Ethnic differences in atrial fibrillation in patients with heart failure from Asia-Pacific

Abstract

ObjectiveEthnic differences in the prevalence of atrial fibrillation (AF) in heart failure (HF) remain unclear. We compared the prevalence and clinical correlates of AF among different ethnicities in an Asian-Pacific population with HF.MethodsPatients with validated HF were prospectively studied across Singapore and New Zealand (NZ).ResultsAmong 1746 patients with HF (62% Asian, 26% women, mean age 66 (SD 13) years, mean ejection fraction (EF) 37 (SD 16%), 39% had AF. The prevalence of AF was markedly lower in Singapore-Asians than NZ-Europeans (24% vs 63%; p<0.001), even after adjusting for age, clinical and echocardiographic covariates, regardless of EF group (pinteraction for EF=0.39). Patients with AF were older, had higher body mass index and were more likely to have a history of hypertension, stroke, peripheral vascular disease, renal disease, chronic respiratory disease and increased alcohol intake, but less likely to have diabetes. Clinical correlates were similar for Asians and NZ-Europeans, except diabetes: Asian diabetic patients with HF had less AF compared with Asian patients without diabetes (OR 0.66, 95% CI 0.50 to 0.88), whereas among NZ-Europeans there was no significant association between diabetes and AF (OR 1.22, 95% CI 0.85 to 1.75) (pinteraction for ethnicity=0.01). AF was associated with a higher crude composite outcome of mortality and HF hospitalisations at 2 years (HR 1.19, 95% CI 1.02 to 1.38).ConclusionThere is a strikingly lower prevalence of AF among Asian compared with NZ-European patients with HF. The underlying mechanisms for the lower prevalence of AF among Asians, particularly in the presence of diabetes, deserve further study.Trial registration numberACTRN12610000374066.

The diabetes-atrial fibrillation paradox

“…We found smaller indexed left atrial volumes in diabetes with and without AF, and in both HF with reduced and preserved ejection fraction 2. Interestingly, diabetes has been shown to be associated with similar negative/inward remodelling in coronary atherosclerosis, aortic disease (paradoxical protection against aortic aneurysms), left ventricular (LV) remodelling (smaller indexed LV volumes in STICH, less LV enlargement postmyocardial infarction in SAVE, more concentric LV remodelling in I-PRESERVE).…”

“…To the Editor We appreciate the editorial by Burden and Timpson1 highlighting collider bias as a potential explanation for our findings of a differential association between diabetes and atrial fibrillation (AF) by ethnicity as well as by heart failure (HF) type 2. Collider bias applies in aetiologic research where causal associations between two independent variables are spuriously created due to stratification by a causally related health outcome.…”

Ethnicity, heart failure, atrial fibrillation and diabetes: collider bias

“…The paper1 is an observational study looking at data from a previous prospective multicentre longitudinal study6 based in NZ and Singapore. In this original study, patients with HF were assessed at baseline and followed over 2 years in two countries, NZ and Singapore.…”

“…Two thousand thirty-nine people took part in the original study. These 2039 were then further reduced to 1746 (18%) in the Tan et al paper1 because ethnic groups were limited to European or Asian. No definition of ethnicity is given.…”

“…In the accompanying paper,1 Tan et al conclude that in people with heart failure (HF) there is a strikingly lower prevalence of atrial fibrillation (AF) among Asian people in Singapore compared with European people in New Zealand (NZ). When seeking an explanation for this, they found that Asian patients with HF with diabetes had less AF than Asian patients without diabetes.…”