Reported Incidence of Atrial Fibrillation Varies by Ethnicity and Presentation in the Multi-Ethnic Study of Atherosclerosis.

Background: Atrial fibrillation (AF) is a common cardiac arrhythmia. Its detection rates vary significantly across ethnic groups, impacting epidemiological and clinical outcomes. We aim to explore ethnic differences in self-reported versus hospital-reported AF using the MESA (Multi-Ethnic Study of Atherosclerosis).

Methods: Six thousand seven hundred seventy-five adults aged 45 to 84 years, free from baseline AF and major cardiovascular events, were monitored over 8.4 years (2000-2012) across 6 US locations. AF incidence was measured via hospital discharge International Classification of Diseases codes and self-reported data, validated by follow-up questionnaires. AF incidence per 1000 person-years was assessed by ethnic group and reporting method. Incidence rate ratios and adjusted hazard ratios were calculated with White participants as the referent group.

Results: The study comprised 2611 White, 800 Chinese, 1485 Hispanic, and 1879 Black participants, with a mean age of 62.15 (10.24) years; 47.1% were male. Chinese had significantly lower incidence rate ratio (0.40 [95% CI, 0.19-0.75]; P=0.009) for AF reported only during hospitalization, whereas Hispanic group had significantly lower incidence rate ratio (0.29 [95% CI, 0.15-0.51]; P<0.001) for AF only via self-reporting. The combined overall reported AF incidence was 6.4%, or 7.72 per 1000 person-years, highest in the White group (10.69 per 1000 person-years) and lower in in Chinese (6.43 [95% CI, 4.61-8.71]; P=0.003), Hispanics (4.79 [95% CI, 3.61-6.24]; P<0.001), and Blacks (6.39 [95% CI, 5.16-7.84]; P<0.001).

Conclusions: The reported incidence of AF varies with the inclusion of self-reported data and across ethnic and racial groups. The inclusion of self-reported data increased the reported incidence of AF the most among Chinese individuals and the least among Hispanic participants. In the MESA study, the inclusion of self-reported data reveals heterogeneous changes across ethnic and racial groups, which may be due to differences in true incidence, methods of ascertainment, symptom perception, or health care access, and deserves further exploration.