Anticoagulant Use Among Afib Patients Wanes Over Time

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ORLANDO -- Barely half of patients with atrial fibrillation who were prescribed rivaroxaban (Xarelto) to prevent stroke remained on the treatment after 2 years, but their adherence was still better than Afib patients on warfarin or dabigatran (Pradaxa), researchers said here.

In a study based on claims data, persistence in taking anticoagulants was 50.4% among patients on rivaroxaban at 2 years compared with 30.6% of patients who were being treated with dabigatran and 26.6% of the patients who were being treated with warfarin, reported Craig Coleman, PharmD, of the University of Connecticut Health Center in Storrs, and colleagues.

The difference in adherence between rivaroxaban and the other two agents was statistically significant (P<0.05), Coleman told MedPage Today at his poster presentation at the American Heart Association meeting.

Coleman's group performed a retrospective cohort analysis of the U.S. MarketScan claims databases. The study included 57,489 individuals with non-valvular Afib, including 11,052 patients newly started on rivaroxaban, 11,100 patients on dabigatran, and 35,337 patients taking warfarin, from 2011-2013.

Patients had a baseline CHA₂DS₂-VASc score ≥2, ≥2 atrial fibrillation diagnosis codes, and ≥6 months of continuous medical and pharmacy benefits prior to anticoagulant initiation. They were followed until the earliest of in-hospital death, end of continuous enrollment, or the end of the study.

The authors defined persistence as the absence of refill gap of >60 days. Discontinuation was defined as no additional refill for >90 days and through end of follow-up.

Using propensity scoring, the researchers analyzed outcomes among 32,634 patients (10,878 in each treatment group).

On regression, rivaroxaban use was associated with a decreased hazard of nonpersistence compared with dabigatran (hazard ratio 0.64, 95% CI 0.62-0.67) and warfarin (HR 0.62, 95% CI 0.59-0.64), and a decreased rate of discontinuation versus dabigatran (HR 0.61, 95% CI 0.58-0.64) and warfarin (HR 0.65, 95% CI 0.62-0.68).

"Optimal and persistent use of non-vitamin K antagonist oral anticoagulants is essential in reducing the risk of ischemic stroke in patients with non-valvular atrial fibrillation," Coleman said. "Future research examining the impact of nonpersistence and treatment discontinuation by non-valvular atrial fibrillation patients on their clinical and economic outcome is needed."

"We found, as former Surgeon General C. Everett Koop often said, 'Drugs don't work in people who don't take them,'" Coleman said.

"We were able to demonstrate that there were differences in persistence between these treatments," he added. "It seems that people receiving rivaroxaban were more likely to remain on their medication. These patients were followed for an average of about a year and a half."

Improving persistence, said Douglas Zipes, MD, past president of the American College of Cardiology "requires the physician to sit down with the patient an educate him or her on why it is vital to take this medication."

"The doctor must find time to educate them to the potential risks of having atrial fibrillation untreated. The doctor, the nurse practitioner, or even the healthcare pharmacist, who is now being included in blood pressure management, can educate these people. The failure to educate these patients is the Achilles heel to these new treatments," said Zipes, who is at the Indiana University Medical School in Indianapolis.

Physicians have to address the common attitudes of patients who are taking drugs for chronic, asymptomatic diseases, Zipes told MedPage Today.

"Patients who feel fine say, 'Ehh, I don't need that medicine any more.' That's the problem. We as healthcare practitioners must reinforce the need for therapy. This is not unique with anticoagulation. We see that with cessation of aspirin, beta-blockers, anti-hypertensive drugs, statins -- you can go through the whole list," he said.

"In my 50-plus years of taking care of patients, the biggest obstacle is to change behavior," he added. "To accomplish this, it requires constant reinforcement by the healthcare practitioner and constant education."

Action Points

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Barely half of patients with atrial fibrillation who were prescribed rivaroxaban to prevent stroke remained on the treatment after 2 years, but their adherence was still better than Afib patients on warfarin or dabigatran.

Note that the study suggests that physicians have to address the common attitudes of patients who are taking drugs for chronic, asymptomatic diseases to help improve adherence.

Coleman agreed. "I tell doctors all the time, 'You have to remind the patients of the need to take their anticoagulants at every visit.'"

Coleman pointed out that by looking at data up to 2013, "it was too early for meaningful apixaban [Eliquis] data."

Also, his group could not confirm why rivaroxaban use persisted versus other agents based on their data.

"But there are logical reasons," he stated. "Dabigatran is associated with more dyspepsia, especially early on in therapy. Rivaroxaban is a once daily drug while dabigatran is twice a day. And because dabigatran was the first of these new oral anticoagulants on the market, people may have switched from dabigatran to other treatments."

The study was supported by Bayer Pharma AG.

Coleman disclosed relevant relationships with Bayer HealthCare, Bayer Pharma AG, Janssen Scientific Affairs, Boehringer-Ingelheim Pharmaceuticals, Daiichi-Sankyo, and Portola Pharmaceuticals. Other co-authors are employees of Bayer.

Zipes disclosed relevant relationships with Medtronic.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

This report is part of a 12-month Curriculum In Context series.

last updated 11.12.2015

Primary Source: American Heart Association

Coleman C, et al. "Treatment persistence and discontinuation with Rivaroxaban, Dabigatran and Warfarin for stroke prevention in patients with non-valvular atrial fibrillation." AHA 2015; Abstract 2077.

This article was first published on MedPage Today and reprinted with permission. Free registration is required