Cardiovascular, bleeding, and mortality risks in elderly Medicare patients treated with dabigatran or warfarin for nonvalvular atrial fibrillation.

Abstract

BACKGROUND:

The comparative safety of dabigatran versus warfarin for treatment of nonvalvular atrial fibrillation in general practice settings has not been established.

METHODS AND RESULTS:

We formed new-user cohorts of propensity score-matched elderly patients enrolled in Medicare who initiated dabigatran or warfarin for treatment of nonvalvular atrial fibrillation between October 2010 and December 2012. Among 134 414 patients with 37 587 person-years of follow-up, there were 2715 primary outcome events. The hazard ratios (95% confidence intervals) comparing dabigatran with warfarin (reference) were as follows: ischemic stroke, 0.80 (0.67-0.96); intracranial hemorrhage, 0.34 (0.26-0.46); major gastrointestinal bleeding, 1.28 (1.14-1.44); acute myocardial infarction, 0.92 (0.78-1.08); and death, 0.86 (0.77-0.96). In the subgroup treated with dabigatran 75 mg twice daily, there was no difference in risk compared with warfarin for any outcome except intracranial hemorrhage, in which case dabigatran risk was reduced. Most patients treated with dabigatran 75 mg twice daily appeared not to have severe renal impairment, the intended population for this dose. In the dabigatran 150-mg twice daily subgroup, the magnitude of effect for each outcome was greater than in the combined-dose analysis.

CONCLUSIONS:

In general practice settings, dabigatran was associated with reduced risk of ischemic stroke, intracranial hemorrhage, and death and increased risk of major gastrointestinal hemorrhage compared with warfarin in elderly patients with nonvalvular atrial fibrillation. These associations were most pronounced in patients treated with dabigatran 150 mg twice daily, whereas the association of 75 mg twice daily with study outcomes was indistinguishable from warfarin except for a lower risk of intracranial hemorrhage with dabigatran.

• Authors: David J Graham, Marsha E Reichman, Michael Wernecke, Rongmei Zhang, Mary Ross Southworth, Mark Levenson, Ting-Chang Sheu, Katrina Mott, Margie R Goulding, Monika Houstoun, Thomas E MaCurdy, Chris Worrall, Jeffrey A Kelman
• Journal: Circulation (Circulation) Vol. 131 Issue 2 Pg. 157-64 (Jan 13 2015) ISSN: 1524-4539 [Electronic] United States
• PMID: 25359164 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 American Heart Association, Inc.

Chemical References

• Anti-Arrhythmia Agents
• Anticoagulants
• Benzimidazoles
• beta-Alanine
• Warfarin
• Dabigatran

Topics

• Aged
• Aged, 80 and over
• Anti-Arrhythmia Agents (therapeutic use)
• Anticoagulants (administration & dosage, adverse effects, therapeutic use)
• Atrial Fibrillation (complications, drug therapy)
• Benzimidazoles (administration & dosage, adverse effects, therapeutic use)
• Comorbidity
• Dabigatran
• Dose-Response Relationship, Drug
• Follow-Up Studies
• Gastrointestinal Hemorrhage (chemically induced, epidemiology)
• Hemorrhage (chemically induced, epidemiology)
• Humans
• Intracranial Hemorrhages (chemically induced, epidemiology)
• Kaplan-Meier Estimate
• Kidney Diseases (epidemiology)
• Medicare (statistics & numerical data)
• Proportional Hazards Models
• Retrospective Studies
• Risk
• Socioeconomic Factors
• Stroke (etiology, prevention & control)
• Treatment Outcome
• United States
• Warfarin (adverse effects, therapeutic use)
• beta-Alanine (administration & dosage, adverse effects, analogs & derivatives, therapeutic use)