One-year risks of stroke and mortality in patients with atrial fibrillation from different clinical settings: The Gulf SAFE registry and Darlington AF registry

Background: Differences exist in oral anticoagulation (OAC) use between different populations with atrial fibrillation (AF), which may be associated with varying outcomes. Purpose: We aimed to provide patient level comparisons of two cohorts of patients with AF, from the United Kingdom (UK) and Middle East (ME). Methods: The clinical characteristics, prescription of OAC, one-year risk of stroke and mortality were compared between individual patients with AF included into the Darlington AF registry (UK, n = 2258) and the Gulf SAFE (Survey of atrial fibrillation events) registry (ME, n = 1740). Results: A high percentage of patients from the Darlington registry were candidates for OAC (i.e., CHA ₂DS ₂-VASc score ≥2 in males or ≥3 in females; 82.0% in Darlington and 57.1% in Gulf SAFE). OAC use was suboptimal (52.0% in Darlington vs 58.4% in Gulf SAFE). One-year rates of stroke and mortality were high in both populations, especially in those with CHA ₂DS ₂-VASc score ≥2 in males and ≥3 in females (Darlington vs. Gulf SAFE: 3.51% vs. 5.63 for stroke; 11.4% vs. 16.8% for mortality). On multivariate analyses, female sex and previous stroke were independently associated with stroke events; while elderly age, female sex, vascular disease and heart failure were independent risk factors for mortality (all p < 0.05). Patients from Gulf SAFE registry had higher risk of stroke (odds ratio, 2.18 [1.47–3.23]) and mortality (odds ratio, 1.67 [1.31–2.14]) compared with those from Darlington registry. The CHA ₂DS ₂-VASc score showed good discrimination in predicting one-year risk of stroke (area under curve, 0.71 [0.65–0.76] in non-anticoagulated patients) and mortality (area under curve, 0.70 [0.68–0.72]) in the whole study population, as well as in Darlington or Gulf SAFE registry separately. Conclusions: Stroke prevention was generally suboptimal in patient cohorts from the two registries, which was associated with high one-year risks of stroke and mortality, particularly so among patients from the Gulf SAFE registry. The higher risks for stroke and mortality in AF patients from the Gulf SAFE registry (compared to a UK cohort) merit further implementation of cardiovascular prevention strategies.