Abstract 19726: Statin Effect in Patients with Atrial Fibrillation Who Are Prescribed Dabigatran
Introduction: Dabigatran is used for stroke prevention in patients with atrial fibrillation (AF) and its use has been associated with an increased risk of myocardial infarction (MI). Concomitant statin use may ameliorate this effect.
Hypothesis: Statin use may protect against MI and death in patients with AF taking dabigatran.
Methods: Patients age 66 or older with new AF from Nov 2010-Dec 2011 who received oral anticoagulation within 90 days of the AF diagnosis were identified in Medicare claims (n=79,134). Outcomes included death, ischemic stroke, and acute MI as identified by CMS enrollment records or inpatient admission records. Probabilities from a multinomial model were used to match patients in four groups (warfarin + statin, warfarin - statin, dabigatran + statin, dabigatran - statin). We used proportional hazards regression on this propensity-matched cohort to examine relative outcomes associated with statin use.
Results: Overall 37,459 patients received statins and 14,452 received dabigatran. Statin use was similar in patients taking dabigatran vs warfarin. A total of 27,572 patients were included in the propensity matched analysis. Unadjusted rates of MI per person-year among patients receiving dabigatran were: 1.57 and 0.65 for patients taking statins and not taking statins, respectively. Among patients taking warfarin, MI rates were 1.35 and 1.01 per person-year with and without statins, respectively. In risk-adjusted analyses of patients taking dabigatran, the hazard ratio [HR] for MI associated with statin use was 2.42 [95% CI 1.44-4.07, p<.001] while the hazard ratio of death was 0.58 [95% CI, 0.48-0.69, p<.001]. Statin use was not significantly associated with stroke risk in patients taking dabigatran, nor was statin use significantly associated with stroke, MI, or death in patients taking warfarin.
Conclusions: In Medicare beneficiaries with new AF prescribed dabigatran, statin medications were associated with an increased risk of developing MI. Despite this, statin use among patients with AF taking dabigatran was strongly protective against mortality. A possible explanation for this phenomenon is that statins reduce the incidence of fatal out-of-hospital MI in this patient population.
Author Disclosures: P. Bhave: None. X. Lu: None. M.S. Vaughan Sarrazin: Research Grant; Significant; AHRQ, HSR&D.
- © 2014 by American Heart Association, Inc.