Rest-Activity Rhythm Is Associated With Obesity Phenotypes: A Cross-Sectional Analysis

BACKGROUND

The prevalence of obesity continues to increase in spite of substantial efforts towards its prevention, posing a major threat to health globally. Circadian disruption has been associated with a wide range of preclinical and clinical disorders, including obesity. However, whether rest-activity rhythm (RAR), an expression of the endogenous circadian rhythm, is associated with excess adiposity is poorly understood. Here we aimed to assess the association of RAR with general and abdominal obesity.

METHODS

Non-institutionalized adults aged ≥20 years participating in the US National Health and Nutrition Examination Survey (NHANES) 2011-2014 who wore accelerometers for at least four 24-hour periods were included (N=7,838). Amplitude, mesor, acrophase and pseudo-F statistic of RAR were estimated using extended cosinor model, and interdaily stability (IS) and intradaily variability (IV) were computed by nonparametric methods. We tested the association between rest-activity rhythm and general obesity defined by body mass index and abdominal obesity by waist circumference. Waist-to-height ratio, sagittal abdominal diameter, and total and trunk fat percentages measured by imaging methods were also analyzed.

RESULTS

In multivariable analysis, low amplitude (magnitude of the rhythm), mesor (rhythm-corrected average activity level), pseudo-F statistic (robustness of the rhythm), IS (day-to-day rhythm stability), or high IV (rhythm fragmentation) were independently associated with higher likelihood of general or abdominal obesity (all Ps<.05). Consistently, RAR metrics were similarly associated with all adiposity measures (all Ps<.01). Delayed phase of RAR (later acrophase) was only significantly related to general and abdominal obesity in women.

CONCLUSIONS

Aberrant RAR is independently associated with anthropometric and imaging measures of general and abdominal obesity. Longitudinal studies assessing whether RAR metrics can predict weight gain and incident obesity are warranted.

CPAP adherence is associated with reduced inpatient utilization among older adult Medicare beneficiaries with pre-existing cardiovascular disease

STUDY OBJECTIVES

To examine the impact of adherence to continuous positive airway pressure (CPAP) therapy on health care utilization among a nationally representative and sample of older adults with multiple morbidities and pre-existing cardiovascular disease and subsequently diagnosed with obstructive sleep apnea in the United States.

METHODS

Our data source was a random 5% sample of Medicare administrative claims data. All participants (n = 1,921) were of age ≥ 65 years, diagnosed with cardiovascular disease and obstructive sleep apnea, and subsequently began treatment with CPAP between 2009-2013. Based on the number of CPAP machine charges, individuals were categorized as low, partial, or high adherers (ie, < 4, 4-12, and > 12 CPAP charges, respectively). The impact of CPAP adherence status on health care utilization was assessed across multiple points of service, including outpatient encounters, inpatient stays, emergency department visits, and prescription fills over 24 months following CPAP initiation.

RESULTS

Significant differences in demographic and comorbid disease characteristics were observed between low adherers (n = 377), partial adherers (n = 236), and high adherers (n = 1,308). After adjusting for covariates and relative to low adherers, high adherers demonstrated reduced inpatient visits (hazard ratio 0.75; 95% confidence interval 0.57, 0.97).

CONCLUSIONS

In this nationally representative sample of older Medicare beneficiaries with multiple morbidities and relative to low adherers, high adherers demonstrated reduced inpatient utilization.

CITATION

Wickwire EM, Bailey MD, Somers VK, et al. CPAP adherence is associated with reduced inpatient utilization among older adult Medicare beneficiaries with pre-existing cardiovascular disease. J Clin Sleep Med. 2022;18(1):39-45.

Association Between Arousals During Sleep and Hypertension Among Patients With Obstructive Sleep Apnea

Background

Sleep fragmentation induced by repetitive arousals is a hallmark of obstructive sleep apnea (OSA). Sleep fragmentation has been linked to hypertension in community‐based studies, but it is unclear if this association is manifest in OSA. We aimed to explore whether frequent arousals from sleep modify the relationship between OSA and prevalent hypertension.

Methods and Results

A total of 10 102 patients with OSA and 1614 primary snorers were included in the study. Hypertension was defined on either direct blood pressure measures or diagnosis by a physician. Spontaneous, respiratory, and movement arousals were derived by polysomnography. Logistic regression models were used to estimate the associations between arousals and prevalent hypertension in patients with OSA and primary snorers. For every 10‐unit increase of total arousal index, odds of hypertension significantly increased in both the total sample (odds ratio [OR], 1.08; 95% CI, 1.03–1.14; P=0.002) and patients with OSA (OR, 1.10; 95% CI, 1.04–1.16; P<0.001), but not in the primary snoring group. Total arousal index was significantly associated with systolic blood pressure and diastolic blood pressure in the total sample (β=0.05 and β=0.06; P<0.001) and in patients with (β=0.05 and β=0.06; P<0.01), but not in primary snorers. In addition, a greater influence of respiratory events with arousals than respiratory events without arousals on blood pressure in OSA was also noted. Results were independent of confounders, including apnea‐hypopnea index and nocturnal hypoxemia.

