Race-specific impact of atrial fibrillation risk factors in blacks and whites in the southern community cohort study

Assessing ascertainment bias in atrial fibrillation across US minority groups

The aim of this study is to define atrial fibrillation (AF) prevalence and incidence rates across minority groups in the United States (US), to aid in diversity enrollment target setting for randomized controlled trials. In AF, US minority groups have lower clinically detected prevalence compared to the non-Hispanic or Latino White (NHW) population. We assess the impact of ascertainment bias on AF prevalence estimates. We analyzed data from adults in Optum's de-identified Clinformatics® Data Mart Database from 2017-2020 in a cohort study. Presence of AF at baseline was identified from inpatient and/or outpatient encounters claims using validated ICD-10-CM diagnosis algorithms. AF incidence and prevalence rates were determined both in the overall population, as well as in a population with a recent stroke event, where monitoring for AF is assumed. Differences in prevalence across cohorts were assessed to determine if ascertainment bias contributes to the variation in AF prevalence across US minority groups. The period prevalence was respectively 4.9%, 3.2%, 2.1% and 5.9% in the Black or African American, Asian, Hispanic or Latino, and NHW population. In patients with recent ischemic stroke, the proportion with AF was 32.2%, 24.3%, 25%, and 24.5%, respectively. The prevalence of AF among the stroke population was approximately 7 to 10 times higher than the prevalence among the overall population for the Asian and Hispanic or Latino population, compared to approximately 5 times higher for NHW patients. The relative AF prevalence difference of the Asian and Hispanic or Latino population with the NHW population narrowed from respectively, -46% and -65%, to -22% and -24%. The study findings align with previous observational studies, revealing lower incidence and prevalence rates of AF in US minority groups. Prevalence estimates of the adult population, when routine clinical practice is assumed, exhibit higher prevalence differences compared to settings in which monitoring for AF is assumed, particularly among Asian and Hispanic or Latino subgroups.

Turkish Real Life Atrial Fibrillation in Clinical Practice: TRAFFIC Study

BACKGROUND

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide and is associated with an increased risk of thromboembolism, ischemic stroke, impaired quality of life, and mortality. The latest research that shows the prevalence and incidence of AF patients in Türkiye was the Turkish Adults' Heart Disease and Risk Factors study, which included 3,450 patients and collected data until 2006/07.The Turkish Real Life Atrial Fibrillation in Clinical Practice (TRAFFIC) study is planned to present current prevalence data, reveal the reflection of new treatment and risk approaches in our country, and develop new prediction models in terms of outcomes.

METHODS

The TRAFFIC study is a national, prospective, multicenter, observational registry. The study aims to collect data from at least 1900 patients diagnosed with atrial fibrillation, with the participation of 40 centers from Türkiye. The following data will be collected from patients: baseline demographic characteristics, medical history, vital signs, symptoms of AF, ECG and echocardiographic findings, CHADS2-VASC2 and HAS-BLED (1-year risk of major bleeding) risk scores, interventional treatments, antithrombotic and antiarrhythmic medications, or other medications used by the patients. For patients who use warfarin, international normalized ratio levels will be monitored. Follow-up data will be collected at 6, 12, 18, and 24 months. Primary endpoints are defined as systemic embolism or major safety endpoints (major bleeding, clinically relevant nonmajor bleeding, and minor bleeding as defined by the International Society on Thrombosis and Hemostasis). The main secondary endpoints include major adverse cardiovascular events (systemic embolism, myocardial infarction, and cardiovascular death), all-cause mortality, and hospitalizations due to all causes or specific reasons.

RESULTS

The results of the 12-month follow-up of the study are planned to be shared by the end of 2023.

CONCLUSION

The TRAFFIC study will reveal the prevalence and incidence, demographic characteristics, and risk profiles of AF patients in Türkiye. Additionally, it will provide insights into how current treatments are reflected in this population. Furthermore, risk prediction modeling and risk scoring can be conducted for patients with AF.

Addressing racial differences in the management of atrial fibrillation: Focus on black patients

Atrial fibrillation (AF) is the most common sustained arrhythmia, affecting between 3 and 6 million people in the United States. It is associated with a reduced quality of life and increased risk of stroke, cognitive decline, heart failure and death. Black patients have a lower prevalence of AF than White patients but are more likely to suffer worse outcomes with the disease. It is important that stakeholders understand the disproportionate burden of disease and management gaps that exists among Black patients living with AF. Appropriate treatments, including aggressive risk factor control, early referral to cardiovascular specialists and improving healthcare access may bridge some of the gaps in management and improve outcomes.

Blood pressure, hypertension and the risk of atrial fibrillation: a systematic review and meta-analysis of cohort studies

Elevated blood pressure and hypertension have been associated with increased risk of atrial fibrillation in a number of epidemiological studies, however, the strength of the association has differed between studies. We conducted a systematic review and meta-analysis of the association between blood pressure and hypertension and atrial fibrillation. PubMed and Embase databases were searched for studies of hypertension and blood pressure and atrial fibrillation up to June 6th 2022. Cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) of atrial fibrillation associated with hypertension or blood pressure were included. A random effects model was used to estimate summary RRs. Sixty eight cohort studies were included in the meta-analysis. The summary RR was 1.50 (95% CI: 1.42-1.58, I2 = 98.1%, n = 56 studies) for people with hypertension compared to those without hypertension (1,080,611 cases, 30,539,230 participants), 1.18 (95% CI: 1.16-1.21, I2 = 65.9%, n = 37 studies) per 20 mmHg increase in systolic blood pressure (346,471 cases, 14,569,396 participants), and 1.07 (95% CI: 1.03-1.11, I2 = 91.5%, n = 22 studies) per 10 mmHg increase in diastolic blood pressure (332,867 cases, 14,354,980 participants). There was evidence of a nonlinear association between diastolic blood pressure and atrial fibrillation with a steeper increase in risk at lower levels of diastolic blood pressure, but for systolic blood pressure the association appeared to be linear. For both systolic and diastolic blood pressure, the risk increased even within the normal range of blood pressure and persons at the high end of systolic and diastolic blood pressure around 180/110 mmHg had a 1.8-2.3 fold higher risk of atrial fibrillation compared to those with a blood pressure of 90/60 mmHg. These results suggest that elevated blood pressure and hypertension increases the risk of atrial fibrillation and there is some increase in risk even within the normal range of systolic and diastolic blood pressure.

The association of disparities in neighborhood median household income and mortality in patients admitted to the hospital with atrial fibrillation

BACKGROUND

Lower neighborhood median household income (nMHI) is associated with increased adverse outcomes in patients with atrial fibrillation (AF). However, its effect on mortality is yet unknown.

METHODS

Data from the regional United States (U.S.) electronic medical records database, Research Action for Health Network (REACHnet), was extracted for adult patients with AF at Tulane Medical Center over 10 years. Annual nMHI & neighborhood high school graduation (HSG) data was collected from the US Census bureau. Only African Americans (AA) and Caucasians (CC) who had socioeconomic data were included. Low nMHI and low HSG were defined as ≤$25,000 & <90% respectively. High nMHI and HSG were defined as >$50,000 & ≥90% respectively. Primary endpoints were all cause and cardiovascular (CV) mortality. Cox-proportional hazard ratios were used to evaluate the endpoints.

