Showing papers by "Susan Redline published in 1997"

The Sleep Heart Health Study: design, rationale, and methods.

Abstract: The Sleep Heart Health Study (SHHS) is a prospective cohort study designed to investigate obstructive sleep apnea (OSA) and other sleep-disordered breathing (SDB) as risk factors for the development of cardiovascular disease. The study is designed to enroll 6,600 adult participants aged 40 years and older who will undergo a home polysomnogram to assess the presence of OSA and other SDB. Participants in SHHS have been recruited from cohort studies in progress. Therefore, SHHS adds the assessment of OSA to the protocols of these studies and will use already collected data on the principal risk factors for cardiovascular disease as well as follow-up and outcome information pertaining to cardiovascular disease. Parent cohort studies and recruitment targets for these cohorts are the following: Atherosclerosis Risk in Communities Study (1,750 participants), Cardiovascular Health Study (1,350 participants), Framingham Heart Study (1,000 participants), Strong Heart Study (600 participants), New York Hypertension Cohorts (1,000 participants), and Tucson Epidemiologic Study of Airways Obstructive Diseases and the Health and Environment Study (900 participants). As part of the parent study follow-up procedures, participants will be surveyed at periodic intervals for the incidence and recurrence of cardiovascular disease events. The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.

An Instrument to Measure Functional Status Outcomes for Disorders of Excessive Sleepiness

Abstract: This article reports the development of the functional outcomes of sleep questionnaire (FOSQ). This is the first self-report measure designed to assess the impact of disorders of excessive sleepiness (DOES) on multiple activities of everyday living. Three samples were used in the development and psychometric analyses of the FOSQ: Sample 1 (n = 153) consisted of individuals seeking medical attention for a sleep problem and persons of similar age and gender having no sleep disorder; samples 2 (n = 24) and 3 (n = 51) were composed of patients from two medical centers diagnosed with obstructive sleep apnea (OSA). Factor analysis of the FOSQ yielded five factors: activity level, vigilance, intimacy and sexual relationships, general productivity, and social outcome. Internal reliability was excellent for both the subscales (alpha = 0.86 to alpha = 0.91) and the total scale (alpha = 0.95). Test-retest reliability of the FOSQ yielded coefficients ranging from r = 0.81 to r = 0.90 for the five subscales and r = 0.90 for the total measure. The FOSQ successfully discriminated between normal subjects and those seeking medical attention for a sleep problem (T157 = -5.88, p = 0.0001). This psychometric evaluation of the FOSQ demonstrated parameters acceptable for its application in research and in clinical practice to measure functional status outcomes for persons with DOES. Thus, the FOSQ can be used to determine how disorders of excessive sleepiness affect patients' abilities to conduct normal activities and the extent to which these abilities are improved by effective treatment of DOES.

Racial differences in sleep-disordered breathing in African-Americans and Caucasians.

Abstract: In this case-control family study of sleep-disordered breathing (SDB), we describe the distributions of SDB and SDB risk factors in African-Americans and Caucasians. A total of 225 African-Americans and 622 Caucasians, ages 2 to 86 yr, recruited as members of families with an individual with known sleep apnea (85 index families) or as members of neighborhood control families (63 families) were studied with an overnight home sleep-study, questionnaires, and physical measurements. A subsample underwent cephalometry. Outcome measures were the respiratory disturbance index (RDI) and a binary variable indicating the presence of increased apneic activity (IAA). In both races, a strong relationship was demonstrated between the (log transformed) RDI and age and age2. African-Americans with SDB were younger than Caucasians with SDB (37.2 +/- 19.5 versus 45.6 +/- 18.7 yr, p < 0.01). In subjects < or = 25 yr, RDI level and IAA prevalence were higher in African-Americans (odds ratio, adjusted for obesity, sex, proban...

Characteristics of inner-city children with asthma: the National Cooperative Inner-City Asthma Study.

Abstract: Asthma morbidity has increased dramatically in the past decade, especially among poor and minority children in the inner cities. The National Cooperative Inner-City Asthma Study (NCICAS) is a multicenter study designed to determine factors that contribute to asthma morbidity in children in the inner cities. A total of 1,528 children with asthma, ages 4 to 9 years old, were enrolled in a broad-based epidemiologic investigation of factors which were thought to be related to asthma morbidity. Baseline assessment included morbidity, allergy evaluation, adherence and access to care, home visits, and pulmonary function. Interval assessments were conducted at 3, 6, and 9 months after the baseline evaluations. Over the one-year period, 83% of the children had no hospitalizations and 3.6% had two or more. The children averaged 3 to 3.5 days of wheeze for each of the four two-week recall periods. The pattern of skin test sensitivity differed from other populations in that positive reactions to cockroach were higher (35%) and positive reactions to house dust mite were lower (31%). Caretakers reported smoking in 39% of households of children with asthma, and cotinine/creatinine ratios exceeded 30 ng/mg in 48% of the sample. High exposure (> 40 ppb) to nitrogen dioxide was found in 24% of homes. Although the majority of children had insurance coverage, 53% of study participants found it difficult to get follow-up asthma care. The data demonstrate that symptoms are frequent but do not result in hospitalization in the majority of children. These data indicate a number of areas which are potential contributors to the asthma morbidity in this population, such as environmental factors, lack of access to care, and adherence to treatment. Interventions to reduce asthma morbidity are more likely to be successful if they address the many different asthma risks found in the inner cities.

