Alanna M. Chamberlain

Incidence of atrial fibrillation in whites and African-Americans: the Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVES To define the incidence and cumulative risk of atrial fibrillation (AF) in a population-based cohort of whites and African Americans. BACKGROUND African-Americans reportedly have a lower risk of AF than whites despite their higher exposure to AF risk factors. However, precise estimates of AF incidence in African Americans have not been previously published. METHODS We studied the incidence of AF in the Atherosclerosis Risk in Communities (ARIC) study, which has followed up 15,792 men and women 45 to 65 years of age at baseline from 4 communities in the United States since 1987. Atrial fibrillation cases were identified from electrocardiograms conducted at baseline and 3 follow-up visits, and from hospitalizations and death certificates through the end of 2004. During follow-up, 1,085 new cases of AF were identified (196 in African Americans, 889 in whites). RESULTS Crude incidence rates of AF were 6.7, 4.0, 3.9, and 3.0 per 1,000 persons per year in white men, white women, African-American men, and African-American women, respectively. Increasing age was exponentially associated with an elevated risk of AF. Compared to whites, African-Americans had a 41% (95% CI: 8%-62%) lower age- and sex-adjusted risk of being diagnosed with AF. The cumulative risk of AF at 80 years of age was 21% in white men, 17% in white women, and 11% in African-American men and women. CONCLUSION In this population-based cohort, African Americans presented a lower risk of AF than whites. Still, the burden of AF among the former is substantial, with 1 in 9 receiving a diagnosis of AF before 80 years of age.

Variants in ZFHX3 are associated with atrial fibrillation in individuals of European ancestry

We conducted meta-analyses of genome-wide association studies for atrial fibrillation (AF) in participants from five community-based cohorts. Meta-analyses of 896 prevalent (15,768 referents) and 2,517 incident (21,337 referents) AF cases identified a new locus for AF (ZFHX3, rs2106261, risk ratio RR = 1.19; P = 2.3 × 10−7). We replicated this association in an independent cohort from the German AF Network (odds ratio = 1.44; P = 1.6 × 10−11; combined RR = 1.25; combined P = 1.8 × 10−15).

Simple risk model predicts incidence of atrial fibrillation in a racially and geographically diverse population: the CHARGE-AF consortium

Background Tools for the prediction of atrial fibrillation (AF) may identify high‐risk individuals more likely to benefit from preventive interventions and serve as a benchmark to test novel putative risk factors. Methods and Results Individual‐level data from 3 large cohorts in the United States (Atherosclerosis Risk in Communities [ARIC] study, the Cardiovascular Health Study [CHS], and the Framingham Heart Study [FHS]), including 18 556 men and women aged 46 to 94 years (19% African Americans, 81% whites) were pooled to derive predictive models for AF using clinical variables. Validation of the derived models was performed in 7672 participants from the Age, Gene and Environment—Reykjavik study (AGES) and the Rotterdam Study (RS). The analysis included 1186 incident AF cases in the derivation cohorts and 585 in the validation cohorts. A simple 5‐year predictive model including the variables age, race, height, weight, systolic and diastolic blood pressure, current smoking, use of antihypertensive medication, diabetes, and history of myocardial infarction and heart failure had good discrimination (C‐statistic, 0.765; 95% CI, 0.748 to 0.781). Addition of variables from the electrocardiogram did not improve the overall model discrimination (C‐statistic, 0.767; 95% CI, 0.750 to 0.783; categorical net reclassification improvement, −0.0032; 95% CI, −0.0178 to 0.0113). In the validation cohorts, discrimination was acceptable (AGES C‐statistic, 0.664; 95% CI, 0.632 to 0.697 and RS C‐statistic, 0.705; 95% CI, 0.664 to 0.747) and calibration was adequate. Conclusion A risk model including variables readily available in primary care settings adequately predicted AF in diverse populations from the United States and Europe.

Heart Disease and Stroke Statistics—2018 Update: A Report From the American Heart Association

Each chapter listed in the Table of Contents (see next page) is a hyperlink to that chapter. The reader clicks the chapter name to access that chapter. Each chapter listed here is a hyperlink. Click on the chapter name to be taken to that chapter. Each year, the American Heart Association (AHA), in conjunction with the Centers for Disease Control and Prevention, the National Institutes of Health, and other government agencies, brings together in a single document the most up-to-date statistics related to heart disease, stroke, and the cardiovascular risk factors listed in the AHA’s My Life Check - Life’s Simple 7 (Figure1), which include core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure [BP], and glucose control) that contribute to cardiovascular health. The Statistical Update represents …

A clinical risk score for atrial fibrillation in a biracial prospective cohort (from the Atherosclerosis Risk in Communities [ARIC] study).

