Oral Anticoagulation Choice and Dosage in Very Elderly Patients with Atrial Fibrillation

Selecting the optimal oral anticoagulation (OAC) therapy for elderly patients with atrial fibrillation (AF) remains challenging. Our real-world study investigates clinical factors guiding OAC prescription patterns and compares outcomes between full- and reduced-dose direct-acting oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) in this demographic.

This post hoc analysis of the MISOAC-AF trial focused on hospitalized AF patients aged ≥ 75 years prescribed OAC at discharge. Predictors of VKA and reduced DOAC dosing were identified using adjusted odds ratios (aORs). Cox regression models calculated adjusted hazard ratios (aHRs) for primary (all-cause mortality) and secondary outcomes (stroke, bleeding, AF or heart failure hospitalization, cardiovascular death).

Among 450 elderly patients, 63.6% received DOACs and 36.4% received VKAs. Higher CHA2DS2-VASc and HAS-BLED scores and antiplatelet use predicted VKA prescription. Hypertension, prior stroke, and bleeding history favored DOAC use. Advanced age and chronic kidney disease correlated with reduced DOAC dosing. Over a 3.7-year follow-up period, there was no significant difference in all-cause mortality between the DOAC and VKA groups (aHR 0.79, 95% CI 0.58-1.06) or between the full-dose and reduced-dose DOAC groups (aHR 0.96, 95% CI 0.60-1.53). Secondary analyses also did not yield statistically significant results in either comparison.

Clinical profile parameters in elderly AF patients predict VKA or DOAC use. Clinical outcomes were similar between different OAC therapies.