Cost-Effectiveness of antiarrhythmic drugs for prevention of thromboembolism in patients with paroxysmal atrial fibrillation.

To determine whether treatment with antiarrhythmic drugs could be cost-effective in preventing thromboembolic events in patients with paroxysmal atrial fibrillation (AF), 4 groups of patients without prior thromboembolism were studied. Group A: 193 patients with paroxysmal AF receiving antiarrhythmic drugs, but not antiplatelets or warfarin; Group B: 228 patients with paroxysmal AF not receiving antiarrhythmics, antiplatelets or warfarin; Group C: 284 patients with chronic AF receiving warfarin; Group D: 394 patients with chronic AF not receiving antiplatelets or warfarin. Direct costs for treatment of AF were determined. During a follow-up period of 4.6 years, the prevalence of thromboembolic episodes was lower by 70% in Group A and by 47% in Group C than in each control group. To prevent one thromboembolic event annually with antiarrhythmic drugs in patients with paroxysmal AF, an extra cost of 6.16 million yen was required. This less favorable cost-effectiveness was mainly because of physician's preference for new antiarrhythmic drugs. In contrast, treatment with warfarin required an extra cost of 1.09 million yen to prevent one thromboembolic event annually in patients with chronic AF. Antiarrhythmic drugs are less cost-effective in preventing thromboembolic events in patients with paroxysmal AF when new, expensive drugs are preferentially selected.