RESULTS

We included 4616 patients diagnosed with AF. During a median follow up of 4.6 years, 434 patients died of which 32.7% patients had CV mortality. There was a stepwise decrease in incidence of both all-cause and CV mortality as nMHI increased. Patients with low nMHI had the greatest risk of all-cause mortality (HR 1.9, C.I. 1.2-3.2, P 0.004). The association between low nMHI and all-cause mortality persisted after adjusting for age, sex, race, HSG and stroke risk factors using CHA₂DS₂VASC, delta CHA₂DS₂VASC scores and oral anticoagulant use. CV mortality followed a similar trend as all-cause mortality, however, this association was not significant after adjusting for the above variables. Apart from low nMHI, CHA₂DS₂VASC delta CHA₂DS₂VASC were statistically significant independent predictors of both all-cause and CV mortality.

CONCLUSION

Low nMHI is an independent risk factor for all cause and CV mortality in AF. Higher burden of co-morbidities is the driving force behind this disparity. Future studies should evaluate the role of educational and therapeutic intervention in these populations to reduce mortality.

Transcriptomics-based network medicine approach identifies metformin as a repurposable drug for atrial fibrillation

Effective drugs for atrial fibrillation (AF) are lacking, resulting in significant morbidity and mortality. This study demonstrates that network proximity analysis of differentially expressed genes from atrial tissue to drug targets can help prioritize repurposed drugs for AF. Using enrichment analysis of drug-gene signatures and functional testing in human inducible pluripotent stem cell (iPSC)-derived atrial-like cardiomyocytes, we identify metformin as a top repurposed drug candidate for AF. Using the active compactor, a new design analysis of large-scale longitudinal electronic health record (EHR) data, we determine that metformin use is significantly associated with a reduced risk of AF (odds ratio = 0.48, 95%, confidence interval [CI] 0.36-0.64, p < 0.001) compared with standard treatments for diabetes. This study utilizes network medicine methodologies to identify repurposed drugs for AF treatment and identifies metformin as a candidate drug.

Ethnic and Racial Disparities in Resource Utilization and In-hospital Outcomes Among Those Admitted for Atrial Fibrillation: A National Analysis

INTRODUCTION

Disparities in overall outcomes for atrial fibrillation (AF) across racial and ethnic groups have been demonstrated in prior studies. We aim to evaluate in-hospital outcomes and resource utilization across three racial/ethnic groups with AF using contemporary data.

METHODS

We identified patients admitted with AF in the National Inpatient Sample registry from 2015 to 2018. ICD-10-CM codes were used to identify variables of interest. The primary outcomes were in-hospital complications and resource utilization.

RESULTS

There were 1,250,075 AF admissions. Our sample was made up of 85.49% White, 8.12% Black, and 6.38% Hispanic patients. Black patients were younger but had a higher burden of cardiovascular comorbidities including obesity, hypertension, and chronic kidney disease. Social determinants were also less favorable in Black patients, with a higher percentage of Medicaid insurance and a high proportion of patients being in the lowest percentile for household income. Total hospital charge was highest in Hispanic patients. Despite higher rates of gastrointestinal bleed, Black patients were least likely to undergo left atrial appendage occlusion device implantation. Black and Hispanic patients were less like to undergo catheter ablation therapy. Black race was an independent predictor of mortality, stroke, mechanical ventilation, acute kidney injury, hemodynamic shock, need for vasopressor, upper GI bleed, need for blood transfusion, total hospital charges, and length of stay when compared to other groups.

CONCLUSION

Disparities exist in the risk of AF, and its management among racial and ethnic groups. Health care costs and inpatient outcomes disproportionately impact minorities in the United States.

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.

Association of Rare Genetic Variants and Early-Onset Atrial Fibrillation in Ethnic Minority Individuals

Importance

Although rare variants in cardiac ion channels, transcription factors, and myocardial structural proteins are associated with early-onset atrial fibrillation (AF) in White individuals of European descent, it remains unclear whether genetic variation also contributes to the cause of AF in those of minority ethnicity.

Objectives

To assess the prevalence of rare and novel pathogenic variants in candidate genes in ethnic minority probands with early-onset AF and determine genotype-phenotype associations.

Design, Setting, and Participants

In this cohort, family-based study, probands of African and Hispanic descent with early-onset AF (defined as AF occurring in individuals aged ≤66 years) prospectively enrolled in a clinical and genetic biorepository underwent sequencing of 60 candidate genes. Recruitment took place from July 1, 2015, to June 30, 2019. Data were analyzed from February 1 to February 28, 2020.

Exposures

Rare and novel variants categorized as pathogenic or likely pathogenic.

Main Outcomes and Measures

The prevalence of rare and novel pathogenic variants in African American and Hispanic/Latinx probands with early-onset AF and genotype-phenotype associations.

Results

Among 227 probands with early-onset AF, mean (SD) age at onset of AF was 51.0 (9.9) years, 132 probands (58.1%) were men, 148 (65.2%) were African American, and 79 (34.8%) were Hispanic/Latinx. A family history of AF was verified in 24 probands with early-onset AF (10.6%). Sequencing 60 candidate genes identified 53 (23 rare and 30 novel) variants with 16 of the 227 (7.0%) probands harboring likely pathogenic (43.8%) or pathogenic (56.2%) variants, with most loss-of-function variants in TTN, the gene encoding the sarcomeric protein titin (46.7%). In 6 families with more than 2 affected members, variants of unknown significance in sodium channel (SCN10A), potassium channel (KCNE5), sarcomeric proteins (MYH6 and TTN), and atrial natriuretic peptide (NPPA) cosegregated with AF.

Conclusions and Relevance

In this study, likely pathogenic and pathogenic variants were identified, with most loss-of-function variants in TTN, that increase susceptibility to early-onset AF in African American and Hispanic/Latinx individuals. These findings provide further understanding toward molecular phenotyping of AF and suggest novel mechanism-based therapeutic approaches for this common arrhythmia in ethnic minority groups.

A survey on a rural in-hospital population diagnosed with Atrial Fibrillation in west Shewa region, Ethiopia

BACKGROUND

Atrial fibrillation (AF) is the most common sustained arrhythmia seen in clinical practice. It has been extensively studied in Western countries but less is known about developing countries.

METHODS

We collected data on a rural population afferent to Wolisso hospital in Ethiopia, analysing epidemiology, clinical and cardiac ultrasound profile.We enrolled 54 patients with first diagnosis of AF who undertook cardiac ultrasound and a questionnaire about personal and clinical profile.

RESULTS

Enrolled patients were younger than reported in the African urban population (mean age 51 years) and females were symptomatic at a younger age than males (61.8% of females were <50 years old versus 30% of males) and had complicated disease (100% of females had CHF). Rheumatic heart disease (RHD) was found in 38.9% of patients, especially in females (41.1%) and young patients, whereas hypertension (HTN) and degenerative valvular disease were predisposing to AF in old patients.

CONCLUSION

Low socio-economic level may explain findings we observed, particularly male to female ratio, more relevant than in urban subsets. RHD and HTN are many etiological factors of AF in our small population, so low-cost strategies to prevent their complications are surely cost-effective in rural catchment area of Wolisso hospital.

