Net Clinical Benefit of Anticoagulant Treatments in Elderly Patients with Non-Valvular Atrial Fibrillation

Background: Oral anticoagulation (OAC) is effective in reducing stroke risk in elderly patients with atrial fibrillation (AF), but older patients are also at greater risk of bleeding. With the emergence of the new anticoagulants, it is timely to examine whether OAC in “real world” practice is beneficial in elderly patients with AF.

Objective: To estimate the net clinical benefit (NCB) of warfarin and NOACs as used in clinical practice, among elderly patients with AF, in terms of risks of stroke and intracranial hemorrhage (ICH) events.

Methods: A prospective cohort study using the Clalit Health Services (CHS) database between 2013 and 2015. We examined patients aged >=75. Incidences of stroke and ICH bleeding were estimated per 100 person years. The NCB was estimated in relation to time in therapeutic range (TTR) (<60% or ≥60%) in patients that were treated with warfarin and in relation to NOACs’ dosage.

Results: We identified 11,760 AF patients aged ≥75 years, 4982 (42%) were treated with OAC, 2042 (17.4%) were treated with warfarin and 2,940 (25.0%) were treated with NOACS. Among patients treated with warfarin, those who achieved TTR>60% had lower incidence rate of stroke (2.54 vs 5.21), lower incidence rate of ICH (0.68 vs 1.1) and higher NCB (9.78 vs 6.52) as compared to those with TTR<60%. Among patients treated with NOACs, patients treated with the higher dose had lower incidence rate of stroke (8.40 vs 9.81), lower incidence rate of ICH (0.33 vs 1.2) and higher NCB (4.42 vs 1.78) compared to the patients treated with the lower dose.

Conclusion: Despite higher stroke risk in elderly patients, a large proportion of these patients are not treated with OAC. The NCB of OAC in the elderly is positive, with the greatest in elderly patients treated with optimal doses of NOACS and warfarin with TTR>60%.