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).

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.

A clustered randomized trial to IMProve treatment with AntiCoagulanTs in patients with Atrial Fibrillation (IMPACT-AF): design and rationale.

Atrial fibrillation (AF) is common, increasing as the population ages, and a major cause of embolic stroke. While oral anticoagulation (OAC) is highly effective at preventing stroke in patients with AF, it continues to be underused in eligible patients worldwide. The objective of this prospective, cluster randomized controlled trial (IMPACT-AF; ClinicalTrials.gov #NCT02082548) is to determine whether a comprehensive customized intervention will increase the rate and persistence of use of OAC in patients with AF. IMPACT-AF will be conducted in approximately 50 centers in 5 low- to middle-income countries. Before randomization, sites within countries will be paired to match in size, practice type and baseline rate of OAC use. Site pairs will be randomized to intervention versus control. In total, 40 to 70 patients with AF and at least 2 CHA2DS2-VASc risk factors will be enrolled at each site using a consecutive enrollment strategy, with the goal of capturing actual practice patterns. We aim for patients with a new diagnosis of AF to comprise at least 30% of the study cohort. Assuming an average baseline OAC use of 60% and a post-intervention use of 70% with a post-control rate of 60%, there will be roughly 94-98% power with 25 clusters per group (intracluster correlation coefficient of 0.02). While this trial focuses on improving treatment use and reducing preventable strokes, we also aim to better understand the reasons for OAC underuse. This will improve the intervention with the goal of creating educational recommendations to improve care for patients with AF.