A Description of Risk Factors for Non-alcoholic Fatty Liver Disease in the Southern Community Cohort Study: A Nested Case-Control Study

Background: Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and hypercholesterolemia. In addition, total fat and folate intake have been associated with NAFLD.

Aims: We investigated risk factors for NAFLD among individuals of largely low socioeconomic status, and whether these associations differed by race.

Methods: A nested case-control study was conducted within the Southern Community Cohort Study. Through linkage of the cohort with Centers for Medicare and Medicaid Services, International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify incident NAFLD cases. Controls were matched 4:1 to cases on enrollment age, sex, and race. A logistic regression was used to estimate odds ratios for the associations of NAFLD with covariates of interest.

Results: Neither total fat nor folate intake was significantly associated with NAFLD. Hypercholesterolemia (odds ratio 1.21) and body mass index (75th vs. 25th percentile) for blacks (odds ratio 1.96) and whites (odds ratio 2.33) were associated with an increased risk of non-alcoholic fatty liver disease. No significant interaction with race for any of the studied variables was noted.

Conclusions: Both hypercholesterolemia and increasing body mass index, but not total fat and folate intake, were risk factors for NAFLD in the Southern Community Cohort Study.

Impact of traditional risk factors for the outcomes of atrial fibrillation across race and ethnicity and sex groups

Background

Although traditional risk factors for atrial fibrillation (AF) and its outcomes are established in whites, their role in the pathogenesis of AF across race-ethnicity and both sexes remain unclear. Cohort studies have consistently shown worse AF-related outcomes in these groups. The objective of this study was to determine the role played by race- and sex-specific risk factors in AF outcomes in non-Hispanic blacks (NHBs), Hispanics/Latinos (H/Ls), and non-Hispanic whites (NHWs).

Methods

Using electronic health records (EHR), 3607 patients with an ICD-9 code for AF were identified over a 7-year period. Risk factors were identified from ICD to 9 CM claims data: hypertension (HTN), type 2 diabetes mellitus (T2DM), stroke/transient ischemic attack (TIA), smoking, chronic obstructive pulmonary disease (COPD), coronary artery disease (CAD), peripheral arterial disease (PAD) and obstructive sleep apnea (OSA). Multivariate analysis of variance was used to compare the incidence of AF risk factors.

Results

NHBs and H/Ls with AF experienced more stroke than NHWs (27% and 24% vs. 19% P < 0.01). Females had less HTN (48.4% vs 51.6% [males], P = 0.0002), CAD (47.4% vs 55.7% [males], P = 0.02), and smoking rates (38.2% vs 61.8% [males], P < 0.0001) but higher stroke rates (25.9% [female] vs 21.8% [males], P < 0.0001). Age-adjusted risk factors for stroke varied markedly across race-ethnicity and sex.

Conclusions

We identified differences in risk factors for AF and stroke across race-ethnicity and sex. The findings of our study are hypothesis generating and should be used to direct future studies.

Risk of Atrial Fibrillation in Black Versus White Medicare Beneficiaries With Implanted Cardiac Devices

Background

Black individuals in the United States experience higher rates of ischemic stroke than other racial groups but have lower rates of clinically apparent atrial fibrillation (AF). It is unclear whether blacks truly have less AF or simply more undiagnosed AF.

Methods and Results

We performed a retrospective cohort study using inpatient and outpatient claims from 2009 to 2015 for a 5% nationally representative sample of Medicare beneficiaries. We included patients aged ≥66 years with at least 1 documented Current Procedural Terminology code for interrogation of an implantable pacemaker, cardioverter‐defibrillator, or loop recorder and no documented history of AF, atrial flutter, or stroke before their first device interrogation. Kaplan–Meier statistics and Cox proportional hazards models were used to examine the association between black race and the composite outcome of AF or atrial flutter while adjusting for age, sex, and vascular risk factors. Among 47 417 eligible patients, the annual incidence of AF/atrial flutter was 12.2 (95% CI, 11.5–13.1) per 100 person‐years among blacks and 17.6 (95% CI, 17.4–17.9) per 100 person‐years among non‐black beneficiaries. After adjustment for confounders, black beneficiaries faced a lower hazard of AF/atrial flutter than non‐black beneficiaries (hazard ratio, 0.75; 95% CI, 0.70–0.80). Despite the lower risk of AF, black patients faced a higher hazard of ischemic stroke (hazard ratio, 1.37; 95% CI, 1.22–1.53).

Conclusions

Among Medicare beneficiaries with implanted cardiac devices capable of detecting atrial rhythm, black patients had a lower incidence of AF despite a higher burden of vascular risk factors and a higher risk of stroke.

Diabetes and Arrhythmias: Pathophysiology, Mechanisms and Therapeutic Outcomes

The prevalence of diabetes is rapidly increasing and closely associated with cardiovascular morbidity and mortality. While the major cardiovascular complication associated with diabetes is coronary artery disease, it is becoming increasingly apparent that diabetes impacts the electrical conduction system in the heart, resulting in atrial fibrillation, and ventricular arrhythmias. The relationship between diabetes and arrhythmias is complex and multifactorial including autonomic dysfunction, atrial and ventricular remodeling and molecular alterations. This review will provide a comprehensive overview of the link between diabetes and arrhythmias with insight into the common molecular mechanisms, structural alterations and therapeutic outcomes.

Racial Differences in Atrial Fibrillation-Related Cardiovascular Disease and Mortality: The Atherosclerosis Risk in Communities (ARIC) Study

IMPORTANCE

The adverse outcomes associated with atrial fibrillation (AF) have been studied in predominantly white cohorts. Racial differences in outcomes associated with AF merit continued investigation.

OBJECTIVE

To evaluate the race-specific associations of AF with stroke, heart failure, coronary heart disease (CHD), and all-cause mortality in a community-based cohort.

DESIGN, SETTING, AND PARTICIPANTS

The Atherosclerosis Risk in Communities (ARIC) Study is a prospective, observational cohort. From 1987 through 1989, the ARIC Study enrolled 15 792 men and women and conducted 4 follow-up examinations (2011-2013) with active surveillance for vital status and hospitalizations. Race was determined by self-report and categorized as white, black, or other.

MAIN OUTCOMES AND MEASURES

Atrial fibrillation (adjudicated using electrocardiograms, hospital discharge codes, and death certificates), stroke, heart failure, CHD, and mortality.

RESULTS

After exclusions, 15 080 participants (mean [SD] age, 54.2 [5.8] years; 8290 women [55.5%]; 3831 black individuals [25.4%]) were included in this analysis. During a mean (SD) follow-up of 20.6 (6.2) years, there were 2348 cases of incident AF. The incident rates of AF per 1000 person-years were 8.1 (95% CI, 7.7-8.5) in white individuals and 5.8 (95% CI, 5.2-6.3) in black individuals. The rates of stroke, heart failure, CHD, and mortality were higher in black individuals with AF than white individuals with AF. The association of AF with these outcomes, estimated with rate differences (rate of the end point in those with AF minus the rate in those without AF per 1000 person-years), also differed by race. The rate difference for stroke in individuals with AF was 10.2 (95% CI, 6.6-13.9) in white individuals and 21.4 (95% CI, 10.2-32.6) in black individuals. For heart failure and CHD, the rate differences were 1.5- to 2.0-fold higher in black individuals than white individuals. White individuals with AF had a rate difference of 55.9 (95% CI, 48.1-63.7) for mortality compared with black individuals, who had a rate difference of 106.0 (95% CI, 86.0-125.9).

