Background: Hypertension is well known to be a risk factor for development of atrial fibrillation (AF). However, it is unknown if patients who are treated for hypertension have the same risk for developing AF regardless of systolic blood pressure (SBP) and if this risk is equal between racial groups.
Methods: We performed a retrospective analysis of 32,250 patients (46% Hispanic, 39% African American, 15% non-Hispanic White). All patients were initially free of AF and followed via ECGs for incidence of new AF. Treatment for hypertension and SBP was determined via chart review. Cox regression analysis controlled for baseline covariates: Diabetes Mellitus, race, BMI, heart failure, gender, age, presence of left ventricular hypertrophy, socioeconomic status, use of digoxin, calcium channel blockers and beta-blockers. Regression analysis was performed for the entire cohort and then stratified by racial/ethnic group.
Results: There were 3,395 incidents of AF with an average age of 70. SBP did not correlate with an incremental increase in risk of developing AF in neither the general population nor when stratified by race/ethnicity. Treatment for hypertension inversely correlated with AF incidence in the general population (OR 0.59 95% CI: 0.402-0.869, p<0.01). When stratified by racial/ethnicity, a significant inverse correlation between treatment for hypertension and AF incidence was seen in African Americans (HR 0.33, CI: 0.162-0.679, p < 0.01) but not in Hispanics or non-Hispanic whites.
Conclusions: While treatment for hypertension is an integral part of AF prevention, the relationship between treating hypertension and risk of developing AF is not equally distributed among racial/ethnic groups. Treatment for hypertension is significantly associated with decreased risk of AF in African Americans but not Hispanics or non-hispanic Whites, suggesting hypertension treatment is protective in African Americans independent of systolic blood pressure.