics did not appear to affect which particular NOAC patients initiated.

Initiation of anticoagulation in atrial fibrillation: which factors are associated with choice of anticoagulant?

“…described patient characteristics and demographics amongst initiators of dabigatran and rivaroxaban compared with warfarin for stroke prophylaxis in AF. Patients who had suffered from stroke, kidney disease, acute myocardial infarction (only for dabigatran) or congestive heart failure had lower odds of being initiated on either dabigatran or rivaroxaban compared with warfarin . Desai et al .…”

“…Baik et al described patient characteristics and demographics amongst initiators of dabigatran and rivaroxaban compared with warfarin for stroke prophylaxis in AF. Patients who had suffered from stroke, kidney disease, acute myocardial infarction (only for dabigatran) or congestive heart failure had lower odds of being initiated on either dabigatran or rivaroxaban compared with warfarin [20]. Desai et al [18] found lower odds of initiation of one of the NOACs compared with warfarin in patients who suffered from congestive heart failure, diabetes, stroke, previous bleeding or renal dysfunction.…”

Geographic Variation in the Use of Oral Anticoagulation Therapy in Stroke Prevention in Atrial Fibrillation

“…3 Then, we estimated the average probability of receiving oral anticoagulation and the average probability of being prescribed an NOAC among patients on oral anticoagulation in each HRR, while holding all predictors mentioned above constant. 6 This methodology enabled us to isolate geographic variation that is not explained by the confounders listed above.…”

“…2 After new oral anticoagulants (NOACs) had entered the market, several studies evaluated the factors associated with the initiation of NOACs, relative to warfarin. 3 However, it remains unclear how the use of oral anticoagulation in AF varies across regions of the United States. To address this question, we used 2013 to 2014 claims data from a 5% random sample of Medicare beneficiaries.…”

Physicians’ views on patient participation in choice of oral anticoagulants in atrial fibrillation—a qualitative study

“…Physicians also report clinical characteristics of the patient, risk of adverse events, their own knowledge, experience and preferences to be important in decision‐making. Database studies have identified mainly clinical factors, such as estimated stroke risk, age and other cardiovascular diseases as factors affecting the choice of an OAC. These studies have also found lower socio‐economic status and poorer medication coverage to favour the use of VKAs.…”