Atrial fibrillation among African Americans, Hispanics and Caucasians: clinical features and outcomes from the AFFIRM trial.

Unlabelled: The Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study concluded that rate control with anticoagulation was equivalent overall to rhythm control with cardioversion for long-term survival and that anticoagulation reduced the risk of stroke. We compared baseline and follow-up data for three ethnic groups: Caucasians (n=3,599), African Americans (n=265) and Hispanics (n=132). Caucasians were older and more likely male, African Americans were more likely female and hypertensive, and Hispanics had higher prevalence of cardiomyopathy. Survival was better for rate control than rhythm control in Caucasians, equivalent in African Americans and better for rhythm control in Hispanics. Outcomes may be influenced by differential baseline characteristics, but low numbers of African Americans and Hispanics warrant caution in data interpretation.

Background: The AFFIRM study compared a rate-control strategy to a rhythm-control strategy for the treatment of atrial fibrillation (AF) in patients at high risk for stroke or death. It concluded that the rhythm-control strategy offered no survival advantage, and it also confirmed the value of anticoagulation to prevent complications of AF. Data have not previously been available for specific racial ethnic populations.

Methods: We compared baseline and follow-up data for the patients randomized to rate-control versus rhythm-control in three population groups-Caucasian, African-American and Hispanic.

Results: Among 4,060 total patients, 3,599 were Caucasian, 265 were African-American and 132 were Hispanic. At baseline, Caucasians were older and had a higher percentage of males, normal ejection fractions, AF as their only cardiac diagnosis, a prior antiarrhythmic drug failure and less congestive heart failure. African Americans were more likely to be female, had more hypertension and qualified for the study with a first episode of AF, compared to Caucasians. Hispanics had more cardiomyopathy at baseline than Caucasians. Overall survival in Caucasians at five years for the rate-control and rhythm-control groups was 78.9% vs. 76.4%, respectively (p=0.04); for African Americans, 79.0% vs. 69.4% (p=0.22); and for Hispanics, 66.5% vs. 83.9% (p=0.01). Overall, survival was not different between the three populations. However, lower rates of event-free survival were recorded for Hispanics and for African Americans (p=0.0182).

Conclusions: Different survival rates were found for rate-control versus rhythm-control in African-American and Hispanic patients, compared to Caucasian. These findings may be influenced by differences in baseline characteristics, but must be interpreted with caution because of the small sample sizes for African-American and Hispanic participants.