Abstract 77: Balancing Risks and Benefits of Anticoagulation Therapy in Atrial Fibrillation in Community Practice: Results from the ORBIT-AF Registry
Background Oral anticoagulation (OAC) can reduce stroke risk at the cost of increased bleeding risk in those with atrial fibrillation (AF). Observational data have shown that higher-risk patients with AF most likely to benefit from OAC are less likely to receive OAC at hospital discharge. Methods We used data from ORBIT-AF Registry, a cohort of 9,589 AF patients enrolled among 173 participating outpatient practices. OAC was defined as warfarin or dabigatran use at study enrollment. Stroke and bleeding risk were calculated using the CHADS2 and ATRIA scores, respectively. Results The study population had a mean age of 73.5 years; 57.8% were men. Overall, 76.4% of patients received OAC. Use of OAC rose with increasing CHADS2 stroke risk, from 67% for CHADS2 <1 to 80% for CHADS2 ≥2 (p<0.0001). OAC use fell slightly with increasing ATRIA bleeding risk, from 77% for ATRIA score ≤3 to 74% with ≥5 (p=0.002 for trend). Among patients with low bleeding risk, rates of OAC increased commensurate with stroke risk (p<0.0001 for interaction; see figure). Higher bleeding risk tended to decrease rates of OAC among patients with a CHADS2 score ≥2 (p=0.13 for interaction). Conclusions In community-based outpatients with AF, use of OAC rose with increasing thromboembolic risk and declined with higher bleeding risk. These findings suggest that the risk-treatment paradox may be less that previously reported. Provision of OAC in community practice appears to appropriately consider patients' stroke and bleeding risks. Further research is required to understand how quality improvement initiatives can further improve stroke prevention.