Validation of a Zio XT Patch Accelerometer for the Objective Assessment of Physical Activity in the Atherosclerosis Risk in Communities (ARIC) Study.

BACKGROUND: Combination devices to monitor heart rate/rhythms and physical activity are becoming increasingly popular in research and clinical settings. The Zio XT Patch (iRhythm Technologies, San Francisco, CA, USA) is US Food and Drug Administration (FDA)-approved for monitoring heart rhythms, but the validity of its accelerometer for assessing physical activity is unknown. OBJECTIVE: To validate the accelerometer in the Zio XT Patch for measuring physical activity against the widely-used ActiGraph GT3X. METHODS: The Zio XT and ActiGraph wGT3X-BT (Actigraph, Pensacola, FL, USA) were worn simultaneously in two separately-funded ancillary studies to Visit 6 of the Atherosclerosis Risk in Communities (ARIC) Study (2016-2017). Zio XT was worn on the chest and ActiGraph was worn on the hip. Raw accelerometer data were summarized using mean absolute deviation (MAD) for six different epoch lengths (1-min, 5-min, 10-min, 30-min, 1-h, and 2-h). Participants who had ≥3 days of at least 10 h of valid data between 7 a.m-11 p.m were included. Agreement of epoch-level MAD between the two devices was evaluated using correlation and mean squared error (MSE). RESULTS: Among 257 participants (average age: 78.5 ± 4.7 years; 59.1% female), there were strong correlations between MAD values from Zio XT and ActiGraph (average r: 1-min: 0.66, 5-min: 0.90, 10-min: 0.93, 30-min: 0.93, 1-h: 0.89, 2-h: 0.82), with relatively low error values (Average MSE × 106: 1-min: 349.37 g, 5-min: 86.25 g, 10-min: 56.80 g, 30-min: 45.46 g, 1-h: 52.56 g, 2-h: 54.58 g). CONCLUSIONS: These findings suggest that Zio XT accelerometry is valid for measuring duration, frequency, and intensity of physical activity within time epochs of 5-min to 2-h.

Race, Body Mass Index, and the Risk of Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis.

Background Higher body mass index (BMI) is associated with increased risk of incident atrial fibrillation (AF), but it is not known whether this relationship varies by race/ethnicity. Methods and Results Eligible participants (6739) from MESA (Multi-Ethnic Study of Atherosclerosis) were surveilled for incident AF using MESA hospital surveillance, scheduled MESA study ECG, and Medicare claims data. After a median 13.8 years of follow-up, 970 participants (14.4%) had incident AF. With BMI modeled categorically in a Cox proportional hazards model, only those with grade II and grade III obesity had increased risks of AF (hazard ratio [HR], 1.50; 95% CI, 1.14-1.98, P=0.004 for grade II obesity and HR, 2.13; 95% CI, 1.48-3.05, P<0.0001 for grade III obesity). The relationship between BMI and AF risk was J-shaped. However, the risk of AF as a function of BMI varied substantially by race/ethnicity (P value for interaction=0.02), with Chinese-American participants having a much higher risk of AF with higher BMI and Black participants having minimal increased risk of AF with higher BMI. Conclusions Obesity is associated with an increased risk of incident AF, but the relationship between BMI and the risk of AF is J-shaped and this relationship differs by race/ethnicity, such that Chinese-American participants have a more pronounced increased risk of AF with higher BMI, while Black participants have minimal increased risk. Further exploration of the differential effects of BMI by race/ethnicity on cardiovascular outcomes is needed.

Association of Cardiac Biomarkers With the Kansas City Cardiomyopathy Questionnaire in Patients With Chronic Kidney Disease Without Heart Failure.