CONCLUSIONS AND RELEVANCE

In the prospective ARIC Study, the outcome of AF on the rates of stroke, heart failure, CHD, and mortality was considerably larger in black individuals than white individuals. These results indicate the vulnerability and increased risk in black individuals with AF. Continued investigation of racial differences in AF and its related adverse outcomes are essential to identify and mitigate racial disparities in the treatment of AF.

Race, Sex, Age, and Regional Differences in the Association of Obstructive Sleep Apnea With Atrial Fibrillation: Reasons for Geographic and Racial Differences in Stroke Study

STUDY OBJECTIVES

To examine the cross-sectional association between obstructive sleep apnea (OSA) risk and atrial fibrillation (AF) in the REasons for Geographic And Racial Differences in Stroke (REGARDS), a cohort of black and white adults.

METHODS

Using REGARDS data from subjects recruited between 2003-2007, we assessed 20,351 participants for OSA status. High OSA risk was determined if the participant met at least two criteria from the Berlin Sleep Questionnaire (persistent snoring, frequent sleepiness, high blood pressure, or obesity). AF was defined as a self-reported history of a previous physician diagnosis or presence of AF on electrocardiogram. Logistic regression was used to determine odds ratio and 95% confidence interval for the association between OSA status and AF with subgroup analysis to examine effect modification by age, race, sex, and geographical region.

RESULTS

The prevalence of AF was 7% (n = 1,079/14,992) and 9% (n = 482/5,359) in participants at low and high risk of OSA, respectively (P < .0001). Persons at high risk of OSA had greater prevalence of diabetes and stroke history, and were more likely to be obese and taking sleep medications. In a multivariable analysis adjusted for demographics, cardiovascular risk factors, and potential confounders, high risk for OSA was associated with an increased odds of AF compared to low risk for OSA (odds ratio = 1.27, 95% confidence interval = 1.13, 1.44). This association differed significantly only by race (P for interaction = .0003). For blacks, there was a significant 58% increase in odds of AF in participants at high risk versus low risk of OSA, compared to a nonsignificant 12% increase in odds in whites. We were limited by self-reported variables, inability to adjust for obesity, and the cross-sectional nature of our study.

CONCLUSIONS

High risk of OSA is associated with prevalent AF among blacks but not whites.

COMMENTARY

A commentary on this article appears in this issue on page 1459.

Association Between Family History and Early-Onset Atrial Fibrillation Across Racial and Ethnic Groups

IMPORTANCE

There is a genetic predisposition to early-onset atrial fibrillation (EOAF) in European American individuals. However, the role of family history in the pathogenesis of EOAF in racial and ethnic minorities remains unclear.

OBJECTIVE

To determine whether probands with EOAF across racial and ethnic groups have a higher rate of AF in first-degree family members than racially and ethnically matched control patients with non-early-onset AF (non-EOAF).

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, patients prospectively enrolled in a clinical and genetic biorepository were administered baseline questionnaires that included questions about family history of AF. Early-onset AF was defined as AF occurring in probands aged 60 years or younger in the absence of structural heart disease. All other forms were categorized as non-EOAF. Recruitment took place from July 2015 to December 2017. Analysis was performed in January 2018.

MAIN OUTCOMES AND MEASURES

Primary analysis of reported family history of AF in first-degree relatives with sensitivity analysis restricted to those in whom a family history was confirmed by medical record review and electrocardiogram.

RESULTS

Of 664 patients enrolled (mean [SD] age, 62 [12] years; 407 [61%] male), 267 (40%) were European American; 258 (39%), African American; and 139 (21%), Hispanic/Latino. There was a family history of AF in 36 probands with EOAF (49%) compared with 128 patients with non-EOAF (22%) (difference, 27%; 95% CI, 14%-40%; P < .001). On multivariable analysis, the adjusted odds of a proband with EOAF who was of African descent (odds ratio [OR], 2.69; 95% CI, 1.06-6.91; P < .001) or Hispanic descent (OR, 9.25; 95% CI, 2.37-36.23; P = .002) having a first-degree relative with AF were greater than those of European descent (OR, 2.51; 95% CI, 1.29-4.87; P = .006). Overall, probands with EOAF were more likely to have a first-degree relative with AF compared with patients with non-EOAF (adjusted OR, 3.02; 95% CI, 1.82-4.95; P < .001) across the 3 racial and ethnic groups. Atrial fibrillation in a first-degree family member was confirmed in 32% of probands with EOAF vs 11% of those with non-EOAF (difference, 21%; 95% CI, 11%-33%; P < .001). Furthermore, African American (28% vs 5%; difference, 23%; 95% CI, 4%-43%; P = .001), European American (35% vs 20%; difference, 15%; 95% CI, 1%-30%; P = .03), and Hispanic/Latino (30% vs 5%; difference, 25%; 95% CI, 4%-54%; P = .02) probands with EOAF were more likely to have a first-degree relative with confirmed AF vs racially and ethnically matched control patients with non-EOAF. The positive and negative predictive values for a family history of confirmed AF were both 89%.

CONCLUSIONS AND RELEVANCE

Probands of African or Hispanic/Latino descent with EOAF were more likely to have a first-degree relative with AF when compared with European American individuals. These findings support genetic predisposition to EOAF across all 3 races.

Diabetes mellitus, blood glucose and the risk of atrial fibrillation: A systematic review and meta-analysis of cohort studies

BACKGROUND

Diabetes and elevated blood glucose have been associated with increased risk of atrial fibrillation in a number of epidemiological studies, however, the findings have not been entirely consistent. We conducted a systematic review and meta-analysis to clarify the association.

MATERIAL AND METHODS

We searched the PubMed and Embase databases for studies of diabetes and blood glucose and atrial fibrillation up to July 18th 2017. Cohort studies were included if they reported relative risk (RR) estimates and 95% confidence intervals (CIs) of atrial fibrillation associated with a diabetes diagnosis, prediabetes or blood glucose. Summary RRs were estimated using a random effects model.

RESULTS

Thirty four studies were included in the meta-analysis of diabetes, pre-diabetes or blood glucose and atrial fibrillation. Thirty two cohort studies (464,229 cases, >10,244,043 participants) were included in the analysis of diabetes mellitus and atrial fibrillation. The summary RR for patients with diabetes mellitus versus patients without diabetes was 1.30 (95% CIs: 1.03-1.66), however, there was extreme heterogeneity, I² = 99.9%) and evidence of publication bias with Begg's test, p < 0.0001. After excluding a very large and outlying study the summary RR was 1.28 (95% CI: 1.22-1.35, I² = 90%, n = 31, 249,772 cases, 10,244,043 participants). The heterogeneity was mainly due to differences in the size of the association between studies and the results persisted in a number of subgroup and sensitivity analyses. The summary RR was 1.20 (95% CI: 1.03-1.39, I² = 30%, n = 4, 2392 cases, 58,547 participants) for the association between prediabetes and atrial fibrillation. The summary RR was 1.11 (95% CI: 1.04-1.18, I² = 61%, n = 4) per 20 mg/dl increase of blood glucose in relation to atrial fibrillation (3385 cases, 247,447 participants) and there was no evidence of nonlinearity, p_nonlinearity = 0.34.

