Faculty Bibliography

OBJECTIVES: To evaluate insomnia symptoms and the extent to which they are associated with clinical and demographic patient characteristics, daytime symptoms, and functional performance in patients with stable heart failure (HF). DESIGN: Cross-sectional, observational. SETTING: Five structured HF disease management programs in the Northeastern U.S. PARTICIPANTS: 173 stable chronic HF patients INTERVENTIONS: N/A MEASUREMENTS AND RESULTS: Full polysomnography was obtained for one night in participants' homes. Participants completed the six-minute walk test, Medical Outcomes Study SF-36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, Centers for the Epidemiological Studies of Depression Scale, and questionnaire items eliciting insomnia symptoms (self-reported difficulty initiating and maintaining sleep and waking too early in the morning). Over half of HF patients reported insomnia symptoms. These were associated with increased daytime symptoms (depression, fatigue), excessive daytime sleepiness, and functional performance in models that statistically controlled for clinical and demographic covariates. These relationships were not explained by sleep disordered breathing. CONCLUSIONS: Insomnia symptoms are common in patients with stable heart failure and are associated with daytime symptoms and decrements in functional performance

RATIONALE: The impact of REM-predominant sleep-disordered breathing (SDB) on sleepiness, quality of life (QOL), and sleep maintenance is uncertain. OBJECTIVE: To evaluate the association of SDB during REM sleep with daytime sleepiness, health-related QOL, and difficulty maintaining sleep, in comparison to their association with SDB during non-REM sleep in a community-based cohort. METHODS: Cross-sectional analysis of 5,649 Sleep Heart Health Study participants (mean age 62.5 [SD = 10.9], 52.6% women, 22.6% ethnic minorities). SDB during REM and non-REM sleep was quantified using polysomnographically derived apnea-hypopnea index in REM (AHI(REM)) and non-REM (AHI(NREM)) sleep. Sleepiness, sleep maintenance, and QOL were respectively quantified using the Epworth Sleepiness Scale (ESS), the Sleep Heart Health Study Sleep Habit Questionnaire, and the physical and mental composites scales of the Medical Outcomes Study Short Form (SF)-36. MEASUREMENTS AND MAIN RESULTS: AHI(REM) was not associated with the ESS scores or the physical and mental components scales scores of the SF-36 after adjusting for demographics, body mass index, and AHI(NREM) x AHI(REM) was not associated with frequent difficulty maintaining sleep or early awakening from sleep. AHI(NREM) was associated with the ESS score (beta = 0.25; 95% confidence interval [CI], 0.16 to 0.34) and the physical (beta = -0.12; 95% CI, -0.42 to -0.01) and mental (beta = -0.20; 95% CI, -0.20 to -0.01) components scores of the SF-36 adjusting for demographics, body mass index, and AHI(REM). CONCLUSIONS: In a community-based sample of middle-aged and older adults, REM-predominant SDB is not independently associated with daytime sleepiness, impaired health-related QOL, or self-reported sleep disruption

The symptoms of chronic fatigue syndrome (CFS) are consistent with cytokine dysregulation. This has led to the hypothesis of immune dysregulation as the cause of this illness. To further test this hypothesis, we did repeated blood sampling for cytokines while patients and matched healthy controls slept in the sleep lab. Because no one method for assaying cytokines is acknowledged to be better than another, we assayed for protein in serum, message in peripheral blood lymphocytes (PBLs), and function in resting and stimulated PBLs. We found no evidence of proinflammatory cytokine upregulation. Instead, in line with some of our earlier studies, we did find some evidence to support a role for an increase in interleukin-10, an anti-inflammatory cytokine. Although the changes were small, they may contribute to the common complaint in CFS patients of disrupted sleep.

