Ethnicity and stroke risk in patients with atrial fibrillation

Objective To examine the prevalence of atrial fibrillation (AF) and stroke risk by ethnic group in south and east London; to compare classification with CHA(2)DS(2)VASc and CHADS(2); to examine the appropriateness of anticoagulant treatment and historic trends in prescribing by gender, age, and ethnicity. Design Cross-sectional study. Setting Routine general practice records from south and east London. Patients Patients aged 18years or over with AF. Main outcome measures Risk of stroke by CHA(2)DS(2)VASc and CHADS(2) score, and prescription of anticoagulant. Results In 2011, we identified 6292 patients with AF, with an age adjusted prevalence of 0.63% (1.2% white, 0.4% black African/Caribbean and 0.2% South Asian). 93% of the AF population were at high risk of stroke with a CHA(2)DS(2)VASc score 1, of whom 54% were on warfarin. South Asian patients were at higher stroke risk than white patients (OR 1.67, 95% CI 1.02 to 2.73). Warfarin under-prescribing in people over 80years of age persisted without improvement throughout 2008-2011. There were no clear differences in warfarin use by ethnic group. Conclusions Despite a reduced prevalence of AF among South Asian patients, their risk of stroke is higher than for white patients or black African/Caribbean patients in association with diabetes, cardiovascular disease, and hypertension. Under-prescription of anticoagulation persists in all ethnic groups, a deficit most pronounced in the elderly. Use of the CHA(2)DS(2)VASc score would enhance optimal management in primary care.