CONCLUSIONS

This meta-analysis suggest that prediabetes and diabetes increase the risk of atrial fibrillation by 20% and 28%, respectively, and there is a dose-response relationship between increasing blood glucose and atrial fibrillation. Any further studies should clarify whether the association between diabetes and blood glucose and atrial fibrillation is independent of adiposity.

Usefulness of the American Heart Association's Life Simple 7 to Predict the Risk of Atrial Fibrillation (from the REasons for Geographic And Racial Differences in Stroke [REGARDS] Study)

The American Heart Association has identified metrics of ideal cardiovascular (CV) health known as Life's Simple 7 (LS7). We determined the prospective relationship between the LS7 and the incident atrial fibrillation (AF) in a biracial cohort. The REasons for Geographic And Racial Differences in Stroke (REGARDS) study enrolled non-Hispanic black and white adults 45 years or older. This analysis included 9,576 REGARDS participants (mean age 63 ± 8.4 years; 57% women; 30% black) who were free of AF at baseline and completed a follow-up examination 9.4 years later. An overall LS7 score was calculated at baseline as the sum of the LS7 component scores and classified as inadequate (0 to 4), average (5 to 9), or optimal (10 to 14) CV health. The primary outcome was incident AF, identified at follow-up by either electrocardiogram or a self-reported medical history of a physician diagnosis. A total of 725 incident AF cases were detected. Compared with the inadequate category (n = 534), participants in the optimal category (n = 1,953) had a 32% lower odds of developing AF (odds ratio 0.68; 95% confidence interval 0.47, 0.99) in a logistic regression model adjusted for demographic characteristics, alcohol use, left ventricular hypertrophy, coronary heart disease, and stroke. A 1-point higher LS7 score was associated with a 5% lower odds of incident AF (odds ratio  = 0.95; 95% confidence interval 0.91, 0.99). In conclusion, better CV health, as defined by the LS7 score, is associated with a reduction in development of AF.

Usefulness of Atrial Premature Complexes on Routine Electrocardiogram to Determine the Risk of Atrial Fibrillation (from the REGARDS Study)

Atrial premature complexes (APCs) serve as acute triggers for atrial fibrillation (AF), but it is currently unknown whether the association between APCs and AF varies by race or sex. We examined the association between APCs and AF in 13,840 (mean age = 63 ± 8.4 years; 56% women; 37% black) participants from the REasons for Geographic And Racial Differences in Stroke study. APCs were detected on baseline electrocardiograms (2003 to 2007). Incident AF was identified by study-scheduled electrocardiograms and self-reported history at a follow-up examination. Logistic regression was used to compute odds ratios (OR) and 95% confidence intervals for the association between APCs and incident AF. A total of 950 participants (6.9%) had APCs at the baseline visit. After a median follow-up of 9.4 years, 1015 incident AF cases (7.3%) were detected. APCs were associated with an increased risk of AF (odds ratios = 1.92, 95% confidence intervals = 1.57, 2.35). The relation between APCs and AF did not vary by race (interaction p value = 0.56) or sex (interaction p value = 0.66). In conclusion, APCs detected on a routine electrocardiogram are associated with an increased risk of AF development, and this association does not vary by race or sex. The findings of this analysis suggest that the risk of AF associated with atrial ectopy does not account for the differential risk of AF that is observed in whites compared with blacks, and in men compared with women.

Relation of Obstructive Sleep Apnea and a Common Variant at Chromosome 4q25 to Atrial Fibrillation

Obstructive sleep apnea (OSA) and single nucleotide polymorphisms (SNPs) at the 4q25 locus are associated with increased risk of atrial fibrillation (AF). Whether these associations are independent of traditional risk factors for AF remains unknown. Using billing code queries and manual chart review, we assembled a cohort of adults that underwent overnight polysomnography and at least 1 12-lead electrocardiogram. Case status was defined by electrocardiographic data in support of AF or documentation of AF by a staff cardiologist. Controls were defined by a lack of primary evidence of AF and absence of a diagnosis of AF in the medical record. OSA severity was categorized based on Apnea-Hypopnea Index. Genotyping for a key 4q25 SNP (rs2200733) was performed using the Sequenom platform. Logistic regression was used to test for associations of AF with OSA category and 4q25 SNP genotype while adjusting for age, gender, body mass index, ancestry, hypertension status, and heart failure status. The cohort consisted of 674 subjects (62 ± 13 years; 44% women), including 132 patients with AF. After adjustment for established risk factors, the association between AF and OSA severity was borderline significant (odds ratio 1.2, 95% CI 1.0 to 1.5). The association between AF and 4q25 SNP status remained significant in a fully adjusted model that included OSA severity (odds ratio 1.5, 95% CI 1.3 to 5.7). In conclusion, OSA severity and the chromosome 4q25 SNP genotype were associated with AF status independent of clinical risk factors. Knowledge of AF-related SNPs may enhance AF risk stratification for those undergoing polysomnography.

Traditional Cardiovascular Risk Factors for Incident Atrial Fibrillation

To prevent atrial fibrillation (AF), it is essential to reduce its risk factors and extend healthy life expectancy as a result. There are few reviews on the AF risk factors. We discuss them and approach the prevention of AF. We briefly review traditional risk factors for incident AF, especially focusing on high blood pressure, overweight/obesity, dyslipidemia, diabetes, tobacco smoking, and excessive drinking. When trying to prevent AF by modifying lifestyle, it is important to comprehensively utilize the risk factors for AF to predict the 10-year as an AF risk score. However, there are only 2 risk scores of AF just for the US population. There are few studies of the AF risk factors in non-Western populations. A risk score for incident AF in non-Westerners is awaited because different race and lifestyles may have different contributions as AF risk factors. An AF risk score in accordance with race could be useful for identifying persons with a high risk of AF in order to encourage them to consult a doctor and encourage lifestyle modifications before the onset of AF. (Circ J 2016; 80: 2415-2422).

Differential Impact of Risk Factors in Blacks and Whites in the Development of Atrial Fibrillation: the Reasons for Geographic And Racial Differences in Stroke (REGARDS) Study

BACKGROUND

Despite a higher prevalence of risk factors, atrial fibrillation (AF) is less prevalent in blacks than whites. To address this paradox, we examined racial differences in the magnitude of AF risk associated with common risk factors.

METHODS

Participants (13,688; mean age = 63 ± 8.4 years; 56 % female; 37 % black) from the Reasons for Geographic And Racial Differences in Stroke study who were free of baseline AF were included. Incident AF was identified at a follow-up examination by electrocardiogram and self-reported medical history. Poisson regression was used to compute relative risk (RR) and 95 % confidence intervals (CI) for the association between risk factors and incident AF in blacks and whites, separately. Age- and sex-adjusted population attributable fractions (PAFs) of modifiable AF risk factors were computed.