A risk score for atrial fibrillation (AF) has been developed by the Framingham Heart Study; however, the applicability of this risk score, derived using data from white patients, to predict new-onset AF in nonwhites is uncertain. Therefore, we developed a 10-year risk score for new-onset AF from risk factors commonly measured in clinical practice using 14,546 subjects from the Atherosclerosis Risk In Communities (ARIC) study, a prospective community-based cohort of blacks and whites in the United States. During 10 years of follow-up, 515 incident AF events occurred. The following variables were included in the AF risk score: age, race, height, smoking status, systolic blood pressure, hypertension medication use, precordial murmur, left ventricular hypertrophy, left atrial enlargement, diabetes, coronary heart disease, and heart failure. The area under the receiver operating characteristics curve (AUC) of a Cox regression model that included the previous variables was 0.78, suggesting moderately good discrimination. The point-based score developed from the coefficients in the Cox model had an AUC of 0.76. This clinical risk score for AF in the Atherosclerosis Risk In Communities cohort compared favorably with the Framingham Heart Studys AF (AUC 0.68), coronary heart disease (CHD) (AUC 0.63), and hard CHD (AUC 0.59) risk scores and the Atherosclerosis Risk In Communities CHD risk score (AUC 0.58). In conclusion, we have developed a risk score for AF and have shown that the different pathophysiologies of AF and CHD limit the usefulness of a CHD risk score in identifying subjects at greater risk of AF.

A Contemporary Appraisal of the Heart Failure Epidemic in Olmsted County, Minnesota, 2000 to 2010

IMPORTANCE Heart failure (HF) is commonly referred to as an epidemic, posing major clinical and public health challenges. Yet, contemporary data on its magnitude and implications are scarce. OBJECTIVE To evaluate recent trends in HF incidence and outcomes overall and by preserved ejection fraction (HFpEF) or reduced ejection fraction (HFrEF). DESIGN, SETTING, AND PARTICIPANTS Incidence rates of HF in Olmsted County, Minnesota (population, approximately 144,248), between January 1, 2000, and December 31, 2010, were assessed. MAIN OUTCOMES AND MEASURES Patients identified with incident HF (n = 2762) (mean age, 76.4 years; 43.1% male) were followed up for all-cause and cause-specific hospitalizations (through December 2012) and death (through March 2014). RESULTS The age- and sex-adjusted incidence of HF declined substantially from 315.8 per 100,000 in 2000 to 219.3 per 100,000 in 2010 (annual percentage change, -4.6), equating to a rate reduction of 37.5% (95% CI, -29.6% to -44.4%) over the last decade. The incidence declined for both HF types but was greater (interaction P = .08) for HFrEF (-45.1%; 95% CI, -33.0% to -55.0%) than for HFpEF (-27.9%; 95% CI, -12.9% to -40.3%). Mortality was high (24.4% for age 60 years and 54.4% for age 80 years at 5 years of follow-up), frequently ascribed to noncardiovascular causes (54.3%), and did not decline over time. The risk of cardiovascular death was lower for HFpEF than for HFrEF (multivariable-adjusted hazard ratio, 0.79; 95% CI, 0.67-0.93), whereas the risk of noncardiovascular death was similar (1.07; 95% CI, 0.89-1.29). Hospitalizations were common (mean, 1.34; 95% CI, 1.25-1.44 per person-year), particularly among men, and did not differ between HFpEF and HFrEF. Most hospitalizations (63.0%) were due to noncardiovascular causes. Hospitalization rates for cardiovascular causes did not change over time, whereas those for noncardiovascular causes increased. CONCLUSIONS AND RELEVANCE Over the last decade, the incidence of HF declined substantially, particularly for HFrEF, contrasting with no apparent change in mortality. Noncardiovascular conditions have an increasing role in hospitalizations and remain the most frequent cause of death. These results underscore the need to augment disease-centric management approaches with holistic strategies to reduce the population burden of HF.

Mortality Associated With Atrial Fibrillation in Patients With Myocardial Infarction A Systematic Review and Meta-Analysis

Background— Atrial fibrillation (AF) is a common finding in patients with myocardial infarction (MI). Atrial fibrillation is not generally perceived by clinicians as a critical event during the acute phase of MI; however, its prognostic influence in MI remains controversial. Furthermore, contradictory data exist concerning the risk of death according to AF timing. This article, a systematic review and first meta-analysis, aims to quantify the mortality risk associated with AF in MI patients and its timing. Methods and Results— A comprehensive search of several electronic databases (1970 to 2010; adults, any language) identified MI studies that evaluated mortality related to AF. Evidence was reviewed by 2 blinded reviewers with a formal assessment of the methodological quality of the studies. Adjusted odds ratios were pooled across studies using the random-effects model. The I2 statistic was used to assess heterogeneity. In the 43 included studies (278 854 subjects), the mortality odds ratio associated with AF was 1.46 (95% confidence interval, 1.35 to 1.58; I2=76%; 23 studies). This worse prognosis persisted regardless of the timing of AF; the odds ratio of mortality for new AF with no prior history of AF was 1.37 (95% confidence interval, 1.26 to 1.49), I2=28%, 9 studies), and for prior AF was 1.28 (95% confidence interval, 1.16 to 1.40; I2=24%; 4 studies). The sensitivity analysis of new AF studies adjusting for confounding factors did not show a decrease in risk of death. Conclusions— Atrial fibrillation is associated with increased risk of mortality in MI patients. New AF with no history of AF before MI remained associated with an increased risk of mortality even after adjustment for several important AF risk factors. These subsequent increases in mortality suggest that AF can no longer be considered a nonsevere event during MI.

