Racial and ethnic differences in atrial fibrillation risk factors and predictors in women: Findings from the Women's Health Initiative

Background
The incidence of atrial fibrillation (AF) is higher in non-Hispanic whites (NHWs) compared with other race-ethnic groups, despite more favorable cardiovascular risk profiles. To explore reasons for this paradox, we compared the hazards of AF from traditional and other risk factors between 4 race-ethnic groups in a large cohort of postmenopausal women.

Methods
We included 114,083 NHWs, 11,876 African Americans, 5,174 Hispanics, and 3,803 Asians from the Women's Health Initiative free of AF at baseline. Women, averaging 63 years old, were followed up for incident AF using hospitalization records and diagnostic codes from Medicare claims.

Results
Over a mean of 13.7 years, 19,712 incident cases of AF were recorded. Despite a higher burden of hypertension, diabetes, and obesity, annual AF incidence was lower among nonwhites (0.7%, 0.4%, and 0.4% for African American, Hispanic, and Asian participants, respectively, compared with 1.2% for NHWs). The hazards of AF from hypertension, diabetes, obesity, heart failure, and coronary artery disease were similar across race-ethnic groups. Major risk factors, including hypertension, obesity, diabetes, smoking, peripheral arterial disease, coronary artery disease, and heart failure, accounted for an attributable risk of 50.3% in NHWs, 83.1% in African Americans, 65.6% in Hispanics, and 37.4% in Asians. Established AF prediction models performed comparably across race-ethnic groups.

Conclusions
In this large study of postmenopausal women, traditional cardiovascular risk factors conferred a similar degree of individual risk of AF among 4 race-ethnic groups. However, major AF risk factors conferred a higher-attributable risk in African Americans and Hispanics compared with NHWs and Asians.