ANTICOAGULATION THERAPY FOR ATRIAL FIBRILLATION IN PATIENTS WITH DEMENTIA: A COST EFFECTIVENESS ANALYSIS

Purpose: Novel anticoagulants, such as apixaban,  dabigatran, and rivaroxaban, are superior to warfarin in preventing ischemic stroke in patients with atrial fibrillation with lower risk of hemorrhage.  Despite the greater cost of these drugs, several studies have found them to be cost effective.  Nevertheless anticoagulation therapy is underused in older patients, in long-term care settings, and, specifically, in patients with dementia.  The purpose of this study is to estimate the effectiveness and cost effectiveness of anticoagulants in patients with atrial fibrillation and Alzheimer’s disease.

Method: We constructed a Markov model to estimate the lifetime costs and quality-adjusted life-years (QALYs) of anticoagulation therapy in patients with atrial fibrillation and Alzheimer’s disease.  We considered alternatives of no anticoagulation therapy,  adjusted-dose warfarin, apixaban,  dabigatran, and rivaroxaban.  We considered patient cohorts which differed in care setting (community dwelling vs. long-term care facility), stage of dementia (mild or moderate), and history of prior stroke.  Health benefits were measured in life-years gained and QALYs gained.  Lifetime discounted costs, including those of unpaid caregivers, and health benefits were estimated using a U.S. societal perspective. 

Result: For patients with atrial fibrillation and mild dementia, anticoagulation therapy increases costs but also increases QALYs by reducing the risk of stroke.  The incremental cost effectiveness ratio (ICER) of warfarin compared to no anticoagulation treatment is less than $10,000 per QALY gained.  Compared to treatment with warfarin, the ICER of rivaroxaban was $87,700 per QALY for community-dwelling individuals and $68,200 per QALY for individuals living in a long-term care facility.  For patients with atrial fibrillation and moderate dementia, the ICER of warfarin compared to no treatment was less than $50,000 per QALY gained.  Compared to warfarin, treatment with rivaroxaban cost just over $100,000 per QALY gained.  The total costs and QALYs for apixaban and dabigatran were similar to those of rivaroxaban in all populations, but these treatment strategies cost more and provided fewer QALYs than another strategy or combination of strategies.

Conclusion: Novel anticoagulation therapies are cost effective in patients with mild dementia.  The strategy of ‘no anticoagulation therapy’ was never the optimal treatment strategy; dementia should not preclude access to anticoagulation therapy in patients with atrial fibrillation.