Metabolic syndrome and incidence of atrial fibrillation among blacks and whites in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND The metabolic syndrome (MetSyn) has been implicated in the development of atrial fibrillation (AF); however, knowledge of this association among blacks is limited. METHODS We determined the risk of incident AF through December 2005 in relation to baseline (1987-1989) MetSyn status in 15,094 participants of the Atherosclerosis Risk in Communities study. RESULTS Over a mean follow-up of 15.4 years, 1,238 incident AF events were identified. The hazard ratio (HR) for AF among individuals with, compared to those without, the MetSyn was 1.67 (95% CI 1.49-1.87), and associations did not differ by race (P for interaction = .73). The population attributable risk of AF from the MetSyn was 22%. The multivariable-adjusted HRs (95% CI) for each MetSyn component were 1.95 (1.72-2.21) (elevated blood pressure), 1.40 (1.23-1.59) (elevated waist circumference), 1.20 (1.06-1.37) (low high-density lipoprotein cholesterol), 1.16 (1.03-1.31) (impaired fasting glucose), and 0.95 (0.84-1.09) (elevated triglycerides). A monotonically increasing risk of AF with increasing number of MetSyn components was observed, with an HR of 4.40 (95% CI 3.25-5.94) for those with all 5 MetSyn components compared to those with 0 components. CONCLUSION In this large cohort, the MetSyn and most of its components were associated with a higher risk of AF in both blacks and whites. Given the high prevalence of the MetSyn, strategies to prevent its development or to control individual components may reduce the burden of AF.

Temporal Relationship and Prognostic Significance of Atrial Fibrillation in Heart Failure Patients with Preserved Ejection Fraction: A Community-Based Study

Background— In patients with heart failure and preserved ejection fraction (HFpEF), atrial fibrillation (AF) may predate, concur with, or develop after HFpEF diagnosis. We sought to define the temporal relationship between AF and HFpEF, to identify factors associated with AF, and to determine the prognostic impact of prevalent and incident AF in HFpEF. Method and Results— From 1983 to 2010, 939 Olmsted County, Minnesota, residents (age, 77±12 years; 61% female) newly diagnosed with HFpEF (EF ≥0.50) were evaluated. Baseline rhythm classification included prior AF (>3 months before HFpEF diagnosis), concurrent AF (±3 months), or sinus rhythm. Incident AF (>3 months after HFpEF diagnosis) and all-cause mortality were ascertained through February 2012. Prior AF (29%) and concurrent AF (23%) were associated with older age, higher brain-type natriuretic peptide, and larger left atrial volume index at HFpEF diagnosis compared with sinus rhythm. Of HFpEF patients in sinus rhythm at diagnosis, 32% developed AF over a median follow-up of 3.7 years (interquartile range, 1.5–6.7 years; 69 events per 1000 person-years). Age and diastolic dysfunction were positively and statin use was inversely associated with incident AF. With no AF used as the referent, prior or concurrent AF (combined hazard ratio, 1.3; 95% confidence interval, 1.0–1.6; P=0.03) and incident AF, modeled as a time-dependent covariate (hazard ratio, 2.1; 95% confidence interval, 1.4–3.0; P<0.001), were independently associated with death after adjustment for pertinent covariates. Conclusions— AF occurs in two thirds of HFpEF patients at some point in the natural history and confers a poor prognosis. Further study is required to determine whether intervention for AF may improve outcomes or if statin use can prevent AF in HFpEF.

Smoking and incidence of atrial fibrillation: Results from the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND Cigarette smoking increases the risk of coronary heart disease, but whether smoking increases atrial fibrillation (AF) is uncertain. OBJECTIVE The purpose of this study was to determine the association of cigarette smoking with incident AF in a population-based cohort of blacks and whites. METHODS We determined the risk of incident AF through December 2002 in relation to baseline (1987-1989) smoking status and cigarette-years of smoking in over 15,000 participants of the prospective Atherosclerosis Risk in Communities (ARIC) study. RESULTS Over a mean follow-up of 13.1 years, 876 incident AF events were identified. Compared to never smokers, the multivariable-adjusted hazard ratios (HRs) for AF were 1.32 (95% confidence interval [CI] 1.10-1.57) in former smokers, 2.05 (95% CI 1.71-2.47) in current smokers, and 1.58 (95% CI 1.35-1.85) in ever smokers. In the highest tertile of accumulated smoking amount (>675 cigarette-years), the incidence of AF was 2.10 times greater (95% CI 1.74-2.53) than in those who never smoked. Associations were similar by gender, race, type of event (AF and atrial flutter), and when only AF events identified by study exam ECGs were included. Finally, individuals who quit smoking exhibited a trend indicating a slightly lower risk of developing AF (HR 0.88, 95% CI 0.65-1.17) compared to those who continued to smoke. CONCLUSION Smoking was associated with the incidence of AF, with more than a two-fold increased risk of AF attributed to current smoking. In addition, a trend toward a lower incidence of AF appeared among smokers who quit compared to continued smokers.