ASIAN-HF: ‘Striking’ ethnic differences in AF prevalence among Asians

While the clinical risk factors for atrial fibrillation (AF) and its associated adverse outcomes are similar across ethnicities in Asia, AF is more common in some ethnic groups than the others, reveal the latest data from the ASIAN-HF* registry.

“There are striking ethnic variations in the prevalence of AF that are not accounted for by known [AF] risk factors,” said the researchers led by Professor Carolyn Lam of Duke-National University of Singapore Medical School, Singapore.

The findings also broach the topic of “nature versus nurture” in the development of AF. The inherent difference with ethnicities suggests that genetic factors may also play a role in the pathogenesis of AF, besides environmental factors.

For heart failure with reduced ejection fraction (HFrEF), Japanese/Koreans were more likely than those of Chinese ethnicity to develop AF — the most common arrhythmia in HF (adjusted odds ratio [aOR], 1.76, 95 percent confidence interval [CI], 1.40–2.21). [ESC Heart Fail 2020;doi:10.1002/ehf2.12696]

In contrast, Indians were the ethnicity with lowest AF prevalence compared with Chinese, regardless of whether it was in HFrEF (aOR, 0.18, 95 percent CI, 0.13–0.24) or HFpEF (aOR, 0.28, 95 percent CI, 0.16–0.49). The associations remained even after adjusting for clinical variables such as risk factors and medications.

Interestingly, within the Indian ethnicity, different AF associations existed among those in geographically distinct locations. Indians from Southeast Asia were threefold as likely to develop AF compared with their South Asian counterparts, even after adjusting for clinical variables (aOR, 3.01, 95 percent CI, 1.60–5.67).

“Local dietary habits, living conditions, and levels of physical activity may differ vastly in different regions of Asia,” Lam and co-authors pointed out.

Similarities despite differences

Regardless of ethnicity, clinical factors associated with a higher risk of AF were similar, including older age, a larger left atrium, prior stroke, and higher NT-proBNP.

Paradoxically, diabetes — an established risk factor for AF — was associated with lower likelihood of AF in both HFrEF (aOR, 0.79, 95 percent CI, 0.66–0.95) and HFpEF (aOR, 0.58, 95 percent CI, 0.39–0.84), across ethnicities in Asia.

Nonetheless, consistent with the Western population, AF was directly associated with a higher risk of all-cause mortality and hospitalization for HF (adjusted hazard ratio, 1.38; p<0.001), regardless of HF type and ethnicity.

In addition, AF was also associated with a poorer quality of life, as indicated by the KCCQ** indices (p=0.02), regardless of HF type.

“[ASIAN-HF] is the first multinational study on ethnic differences and clinical correlates of AF in Asia … [with] good representation of different ethnicities in Asia from countries at divergent economic levels,” highlighted Lam and co-authors.

Participants in the prospective, observational, multinational ASIAN-HF registry were 5504 patients (mean age 61 years, 27 percent women) with HF recruited across 11 Asian regions, including Singapore, Malaysia, Philippines, Thailand, Indonesia, China, India, Japan, Korea, and Taiwan.