Background The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a measure of heart failure (HF) health status. Worse KCCQ scores are common in patients with chronic kidney disease (CKD), even without diagnosed heart failure (HF). Elevations in the cardiac biomarkers GDF-15 (growth differentiation factor-15), galectin-3, sST2 (soluble suppression of tumorigenesis-2), hsTnT (high-sensitivity troponin T), and NT-proBNP (N-terminal pro-B-type natriuretic peptide) likely reflect subclinical HF in CKD. Whether cardiac biomarkers are associated with low KCCQ scores is not known. Methods and Results We studied participants with CKD without HF in the multicenter prospective CRIC (Chronic Renal Insufficiency Cohort) Study. Outcomes included (1) low KCCQ score <75 at year 1 and (2) incident decline in KCCQ score to <75. We used multivariable logistic regression and Cox regression models to evaluate the associations between baseline cardiac biomarkers and cross-sectional and longitudinal KCCQ scores. Among 2873 participants, GDF-15 (adjusted odds ratio 1.42 per SD; 99% CI, 1.19-1.68) and galectin-3 (1.28; 1.12-1.48) were significantly associated with KCCQ scores <75, whereas sST2, hsTnT, and NT-proBNP were not significantly associated with KCCQ scores <75 after multivariable adjustment. Of the 2132 participants with KCCQ ≥75 at year 1, GDF-15 (adjusted hazard ratio, 1.36 per SD; 99% CI, 1.12-1.65), hsTnT (1.20; 1.01-1.44), and NT-proBNP (1.30; 1.08-1.56) were associated with incident decline in KCCQ to <75 after multivariable adjustment, whereas galectin-3 and sST2 did not have significant associations with KCCQ decline. Conclusions Among participants with CKD without clinical HF, GDF-15, galectin-3, NT-proBNP, and hsTnT were associated with low KCCQ either at baseline or during follow-up. Our findings show that elevations in cardiac biomarkers reflect early symptomatic changes in HF health status in CKD patients.

Association between excessive daytime sleepiness and measures of supraventricular arrhythmia burden: evidence from the Atherosclerosis Risk in Communities (ARIC) study.

PURPOSE: Excessive daytime sleepiness is a common sleep complaint among older adults. Assessment of excessive daytime sleepiness is used to screen for obstructive sleep apnea, which may be linked to atrial fibrillation (AF) and other sustained arrhythmias. Using data from the Atherosclerosis Risk in Communities (ARIC) Study cohort, we examined the association of excessive daytime sleepiness with measures of arrhythmia burden derived from a continuous ECG recording device in a community-based sample of older adults. METHODS: Participating older adults (N = 2306, mean age: 78.9 ± 4.5 years, 57.8% female) wore a Zio® XT Patch for 14 days. Excessive daytime sleepiness was assessed with the Epworth Sleepiness Scale. Measures of AF and supraventricular arrhythmia burden were derived from the Zio® XT Patch. Multiple adjusted logistic, multinomial, and linear regression models were used to assess associations of excessive daytime sleepiness with AF, AF burden, and supraventricular arrhythmia burden. RESULTS: Approximately 18% of the sample had excessive daytime sleepiness, and 8.5% had AF. After adjustment, excessive daytime sleepiness was not significantly associated with AF (odds ratio (OR), 1.20; Confidence Interval (CI), 0.81-1.75), continuous AF burden (OR, 1.36; CI, 0.85-2.16), or measures of supraventricular arrhythmia burden (SVE burden: ß 0.01; 95% CI, -0.09-0.11; SVT burden: ß 0.02; 95% CI, -0.04-0.08). CONCLUSION: In this community-based sample of older adults, excessive daytime sleepiness was not associated with measures of arrhythmia burden. Future studies with objective measures of sleep are needed to further examine the role of sleep in the development and progression of arrhythmia burden.

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.

Happier countries, longer lives: an ecological study on the relationship between subjective sense of well-being and life expectancy.

The relationship between sense of well-being and longevity is not well-established across populations of varying levels of socioeconomic status. We sought to examine the relationship between happiness, or subjective sense of well-being and life expectancy using data from 151 countries. This analysis is based on the 2012 Happy Planet Index project conducted by the Center of Well-Being of the New Economics Foundation, based in the United Kingdom. Well-being data for each country were taken from responses to the 'Ladder of Life' question in the 2012 Gallup World Poll in which participants were asked to rate their quality of life on a scale from 1 (worst possible life) to 10 (best possible life). Life expectancy and gross domestic product data were taken from the 2011 United Nations records. Ecological footprint data were taken from Global Footprint Network records. Subjective sense of well-being was highly correlated with life expectancy (Pearson correlation r = 0.71, p < 0.0001). In a multivariable linear regression model adjusted for gross domestic product, ecological footprint, and population, each 1 unit of the well-being scale was associated with an increase in life expectancy of 4.0 years (95% confidence interval = 2.7-5.3). In conclusion, better sense of well-being has a strong relationship with life expectancy regardless of economic status or population size, suggesting that governments should foster happiness in order to support long-living populations.

Lifetime Risk of Atrial Fibrillation by Race and Socioeconomic Status: ARIC Study (Atherosclerosis Risk in Communities).

