Why are South Asians seemingly protected against the development of atrial fibrillation? A review of current evidence

Atrial fibrillation in UK South Asian hospitalized ischemic stroke patients: The BRAINS study

INTRODUCTION

South Asian diaspora comprise one of the largest ethnic minority groups in the world yet data about atrial fibrillation (AF) in this demographic is understudied. Our aim is to identify differences in AF prevalence and treatment between South Asians and white British stroke patients.

METHOD

The UK arm of a prospective ongoing large international repository on stroke was analysed. Ethnic differences in AF prevalence and management in those with ischemic stroke were analysed.

RESULTS

Of the 3515 individuals recruited with ischemic stroke, 1482 (men: 972, women: 510) were South Asian and 2033 (men:1141, women:892) of white British ethnicity. AF was present in 462 white British and 193 South Asians stroke patients, with South Asians displaying a lower prevalence of AF (South Asians: 13.0% vs white British 22.7%, P<0.001). Despite adjustment for traditional AF risk factors, South Asians had a significantly lower OR of AF compared to white British stroke patients (OR: 0.40, 95%CI: 0.33:0.49, P<0.001). Among confirmed AF cases, 31.8% of South Asians and 41.4% of white British were untreated at admission (P = 0.02). Antiplatelet treatment was significantly higher among South Asians at both admission (South Asian: 47.4% vs. white British: 29.9%, P<0.001) and discharge (South Asian: 49.5% vs. white British: 34.7%, P = 0.001), although anticoagulation treatment was similar across both ethnic groups at admission (South Asian: 28.5% vs white British: 28.1%, P = 0.93), and discharge (South Asian: 45.1% vs white British: 43.1%, P = 0.64).

CONCLUSION

Stroke patients of South Asian descent are at significantly lower risk of AF but more likely to be on antiplatelet treatment compared to their white British counterparts.

Prevalence of atrial fibrillation in Northern Sri Lanka: a study protocol for a cross-sectional household survey

INTRODUCTION

Atrial fibrillation (AF) is the most common arrhythmia globally. It is associated with a fivefold risk in stroke, but early diagnosis and effective treatment can reduce this risk. AF is often underdiagnosed, particularly in low-income and middle-income countries (LMICs) where screening for AF is not always feasible or considered common practice in primary care settings. Epidemiological data on AF in LMICs is often incomplete particularly in vulnerable populations. This LMIC research collaborative aims to identify the prevalence of AF in the Northern Sri Lankan community.

METHODS AND ANALYSIS

A cross-sectional household survey piloted and codesigned through a series of community engagement events will be administered in all five districts in Northern Province, Sri Lanka. A multistage cluster sampling approach will be used starting at district level, then the Divisional Secretariats followed by Grama Niladhari divisions. Twenty households will be selected from each cluster. The study aims to recruit 10 000 participants aged 50 years or older, 1 participant per household. Demographic and socioeconomic characteristics, well-being and lifestyle and anthropometric measurements will be collected using a digital data platform (REDCap, Research Electronic Data Capture) by trained data collectors. Participants will be screened for AF using a fingertip single-lead ECG via a smartphone application (AliveCor) with rhythm strips reviewed by a consultant cardiologist. Prevalence of AF and risk factors will be established at province and district-levels. Adjusted ORs and population attributable fractions for AF risk factors will be determined.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Review Committee of Faculty of Medicine at University of Jaffna. Written informed consent will be obtained from all participants. Findings will be disseminated through publication in a peer-reviewed journal and presentations at conferences. The findings will enable early treatment for new AF diagnoses and inform interventions to improve community-based management of AF in LMICs.

Sex and ethnicity modified high 1-year mortality in patients in Singapore with newly diagnosed atrial fibrillation

INTRODUCTION

We investigated sex and ethnic differences in the incidence, clinical characteristics and 1-year mortality of patients with newly diagnosed AF in a multi-ethnic population.

METHOD

This retrospective cohort study of patients diagnosed with AF from 2008 to 2015 was based on medical claims, casemix and subvention data submitted to the Ministry of Health. Patients with AF were matched with controls without AF for age (3-year bands), sex and ethnicity, and categorised as middle-aged (45-64 years) or elderly (≥65 years) among major ethnic groups in Singapore (Chinese, Malay and Indian).

RESULTS

Among 40,602 adults with AF (elderly 74%), Malays had the highest age-standardised incidence rate of AF, followed by Chinese and Indians; and the rate was higher in men. Despite having the worst cardiovascular risk profile, Indians had the lowest prevalence and incidence of AF. The 1-year mortality rate after newly diagnosed AF was 22-26 deaths per 100 people. Newly diagnosed AF was independently associated with increased 1-year all-cause mortality among middle-aged (adjusted odds ratio [AOR] 9.08, 95% confidence interval [CI] 7.36-11.20) and elderly adults (AOR 3.60, 95% CI 3.40-3.80) compared with those without AF. Sex differences in mortality among patients with AF were limited to elderly adults (men: AOR 1.17, 95% CI 1.11-1.24), while Indians were associated with a 30% increased odds of mortality compared with Chinese regardless of age (middle-aged: AOR 1.27, 95% CI 1.09-1.548 elderly: AOR 1.33, 95% CI 1.22-1.45).

CONCLUSION

Variations in incidence, clinical profile and 1-year mortality of patients with AF in a nationwide cohort were influenced by sex and ethnicity. Newly diagnosed AF portends a worse prognosis and is a marker of high mortality within the first year.