Conclusions

We conclude that repetitive arousals from sleep are independently associated with prevalent hypertension in patients with OSA.

Waist-To-Hip Ratio Predicts Abnormal Overnight Oximetry in Men Independent of Body Mass Index

Background: Ambulatory overnight oximetry (OXI) has emerged as a cost-effective initial test for sleep disordered breathing. Obesity is closely associated with obstructive sleep apnea (OSA); however, whether body mass index (BMI) or waist-to-hip ratio (WHR) predicts abnormal overnight OXI remains unknown. Methods: We performed a retrospective cross-sectional study of 393 men seen in the Executive Health Program at Mayo Clinic in Rochester, Minnesota who underwent ambulatory overnight OXI ordered by preventive medicine physicians between January 1, 2004 through December 31, 2010. We compared participant/spouse-reported symptoms (sleepiness, snoring), physician indications for OXI (obesity, fatigue), Epworth Sleepiness Scale scores, anthropomorphic measurements (WHR, BMI), and comorbid medical conditions (hypertension, diabetes) with OXI results. Results: 295 of the 393 men who completed OXI had abnormal results. During multivariate analysis, the strongest independent predictor of abnormal OXI for men was WHR (≥1.0, OR = 5.59) followed by BMI (≥30.0 kg/m2, OR = 2.75), age (≥55 yrs, OR = 2.06), and the presence of snoring (OR = 1.91, P < 0.05 for all). A strong association was observed between WHR and abnormal OXI in obese (BMI ≥ 30.0 kg/m2, OR = 6.28) and non-obese (BMI < 29.9 kg/m2, OR = 6.42, P < 0.01 for both) men. Furthermore, 88 men with abnormal OXI underwent polysomnography with 91% being subsequently diagnosed with OSA. Conclusions: In ambulatory, predominantly middle-aged men undergoing preventive services evaluation many physician indications for OXI were not predictors of abnormal results; however, WHR strongly predicted abnormal OXI in obese and non-obese men. As such, we suggest middle-aged men who snore and have a WHR ≥1.0 should be directly referred to a sleep clinic for polysomnography.

Louis EK, Reichard RR, Edwards WD, Ackerman MJ, Somers VK. Confirmation of Cause of Death Via Comprehensive Autopsy and Whole Exome Molecular Sequencing in People With Epilepsy and Sudden Unexpected Death

Background

Sudden cardiac arrest is the leading mode of death in the United States. Epilepsy affects 1% of Americans; yet epidemiological data show a prevalence of 4% in cases of sudden cardiac arrest. Sudden unexpected death in epilepsy (SUDEP) may share features with sudden cardiac arrest. The objective of this study was to report autopsy and genomic findings in a large cohort of SUDEP cases.

Methods and Results

Mayo Clinic Sudden Death Registry containing cases (ages 0–90 years) of sudden unexpected and unexplained deaths 1960 to present was queried. Exome sequencing performed on decedent cases. From 13 687 cases of sudden death, 656 (4.8%) had a history of seizures, including 368 confirmed by electroencephalography, 96 classified as SUDEP, 58 as non‐SUDEP, and 214 as unknown (insufficient records). Mean age of death in SUDEP was 37 (±19.7) years; 56 (58.3%) were male; 65% of deaths occurred at night; 54% were found in bed; and 80.6% were prone. Autopsies were obtained in 83 cases; bystander coronary artery disease was frequently reported as cause of death; nonspecific fibrosis was seen in 32.6% of cases, in structurally normal hearts. There were 4 cases of Dravet syndrome with pathogenic variants in SCN1A gene. Using whole exome sequencing in 11 cases, 18 ultrarare nonsynonymous variants were identified in 6 cases including CACNB2, RYR2, CLNB, CACNA1H, and CLCN2.

Conclusions

This study examined one of the largest single‐center US series of SUDEP cases. Several cases were reclassified as SUDEP, 15% had an ECG when alive, and 11 (11.4%) had blood for whole exome sequencing analysis. The most frequent antemortem genetic finding was pathogenic variants in SCN1A; postmortem whole exome sequencing identified 18 ultrarare variants.

Overfeeding-induced weight gain elicits decreases in sex hormone-binding globulin in healthy males-Implications for body fat distribution

OBJECTIVE

Obesity and upper-body fat elevates cardiometabolic risk. However, mechanisms predisposing to upper-body fat accumulation are not completely understood. In males, low testosterone (T) frequently associates with obesity, and estrogen deficiency may contribute to upper-body adiposity. This study examines the effects of overfeeding-induced weight gain on changes in gonadal hormones in healthy males and its association with regional fat depots.

