The IMPact of untReated nOn-Valvular atrial fibrillation on short-tErm clinical and economic outcomes in the US Medicare population: the IMPROVE-AF model

• Published in: Journal of medical economics Vol. 24; no. 1; p. 1070
• Main Authors: Sussman, Matthew, Di Fusco, Manuela, Tao, Charles Y, Guo, Jennifer D, Gillespie, John A, Ferri, Mauricio, Adair, Nicholas, Cato, Matthew S, Shirkhorshidian, Ilnaz, Barnes, Geoffrey D
• Format: Journal Article
• Language: English
• Published: England 01-01-2021
• Subjects: Administration, Oral; Aged; Anticoagulants - therapeutic use; Atrial Fibrillation - drug therapy; Cost Savings; Humans; Medicare; Stroke - drug therapy; Stroke - epidemiology; Stroke - prevention & control; United States - epidemiology; United States; direct oral anticoagulants; H61; C; bleeding; Medicare; C67; Non-valvular atrial fibrillation; H; budget impact; stroke; H6; burden; warfarin; C6; economic model
• ISSN: 1941-837X
• DOI: 10.1080/13696998.2021.1970954

Despite treatment guidelines recommending the use of oral anticoagulants (OACs) for patients with non-valvular atrial fibrillation (NVAF) and moderate to high risk of stroke (CHA
DS
-VASc score ≥1), many patients remain untreated. A study conducted among Medicare beneficiaries with AF and a CHA
DS
-VASc score of ≥2 found that 51% of patients were not prescribed an OAC despite being eligible for treatment. When left untreated, NVAF poses an enormous burden to society, as stroke events are estimated to cost the US healthcare system about $34 billion each year in both direct medical costs and indirect productivity losses. This research explored the short-term clinical implications and budget impact (BI) of increasing OAC use among Medicare beneficiaries with NVAF.
A decision-analytic model was developed from the payer and societal perspectives to estimate the impact of increasing treatment rates among Medicare-eligible NVAF patients with a moderate-to-high risk of stroke over 1 year. Results of the model compared (1) a base case scenario using literature-derived rates of OAC use, and (2) a hypothetical scenario assuming an absolute 5% increase in overall OAC use. Clinical outcomes included the incremental annual number of ischemic stroke, hemorrhagic stroke, and gastrointestinal bleeding events, and stroke-related deaths. Economic outcomes included incremental annual and per-member per-month (PMPM) direct medical costs for the payer perspective and the incremental sum of annual direct medical and indirect costs from productivity loss and caregiver burden for the societal perspective.
In total, 1.95 million Medicare patients with NVAF were estimated to be treated with OACs in the base case (3.8% of beneficiaries). In the hypothetical scenario analysis, nearly 200,000 more patients were treated resulting in 3,705 fewer ischemic strokes, 14 fewer gastrointestinal bleeds, 141 more hemorrhagic strokes, and 175 fewer deaths. The total incremental BI was $399.16 million ($0.65 PMPM) from the payer perspective and $377.10 million from the societal perspective due to indirect cost savings ($22.06 million).
Our findings suggest that increased overall OAC use has a positive clinical benefit on the annual number of ischemic stroke events and deaths avoided in the Medicare population, while maintaining a modest increase in the overall BI to the Medicare system.