Regional differences in presentation and antithrombotic treatment of patients with atrial fibrillation: Baseline characteristics from a clustered randomized trial to IMProve treatment with AntiCoagulanTs in patients with atrial fibrillation (IMPACT-AF).

Unlabelled: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide. However, there are few contemporary comparative data on AF from middle-income countries.

Methods: Baseline characteristics of the IMPACT-AF trial were analyzed to assess regional differences in presentation and antithrombotic treatment of AF from 5 middle-income countries (Argentina, Brazil, China, India, and Romania) and factors associated with antithrombotic treatment prescription.

Results: IMPACT-AF enrolled 2281 patients (69 ± 11 years, 47% women) at 48 sites. Overall, 66% of patients were on anticoagulation at baseline, ranging from 38% in China to 91% in Brazil. The top 3 reasons for not prescribing an anticoagulant were patient preference/refusal (26%); concomitant antiplatelet therapy (15%); and risks outweighing the benefits, as assessed by the physician (13%). In a multivariable model, the most significant factors associated with prescription of oral anticoagulants were no prior major bleeding (odds ratio [OR] = 4.34; 95% CI = 2.22-8.33), no alcohol abuse (OR = 2.27; 95% CI = 1.12-4.55), and history of rheumatic valvular heart disease (OR = 2.10; 95% CI = 1.36-3.26), with a strong predictive accuracy (c statistic = 0.85), whereas the most significant factors associated with prescription of a combination of oral anticoagulants and antiplatelet drugs were prior coronary revascularization (OR = 5.10; 95% CI = 2.88-9.05), prior myocardial infarction (OR = 2.24; 95% CI = 1.38-3.63), and no alcohol abuse (OR = 2.22; 95% CI = 1.11-4.55), with a good predictive accuracy (c statistic = 0.76).

Conclusions: IMPACT-AF provides contemporary data from 5 middle-income countries regarding antithrombotic treatment of AF. Lack of prior major bleeding and coronary revascularization were the most important factors associated with prescription of oral anticoagulants and their combination with antiplatelet drugs, respectively.