Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 594

As the risk of stroke rises dramatically with age, the absolute stroke reduction by oral anticoagulants (OACs) seems to be highest in elderly populations, outweighing the bleeding risk. Singer et al. found that the average net benefit of warfarin anticoagulation for AF was greater, the older the patient, with a substantially greater net clinical benefit for the oldest age group (≥85), suggesting that age 85 or older may be an additional risk indication for anticoagulation.⁴¹ Warfarin therapy for three months is preferred in patients age ≥80 with unprovoked VTE.⁴²

The randomised Birmingham Atrial Fibrillation Treatment of the Aged (BAFTA) trial was conducted on AF patients age ≥75. This trial showed that, compared to aspirin 75 mg once a day, the use of warfarin (target INR 2–3) was associated with a significant 52% relative risk reduction of the composite outcome measure, including stroke, systemic embolism, and intracranial bleeding.⁴³ In a sub‐analysis from PREFER in AF (PREvention oF Thromboembolic Events‐European Registry in Atrial Fibrillation), data from 505 patients over 85 years old were analysed. It was found that the incidence of thromboembolic events was 2.8% per year without oral anticoagulant treatment versus 2.3% per year with OAC, which is equal to a 0.5% absolute risk reduction. Moreover, in very old patients, the risk of major bleeding was similar in patients on OAC and those on antiplatelet therapy or without antithrombotic treatment.¹⁵

Current evidence shows that DOAC efficacy in elderly patients was similar or superior to VKAs, as a result of summarized data from a meta‐analysis of 11 randomised trials comparing DOACs with VKAs in older patients (≥75) treated for acute venous thromboembolism or stroke prevention in AF.⁴⁴ In the past decade, the four drugs were evaluated in large Phase III trials as alternatives to VKAs in patients with AF at risk of stroke, proving that DOACs are non‐inferior, if not superior, to warfarin for the prevention of stroke/systemic embolic events and for reducing bleeding.¹² However, the results in elderly patients varied according to which drug was used, so different meta‐analyses have evaluated results in patients over 75. All DOACs demonstrated a similar‐to‐lower risk of stroke compared to the warfarin, while only apixaban and edoxaban significantly reduced major haemorrhagic events.^2,45‐47