RESULTS

After median follow-up of 9.4 years, 997 (7.3 %) incident AF cases were detected. Black race was associated with a lower risk of AF (RR = 0.46, 95 % CI = 0.39, 0.53). Significant risk factors for AF were age, male sex, hypertension, obesity, and cardiovascular disease. A differential association was detected for smoking by race, with the association being stronger in blacks (RR = 1.41, 95 % CI = 1.07, 1.85) compared with whites (RR = 1.01, 95 % CI = 0.88, 1.16; P interaction = 0.030). The PAFs for hypertension (blacks = 27.4 %, whites = 19.4 %), obesity (blacks = 16.9 %, whites = 11.8 %), and smoking (blacks = 17.9 %, whites = 2.5 %) were higher for blacks than whites.

CONCLUSION

Modifiable risk factors are important in AF development among blacks despite a lower risk of the arrhythmia. Racial differences in the magnitude of the association of individual AF risk factors do not explain the AF paradox.

Investigation of selection bias in the association of race with prevalent atrial fibrillation in a national cohort study: REasons for Geographic And Racial Differences in Stroke (REGARDS)

PURPOSE

Atrial fibrillation (AF) is diagnosed more commonly in whites than blacks in the United States. In epidemiologic studies, selection bias could induce a noncausal positive association of white race with prevalent AF if voluntary enrollment was influenced by both race and AF status. We investigated whether nonrandom enrollment biased the association of race with prevalent self-reported AF in the US-based REasons for Geographic And Racial Differences in Stroke Study (REGARDS).

METHODS

REGARDS had a two-stage enrollment process, allowing us to compare 30,183 fully enrolled REGARDS participants with 12,828 people who completed the first-stage telephone survey but did not complete the second-stage in-home visit to finalize their REGARDS enrollment (telephone-only participants).

RESULTS

REGARDS enrollment was higher among whites (77.1%) than among blacks (62.3%) but did not differ by self-reported AF status. The prevalence of AF was 8.45% in whites and 5.86% in blacks adjusted for age, sex, income, education, and perceived general health. The adjusted white/black prevalence ratio of self-reported AF was 1.43 (95% CI, 1.32-1.56) among REGARDS participants and 1.38 (1.22-1.55) among telephone-only participants.

CONCLUSIONS

These findings suggest that selection bias is not a viable explanation for the higher prevalence of self-reported AF among whites in population studies such as REGARDS.

Racial and ethnic differences in atrial fibrillation risk factors and predictors in women: Findings from the Women's Health Initiative

BACKGROUND

The incidence of atrial fibrillation (AF) is higher in non-Hispanic whites (NHWs) compared with other race-ethnic groups, despite more favorable cardiovascular risk profiles. To explore reasons for this paradox, we compared the hazards of AF from traditional and other risk factors between 4 race-ethnic groups in a large cohort of postmenopausal women.

METHODS

We included 114,083 NHWs, 11,876 African Americans, 5,174 Hispanics, and 3,803 Asians from the Women's Health Initiative free of AF at baseline. Women, averaging 63 years old, were followed up for incident AF using hospitalization records and diagnostic codes from Medicare claims.

RESULTS

Over a mean of 13.7 years, 19,712 incident cases of AF were recorded. Despite a higher burden of hypertension, diabetes, and obesity, annual AF incidence was lower among nonwhites (0.7%, 0.4%, and 0.4% for African American, Hispanic, and Asian participants, respectively, compared with 1.2% for NHWs). The hazards of AF from hypertension, diabetes, obesity, heart failure, and coronary artery disease were similar across race-ethnic groups. Major risk factors, including hypertension, obesity, diabetes, smoking, peripheral arterial disease, coronary artery disease, and heart failure, accounted for an attributable risk of 50.3% in NHWs, 83.1% in African Americans, 65.6% in Hispanics, and 37.4% in Asians. Established AF prediction models performed comparably across race-ethnic groups.

CONCLUSIONS

In this large study of postmenopausal women, traditional cardiovascular risk factors conferred a similar degree of individual risk of AF among 4 race-ethnic groups. However, major AF risk factors conferred a higher-attributable risk in African Americans and Hispanics compared with NHWs and Asians.

Racial Differences in the Prevalence and Outcomes of Atrial Fibrillation in Patients Hospitalized With Heart Failure

Previous research has shown that roughly 15% to 30% of those with heart failure (HF) develop atrial fibrillation (AF). Although studies have shown variations in the incidence of AF in patients with HF, there has been no evidence of mortality differences by race. The purpose of this study was to assess AF prevalence and inhospital mortality in patients with HF among different racial groups in the United States. Using the National Inpatient Sample registry, the largest publicly available all-payer inpatient care database representing >95% of the US inpatient population, we analyzed subjects hospitalized with a primary diagnosis of HF from 2001 to 2011 (n = 11,485,673) using the International Classification of Diseases, Ninth Edition (ICD 9) codes 428.0-0.1, 428.20-0.23, 428.30-0.33, 428.40-0.43, and 428.9; patients with AF were identified using the ICD 9 code 427.31. We assessed prevalence and mortality among racial groups. Using logistic regression, we examined odds of mortality adjusted for demographics and co-morbidity using Elixhauser co-morbidity index. We also examined utilization of procedures by race. Of the 11,485,673 patients hospitalized with HF in our study, 3,939,129 (34%) had AF. Patients with HF and AF had greater inhospital mortality compared with those without AF (4.6% vs 3.3% respectively, p <0.0001). Additionally, black, Hispanic, Asian, and white patients with HF and AF had a 24%, 17%, 13%, and 6% higher mortality, respectively, than if they did not have AF. Among patients with HF and AF, minority racial groups had underutilization of catheter ablation and cardioversion compared with white patients. In conclusion, minority patients with HF and AF had a disproportionately higher risk of inpatient death compared with white patients with HF. We also found a significant underutilization of cardioversion and catheter ablation in minority racial groups compared with white patients.

Hypertension Is a Risk Factor for Several Types of Heart Disease: Review of Prospective Studies

Many prospective cohort studies have demonstrated that hypertension is a strong risk factor for total mortality and cardiovascular disease (CVD). Heart disease includes coronary heart disease (CHD), heart failure, atrial fibrillation, valvular disease, sudden cardiac death (SCD), sick sinus syndrome (SSS), cardiomyopathy, and aortic aneurysms. Most of the epidemiologic prospective studies of heart disease focused on coronary/ischemic heart disease. Here we comprehensively reviewed the association between hypertension and the above-mentioned heart diseases. We found that CHD, heart failure, atrial fibrillation, aortic valvular disease, SCD, SSS, left ventricular hypertrophy, and abdominal aortic aneurysms were all associated with hypertension. Those relations tended to be stronger in men. The prevention of hypertension and lowering one's blood pressure may help reduce the risk of developing heart disease.

Increased body mass index may be associated with greater risk of end-stage renal disease in whites compared to blacks: A nested case-control study

BACKGROUND

The relationship between body mass index (BMI) and end-stage renal disease (ESRD) may differ between blacks and whites due to underlying metabolic differences.

METHODS

We conducted a nested case-control study of 631 incident ESRD cases and 1,897 matched controls within the Southern Community Cohort Study. Current weight, height, and weight at age 21 were reported at enrollment. Occurrence of ESRD was ascertained by linkage with the United States Renal Data System. With normal BMI (18.5-24.9 kg/m²) as reference, conditional logistic regression was used to calculate adjusted odds ratios (OR) and corresponding 95% confidence intervals (CI) for ESRD across other BMI categories by race. In subsequent analysis, BMI at age 21 was modeled using restricted cubic splines with 5 knots. Predicted probabilities of incident ESRD were computed from the multivariable logistic models and plotted against BMI at age 21.