METHODS

Twenty-five males (age: 29.7 ± 6.9 years; BMI: 24.7 ± 3.1 kg/m2 ) were overfed for 8 weeks to gain approximately 5% body weight. Changes in total and regional fat depots were assessed using dual-energy x-ray absorptiometry and abdominal computed tomography scans. Circulating T, estrone (E1), 17-β estradiol (E2), and sex hormone-binding globulin (SHBG) concentrations were measured at baseline and after weight gain.

RESULTS

Overfeeding resulted in 3.8 (3.3, 4.9) kg weight gain with increased total body fat. Weight gain did not alter circulating T (p = 0.82), E1 (p = 0.52), or E2 (p = 0.28). However, SHBG decreased (p = 0.04) along with consequent increases in T/SHBG (p = 0.02) and E2/SHBG (p = 0.03) ratios. Importantly, baseline E2/SHBG ratio was inversely associated with increases in upper-body fat mass (ρ = -0.43, p = 0.03).

CONCLUSIONS

Modest weight gain does not alter circulating gonadal hormones in males but may increase bioavailability of T and E2 via decreases in SHBG. The association between baseline E2/SHBG and regional fat mass suggests that higher levels of bioavailable E2 may protect from upper-body fat accumulation during overfeeding-induced modest weight gain in healthy males. Our study suggests a complex relationship between adipose tissue, gonadal hormones, and fat accumulation in males.

QT prolongation in patients with index evaluation for seizure or epilepsy is predictive of all-cause mortality

BACKGROUND

Refractory epilepsy confers a considerable lifetime risk of sudden unexplained death in epilepsy (SUDEP). Mechanisms may overlap with sudden cardiac death (SCD), particularly regarding QTc prolongation. Guidelines in the United States do not mandate the use of electrocardiography (ECG) in diagnostic evaluation of seizures or epilepsy.

OBJECTIVE

The purpose of this study was to determine the frequency of ECG use and of QT prolongation, and whether QT prolongation predicts mortality in patients with seizures.

METHODS

We performed a retrospective cohort study including all patients seen at Mayo Clinic in Rochester, Minnesota, from January 1, 2000, to July 31, 2015, with index evaluation for seizure or epilepsy. Patients with an ECG were categorized by the presence of a prolonged QT interval with a primary endpoint of all-cause mortality after the 15-year observation period.

RESULTS

Optimal cutoff QT intervals most predictive of mortality were identified. Median age was 40.0 years. An ECG was obtained in 18,222 patients (57.4%). After patients with confounding ECG findings were excluded, primary prolonged QT intervals were seen in 223 cases (1.4%), similar to the general population. Kaplan-Meier analysis demonstrated a significant increase in mortality (Cox hazard ratio [HR] 1.90; 95% confidence interval [CI] 1.76-2.05) for prolonged optimal cutoff QT, maintained after adjustments for age, Charlson comorbidity index, and sex (HR 1.48; 95% CI 1.37-1.59).

CONCLUSION

Use of ECG in diagnostic workup of patients with seizures is poor. A prolonged optimal cutoff QTc interval predicts all-cause mortality in patients evaluated for seizure and those diagnosed with epilepsy. We advocate the routine use of a 12-lead ECG at index evaluation in patients with seizure or epilepsy.

Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 2: Population and Clinical Considerations

Sudden cardiac death (SCD) is the sudden, unexpected death due to abrupt loss of heart function secondary to cardiovascular disease. In certain populations living with cardiovascular disease, SCD follows a distinct 24-hour pattern in occurrence, suggesting day/night rhythms in behavior, the environment, and endogenous circadian rhythms result in daily spans of increased vulnerability. The National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death to identify fundamental questions regarding the role of the circadian rhythms in SCD. Part 2 summarizes research gaps and opportunities in the areas of population and clinical research identified in the workshop. Established research supports a complex interaction between circadian rhythms and physiological responses that increase the risk for SCD. Moreover, these physiological responses themselves are influenced by several biological variables, including the type of cardiovascular disease, sex, age, and genetics, as well as environmental factors. The emergence of new noninvasive biotechnological tools that continuously measure key cardiovascular variables, as well as the identification of biomarkers to assess circadian rhythms, hold promise for generating large-scale human data sets that will delineate which subsets of individuals are most vulnerable to SCD. Additionally, these data will improve our understanding of how people who suffer from circadian disruptions develop cardiovascular diseases that increase the risk for SCD. Emerging strategies to identify new biomarkers that can quantify circadian health (eg, environmental, behavioral, and internal misalignment) may lead to new interventions and therapeutic targets to prevent the progression of cardiovascular diseases that cause SCD.

Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 1: Basic and Translational Aspects

Sudden cardiac death (SCD), the unexpected death due to acquired or genetic cardiovascular disease, follows distinct 24-hour patterns in occurrence. These 24-hour patterns likely reflect daily changes in arrhythmogenic triggers and the myocardial substrate caused by day/night rhythms in behavior, the environment, and endogenous circadian mechanisms. To better address fundamental questions regarding the circadian mechanisms, the National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death. We present a 2-part report of findings from this workshop. Part 1 summarizes the workshop and serves to identify research gaps and opportunities in the areas of basic and translational research. Among the gaps was the lack of standardization in animal studies for reporting environmental conditions (eg, timing of experiments relative to the light dark cycle or animal housing temperatures) that can impair rigor and reproducibility. Workshop participants also pointed to uncertainty regarding the importance of maintaining normal circadian rhythmic synchrony and the potential pathological impact of desynchrony on SCD risk. One related question raised was whether circadian mechanisms can be targeted to reduce SCD risk. Finally, the experts underscored the need for studies aimed at determining the physiological importance of circadian clocks in the many different cell types important to normal heart function and SCD. Addressing these gaps could lead to new therapeutic approaches/molecular targets that can mitigate the risk of SCD not only at certain times but over the entire 24-hour period.

Sleep Disordered Breathing and Mortality in Patients With Hypertrophic Obstructive Cardiomyopathy Undergoing Septal Myectomy

OBJECTIVE

To determine the impact of sleep-disordered breathing (SDB) on survival in patients with hypertrophic cardiomyopathy (HCM) following septal myectomy.

PATIENTS AND METHODS

Patients with obstructive HCM undergoing septal myectomy from 2007 to 2016 were reviewed. Those who had an overnight oximetry test within 6 months before myectomy were included in analysis. Oxygen desaturation index was examined continuously and also categorically (SDB [>5/h] and severe SDB [>15/h]).

RESULTS

A total of 619 of 1500 patients undergoing septal myectomy had overnight oximetry tests. Sleep-disordered breathing (oxygen desaturation index >5/h) was identified in 338 (54.6%) patients, and among those patients, 117 (18.9%) were classified as severe. Patients with SDB were older, had greater body mass index and body surface area, were more likely to have arterial hypertension and atrial fibrillation, and had an increased E/e' ratio on Doppler echocardiography. Notably, there was no difference in preoperative resting left ventricular outflow tract pressure gradient between patients with SDB and those with normal overnight oximetry (55 (interquartile range: 25 to 86) mm Hg versus 52 (interquartile range: 21 to 85) mm Hg; P=.29). There was no difference in age-adjusted survival among patients with normal oximetry compared with those with mild SDB (hazard ratio: 0.98; 95% CI: 0.45 to 2.17), and severe SDB (hazard ratio: 1.06, 95% CI 0.42 - 2.71).

CONCLUSION

Sleep-disordered breathing is present in more than half of patients with obstructive HCM in whom septal myectomy is indicated, and is mainly associated with aging, overweight, and male sex. However, SDB does not alter survival following septal myectomy.

Demographic characteristics associated with circadian rest-activity rhythm patterns: a cross-sectional study

BACKGROUND

Rest-activity rhythm (RAR), a manifestation of circadian rhythms, has been associated with morbidity and mortality risk. However, RAR patterns in the general population and specifically the role of demographic characteristics in RAR pattern have not been comprehensively assessed. Therefore, we aimed to describe RAR patterns among non-institutionalized US adults and age, sex, and race/ethnicity variation using accelerometry data from a nationally representative population.

METHODS

This cross-sectional study was conducted using the US National Health and Nutrition Examination Survey (NHANES) 2011-2014. Participants aged ≥20 years who were enrolled in the physical activity monitoring examination and had at least four 24-h periods of valid wrist accelerometer data were included in the present analysis. 24-h RAR metrics were generated using both extended cosinor model (amplitude, mesor, acrophase and pseudo-F statistic) and nonparametric methods (interdaily stability [IS] and intradaily variability [IV]). Multivariable linear regression was used to assess the association between RAR and age, sex, and race/ethnicity.

RESULTS

Eight thousand two hundred participants (mean [SE] age, 49.1 [0.5] years) were included, of whom 52.2% were women and 67.3% Whites. Women had higher RAR amplitude and mesor, and also more robust (pseudo-F statistic), more stable (higher IS) and less fragmented (lower IV) RAR (all P trend < 0.001) than men. Compared with younger adults (20-39 years), older adults (≥ 60 years) exhibited reduced RAR amplitude and mesor, but more stable and less fragmented RAR, and also reached their peak activity earlier (advanced acrophase) (all P trend < 0.001). Relative to other racial/ethnic groups, Hispanics had the highest amplitude and mesor level, and most stable (highest IS) and least fragmented (lowest IV) RAR pattern (P trend < 0.001). Conversely, non-Hispanic blacks had the lowest peak activity level (lowest amplitude) and least stable (lowest IS) RAR pattern (all P trend < 0.001).

