Racial differences in incident atrial fibrillation among hypertensive patients during antihypertensive therapy.

BACKGROUND: Blacks have a higher prevalence of risk factors for atrial fibrillation (AF), such as hypertension, obesity, and heart failure, than nonblacks. Although population-based studies have demonstrated a lower prevalence and incidence of AF in blacks, the relationship of incident AF to race among hypertensive patients undergoing blood pressure lowering has been less extensively examined.

METHODS: Incident AF was examined in 518 black and 8,313 nonblack hypertensive patients with electrocardiographic left ventricular hypertrophy (LVH) with no history of AF in sinus rhythm on their baseline electrocardiogram, who were randomly assigned to losartan- or atenolol-based treatment.

RESULTS: During a mean of 4.7±1.1 years of follow-up, new-onset AF occurred in 701 patients (7.9%); 5-year AF incidence was significantly lower in black than nonblack patients (6.1 vs. 8.3%; P = 0.03). In univariable Cox analyses, black race was associated with a 37% lower risk of new AF (hazard ratio (HR) = 0.63; 95% confidence interval (CI) = 0.45-1.00; P = 0.05). In multivariable Cox analyses adjusting for randomized treatment, age, sex, diabetes, history of heart failure, myocardial infarction, ischemic heart disease, stroke, peripheral vascular disease, smoking status, baseline body mass index, serum total and high-density lipoprotein cholesterol, creatinine, glucose, and urine albumin/creatinine ratio as standard risk factors, and for incident myocardial infarction, in-treatment heart rate, systolic and diastolic pressure, Cornell product, and Sokolow-Lyon voltage LVH treated as time-varying covariables, black race remained associated with a 45% decreased risk of developing new AF (HR = 0.55; 95% CI = 0.35-0.87; P = 0.01).

CONCLUSIONS: Incident AF is substantially less common among black than nonblack hypertensive patients.