Clinical Characteristics, Oral Anticoagulation Patterns, and Outcomes of Medicaid Patients With Atrial Fibrillation: Insights From the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT‐AF I) Registry

BACKGROUND Whereas insurance status has been previously associated with care patterns, little is currently known about the association between Medicaid insurance and the clinical characteristics, treatment, or outcomes of patients with atrial fibrillation (AF). METHODS AND RESULTS We used data from adults with AF enrolled in the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF), a national outpatient registry conducted at 176 community, multispecialty sites. The primary outcome of interest was the proportion of patients prescribed any oral anticoagulation (OAC; warfarin or novel oral anticoagulants [NOAC]). Secondary outcomes of interest included the proportion of patients prescribed NOACs (dabigatran or rivaroxaban); time in therapeutic range (TTR) for warfarin users, all-cause mortality, stroke/systemic embolism, and major bleed. Of 10 133 patients, N=470 (4.6%) had Medicaid insurance. Medicaid patients were similarly likely to receive OAC at baseline (72.8% vs 76.3%; unadjusted P=0.079), but less likely to receive NOAC at baseline or follow-up (12.1% vs 16.3%; unadjusted P=0.019). After risk adjustment, Medicaid status was associated with lower use of OAC at baseline among patients with high stroke risk (odds ratio [OR]=0.68; 95% CI=0.49, 0.94), but was not associated with OAC use overall (OR=0.82; 95% CI=0.61, 1.09). Among warfarin users, median TTR was lower among Medicaid patients (60% vs 68%; P<0.0001; adjusted TTR difference, -2.9; 95% CI=-5.7, -0.2; P=0.04). Use of an NOAC over 2 years of follow-up was not statistically different by insurance. Compared with non-Medicaid patients, Medicaid patients had higher unadjusted rates of mortality, stroke/systemic embolism, and major bleeding; however, these differences were attenuated following adjustment for clinical characteristics. CONCLUSIONS In a contemporary AF cohort, use of OAC overall and use of NOACs were not significantly lower among Medicaid patients relative to others. However, among warfarin users, Medicaid patients spent less time in therapeutic range compared with those with other forms of insurance.