STUDY OBJECTIVES: To evaluate characteristics of sleep disordered breathing (SDB); clinical and demographic correlates of SDB; and the extent to which SDB explains functional performance and symptoms in stable heart failure patients receiving care in structured HF disease management programs. DESIGN: Cross-sectional, observational study. SETTING: Structured heart failure disease management programs. PARTICIPANTS: 170 stable chronic heart failure patients (mean age = 60.3 +/- 16.8 years; n = 60 [35%] female; n = 50 [29%] African American; left ventricular ejection fraction mean = 32 +/- 14.6). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Full polysomnography was obtained for one night on participants in their homes. Participants completed the 6-minute walk, 3 days of actigraphy, MOS-SF 36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, and the Centers for the Epidemiological Studies of Depression Scale. Fifty-one percent had significant SDB; Sixteen (9%) of the total sample had central sleep apnea. Severe SDB was associated with a 4-fold increase in the likelihood of poor self-reported physical function (OR = 4.15, 95%CI = 1.19-14.57) and CSA was associated with low levels of daytime mobility (OR = 4.09, 95%CI = 1.23-13.62) after controlling for clinical and demographic variables. There were no statistically significant relationships between SDB and daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB. CONCLUSIONS: Severe SDB is associated with poor physical function in patients with stable HF but not with daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

STUDY OBJECTIVES: We examined agreement among multiple sleep clinicians when presented with clinical data plus the full tracings and data obtained from unattended limited monitoring (ULM) or a full polysomnography (PSG). METHODS: Subjects included 66 patients with complaints of sleep disordered breathing (SDB) and 19 volunteers willing to undergo 2 nights of ULM followed by PSG. Two assessment packages were created for each subject with identical clinical history (Hx) and ARES Symptom Questionnaire, plus the electronic record of signals collected on the ARES Unicorder (Hx+ULM) or on the PSG (Hx+PSG). Data were presented to 4 sleep-trained clinicians for diagnosis and treatment recommendation. For agreement on diagnosis and treatment, comparisons were made between clinicians using ULM or PSG, and within clinicians comparing both techniques. RESULTS: For diagnosis, agreement between pairs of clinicians using Hx+PSG ranged from 74% to 86% and 66% to 85% when using Hx+ULM. For treatment, agreement using Hx+PSG ranged from 74% to 86% and 58% to 77% when using Hx+ULM. Agreement between clinicians was highest in the subjects with the highest RDI and fell off markedly at the lowest RDI, irrespective of whether the clinicians used the Hx+PSG or Hx+ULM. This pattern was also seen for the decisions made by an individual clinician using Hx+ULM vs. Hx+PSG. CONCLUSION: Our data show that sleep clinicians have significant disagreements for diagnosis even when presented with the 'gold standard' of a PSG and clinical data. Agreement was high when the SDB index was elevated and lower when the SDB index was in the mild-to-moderate range, regardless of the technique used to obtain it

STUDY OBJECTIVES: To evaluate the use of sham-continuous positive airway pressure (CPAP) treatment as a placebo intervention. DESIGN AND SETTING: Analysis of polysomnograms performed in fixed order without sham-CPAP and on the first night of the sham-CPAP intervention in participants in the CPAP Apnea Trial North American Program (CATNAP), a randomized, placebo controlled trial evaluating the effects of CPAP treatment on daytime function in adults with newly diagnosed mild to moderate obstructive sleep apnea (apnea hypopnea index (AHI) 5-30). PARTICIPANTS: The first 104 CATNAP participants randomized to the sham-CPAP intervention arm. MEASUREMENTS AND RESULTS: Compared to the polysomnographic measures without sham-CPAP, the study on the first night with sham-CPAP had statistically significant differences that suggested a decrease in sleep quality: decreased sleep efficiency, increased arousal index, increased time in stage 1 NREM sleep, and prolonged latency to REM sleep. However, all of these differences had a relatively small effect size. Compared to the polysomnogram without sham-CPAP, the number of hypopneas on the sham-CPAP polysomnogram was significantly increased and the number of apneas significantly decreased. Relatively minor differences in AHI with and without sham-CPAP were present and were dependent on the criteria used to score hypopneas. CONCLUSION: Comparison of polysomnograms with and without sham-CPAP revealed differences that, although statistically significant, were small in magnitude and had relatively low effect sizes suggesting minimal clinical significance. The results support the use of sham-CPAP as a placebo intervention in trials evaluating the effects of CPAP treatment in patients with obstructive sleep apnea. CLINICAL TRIAL INFORMATION: This paper was a secondary analysis of clinical trial data. CATNAP: CPAP Apnea Trial North American Program, the trial from which the data were obtained, is registered with clinicaltrial.gov. Registration #NCT00089752