CONCLUSIONS

In the general adult population, RAR patterns vary significantly according to sex, age and race/ethnicity. These results may reflect demographic-dependent differences in intrinsic circadian rhythms and may have important implications for understanding racial, ethnic, sex and other disparities in morbidity and mortality risk.

Research Priorities in the Secondary Prevention of Atrial Fibrillation: A National Heart, Lung, and Blood Institute Virtual Workshop Report

There has been sustained focus on the secondary prevention of coronary heart disease and heart failure; yet, apart from stroke prevention, the evidence base for the secondary prevention of atrial fibrillation (AF) recurrence, AF progression, and AF-related complications is modest. Although there are multiple observational studies, there are few large, robust, randomized trials providing definitive effective approaches for the secondary prevention of AF. Given the increasing incidence and prevalence of AF nationally and internationally, the AF field needs transformative research and a commitment to evidenced-based secondary prevention strategies. We report on a National Heart, Lung, and Blood Institute virtual workshop directed at identifying knowledge gaps and research opportunities in the secondary prevention of AF. Once AF has been detected, lifestyle changes and novel models of care delivery may contribute to the prevention of AF recurrence, AF progression, and AF-related complications. Although benefits seen in small subgroups, cohort studies, and selected randomized trials are impressive, the widespread effectiveness of AF secondary prevention strategies remains unknown, calling for development of scalable interventions suitable for diverse populations and for identification of subpopulations who may particularly benefit from intensive management. We identified critical research questions for 6 topics relevant to the secondary prevention of AF: (1) weight loss; (2) alcohol intake, smoking cessation, and diet; (3) cardiac rehabilitation; (4) approaches to sleep disorders; (5) integrated, team-based care; and (6) nonanticoagulant pharmacotherapy. Our goal is to stimulate innovative research that will accelerate the generation of the evidence to effectively pursue the secondary prevention of AF.

Effects of Experimental Sleep Restriction on Ambulatory and Sleep Blood Pressure in Healthy Young Adults: A Randomized Crossover Study

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Carotid body chemoreceptors: physiology, pathology, and implications for health and disease

The carotid body (CB) is the main peripheral chemoreceptor for arterial respiratory gases O2 and CO2 and pH, eliciting reflex ventilatory, cardiovascular, and humoral responses to maintain homeostasis. This review examines the fundamental biology underlying CB chemoreceptor function, its contribution to integrated physiological responses, and its role in maintaining health and potentiating disease. Emphasis is placed on 1) transduction mechanisms in chemoreceptor (type I) cells, highlighting the role played by the hypoxic inhibition of O2-dependent K+ channels and mitochondrial oxidative metabolism, and their modification by intracellular molecules and other ion channels; 2) synaptic mechanisms linking type I cells and petrosal nerve terminals, focusing on the role played by the main proposed transmitters and modulatory gases, and the participation of glial cells in regulation of the chemosensory process; 3) integrated reflex responses to CB activation, emphasizing that the responses differ dramatically depending on the nature of the physiological, pathological, or environmental challenges, and the interactions of the chemoreceptor reflex with other reflexes in optimizing oxygen delivery to the tissues; and 4) the contribution of enhanced CB chemosensory discharge to autonomic and cardiorespiratory pathophysiology in obstructive sleep apnea, congestive heart failure, resistant hypertension, and metabolic diseases and how modulation of enhanced CB reactivity in disease conditions may attenuate pathophysiology.

Sex-specific associations between erythrocyte measures and obstructive sleep apnea

STUDY OBJECTIVES

Hypoxemic effects of obstructive sleep apnea (OSA) have been implicated in changes in erythropoiesis and hence erythrocyte measures. Sex differences are evident in both OSA and erythropoiesis. Whether sex modulates the relationship between severity of OSA and erythrocyte measures has not previously been studied.

METHODS

We examined a sample of 976 patients (38% women) who underwent overnight polysomnography and measurement of red blood cell count, hemoglobin, and hematocrit. Patients were divided into primary snoring and mild, moderate, and severe OSA groups, separately by sex.

RESULTS

In multiple regression models, we found significant interactions between sex and oxygen desaturation index and apnea-hypopnea index on erythrocyte measures. Higher oxygen desaturation index and higher apnea-hypopnea index were independently associated with higher red blood cell count, hemoglobin, and hematocrit in women but not in men. Further ordinal logistic regression analysis showed a significant association between oxygen desaturation index (odds ratio, 2.33; 95% confidence interval, 1.17-4.66) and apnea-hypopnea index (odds ratio, 2.44; 95% confidence interval, 1.23-4.84) and red blood cell count in women only. Correlation analysis also showed that erythrocyte measures and markers of cardiometabolic risk were more closely correlated in women than in men.