BACKGROUND: Limited information exists on the lifetime risk of atrial fibrillation (AF) in African Americans and by socioeconomic status. METHODS: We studied 15 343 participants without AF at baseline from the ARIC (Atherosclerosis Risk in Communities) cohort recruited in 1987 to 1989 from 4 communities in the United States when they were 45 to 64 years of age. Participants have been followed through 2014. Incidence rates of AF were calculated dividing the number of new cases by person-years of follow-up. Lifetime risk of AF was estimated by a modified Kaplan-Meier method considering death as a competing risk. Participants' family income and education were obtained at baseline. RESULTS: We identified 2760 AF cases during a mean follow-up of 21 years. Lifetime risk of AF was 36% (95% confidence interval, 32%-38%) in white men, 30% (95% confidence interval, 26%-32%) in white women, 21% (95% confidence interval, 13%-24%) in African American men, and 22% (95% confidence interval, 16%-25%) in African American women. Regardless of race and sex, incidence rates of AF decreased from the lowest to the highest categories of income and education. In contrast, lifetime risk of AF increased in individuals with higher income and education in most sex-race groups. Cumulative incidence of AF was lower in those with higher income and education compared with their low socioeconomic status counterparts through earlier life but was reversed after age 80. CONCLUSIONS: Lifetime risk of AF in the ARIC cohort was ≈1 in 3 among whites and 1 in 5 among African Americans. Socioeconomic status was inversely associated with cumulative incidence of AF before the last decades of life.

New diagnosis of cancer and the risk of subsequent cerebrovascular events.

OBJECTIVE: We aimed to evaluate the association between cancer and cerebrovascular disease in a prospective cohort study with adjudicated cerebrovascular diagnoses. METHODS: We analyzed participants from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who were 45 years and older and had Medicare coverage for 365 days before their baseline study visit. Participants with a history of cancer or cerebrovascular events were excluded. The time-dependent exposure was a new diagnosis of malignant cancer identified through Medicare claims algorithms. Participants were prospectively followed from their baseline study visit (2003-2007) through 2014 for the outcome of a neurologist-adjudicated cerebrovascular event defined as a composite of stroke (ischemic or hemorrhagic) or TIA. Cox regression was used to evaluate the association between a new cancer diagnosis and subsequent cerebrovascular events. Follow-up time was modeled in discrete time periods to fulfill the proportional hazard assumption. RESULTS: Among 6,602 REGARDS participants who met eligibility criteria, 1,149 were diagnosed with cancer during follow-up. Compared to no cancer, a new cancer diagnosis was associated with subsequent cerebrovascular events in the first 30 days after diagnosis (hazard ratio 6.1, 95% confidence interval 2.7-13.7). This association persisted after adjustment for demographics, region of residence, and vascular risk factors (hazard ratio 6.6, 95% confidence interval 2.7-16.0). There was no association between cancer diagnosis and incident cerebrovascular events beyond 30 days. Cancers considered high risk for venous thromboembolism demonstrated the strongest associations with cerebrovascular event risk. CONCLUSION: A new diagnosis of cancer is associated with a substantially increased short-term risk of cerebrovascular events.

Blood pressure indices and cardiovascular disease mortality in persons with or without diabetes mellitus.

BACKGROUND: We examined the associations between blood pressure indices (SBP, DBP, mean arterial pressure and pulse pressure) and cardiovascular disease (CVD) mortality among persons with or without diabetes mellitus (NON-DM) in a multiethnic cohort. METHODS: We included 17 650 participants from National Health and Nutrition Examination Survey III and 1439 participants from Diabetes Heart Study (total n = 19 089, 16.3% had diabetes mellitus, mean age 48.5 years, 44.4% white, 27.1% black, 28.5% other race, 54.4% women). Cox proportional hazard, cubic spline and area under the curve analyses were used to assess the associations. CVD death was ascertained via social security registry or the National Death Index. RESULTS: After a mean (SD) of 16.2 (6.1) years of follow-up, 17.9% of diabetes mellitus and 8.8% of those NON-DM died of CVD. Diabetes mellitus was associated with an increased risk of CVD death [hazard ratio (95% confidence interval): 1.50 (1.25-1.82)]. One SD increase in SBP was significantly associated with CVD mortality in NON-DM [1.28 (1.18-1.39)] but not diabetes mellitus [1.04 (0.88-1.23)] in the full Cox models. Adjusted cubic spline analysis showed significant nonlinear but different association between SBP and CVD mortality among diabetes mellitus (U-shaped) and NON-DM (J-shaped). The C-statistics of our full model in NON-DM and diabetes mellitus were (0.888 vs. 0.735, P < 0.001). SBP showed a trend toward improving C statistics in NON-DM but not diabetes mellitus. CONCLUSION: The association between SBP and CVD mortality risk is nonlinear but different in diabetes mellitus (U-shaped) and NON-DM (J-shaped), explaining why aggressive blood pressure lowering may have different outcomes in these two groups.

