Anticoagulation Therapy by Age and Embolic Risk for Nonvalvular Atrial Fibrillation in Mexico, an Upper-Middle-Income Country: The CARMEN-AF Registry

Background: Documenting the patterns of oral anticoagulation therapy (OAT) is essential to prevent thromboembolic complications of nonvalvular atrial fibrillation (NVAF).

Objective: To report the patterns of OAT according to age and thromboembolic risk in patients included in CARMEN-AF, a nationwide registry of NVAF in Mexico, an upper middle-income country.

Material and methods: There were 1,423 consecutive patients ≥18 years old and with at least one thromboembolic risk factor enrolled in the CARMEN-AF Registry at their regular clinical visit during a three-year period. They were analyzed according to 1) age, 2) AF type, and 3) CHA₂DS₂-VASc score.

Results: Overall, 16.4% of patients did not receive antithrombotic treatment, 19.4% received antiplatelet drugs (APD), 29.2% vitamin K antagonists (VKA), and 34.6% direct oral anticoagulants (DOAC). With increasing age, the proportion of subjects treated with VKA decreased significantly from 36.2% in subjects <65 years to 22.5% in those ≥75 years old (P <0.0001). Concomitantly, an increase in both APD and no antithrombotic treatment was observed with increasing age. DOAC were prescribed equally among all age groups (34.2% in <65, 36.0% in 65-74, and 33.9% in ≥75). According to the type of AF, VKA use was more common in patients with permanent AF (32.7%). A lower use of DOAC was observed in high thromboembolic risk subjects (33.6% in CHA₂DS₂-VASc ≥2) compared with the moderate risk group (41% in CHA₂DS₂-VASc = 1).

Conclusions: VKA use for NVAF in Mexico decreased in relation to increasing age. The proportion of DOAC therapy was the same in all age groups. Nevertheless, elderly patients with high thromboembolic risk received a suboptimal thromboprophylaxis. These data could help to improve gaps in the implementation of global guidelines.

Clinical trial registration: http://www.clinicaltrials.gov. Unique identifier: NCT02334852.

Highlights: CARMEN-AF is a nationwide multi-centric registry seeking to bridge the data gap on anticoagulation therapy for NVAF in Mexico.Elderly patients are more prone to receive suboptimal OAT for NVAF.DOAC were less frequently used in high thromboembolic risk patients (CHA₂DS₂-VASc ≥2).