CONCLUSIONS

This study provides novel data suggesting a significant association between erythrocyte measures and OSA severity in women but not in men. Similarly, the relationship between hematologic metrics and cardiometabolic risk markers was more pronounced in women than in men. Our findings suggest a sex-specific impact of OSA on erythrocyte measures and on their relationship with indexes of cardiometabolic risk.

Frequency of sleep-disordered breathing in a referral population of Somali-Americans

STUDY OBJECTIVES

To study the frequency of obstructive sleep apnea (OSA) in individuals of Somali ancestry referred to a clinical sleep laboratory.

METHODS

This was a retrospective study using a large registry of patients who underwent diagnostic polysomnography between 17 November 2009 and 15 April 2017. Adult patients self-reporting as being of Somali origin were confirmed using the electronic medical record.

RESULTS

Somali-American patients comprised approximately 0.2% of all patients undergoing polysomnography at the Mayo Clinic Center for Sleep Medicine. The median (interquartile range) age was 52.6 (35, 64) years with 66% males and a median (interquartile range) body mass index of 31.2 (27, 34) kg/m². OSA was diagnosed in 77% of patients, with approximately 50% having moderate to severe OSA. OSA was more frequent in older patients and similar between men and women, and only age predicted an OSA diagnosis while sex and body mass index did not. All patients with diabetes mellitus type 2 (n = 7) and all but one of the hypertensive patients (n = 11) had significant OSA.

CONCLUSIONS

Less than 0.2% of all patients undergoing polysomnography at Mayo Clinic were of Somali origin. Moderate-to-severe OSA was frequent in this select sample of individuals who underwent polysomnography. Hypertension and diabetes were present in most Somali-Americans with OSA. Given the rising prevalence of diabetes and hypertension in Somali-Americans, and the likely high prevalence of undiagnosed OSA, screening Somali-Americans for sleep disorders may contribute importantly to prevention, early detection, and reduction of cardiovascular and metabolic diseases in this population.

Obstructive Sleep Apnea and Cardiovascular Disease: A Scientific Statement From the American Heart Association

Obstructive sleep apnea (OSA) is characterized by recurrent complete and partial upper airway obstructive events, resulting in intermittent hypoxemia, autonomic fluctuation, and sleep fragmentation. Approximately 34% and 17% of middle-aged men and women, respectively, meet the diagnostic criteria for OSA. Sleep disturbances are common and underdiagnosed among middle-aged and older adults, and the prevalence varies by race/ethnicity, sex, and obesity status. OSA prevalence is as high as 40% to 80% in patients with hypertension, heart failure, coronary artery disease, pulmonary hypertension, atrial fibrillation, and stroke. Despite its high prevalence in patients with heart disease and the vulnerability of cardiac patients to OSA-related stressors and adverse cardiovascular outcomes, OSA is often underrecognized and undertreated in cardiovascular practice. We recommend screening for OSA in patients with resistant/poorly controlled hypertension, pulmonary hypertension, and recurrent atrial fibrillation after either cardioversion or ablation. In patients with New York Heart Association class II to IV heart failure and suspicion of sleep-disordered breathing or excessive daytime sleepiness, a formal sleep assessment is reasonable. In patients with tachy-brady syndrome or ventricular tachycardia or survivors of sudden cardiac death in whom sleep apnea is suspected after a comprehensive sleep assessment, evaluation for sleep apnea should be considered. After stroke, clinical equipoise exists with respect to screening and treatment. Patients with nocturnally occurring angina, myocardial infarction, arrhythmias, or appropriate shocks from implanted cardioverter-defibrillators may be especially likely to have comorbid sleep apnea. All patients with OSA should be considered for treatment, including behavioral modifications and weight loss as indicated. Continuous positive airway pressure should be offered to patients with severe OSA, whereas oral appliances can be considered for those with mild to moderate OSA or for continuous positive airway pressure-intolerant patients. Follow-up sleep testing should be performed to assess the effectiveness of treatment.

CPAP adherence is associated with reduced risk for stroke among older adult Medicare beneficiaries with obstructive sleep apnea

STUDY OBJECTIVES

To examine the impact of adherence to continuous positive airway pressure (CPAP) therapy on risk of stroke among a nationally representative sample of older adults with obstructive sleep apnea.

METHODS

We performed a retrospective cohort study among Medicare beneficiaries aged ≥ 65 years who were newly diagnosed with obstructive sleep apnea and had initiated CPAP (2009-2013). Monthly indicators of CPAP adherence included charges for machines, masks, or supplies and were summed over a 25-month follow-up to create a CPAP adherence variable. Stroke was modeled as a function of CPAP adherence using generalized estimating equations.