Comparative Risks of Ischemic Stroke in Atrial Flutter versus Atrial Fibrillation.

INTRODUCTION: The aim of this study was to compare the risk of ischemic stroke in patients who have atrial fibrillation and patients who have atrial flutter. METHODS: Using inpatient and outpatient Medicare claims data from 2008 to 2014 for a 5% sample of all beneficiaries 66 years of age or older, we identified patients diagnosed with atrial fibrillation and those diagnosed with atrial flutter. The primary outcome was ischemic stroke. In the primary analysis, patients with atrial flutter were censored upon converting to fibrillation; in a secondary analysis, they were not. Survival statistics were used to compare incidence of stroke in patients with flutter and patients with fibrillation. Cox proportional hazards analysis was used to compare the associations of flutter and fibrillation with ischemic stroke after adjustment for demographics and risk factors. RESULTS: We identified 14,953 patients with flutter and 318,138 with fibrillation. During a mean follow-up period of 2.8 (±2.3) years, we identified 18,900 ischemic strokes. The annual incidence of ischemic stroke in patients with flutter was 1.38% (95% confidence interval [CI] 1.22%-1.57%) compared with 2.02% (95% CI 1.99%-2.05%) in patients with fibrillation. After adjustment for demographics and stroke risk factors, flutter was associated with a lower risk of stroke compared with fibrillation (hazard ratio .69; 95% CI .60-.79, P < .05). Within 1 year, 65.7% (95% CI 64.9%-66.4%) of patients with flutter converted to fibrillation but remained at a lower risk of ischemic stroke (hazard ratio .85; 95% CI .78-.92). CONCLUSIONS: Patients with atrial flutter faced a lower risk of ischemic stroke than patients with atrial fibrillation.

Normal findings on noninvasive cardiac assessment and the prediction of heart failure: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: It is unknown if normal findings on noninvasive cardiac assessment are able to identify individuals who are low risk for developing heart failure (HF). METHODS: We examined if normal findings on the routine electrocardiogram (ECG) and cardiac magnetic resonance imaging (MRI) were able to identify individuals who are low risk for developing HF in 4986 (mean age=62±10years; 52% women; 39% White; 13% Chinese-American; 26% Black; 22% Hispanic) participants from the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent HF at baseline. A normal ECG was defined as the absence of major abnormalities by Minnesota Code Classification, and a normal MRI was defined as absence of structural abnormalities and systolic dysfunction. RESULTS: There were 3988 (80%) participants with normal findings at baseline on both ECG and MRI, 894 (18%) who had either a normal ECG or normal MRI, and 104 (2%) who had abnormal findings on ECG and MRI. Over a median follow-up of 12.2years, 177 (3.6%) HF events occurred. Normal ECG (HR=0.41, 95%CI=0.29, 0.56) and MRI (HR=0.32, 95%CI=0.23, 0.45) were each associated with lower risk of HF compared with abnormal, and their combination was associated with a lower HF risk (HR=0.13, 95%CI=0.08, 0.21) than either in isolation. CONCLUSION: Normal findings on noninvasive cardiac assessment identify individuals in whom the risk of HF is low. Further studies are needed to explore the utility of this low-risk profile in HF prevention strategies.

Feasibility of Using Mobile ECG Recording Technology to Detect Atrial Fibrillation in Low-Resource Settings.

BACKGROUND: Screening for atrial fibrillation (AF), a major risk factor for stroke that is on the rise in Africa, is becoming increasingly critical. OBJECTIVES: This study sought to examine the feasibility of using mobile electrocardiogram (ECG) recording technology to detect AF. METHODS: In this prospective observational study, we used a mobile ECG recorder to screen 50 African adults (66% women; mean age 54.3 ± 20.5 years) attending Kijabe Hospital (Kijabe, Kenya). Five hospital health providers involved in this study's data collection process also completed a self-administered survey to obtain information on their access to the Internet and mobile devices, both factors necessary to implement ECG mobile technology. Outcome measures included feasibility (completion of the study and recruitment of the patients on the planned study time frame) and the yield of the screening by the mobile ECG technology (ability to detect previously undiagnosed AF). RESULTS: Patients were recruited in a 2-week period as planned; only 1 of the 51 patients approached refused to participate (98% acceptance rate). All of the 50 patients who agreed to participate completed the test and produced readable ECGs (100% study completion rate). ECG tracings of 4 of the 50 patients who completed the study showed AF (8% AF yield), and none had been previously diagnosed with AF. When asked about continuous access to Internet and personal mobile devices, almost all of the health care providers surveyed answered affirmatively. CONCLUSIONS: Using mobile ECG technology in screening for AF in low-resource settings is feasible, and can detect a significant proportion of AF cases that will otherwise go undiagnosed. Further study is needed to examine the cost-effectiveness of this approach for detection of AF and its effect on reducing the risk of stroke in developing countries.

