What question did this study set out to answer?

The study aims to compare outcomes between elderly patients with non-valvular atrial fibrillation treated with VKAs versus those switched to DOACs.

January 10, 2026Internal and Emergency Medicine0 citations

Outcomes of non-valvular atrial fibrillation elderly patients maintained on VKAs’ treatment compared to patients switched to DOACs: results from the START2-AF registry

CCChiara CappugiUniversity of Florence EAEmilia Antonucci WAWalter AgenoUniversity of Padua

Key Result

Elderly AF patients switched from VKAs to DOACs had a higher risk of thrombotic events (1.0 vs 0.6 per 100 patient-years, p=0.05) but lower mortality (2.9 vs 6.7, p=0.05).

Key Points

The study aims to compare outcomes between elderly patients with non-valvular atrial fibrillation treated with VKAs versus those switched to DOACs.
Analyzed data from 4230 elderly patients with non-valvular atrial fibrillation.
Compared events between patients maintained on VKAs and those switched to DOACs.
Collected data on bleeding, thrombotic events, and mortality during follow-up.
Thrombotic events occurred more frequently among patients switched to DOACs (1.0 vs 0.6 per 100 patient-years).
Bleeding events were similar between VKAs and DOACs (3.0 vs 2.5 per 100 patient-years).
Mortality was higher in VKA patients compared to DOACs (6.7 vs 2.9 per 100 patient-years).

Structured PICO

Does switching from VKAs to DOACs alter the risk of thrombotic events, bleeding, and mortality in elderly patients (≥75 years) with non-valvular atrial fibrillation compared to maintaining VKA treatment?

Population

4,230 patients aged ≥ 75 years with non-valvular atrial fibrillation enrolled in the START-AF Register.

Intervention

Switched from Vitamin K Antagonists (VKAs) to Direct Oral Anticoagulants (DOACs) (n=1,300), including low-dose and off-label low-dose regimens.

Comparator

Maintained on Vitamin K Antagonists (VKAs) (n=2,930).

Outcome

Bleedings, thrombotic events, and deaths during follow-up.hard clinical

In elderly AF patients (≥75 years), switching from VKAs to DOACs is associated with lower mortality but a higher risk of thrombotic events, which is driven in part by the use of off-label low-dose DOACs.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Direct oral anticoagulants (DOAC) have similar efficacy for stroke prevention in patients with non-valvular atrial fibrillation (AF) with improved safety. Recently, a higher bleeding risk was reported when elderly AF patients were switched from VKAs to DOACs. AF patients aged ≥ 75 years who were maintained on VKA treatment or who were switched from VKAs to DOACs at the time of enrollment in the START-AF Register were followed. Bleedings, thrombotic events, and deaths that occurred during follow-up were collected. We included 4230 AF patients, 2930 (69.3%) on VKAs and 1300 patients (30.7%) shifted to DOACs. Low-dose DOACs were prescribed to 732 (56.3%) patients, 257 (35.1%) of whom received off-label low-dose. Thrombotic events were more frequent among patients switched to DOACs compared to patients continuing VKAs (1.0 and 0.6 × 100pt-yrs p = 0.05). The rate of bleeding events was similar between the two groups (3.0 and 2.5 × 100pt-yrs; p = 0.2), and was higher in the subgroup treated with on-label low-dose DOACs (3.4 × 100pt/yrs) compared to patients on VKAs (2.5 × 100pt-yrs)(RR1.4, 95%CI 0.9-2.0; p = 0.1). Conversely, patients on off-label low-dose DOACs showed higher rates of thrombotic events compared to patients on VKAs (1.4 vs 0.6 × 100pt/yrs, p = 0.05). Mortality was significantly higher in VKA patients than in DOACs patients independently from the dosage (6.7 and 2.9 × 100pt-years; p = 0.05). Elderly AF patients switched from VKAs to DOACs are at increased risk of thrombotic events than patients who remain on VKAs but with a lower risk of mortality. Switching to low-dose DOACs may expose patients to a higher risk of adverse outcomes.

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