The Long-Term Multicenter Observational Study of Dabigatran Treatment in Patients With Atrial Fibrillation (RELY-ABLE) Study

Study Questions:

What are long-term effects of the two doses of dabigatran—110 and 150 mg twice daily—in patients completing the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial?

Methods:

Patients were eligible for RELY-ABLE (The Long-Term Multicenter Observational Study of Dabigatran Treatment in Patients With Atrial Fibrillation) if they were participating in RE-LY and had not permanently discontinued study medication at the time of their final RE-LY study visit. Patients were followed prospectively and continued to receive the double-blind dabigatran dose received in RE-LY for up to 28 months of follow-up after RE-LY. The study outcomes of RELY-ABLE were the same as those of RE-LY; safety outcomes included major, life-threatening, minor, and total bleeding, and deep vein thrombosis.

Results:

Median duration of follow-up for the 5,851 patients enrolled (representing 48% of patients originally randomly assigned to receive dabigatran) was 2.3 years. Annual rates of stroke or systemic embolism were 1.46% and 1.60%/year on dabigatran 150 and 110 mg twice daily, respectively (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.69-1.20). Annual rates of major bleeding were 3.74% and 2.99%/year on dabigatran 150 and 110 mg twice daily, respectively (HR, 1.26; 95% CI, 1.04-1.53). Mortality rates were similar for the two doses (3.10% and 3.02%/year for 110 mg and 150 mg, respectively).

Conclusions:

In extended treatment with dabigatran among patients enrolled in RE-LY, dabigatran 150 and 110 mg twice daily were associated with similar rates of stroke and mortality, but there was a higher rate of major bleeding with 150 mg twice daily.

Perspective:

The limitations of RELY-ABLE aside and recognizing that only about one-half of the patients continued from RE-LY to RELY-ABLE, the current analysis offers longer-term data on the randomized comparison of the two doses of dabigatran. A comparison of the two dabigatran doses suggests minimal benefit in stroke reduction with the higher dose (in contrast to the RE-LY data), at the expense of a significantly greater rate of major bleeding. Such data have implications for practice and regulatory patterns for the two doses of dabigatran.

Keywords: Thromboembolism, Stroke, Follow-Up Studies, beta-Alanine, Benzimidazoles, Cardiology, Confidence Intervals, Hemorrhage


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