RESULTS

Among blacks, odds of ESRD were significantly increased among those who were overweight (OR: 1.41; 95%CI: 1.09, 1.83) or obese (OR: 2.56; 95%CI: 1.88, 3.47) at age 21. Among whites, the association between ESRD and BMI at age 21 was more pronounced, with corresponding ORs of 2.13 (95%CI: 0.92, 4.93) and 7.46 (95%CI: 2.90, 19.21; p-interaction 0.05). Only among whites was high BMI at enrollment associated with ESRD risk; OR for BMI≥40 kg/m², was 3.31 (95%CI: 1.08, 10.12). The plot of the predicted probabilities of incident ESRD vs BMI at age 21 showed a monotonic increase in the probability of ESRD after a BMI cutoff ≈ 25Kg/m² in both whites and blacks but the slope of the curve for whites appeared greater.

CONCLUSIONS

Our results suggest racial differences in the relationship between BMI, both in early adulthood and middle age, and ESRD. These findings warrant further research into understanding the underlying metabolic differences that may explain these differences.

Intake of polyunsaturated fat in relation to mortality among statin users and non-users in the Southern Community Cohort Study

BACKGROUND AND AIMS

Consumption of polyunsaturated fatty acids (PUFA), especially the n3-series, may protect against cardiovascular disease (CVD), but recent randomized studies have failed to demonstrate these benefits. One of the prevailing hypotheses is that PUFA intake may not confer benefits beyond those provided by statins, but studies comparing statin users to non-users with regard to effects of PUFA are lacking.

METHODS AND RESULTS

Black and white men and women (n = 69,559) in the Southern Community Cohort Study were studied. Cox regression models adjusting for age, sex, race, BMI, recruitment site, education, income, smoking, diabetes, and dietary variables were used.

RESULTS

At baseline the mean ± SD age was 52 ± 9 years, 60% of participants were women, 54% had hypertension and 16% used statins. We observed modest inverse associations between n3-PUFA and n6-PUFA intake with mortality among non-statin users but not among statin users. In adjusted analyses, the HRs (95% CIs) for all-cause mortality (6,396 deaths over a median of 6.4 years) comparing the highest to the lowest quintile were 0.90 (0.82-1.00) for n3-PUFA and 0.80 (0.70-0.92) for n6-PUFA among non-statin users, whereas they were 1.06 (0.87-1.28) and 0.96 (0.78-1.19) for n3-PUFA and n6-PUFA, respectively, among statin users.

CONCLUSIONS

Our results suggest potential benefits of PUFA consumption on mortality which are only apparent in the absence of statin therapy. It seems prudent to consider the potential benefit of PUFA consumption in the primary prevention of CVD among patients who are not candidates for statin therapy but are at increased risk for CVD and mortality.

Diabetes mellitus and atrial fibrillation: Pathophysiological mechanisms and potential upstream therapies

Diabetes mellitus (DM) represents one of the most important risk factors for atrial fibrillation (AF) while AF is a strong and independent marker of overall mortality and cardiovascular morbidity in diabetic patients. Autonomic, electrical, electromechanical, and structural remodeling, including oxidative stress, connexin remodeling and glycemic fluctuations seem to be implicated in AF pathophysiology in the setting of DM. The present review highlights the association between DM and AF, provides a comprehensive overview of the responsible pathophysiological mechanisms and briefly discusses potential upstream therapies for DM-related atrial remodeling.

Atrial fibrillation incidence and risk factors in relation to race-ethnicity and the population attributable fraction of atrial fibrillation risk factors: the Multi-Ethnic Study of Atherosclerosis

PURPOSE

We studied incident atrial fibrillation (AF) in the prospective community-based Multi-Ethnic Study of Atherosclerosis (MESA). Reportedly, non-Hispanic blacks (NHBs) have a lower AF burden compared with their non-Hispanic white (NHW) counterparts. Information on the epidemiology of AF in Hispanic and Asian populations is much more limited.

METHODS

We excluded participants with a history of AF at enrollment. A total of 6721 MESA participants were monitored for the first AF event ascertained according to hospital discharge International Classification of Diseases, Ninth Revision, codes. Age- and sex-adjusted incidence rates (IRs) of AF were calculated per 1000 person-years of observation. IR ratios were calculated using NHWs as the reference group. Age- and sex-adjusted population attributable fractions (PAFs) of established modifiable AF risk factors were ascertained.

RESULTS

In the MESA cohort, 47.2% was male; at baseline, 25.7% had hypertension; 12.5% had diabetes. Three hundred five incident hospitalized AF events occurred over a mean follow-up of 7.3 years. Age- and sex-adjusted IRs and IR ratios showed that overall AF incidence was significantly lower among Hispanics, NHBs and Chinese compared with NHWs (all P < .001). Among participants 65 years of age or greater, Hispanics, Chinese, and blacks had significantly lower AF incidence than NHWs (all P ≤ .01), but IRs were similar among participants under age 65 years. The PAF for smoking was 27% among NHBs but lower among other race-ethnic groups. Among NHWs, the PAF for hypertension was 22.2%, but this was higher among NHBs (33.1%), Chinese (46.3%), and Hispanics (43.9%).

CONCLUSIONS

Overall, the incidence of hospitalized AF was significantly lower in Hispanics, NHBs, and Chinese than in NHWs. A larger proportion of AF events appear to be attributable to hypertension among nonwhite populations compared with NHWs.

Smoking, sex, risk factors and abdominal aortic aneurysms: a prospective study of 18 782 persons aged above 65 years in the Southern Community Cohort Study

BACKGROUND

Abdominal aortic aneurysm (AAA) is a leading cause of death in the USA. We evaluated the incidence and predictors of AAA in a prospectively followed cohort.

METHODS

We calculated age-adjusted AAA incidence rates (IR) among 18 782 participants aged ≥65 years in the Southern Community Cohort Study who received Medicare coverage from 1999-2012, and assessed predictors of AAA using multivariable Cox proportional hazards models, overall and stratified by sex, adjusting for demographic, lifestyle, socioeconomic, medical and other factors. HRs and 95% CIs were calculated for AAA in relation to factors ascertained at enrolment.

RESULTS

Over a median follow-up of 4.94 years, 281 cases were identified. Annual IR was 153/100,000, 401, 354 and 174 among blacks, whites, men and women, respectively. AAA risk was lower among women (HR 0.48, 95% CI 0.36 to 0.65) and blacks (HR 0.51, 95% CI 0.37 to 0.69). Smoking was the strongest risk factor (former: HR 1.91, 95% CI 1.27 to 2.87; current: HR 5.55, 95% CI 3.67 to 8.40), and pronounced in women (former: HR 3.4, 95% CI 1.83 to 6.31; current: HR 9.17, 95% CI 4.95 to 17). A history of hypertension (HR 1.44, 95% CI 1.04 to 2.01) and myocardial infarction or coronary artery bypass surgery (HR 1.9, 95% CI 1.37 to 2.63) was negatively associated, whereas a body mass index ≥25 kg/m(2) (HR 0.72; 95% CI 0.53 to 0.98) was protective. College education (HR 0.6, 95% CI 0.37 to 0.97) and black race (HR 0.44, 95% CI 0.28 to 0.67) were protective among men.

