The Risk Stratification and Stroke Prevention Therapy Care Gap in Canadian Atrial Fibrillation Patients

Background: Canadian atrial fibrillation (AF) guidelines recommend that all AF patients be risk stratified with respect to stroke and bleeding, and that most should receive antithrombotic therapy.

Methods: As part of the Canadian Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation (FREEDOM AF) chart audit, data were collected on 4670 patients ≥ 18 years old without significant valvular heart disease from the primary care practices of 474 physicians (February to September, 2011).

Results: Physicians did not provide an estimate of stroke and bleeding risk in 15% and 25% of patients, respectively. When risks were provided, they were on the basis of a predictive stroke and bleeding risk index in only 50% and 26% of patients, respectively. There were over- and underestimation of stroke and bleeding risk in a large proportion of patients. Antithrombotic therapy included warfarin (90%); 24% of patients had a time in the therapeutic range (TTR) < 50%, 9% between 50% and 60%, 11% between 60% and 70%, and 56% had a TTR ≥ 70%.

Conclusions: In a large Canadian AF population, primary care physicians did not provide a stroke or bleeding risk in a substantial proportion of their AF patients. When estimates were provided, they were on the basis of a predictive stroke and bleeding risk index in less than half of the patients. Furthermore, there was under- and overestimation of stroke and bleeding risk in a substantial proportion of patients. As many as 1 in 3 patients receiving warfarin have their TTR < 60%. These findings suggest an opportunity to enhance knowledge translation to primary care physicians.