Neuropsychological Function in Mild Sleep-Disordered Breathing

Abstract: Although a broad range of neuropsychological deficits has been reported in patients with severe sleep disordered breathing (SDB), little is known about the impact of mild SDB on neuropsychological performance. In this study, we compared neuropsychological test performance in two groups of carefully screened volunteers who differed clearly according to the respiratory disturbance index (RDI). Controls (n = 20) were identified on the basis of an RDI < 5; cases (n = 32) had an RDI in the range of 10-30. Cases and controls were well matched with regard to IQ, age, and sex. Cases had significantly more self-reported snorting and apneas and a higher body mass index than controls but did not differ according to sleepiness as measured by either the multiple sleep latency test or the Epworth sleepiness scale. An extensive battery of neuropsychological and performance tests was administered after an overnight sleep study. Cases performed significantly more poorly on a visual vigilance task (perceptual sensitivity, d': 2.24 +/- 0.64 vs. 2.70 +/- 0.53, p = 0.01, for cases and controls, respectively) and a test of working memory, the Wechsler adult intelligence scale-revised digits backwards test (6.12 +/- 2.20 vs. 7.55 +/- 2.22, p = 0.02), than controls. The groups did not differ in their performance on other tests of memory, information processing, and executive functioning. In summary, subjects with mild SDB may manifest a vigilance deficit in the absence of substantial sleepiness. Subjects with a mildly elevated RDI (10-30) without sleepiness do not appear to suffer appreciable deficits in more complex neuropsychological processes (e.g. executive functions).

Hypopnea, a floating metric: Implications for prevalence, morbidity estimates, and case finding

Abstract: The respiratory disturbance index (RDI) is the most frequently used metric to characterize sleep-disordered breathing. Clinically, the RDI is used to classify disease status and guide treatment decisions. For research purposes, the RDI is used to describe population distributions of sleep-disordered breathing. Its popularity as a cardinal disease-defining measure, however, may not be justified given that standardized criteria do not exist for defining hypopnea, a key component of the RDI. This paper reviews sources of variability in identifying hypopneas, including: the magnitude of changes in breathing amplitude necessary to describe breathing as "reduced" (from "discernible" to >50%), variations in the utilization of sensors with different sensitivities to detect airflow/ventilation (i.e. thermocouples, thermistors, and pressure transducers), and differential use of data on oxygen saturation and arousals to discriminate normal breathing from hypopneas. The extent to which disparate approaches influence the overall RDI and population estimates of disease also is discussed.

Ventilatory-control Abnormalities in Familial Sleep Apnea

Abstract: The role of ventilatory-control abnormalities in predisposing to familial sleep-disordered breathing (SDB) was assessed in 31 subjects 28 ± 10 yr of age (mean ± SD). Subjects with (n = 10) and without SDB (n = 12) were recruited from 13 families having two or more members with SDB. Nine age- and gender-matched controls were recruited from families having no member with SDB. Respiratory responses to eucapnic hypoxia, and ventilatory and occlusion pressure responses to hyperoxic hypercapnia with and without added resistive loads (6.5 cm H2O/L/s), were assessed through rebreathing. Age, FEV1, and FVC did not differ among the groups. Hypoxic responses ( Δ Ve/ Δ SaO2 ) were significantly lower among the first-degree relatives of SDB families than among controls ( − 0.76 ± 0.47 L/min/% SaO2 , and − 1.32 ± 0.92 L/min/% SaO2 , respectively, p < 0.05). Respiratory responses to hypercapnia during unloaded conditions were similar among the groups. With resistive loading, inspiratory impedance, as measured through th...

Health care delivery in a sleep center.

Abstract: This report presents and describes measures developed for the tracking of care provided to patients referred for evaluation to a sleep clinic and center in a U.S. federal health facility. We provide qualitative and quantitative indicators, tracked for a two-year period of time, for system management, information flow, measures of consultation and subsequent identification of apneic activity (Respiratory Disturbance Index > 10) and treatment for sleep apnea, and the satisfaction with diagnostic testing and treatment. Measures of laboratory efficiency were generally stable, except for the time from the clinic visit to PSG and the time from PSG interpretation to the final written report. We have some evidence that patient satisfaction with CPAP/BiLevel care may vary with a change in a home health care provider. Also, there was a surprisingly high rate of replacement of masks during nasal CPAP therapy. Results indicate the feasibility of such an approach and identify certain areas for improvement in process and communication relevant to the management of sleep disordered breathing.