CONCLUSIONS

Smoking is a major risk factor for incident AAA, with a strong and similar association between men and women. Further studies are needed to evaluate benefits of ultrasound screening for AAA among women smokers.

Defining disease phenotypes using national linked electronic health records: a case study of atrial fibrillation

BACKGROUND

National electronic health records (EHR) are increasingly used for research but identifying disease cases is challenging due to differences in information captured between sources (e.g. primary and secondary care). Our objective was to provide a transparent, reproducible model for integrating these data using atrial fibrillation (AF), a chronic condition diagnosed and managed in multiple ways in different healthcare settings, as a case study.

METHODS

Potentially relevant codes for AF screening, diagnosis, and management were identified in four coding systems: Read (primary care diagnoses and procedures), British National Formulary (BNF; primary care prescriptions), ICD-10 (secondary care diagnoses) and OPCS-4 (secondary care procedures). From these we developed a phenotype algorithm via expert review and analysis of linked EHR data from 1998 to 2010 for a cohort of 2.14 million UK patients aged ≥ 30 years. The cohort was also used to evaluate the phenotype by examining associations between incident AF and known risk factors.

RESULTS

The phenotype algorithm incorporated 286 codes: 201 Read, 63 BNF, 18 ICD-10, and four OPCS-4. Incident AF diagnoses were recorded for 72,793 patients, but only 39.6% (N = 28,795) were recorded in primary care and secondary care. An additional 7,468 potential cases were inferred from data on treatment and pre-existing conditions. The proportion of cases identified from each source differed by diagnosis age; inferred diagnoses contributed a greater proportion of younger cases (≤ 60 years), while older patients (≥ 80 years) were mainly diagnosed in SC. Associations of risk factors (hypertension, myocardial infarction, heart failure) with incident AF defined using different EHR sources were comparable in magnitude to those from traditional consented cohorts.

CONCLUSIONS

A single EHR source is not sufficient to identify all patients, nor will it provide a representative sample. Combining multiple data sources and integrating information on treatment and comorbid conditions can substantially improve case identification.

The paradox of atrial fibrillation in African Americans

The reported lower prevalence and incidence of atrial fibrillation (AF) despite the higher prevalence of AF risk factors in African Americans compared to Caucasian whites has been referred to as the paradox of AF in African Americans. In this report we highlight this paradox and address potential explanations using data from several US populations studies. These possible explanations include limited methodology to detect AF patterns that are harder to detect (e.g. paroxysmal/intermittent AF or atrial flutter) coupled with the possibility of African Americans having more of these patterns, differential access to health care with African Americans having less access and subsequently less detected AF, survival bias with Caucasian whites living longer and subsequently having more AF, and finally differential impact of AF risk factors with Caucasian whites being more affected or African Americans less affected by AF risk factors whether this is genetically determined or via other unknown predispositions.

Scarcity of atrial fibrillation in a traditional African population: a community-based study

Background

In western societies, atrial fibrillation is an increasingly common finding among the elderly. Established risk factors of atrial fibrillation include obesity, diabetes, hypertension, and cardiovascular disease. Atrial fibrillation has almost exclusively been studied in western populations where these risk factors are widely present. Therefore, we studied the epidemiology of atrial fibrillation in a traditional African community.

Methods

In rural Ghana, among 924 individuals aged 50 years and older, we recorded electrocardiograms to detect atrial fibrillation. As established risk factors, we documented waist circumference, body mass index (BMI), capillary glucose level, blood pressure, and electrocardiographic myocardial infarction. In addition, we determined circulating levels of interleukin-6 (IL6), a proinflammatory cytokine, and C-reactive protein (CRP), a marker of systemic inflammation. We compared the risk factors with reference data from the USA.

Results

Atrial fibrillation was detected in only three cases, equalling 0.3% (95% CI 0.1–1.0%). Waist circumference, BMI, and capillary glucose levels were very low. Hypertension and myocardial infarction were uncommon. Circulating levels of IL6 were similar, but those of CRP were lower compared with the USA.

Conclusion

Atrial fibrillation is very scarce in this traditional African community. Its low prevalence compared with western societies can be explained by the rareness of its established risk factors, which are closely related to lifestyle, and by possible unmeasured differences in other risk factors or genetic factors.

Atrial fibrillation, stroke, and anticoagulation in Medicare beneficiaries: trends by age, sex, and race, 1992-2010

BACKGROUND

We evaluated temporal trends in ischemic stroke and warfarin use among demographic subsets of the US Medicare population that are not well represented in randomized trials of warfarin for stroke prevention in nonvalvular atrial fibrillation (AF).

METHODS AND RESULTS

One-year cohorts of Medicare-primary payer patients (1992-2010) were created using the Medicare 5% sample. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify AF and ischemic and hemorrhagic stroke; ≥ 3 consecutive prothrombin time claims were used to identify warfarin use. Ischemic stroke rates (per 1000 patient-years) decreased markedly from 1992 to 2010. Among women, rates decreased from 37.1 to 13.6 for ages 65 to 74 years, from 55.2 to 16.5 for ages 74 to 84, and from 66.9 to 22.9 for age ≥ 85; warfarin use increased 31% to 59%, 27% to 63%, and 15% to 49%, respectively. Among men, rates decreased from 33.8 to 11.7 for ages 65 to 74 years, from 49.2 to 13.8 for ages 75 to 84, and from 51.5 to 18.0 for age ≥ 85; warfarin use increased 34% to 63%, 28% to 66%, and 15% to 55%, respectively. Rates decreased from 47.0 to 14.8 for whites and 73.0 to 29.3 for blacks; warfarin use increased 27% to 61% and 19% to 52%, respectively. In all age categories, the thromboembolic risk (CHADS [congestive heart failure, hypertension, age ≥ 75 years, diabetes, stroke]) score was significantly higher among women (versus men) and blacks (versus whites).

CONCLUSIONS

Ischemic stroke rates among Medicare AF patients decreased significantly in all demographic subpopulations from 1992-2010, coincident with increasing warfarin use. Ischemic stroke rates remained higher and warfarin use rates remained lower for women and blacks with AF, groups whose baseline CHADS scores were higher.

Atrial Fibrillation and Race - A Contemporary Review

Atrial fibrillation (AF) is the most commonly encountered clinical arrhythmia and is associated with adverse outcomes and increased healthcare costs. Racial variations in AF are recognized yet poorly understood. In this review we summarize racial differences in AF epidemiology, risk factors, genetics, and outcomes. We identify novel risk factors, inflammatory mediators and biomarkers associated with AF, which have had limited study in racial and ethnic minorities. We describe the mismatch between risk factor burden and AF. We highlight the limited participation of minorities in trials for AF management and stroke prevention that contrasts with observed racial variability in anticoagulation efficacy and practice. Throughout we provide specific strategies for future directions to address gaps in the epidemiology of racial differences and to meet identified racial disparities. We specifically identify areas for further research. We conclude that addressing disparities in prevention and healthcare resource allocation will likely improve AF-related outcomes in minorities.