The clinical utility of normal findings on noninvasive cardiac assessment in the prediction of atrial fibrillation.

BACKGROUND: The absence of abnormalities on noninvasive cardiac assessment possibly confers a reduced risk of atrial fibrillation (AF) despite the presence of traditional risk factors. HYPOTHESIS: Normal findings on noninvasive cardiac assessment are associated with a lower risk of AF development. METHODS: We examined the clinical utility of normal findings on routine noninvasive cardiac assessment in 5331 participants (85% white; 57% women) from the Cardiovascular Health Study who were free of baseline AF. The combination of a normal electrocardiogram (ECG) + normal echocardiogram was assessed for the development of AF events. A normal ECG was defined as the absence of major or minor Minnesota code abnormalities. A normal echocardiogram was defined as the absence of contractile dysfunction, wall motion abnormalities, or abnormal left ventricular mass. Cox regression was used to compute the 10-year risk of developing AF. RESULTS: During the 10-year study period, a total of 951 (18%) AF events were detected. A normal ECG (multivariable hazard ratio [HR]: 0.80, 95% confidence interval [CI]: 0.69-0.92) and normal echocardiogram (multivariable HR: 0.75, 95% CI: 0.65-0.87) were associated with a reduced risk of AF in isolation. This association improved in those with normal ECG + normal echocardiogram (multivariable HR: 0.66, 95% CI: 0.55-0.79) compared with participants who had abnormal ECG + abnormal echocardiogram (referent). CONCLUSIONS: Normal findings on routine noninvasive cardiac assessment identify persons in whom the risk of AF is low. Further studies are needed to explore the utility of this profile regarding the decision to implement certain risk factor modification strategies in older adults to reduce AF burden.

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.

Where to Focus Efforts to Reduce the Black-White Disparity in Stroke Mortality: Incidence Versus Case Fatality?

BACKGROUND AND PURPOSE: At age 45 years, blacks have a stroke mortality ≈3× greater than their white counterparts, with a declining disparity at older ages. We assess whether this black-white disparity in stroke mortality is attributable to a black-white disparity in stroke incidence versus a disparity in case fatality. METHODS: We first assess if black-white differences in stroke mortality within 29 681 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort reflect national black-white differences in stroke mortality and then assess the degree to which black-white differences in stroke incidence or 30-day case fatality after stroke contribute to the disparities in stroke mortality. RESULTS: The pattern of stroke mortality within the study mirrors the national pattern, with the black-to-white hazard ratio of ≈4.0 at age 45 years decreasing to ≈1.0 at age 85 years. The pattern of black-to-white disparities in stroke incidence shows a similar pattern but no evidence of a corresponding disparity in stroke case fatality. CONCLUSIONS: These findings show that the black-white differences in stroke mortality are largely driven by differences in stroke incidence, with case fatality playing at most a minor role. Therefore, to reduce the black-white disparity in stroke mortality, interventions need to focus on prevention of stroke in blacks.

