The economic burden to medicare of stroke events in atrial fibrillation populations with and without thromboprophylaxis.

Some 3 million people in the United States have atrial fibrillation (AF). Without thromboprophylaxis, AF increases overall stroke risk 5-fold. Prevention is paramount as AF-related strokes tend to be severe. Thromboprophylaxis reduces the annual incidence of stroke in AF patients by 22%-62%. However, antithrombotics are prescribed for only about half of appropriate AF patients. The study team estimates the economic implications for Medicare of fewer stroke events resulting from increased thromboprophylaxis among moderate- to high-risk AF patients. The decision model used considers both reduced stroke and increased bleeding risk from thromboprophylaxis for a hypothetical cohort on no thromboprophylaxis (45%), antiplatelets (10%), and anticoagulation (45%). AF prevalence, stroke risk, and stroke risk reduction are adjusted for age, comorbidities, and anticoagulation/antiplatelet status. Health care costs are literature based. At baseline, an estimated 24,677 ischemic strokes, 9127 hemorrhagic strokes, and 9550 bleeding events generate approximately $2.63 billion in annual event-related health care costs to Medicare for every million AF patients eligible for thromboprophylaxis. A 10% increase in anticoagulant use in the untreated population would reduce stroke events by 9%, reduce stroke fatalities by 9%, increase bleed events by 5%, and reduce annual stroke/bleed-related costs to Medicare by about $187 million (7.1%) for every million eligible AF patients. A modest 10% increase in the use of thromboprophylaxis would reduce event-related costs to Medicare by 7.1%, suggesting a compelling economic motivation to improve rates of appropriate thromboprophylaxis. New oral anticoagulants offering better balance between the risks of stroke and major bleeding events may improve these clinical and economic outcomes.