Racial and Ethnic Differences in the Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinical arrhythmia, and it results in adverse outcomes and increased healthcare costs. Racial and ethnic differences in AF management, although recognized, are poorly understood. This review summarizes racial differences in AF epidemiology, genetics, clinical presentation, and management. In addition, it highlights the underrepresentation of racial and ethnic populations in AF clinical trials, especially trials focused on stroke prevention. Specific strategies are proposed for future research and initiatives that have potential to eliminate racial and ethnic differences in the care of patients with AF. Addressing racial and ethnic disparities in healthcare access, enrollment in clinical trials, resource allocation, prevention, and management will likely narrow the gaps in the care and outcomes of racial and ethnic minorities suffering from AF.

Ethnic differences in atrial fibrillation among patients with heart failure in Asia

AIMS

We aimed to characterize ethnic differences in prevalence, clinical correlates, and outcomes of atrial fibrillation (AF) in heart failure (HF) with preserved and reduced ejection fraction (HFpEF and HFrEF) across Asia.

METHODS AND RESULTS

Among 5504 patients with HF prospectively recruited across 11 Asian regions using identical protocols in the Asian Sudden Cardiac Death in Heart Failure study (mean age 61 ± 13 years, 27% women, 83% HFrEF), 1383 (25%) had AF defined as a history of AF and/or AF/flutter on baseline electrocardiogram. Clinical correlates of AF were similar across ethnicities and included older age, prior stroke, higher NT-proBNP, and larger left atria. Diabetes was associated with lower odds of AF in HFrEF [adjusted odds ratio (AOR) 0.79, 95% CI 0.66-0.95] and HFpEF (AOR 0.58, 95% CI 0.39-0.84) regardless of ethnicity. Compared with Chinese ethnicity, Japanese/Koreans had higher odds of AF in HFrEF (AOR 1.76, 95% CI 1.40-2.21), while Indians had lower odds in HFrEF (AOR 0.18, 95% CI 0.13-0.24) and HFpEF (AOR 0.28, 95% CI 0.16-0.49) even after adjusting for clinical covariates. Interaction between ethnicity and region was observed among Indians, with Southeast Asian Indians having higher odds of AF (AOR 3.01, 95% CI 1.60-5.67) compared with South Asian Indians. AF was associated with poorer quality of life and increased risk of 1 year all-cause mortality or HF hospitalisation (adjusted hazard ratio 1.39, 95% CI 1.18-1.63) regardless of ethnicity.

CONCLUSIONS

Among patients with HF across Asia, clinical correlates and adverse outcomes associated with AF are similar across ethnicities; however, there are striking ethnic variations in the prevalence of AF that are not accounted for by known risk factors.

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

OBJECTIVE

Ethnic 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.

METHODS

Patients with validated HF were prospectively studied across Singapore and New Zealand (NZ).

RESULTS

Among 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 (p_interaction 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) (p_interaction 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).

CONCLUSION

There 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 NUMBER

ACTRN12610000374066.

A Culturally Tailored Community Health Worker Intervention Leads to Improvement in Patient-Centered Outcomes for Immigrant Patients With Type 2 Diabetes

IN BRIEF This article reports results from a patient-centered intervention to improve management of type 2 diabetes in the New York City Bangladeshi community. The DREAM (Diabetes Research, Education, and Action for Minorities) intervention is a randomized trial among Bangladeshi immigrants with type 2 diabetes comparing those enrolled in a community health worker (CHW) intervention to those in usual care. Participants in the intervention group received five group-based educational sessions and two one-on-one visits delivered by a trained CHW, whereas those in the control group received only the first group educational session. Main outcomes include changes in A1C, systolic and diastolic blood pressure, cholesterol, triglycerides, weight, BMI, and patient-centered outcomes such as knowledge and behavior related to type 2 diabetes management.

Prevalence of Cardiac Arrhythmias in Asian Patients With Obstructive Sleep Apnea: A Singapore Sleep Center Experience

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. Cardiac arrhythmias are common in patients with OSA. However, the prevalence and significance of cardiac arrhythmias in Asian patients with OSA are not well studied. The aim of this study is to determine the prevalence of cardiac arrhythmias in patients with OSA in Singapore and to evaluate possible factors that may predispose patients with OSA to arrhythmias.

METHODS

A retrospective study of 2,019 patients was carried out from January 2011 to December 2012 at a sleep center in a tertiary medical center. Of the population, 1,457 patients were found to have OSA and 144 patients were found to have cardiac arrhythmias. Data collected included patient demographics, comorbidities, and polysomnogram parameters.

RESULTS

The prevalence of cardiac arrhythmias in our OSA population is 8.0%, compared to that of primary snorers at 4.8% (P = .015). The univariate analysis revealed that older age, higher body mass index, comorbidities, and severity of OSA, including apnea-hypopnea index (AHI), lowest oxygen saturation (LSAT) and hypoxic time were correlated with a higher prevalence of cardiac arrhythmias (P < .05). However, the multivariate analysis showed that only age and body mass index were significantly correlated with arrhythmias. AHI, LSAT, and hypoxic time were no longer statistically significant.

CONCLUSIONS

Our study demonstrated that cardiac arrhythmias are common in patients with OSA in Singapore. It also suggests that given the different demographics of our population, ethnicity may play a significant role in the development of cardiovascular disease among patients with OSA.

COMMENTARY

A commentary on this article appears in this issue on page 1229.