Differences between perspectives of physicians and patients on anticoagulation in patients with atrial fibrillation: observational study

Objective To determine and compare physicians' and patients' thresholds for how much reduction in risk of stroke is necessary and how much risk of excess bleeding is acceptable with antithrombotic treatment in people with atrial fibrillation. Design Prospective observational study. Setting Tertiary and peripheral referral centre, itt Nova Scotia. Canada. Participants 63 physicians who were treating patients with atrial fibrillation and 61 patients at high risk for atrial fibrillation. Main outcome measures Participants underwent a face to farce interview with a probability trade-off tool. Thresholds were determined for the minimum reduction in risk of stroke necessary and the maximum increase in risk of excess bleeding acceptable for treatment with aspirin and warfarin in people with atrial fibrillation. Results The minimum number of strokes that needed to be prevented in 100 patients over two years for warfarin to be justified was significantly lower for patients than fin physicians (1.8 (SD 1.9) v 2.5 (1.6), P=0.009). whereas fur aspirin there was no difference between patients and physicians (1.3 (1.3) v 1.6 (1.5), P=0.29). The maximum number mf excess bleeds acceptable in 100 patients over two years for use of warfarin and aspirin was significantly higher for patients than for physicians (warfarin 17.4 (7.1) v 10.3 (6.1); aspirin 14.7 (8.5) v 6.7 (6.2); P < 0.001 for both comparisons). Conclusions Patients at high risk for atrial fibrillation placed more value on the avoidance of stroke and less value nn the avoidance of bleeding than did physicians who treat patients with atrial fibrillation. Tine views of the individual patient should be considered when decisions are being trade about antithrombotic treatment for people with atrial fibrillation.