RESULTS

We found that 5,757 beneficiaries met the inclusion criteria and were included in the final sample. Of these, 407 (7%) experienced stroke. After adjusting for demographic and clinical characteristics, CPAP adherence was associated with a reduced risk of stroke (hazard ratio, 0.98; 95% confidence interval, 0.96-0.99) over 25 months, indicating a 2% reduction in risk of stroke for each month of CPAP adherence. When sensitivity analyses were performed to stratify results by time since the first CPAP charge, the protective effect remained significant for the 12- and 6-month but not the 3-month outcome models.

CONCLUSIONS

In this national analysis of older adult Medicare beneficiaries with obstructive sleep apnea, CPAP adherence was associated with significantly reduced risk of stroke.

Cardiac Involvement in Facioscapulohumeral Muscular Dystrophy (FSHD)

Background: Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common muscular dystrophies and predominantly affects facial and shoulder girdle muscles. Previous case reports and cohort studies identified minor cardiac abnormalities in FSHD patients, but their nature and frequency remain incompletely characterized. Methods: We reviewed cardiac, neurological and genetic findings of 104 patients with genetically confirmed FSHD. Results: The most common conduction abnormality was complete (7%) or incomplete (5%) right bundle branch block (RBBB). Bifascicular block, left anterior fascicular block, complete atrioventricular block, and 2:1 atrioventricular block each occurred in 1% of patients. Atrial fibrillation or flutter were seen in 5% of patients. Eight percent of patients had heart failure with reduced ejection fraction and 25% had valvular disease. The latter included aortic stenosis in 6% (severe in 4% and moderate in 2%) and moderate aortic regurgitation in 8%. Mitral valve prolapse (MVP) was present in 9% of patients without significant mitral regurgitation. There were no significant associations between structural or conduction abnormalities and age, degree of muscle weakness, or size of the 4q deletion. Conclusions: Both structural and conduction abnormalities can occur in FSHD. The most common abnormalities are benign (RBBB and MVP), but more significant cardiac involvement was also observed. The presence of cardiac abnormalities cannot be predicted from the severity of the neurological phenotype, nor from the genotype.

Research Priorities for Patients with Heart Failure and Central Sleep Apnea. An Official American Thoracic Society Research Statement

Background: Central sleep apnea (CSA) is common among patients with heart failure and has been strongly linked to adverse outcomes. However, progress toward improving outcomes for such patients has been limited. The purpose of this official statement from the American Thoracic Society is to identify key areas to prioritize for future research regarding CSA in heart failure.

Methods: An international multidisciplinary group with expertise in sleep medicine, pulmonary medicine, heart failure, clinical research, and health outcomes was convened. The group met at the American Thoracic Society 2019 International Conference to determine research priority areas. A statement summarizing the findings of the group was subsequently authored using input from all members.

Results: The workgroup identified 11 specific research priorities in several key areas: 1) control of breathing and pathophysiology leading to CSA, 2) variability across individuals and over time, 3) techniques to examine CSA pathogenesis and outcomes, 4) impact of device and pharmacological treatment, and 5) implementing CSA treatment for all individuals

Conclusions: Advancing care for patients with CSA in the context of heart failure will require progress in the arenas of translational (basic through clinical), epidemiological, and patient-centered outcome research. Given the increasing prevalence of heart failure and its associated substantial burden to individuals, society, and the healthcare system, targeted research to improve knowledge of CSA pathogenesis and treatment is a priority.

The Association of Sleep Apnea and Cardiorespiratory Fitness With Long-Term Major Cardiovascular Events

OBJECTIVE

To determine the risk of long-term major adverse cardiovascular events (MACE) when sleep-disordered breathing (SDB) and decreased cardiorespiratory fitness (CRF) co-occur.

METHODS

We included consecutive patients who underwent symptom-limited cardiopulmonary exercise tests between January 1, 2005, and January 1, 2010, followed by first-time diagnostic polysomnography within 6 months. Patients were stratified based on the presence of moderate-to-severe SDB (apnea/hypopnea index ≥15 per hour) and decreased CRF defined as <70% predicted peak oxygen consumption (VO₂). Long-term MACE was a composite outcome of myocardial infarction (MI), coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), stroke or transient ischemic attack (TIA), and death, assessed until May 21, 2018. Cox-proportional hazard models were adjusted for factors known to influence CRF and MACE.

