@article {643, title = {Reliability of scoring respiratory disturbance indices and sleep staging.}, journal = {Sleep}, volume = {21}, year = {1998}, month = {1998 Nov 01}, pages = {749-57}, abstract = {

STUDY OBJECTIVES: Unattended, home-based polysomnography (PSG) is increasingly used in both research and clinical settings as an alternative to traditional laboratory-based studies, although the reliability of the scoring of these studies has not been described. The purpose of this study is to describe the reliability of the PSG scoring in the Sleep Heart Health Study (SHHS), a multicenter study of the relation between sleep-disordered breathing measured by unattended, in-home PSG using a portable sleep monitor, and cardiovascular outcomes.

DESIGN: The reliability of SHHS scorers was evaluated based on 20 randomly selected studies per scorer, assessing both interscorer and intrascorer reliability.

RESULTS: Both inter- and intrascorer comparisons on epoch-by-epoch sleep staging showed excellent reliability (kappa statistics >0.80), with stage 1 having the greatest discrepancies in scoring and stage 3/4 being the most reliably discriminated. The arousal index (number of arousals per hour of sleep) was moderately reliable, with an intraclass correlation (ICC) of 0.54. The scorers were highly reliable on various respiratory disturbance indices (RDIs), which incorporate an associated oxygen desaturation in the definition of respiratory events (2\% to 5\%) with or without the additional use of associated EEG arousal in the definition of respiratory events (ICC>0.90). When RDI was defined without considering oxygen desaturation or arousals to define respiratory events, the RDI was moderately reliable (ICC=0.74). The additional use of associated EEG arousals, but not oxygen desaturation, in defining respiratory events did little to increase the reliability of the RDI measure (ICC=0.77).

CONCLUSIONS: The SHHS achieved a high degree of intrascorer and interscorer reliability for the scoring of sleep stage and RDI in unattended in-home PSG studies.

}, keywords = {Humans, Polysomnography, Reproducibility of Results, Research Design, Sleep Apnea Syndromes, Sleep Stages}, issn = {0161-8105}, doi = {10.1093/sleep/21.7.749}, author = {Whitney, C W and Gottlieb, D J and Redline, S and Norman, R G and Dodge, R R and Shahar, E and Surovec, S and Nieto, F J} } @article {613, title = {Association of sleep-disordered breathing, sleep apnea, and hypertension in a large community-based study. Sleep Heart Health Study.}, journal = {JAMA}, volume = {283}, year = {2000}, month = {2000 Apr 12}, pages = {1829-36}, abstract = {

CONTEXT: Sleep-disordered breathing (SDB) and sleep apnea have been linked to hypertension in previous studies, but most of these studies used surrogate information to define SDB (eg, snoring) and were based on small clinic populations, or both.

OBJECTIVE: To assess the association between SDB and hypertension in a large cohort of middle-aged and older persons.

DESIGN AND SETTING: Cross-sectional analyses of participants in the Sleep Heart Health Study, a community-based multicenter study conducted between November 1995 and January 1998.

PARTICIPANTS: A total of 6132 subjects recruited from ongoing population-based studies (aged > or = 40 years; 52.8\% female).

MAIN OUTCOME MEASURES: Apnea-hypopnea index (AHI, the average number of apneas plus hypopneas per hour of sleep, with apnea defined as a cessation of airflow and hypopnea defined as a > or = 30\% reduction in airflow or thoracoabdominal excursion both of which are accompanied by a > or = 4\% drop in oxyhemoglobin saturation) [corrected], obtained by unattended home polysomnography. Other measures include arousal index; percentage of sleep time below 90\% oxygen saturation; history of snoring; and presence of hypertension, defined as resting blood pressure of at least 140/90 mm Hg or use of antihypertensive medication.

RESULTS: Mean systolic and diastolic blood pressure and prevalence of hypertension increased significantly with increasing SDB measures, although some of this association was explained by body mass index (BMI). After adjusting for demographics and anthropometric variables (including BMI, neck circumference, and waist-to-hip ratio), as well as for alcohol intake and smoking, the odds ratio for hypertension, comparing the highest category of AHI (> or = 30 per hour) with the lowest category (< 1.5 per hour), was 1.37 (95\% confidence interval [CI], 1.03-1.83; P for trend = .005). The corresponding estimate comparing the highest and lowest categories of percentage of sleep time below 90\% oxygen saturation (> or = 12\% vs < 0.05\%) was 1.46 (95\% CI, 1.12-1.88; P for trend <.001). In stratified analyses, associations of hypertension with either measure of SDB were seen in both sexes, older and younger ages, all ethnic groups, and among normal-weight and overweight individuals. Weaker and nonsignificant associations were observed for the arousal index or self-reported history of habitual snoring.

CONCLUSION: Our findings from the largest cross-sectional study to date indicate that SDB is associated with systemic hypertension in middle-aged and older individuals of different sexes and ethnic backgrounds.

}, keywords = {Adult, Aged, Cohort Studies, Cross-Sectional Studies, Female, Humans, Hypertension, Logistic Models, Male, Middle Aged, Obesity, Polysomnography, Sleep Apnea Syndromes, Snoring}, issn = {0098-7484}, doi = {10.1001/jama.283.14.1829}, author = {Nieto, F J and Young, T B and Lind, B K and Shahar, E and Samet, J M and Redline, S and D{\textquoteright}Agostino, R B and Newman, A B and Lebowitz, M D and Pickering, T G} } @article {636, title = {Sleep-disordered breathing and cardiovascular disease: cross-sectional results of the Sleep Heart Health Study.}, journal = {Am J Respir Crit Care Med}, volume = {163}, year = {2001}, month = {2001 Jan}, pages = {19-25}, abstract = {

Disordered breathing during sleep is associated with acute, unfavorable effects on cardiovascular physiology, but few studies have examined its postulated association with cardiovascular disease (CVD). We examined the cross-sectional association between sleep- disordered breathing and self-reported CVD in 6,424 free-living individuals who underwent overnight, unattended polysomnography at home. Sleep-disordered breathing was quantified by the apnea-hypopnea index (AHI)-the average number of apneas and hypopneas per hour of sleep. Mild to moderate disordered breathing during sleep was highly prevalent in the sample (median AHI: 4.4; interquartile range: 1.3 to 11.0). A total of 1,023 participants (16\%) reported at least one manifestation of CVD (myocardial infarction, angina, coronary revascularization procedure, heart failure, or stroke). The multivariable-adjusted relative odds (95\% CI) of prevalent CVD for the second, third, and fourth quartiles of the AHI (versus the first) were 0.98 (0.77-1.24), 1.28 (1.02-1.61), and 1.42 (1.13-1.78), respectively. Sleep-disordered breathing was associated more strongly with self-reported heart failure and stroke than with self-reported coronary heart disease: the relative odds (95\% CI) of heart failure, stroke, and coronary heart disease (upper versus lower AHI quartile) were 2.38 (1.22-4.62), 1.58 (1.02- 2.46), and 1.27 (0.99-1.62), respectively. These findings are compatible with modest to moderate effects of sleep-disordered breathing on heterogeneous manifestations of CVD within a range of AHI values that are considered normal or only mildly elevated.

}, keywords = {Aged, Cardiovascular Diseases, Cohort Studies, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Sleep Apnea Syndromes}, issn = {1073-449X}, doi = {10.1164/ajrccm.163.1.2001008}, author = {Shahar, E and Whitney, C W and Redline, S and Lee, E T and Newman, A B and Nieto, F J and O{\textquoteright}Connor, G T and Boland, L L and Schwartz, J E and Samet, J M} }