Real-world comparison of bleeding risks among non-valvular atrial fibrillation patients prescribed apixaban, dabigatran, or rivaroxaban

Limited real-world data are available regarding the comparative safety of non-vitamin K antagonist oral anticoagulants (NOACs). The objective of this retrospective claims observational cohort study was to compare the risk of bleeding among non-valvular atrial fibrillation (NVAF) patients prescribed apixaban, dabigatran, or rivaroxaban. NVAF patients aged ≥18 years with a 1-year baseline period were included if they were new initiators of NOACs or switched from warfarin to a NOAC. Cox proportional hazards modelling was used to estimate the adjusted hazard ratios of any bleeding, clinically relevant non-major (CRNM) bleeding, and major inpatient bleeding within 6 months of treatment initiation for rivaroxaban and dabigatran compared to apixaban. Among 60,227 eligible patients, 8,785 were prescribed apixaban, 20,963 dabigatran, and 30,529 rivaroxaban. Compared to dabigatran or rivaroxaban patients, apixaban patients were more likely to have greater proportions of baseline comorbidities and higher CHA2DS2-VASc and HAS-BLED scores. After adjusting for baseline clinical and demographic characteristics, patients prescribed rivaroxaban were more likely to experience any bleeding (HR: 1.35, 95% confidence interval [CI]: 1.26-1.45), CRNM bleeding (HR: 1.38, 95% CI: 1.27-1.49), and major inpatient bleeding (HR: 1.43, 95% CI: 1.17-1.74), compared to patients prescribed apixaban. Dabigatran patients had similar bleeding risks as apixaban patients. In conclusion, NVAF patients treated with rivaroxaban appeared to have an increased risk of any bleeding, CRNM bleeding, and major inpatient bleeding, compared to apixaban patients. There was no significant difference in any bleeding, CRNM bleeding, or inpatient major bleeding risks between patients treated with dabigatran and apixaban

Estimated prevalence of undiagnosed atrial fibrillation in the United States.

As atrial fibrillation (AF) is often asymptomatic, it may remain undiagnosed until or even after development of complications, such as stroke. Consequently the observed prevalence of AF may underestimate total disease burden.To estimate the prevalence of undiagnosed AF in the United States, we performed a retrospective cohort modeling study in working age (18-64) and elderly (≥65) people using commercial and Medicare administrative claims databases. We identified patients in years 2004-2010 with incident AF following an ischemic stroke. Using a back-calculation methodology, we estimated the prevalence of undiagnosed AF as the ratio of the number of post-stroke AF patients and the CHADS2-specific stroke probability for each patient, adjusting for age and gender composition based on United States census data.The estimated prevalence of AF (diagnosed and undiagnosed) was 3,873,900 (95%CI: 3,675,200-4,702,600) elderly and 1,457,100 (95%CI: 1,218,500-1,695,800) working age adults, representing 10.0% and 0.92% of the respective populations. Of these, 698,900 were undiagnosed: 535,400 (95%CI: 331,900-804,400) elderly and 163,500 (95%CI: 17,700-400,000) working age adults, representing 1.3% and 0.09% of the respective populations. Among all undiagnosed cases, 77% had a CHADS2 score ≥1, and 56% had CHADS2 score ≥2.Using a back-calculation approach, we estimate that the total AF prevalence in 2009 was 5.3 million of which 0.7 million (13.1% of AF cases) were undiagnosed. Over half of the modeled population with undiagnosed AF was at moderate to high risk of stroke

Baseline characteristics of patients with AF diagnosed before stroke versus after stroke.

<p>Baseline characteristics of patients with AF diagnosed before stroke versus after stroke.</p

Prevalence of diagnosed and undiagnosed AF.

<p>Prevalence of diagnosed and undiagnosed AF.</p

Imputing the prevalence of undiagnosed atrial fibrillation via back-calculation.

<p>Imputing the prevalence of undiagnosed atrial fibrillation via back-calculation.</p

Baseline characteristics of patients with observed and unobserved AF.

<p>Baseline characteristics of patients with observed and unobserved AF.</p

Cohort diagram.

<p>Cohort diagram.</p