RESULTS

Of 498 included patients (60±13 years, 28.1% female), 175 (35%) had MACE (MI=17, PCI=14, CABG=13, stroke=20, TIA=12, deaths=99) at a median follow-up of 8.7 years (interquartile range=6.5 to 10.3 years). After adjusting for age, sex, beta blockers, systemic hypertension, diabetes mellitus, coronary artery disease, cardiac arrhythmia, chronic obstructive pulmonary disease, smoking, and use of positive airway pressure (PAP), decreased CRF alone (hazard ratio [HR]=1.91, 95% confidence interval [CI], 1.15 to 3.18; P=.01), but not SDB alone (HR=1.26, 95% CI, 0.75 to 2.13, P=.39) was associated with increased risk of MACE. Those with SDB and decreased CRF had greater risk of MACE compared with patients with decreased CRF alone (HR=1.85; 95% CI, 1.21 to 2.84; P<.005) after accounting for these confounders. The risk of MACE was attenuated in those with reduced CRF alone after additionally adjusting for adequate adherence to PAP (HR=1.59; 95% CI, 0.77 to 3.31; P=.21).

CONCLUSION

The incidence of MACE, especially mortality, was high in this sample. Moderate-to-severe SDB with concurrent decreased CRF was associated with higher risk of MACE than decreased CRF alone. These results highlight the importance of possibly including CRF in the risk assessment of patients with SDB and, conversely, that of screening for SDB in patients with low peak VO₂.

Obstructive Sleep Apnea as a Cardiovascular Risk Factor-Beyond CPAP

Patients with obstructive sleep apnea (OSA) experience repetitive partial or complete airway collapse during sleep resulting in nocturnal hypoxia-normoxia cycling, and are at increased cardiovascular risk. The number of apneas and hypopneas indexed per hour of sleep (apnea-hypopnea index) along with the associated intermittent hypoxia predict the increased cardiovascular risk; thus, their attenuation or prevention are objectives of OSA therapy. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA and, when effective, mitigates the apnea-hypopnea index and hypoxemia. As such, it is reasonable to expect CPAP would decrease cardiovascular risk. However, 3 recent randomized clinical trials of CPAP vs usual care did not show any significant effects of CPAP in attenuating incident cardiovascular events in patients with OSA. In this review, we discuss these studies in addition to potential complementary therapeutic options to CPAP (eg, neurostimulation) and conclude with suggested therapeutic targets for future interventional studies (eg, the autonomic nervous system). Although these areas of research are exciting, they have yet to be tested to any similar degree of rigour as CPAP.

Evaluation of Optimal Diastolic Blood Pressure Range Among Adults With Treated Systolic Blood Pressure Less Than 130 mm Hg

IMPORTANCE

Extremely low diastolic blood pressure has been reported to be associated with increased adverse cardiovascular events (ie, the diastolic J-shape phenomenon); however, current US guidelines recommend an intensive blood pressure target of less than 130/80 mm Hg without mentioning the lower limits of diastolic blood pressure.

OBJECTIVES

To evaluate whether there is a diastolic J-shape phenomenon for patients with an treated systolic blood pressure of less than 130 mm Hg and to explore the safe and optimal diastolic blood pressure ranges for this patient population.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed outcome data of patients at high cardiovascular risk who were randomized to intensive or standard blood pressure control and achieved treated systolic blood pressure of less than 130 mm Hg in the Systolic Blood Pressure Intervention Trial (SPRINT) and Action to Control Cardiovascular Risk in Diabetes-Blood Pressure (ACCORD-BP) trial. Data were collected from October 2010 to August 2015 (SPRINT) and from September 1999 to June 2009 (ACCORD-BP). Data were analyzed from January to May 2020.

EXPOSURE

Treated diastolic blood pressure, divided in intervals of less than 60, 60 to less than 70, 70 to less than 80, and 80 mm Hg and greater.

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite of all-cause death, nonfatal myocardial infarction, and nonfatal stroke. A composite cardiovascular outcome, including cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke, was among the key secondary outcomes.

RESULTS

A total of 7515 patients (mean [SD] age, 65.6 [8.7] years; 4553 [60.6%] men) were included in this analysis. The nominally lowest risk was observed at a diastolic blood pressure between 70 and 80 mm Hg for the primary outcome, the composite cardiovascular outcome, nonfatal myocardial infarction, and cardiovascular death. A mean diastolic blood pressure of less than 60 mm Hg was associated with significantly increased risk of the primary outcome (hazard ratio [HR], 1.46; 95% CI, 1.13-1.90; P = .004), the composite cardiovascular outcome (HR, 1.74; 95% CI, 1.26-2.41; P = .001), nonfatal myocardial infarction (HR, 1.73; 95% CI, 1.15-2.59; P = .008), and nonfatal stroke (HR, 2.67; 95% CI, 1.26-5.63; P = .01).

CONCLUSIONS AND RELEVANCE

This cohort study found that lowering diastolic blood pressure to less than 60 mm Hg was associated with increased risk of cardiovascular events in patients with high cardiovascular risk and an treated systolic blood pressure less than 130 mm Hg. The finding that a diastolic blood pressure value between 70 and 80 mm Hg was an optimum target for this patient population merits further study.