A depressing state of knowledge.

Abstract: Authors address: Susan Redhne, MD, MPH; Associate Professor of Medicine, Case Western Reserve School of Medicine, Cleveland, OH; 10701 East Blvd Cleveland OH 44106, Phone 216-791-3800, x5175 Fax 216-231-3420 Mood disturbances, particularly depression, are thought to be among the most troublesome consequences of sleep disordered breathing, impairing quality of life. This conclusion is based on studies of patients with predominantly severe sleep apnea referred to speciality laboratories. Among 50 patients with sleep apnea severe enough to warrant tracheostomy, 56%, 35% and 29% demonstrated findings consistent with depression, hypochondriasis, and conversion-hysteria, respectively [1]. Depression also has been demonstrated in > 25% of patients with sleep apnea who were the subjects of 2 other studies [2, 3]. Depression appears to be greater in those subjects with more severe sleep apnea (3). It has been postulated that such mood changes may be due to sleepiness and impaired neurocognitive functions associated hypoxemia and/or sleep fragmentation. One beneficial effect of treating patients for sleep apnea may be reversal of depression, as has been reported anecdotally [4] and in small studies [5, 6]. The article by Husain and colleagues in this month's journal also reports a high prevalence of depression, assessed by the Beck Depression Inventory, in patients referred to a Sleep Disorders Clinic (found in 29% of patients, regardless of specific presenting symptoms/ disease.) Interestingly, within the group that also had polysomnography, depression was no grater among those with more sleep apnea. However, grater obesity was more common in the depressed subjects. This report points to two problems that have been common in studies of sleep apnea and have limited our understanding of the morbidity that can be attributed specifically to this condition. The first is the problem interpreting morbidity patterns in patients referred to a sleep center, referral patterns are influenced by local practice patterns as well as by the local understanding and interpretations of diseaseeffect relationships. The perceived consequences of a disease will influence which types of patients are referred for further evaluation. This may change over time as differences in local \"medical culture\". The second problems relates to complicated patterns of co-morbidity found in sleep apnea patients. The high prevalence of obesity and underlying cardiopulmonary disorders makes interpreting the independent effects Stimmungsst6rungen, insbesondere Depressionen, werden zu den schlimmsten Folgen schlafbezogener Atembehinderungen gez~hlt, weil sie die Lebensqualit~t beeintr~chtigen. Diese Folgerung basiert auf Untersuchungen von Patienten in Schlaflabors, in die sie vorwiegend wegen schwerer Schlafapnoe 0berwiesen worden waren. Von 50 Patienten mit so schwerer Schlafapnoe, dal~ for sie eine Tracheostomie gerechtfertigt war, fanden sich bei 56% diagnostische Befunde von Depression, bei 35% solche von Hypochondrie und bei 29% Befunde einer Konversionshysterie [1]. Depression wurde auch in zwei weiteren Studien bei >25% der Patienten mit Schlafapnoe nachgewiesen [2, 3]. Die Depression scheint bei Patienten mit schwerer Schlafapnoe ebenfalls schwerer zu sein [3]. Es wurde postuliert, dai~ solche Ver~inderungen der seelischen Stimmungslage auf Schl~frigkeit und beeintr~ichtigten neurokognitiven Funktionen infolge von Hypox~mie und/oder fragmentiertem Schlaf beruhen d0rfte. Eine g0nstige Wirkung der Behandlung yon Schlafapnoepatienten k6nnte somit die Behebung einer Depression sein, wie sowohl anekdotisch [4] als auch yon kleinen Studien [5, 6] berichtet wird. Der Beitrag yon Husain und Kollegen in dieser Ausgabe der Zeitschrift berichtet auch von einer hohen Rate von Depressionen bei Patienten, die in einer Klinik for Schlafst6rungen mit Hilfe des Beckschen Depressionstests ermittelt wurde. Die Depression bestand bei 29% der untersuchten Schlafpatienten, unabh~ngig von den spezifischen Symptomen bzw. Erkrankungen. Interessanterweise war innerhalb der Gruppe derer, die polysomnographisch untersucht wurden, die Depression bei denen mit st~rkerem Schlafapnoesyndrom nicht vermehrt gegeben. Hingegen war st~rkere Korpulenz bei den Depressiven allgemeiner. Dieser Bericht weist auf zwei Probleme hin, die sich in Untersuchungen der Schlafapnoe immer wieder zeigen und unser Verst~ndnis der Morbidit~t begrenzen, die spezifisch dieser Kondition zugeordnet werden kann. Zum einen ist es das Problem, dal~ die Interpretation der Morbidit~itsmuster auf Patienten beschr~nkt bleibt, die an Schlafzentren 0berwiesen werden. 0berweisungspatienten stehen unter dem Einflul~ sowohl