With the introduction of novel oral anticoagulants ( NOACs ), the factors driving anticoagulant selection in atrial fibrillation ( AF ) in real-world practice are unclear.
The goal was to examine whether and to what extent utilization has been driven by predictions of stroke risk ( treatment benefit ), bleeding risk ( treatment harm ), or prescription benefits' coverage.
Researchers extracted a cohort of patients with nonvalvular atrial fibrillation initiating anticoagulation from 2010 to 2012 from a large US database of commercial and Medicare supplement claims.
Multivariable regression examined associations between ischemic stroke ( CHA2DS2-VASc ) and bleeding ( Anticoagulation and Risk Factors in Atrial Fibrillation [ ATRIA ] ) risk scores and benefits' generosity ( proportion of costs covered by patients relative to total ) with Warfarin ( Coumadin ) and novel oral anticoagulant ( NOAC ) selection and also between Dabigatran ( Pradaxa ) and Rivaroxaban ( Xarelto ).
Of 70,498 patients initiating anticoagulation, 29.9% and 7.9% used Dabigatran and Rivaroxaban, respectively.
Compared with Warfarin, patients were less likely to receive a novel oral anticoagulant with high ischemic stroke risk ( CHA2DS2-VASc greater than or equal to 2; adjusted relative risk [ aRR ] 0.75, 95% confidence interval [ CI ] 0.72 to 0.77 ) and high bleeding risk ( ATRIA greater than or equal to 5; aRR 0.66, 95% CI 0.64 to 0.69 ) but more likely with good benefits' generosity ( less than or equal to 20% of costs borne by patient; aRR 2.03, 95% CI 1.92 to 2.16 ).
Compared with Dabigatran, patients were more likely to fill Rivaroxaban with high bleeding risk ( aRR 1.16, 95% CI 1.09 to 1.24 ).
In conclusion, patients with greater bleeding and ischemic stroke risk were more likely to initiate Warfarin, but generous benefits more strongly predicted NOAC usage and drove more selection. ( Xagena )
Lauffenburger JC et al, Am J Cardiol 2015; Epub ahead of print