Prediction of Atrial Fibrillation in a Racially Diverse Cohort: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: Existing equations for prediction of atrial fibrillation (AF) have been developed and validated in white and African-American populations. Whether these models adequately predict AF in more racially and ethnically diverse populations is unknown. METHODS AND RESULTS: We studied 6663 men and women 45 to 84 years of age without AF at baseline (2000-2002) enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA). Of these, 38% were non-Hispanic whites, 28% non-Hispanic African Americans, 22% Hispanics, and 12% Chinese Americans. AF during follow-up was ascertained from hospitalization discharge codes through 2012. Information collected at baseline was used to calculate predicted 5-year risk of AF using the previously published simple CHARGE-AF model, which only includes clinical variables, and a biomarker-enriched CHARGE-AF model, which also considers levels of circulating N-terminal of the prohormone B-type natriuretic peptide and C-reactive protein. For comparison purposes, we also assessed performance of the 10-year Framingham AF model. During a mean follow-up of 10.2 years, 351 cases of AF were identified. The C-statistic of the CHARGE-AF models were 0.779 (95% CI, 0.744-0.814) for the simple model and 0.825 (95% CI, 0.791-0.860) for the biomarker-enriched model. Calibration was adequate in the biomarker-enriched model (χ(2)=7.9; P=0.55), but suboptimal in the simple model (χ(2)=25.6; P=0.002). In contrast, the 10-year Framingham score had a C-statistic (95% CI) of 0.746 (0.720-0.771) and showed poor calibration (χ(2)=57.4; P<0.0001). CONCLUSION: The CHARGE-AF risk models adequately predicted 5-year AF risk in a large multiethnic cohort. These models could be useful to select high-risk individuals for AF screening programs or for primary prevention trials in diverse populations.

Impact of Awareness and Patterns of Nonhospitalized Atrial Fibrillation on the Risk of Mortality: The Reasons for Geographic And Racial Differences in Stroke (REGARDS) Study.

BACKGROUND: Although mortality associated with atrial fibrillation (AF) has been reported to decrease over prior decades, the mortality risk of asymptomatic, nonhospitalized AF has not been examined. HYPOTHESIS: Asymptomatic, nonhospitalized AF is associated with an increased risk of death. METHODS: This analysis included 25,976 participants (mean age, 65 ± 9.4 years; 55% female; 38% black) from the Reasons for Geographic And Racial Differences (REGARDS) study. Atrial fibrillation was detected on the baseline electrocardiogram (ECG AF) or by self-reported history. Atrial fibrillation unawareness was defined as present if ECG evidence of the arrhythmia was detected but no self-reported history was reported. All-cause mortality was confirmed during follow-up through March 31, 2014. RESULTS: A total of 2208 (8.5%) participants had AF at baseline (ECG: n = 371/17%; self-reported: n = 1837/83%). Over a median follow-up of 7.6 years, 3481 deaths occurred. In a multivariable Cox regression model, AF was associated with a 32% increased risk of mortality (95% confidence interval [CI]: 1.19-1.46). Risk of death was higher among those with ECG AF (hazard ratio: 1.71, 95% CI: 1.42-2.07) compared with self-reported cases (hazard ratio: 1.15, 95% CI: 1.03-1.29). Those who were unaware of their AF diagnosis had a 94% increased risk of death (95% CI: 1.50-2.52) compared with AF participants who were aware of their diagnosis. CONCLUSIONS: Asymptomatic, nonhospitalized AF is associated with an increased risk of mortality in the general population. Mortality is higher in those with ECG-confirmed cases and among those who are unaware of their diagnosis.

Rates of Atrial Fibrillation in Black Versus White Patients With Pacemakers.

BACKGROUND: Black US residents experience higher rates of ischemic stroke than white residents but have lower rates of clinically apparent atrial fibrillation (AF), a strong risk factor for stroke. It is unclear whether black persons truly have less AF or simply more undiagnosed AF. METHODS AND RESULTS: We obtained administrative claims data from state health agencies regarding all emergency department visits and hospitalizations in California, Florida, and New York. We identified a cohort of patients with pacemakers, the regular interrogation of which reduces the likelihood of undiagnosed AF. We compared rates of documented AF or atrial flutter at follow-up visits using Kaplan-Meier survival statistics and Cox proportional hazards models adjusted for demographic characteristics and vascular risk factors. We identified 10 393 black and 91 380 white patients without documented AF or atrial flutter before or at the index visit for pacemaker implantation. During 3.7 (±1.8) years of follow-up, black patients had a significantly lower rate of AF (21.4%; 95% CI 19.8-23.2) than white patients (25.5%; 95% CI 24.9-26.0). After adjustment for demographic characteristics and comorbidities, black patients had a lower hazard of AF (hazard ratio 0.91; 95% CI 0.86-0.96), a higher hazard of atrial flutter (hazard ratio 1.29; 95% CI 1.11-1.49), and a lower hazard of the composite of AF or atrial flutter (hazard ratio 0.94; 95% CI 0.88-99). CONCLUSIONS: In a population-based sample of patients with pacemakers, black patients had a lower rate of AF compared with white patients. These findings indicate that the persistent racial disparities in rates of ischemic stroke are likely to be related to factors other than undiagnosed AF.