Diabetes sleep treatment trial: Premise, design, and methodology

Risk stratification by sex and menopausal status in the multivariable apnea prediction index

STUDY OBJECTIVES

To determine the sensitivity of the Multivariable Apnea Prediction (MAP) index for obstructive sleep apnea (OSA) in pre- and post-menopausal women with the goal of developing a tailored scoring classification approach.

METHODS

Data from two studies (N = 386); the diabetes sleep treatment trial (N = 236) and EMPOWER (N = 150) were used to assess the sensitivity and specificity of the MAP index by comparing men (n = 129) to women (n = 257), and premenopausal (n = 100) to post-menopausal women (n = 136). We evaluated participants at two cut points, apnea-hypopnea index (AHI) values of ≥ 5 and ≥ 10, using 0.5 as a predicted probability cut point to establish baseline sensitivity and specificity. Contingency tables and receiver operating characteristic (ROC) analysis were conducted to evaluate the accuracy of the MAP index in predicting OSA in men versus women, and in pre-versus post-menopausal women. To select optimal predicted probabilities for classification by sex and menopausal status, Youden's J statistic was generated from ROC coordinates.

RESULTS

The MAP index was more sensitive to women in the AHI ≥ 5 group (76%) compared to AHI ≥ 10 group (30%). Among post-menopausal women with AHI ≥ 5, sensitivity was similar to men (98%), but less than men when AHI ≥ 10 (32%). Suggested probability cut points for women with an AHI ≥ 10 are 0.24 overall; 0.15 for premenopausal, and 0.38 for postmenopausal women.

CONCLUSIONS

Because women's risk for OSA (AHI ≥ 10) was underestimated by the MAP index, we suggest the use of tailored cut points based on sex and menopausal status or assessing for OSA risk with an AHI of ≥ 5.

Financial Hardship and its Associations with Perceived Sleep Quality in Participants with Type 2 Diabetes and Obstructive Sleep Apnea

OBJECTIVES

The purpose of this study was to explore social determinants of health (SDoH), and disease severity as predictors of sleep quality in persons with both Obstructive Sleep Apnea (OSA) and type 2 diabetes (T2D).

METHODS

Disease severity was measured by Apnea-Hypopnea Index [(AHI) ≥ 5] and HbA1c for glycemic control. SDoH included subjective and objective financial hardship, race, sex, marital status, education, and age. Sleep quality was measured by Pittsburgh Sleep Quality Index (PSQI).

RESULTS

The sample (N = 209) was middle-aged (57.6 ± 10.0); 66% White and 34% African American; and 54% men and 46% women. Participants carried a high burden of disease (mean AHI = 20.7 ± 18.1, mean HbA1c = 7.9% ± 1.7%). Disease severity was not significantly associated with sleep quality (all p >.05). Worse sleep quality was associated with both worse subjective (b = -1.54, p = .015) and objective (b = 2.58, p <.001) financial hardship. Characteristics significantly associated with both subjective and objective financial hardship included being African American, female, ≤ 2 years post high school, and of younger ages (all p < .01).Discussion: Financial hardship is a more important predictor of sleep quality than disease severity, age, sex, race, marital status, and educational attainment, in patients with OSA and T2D.

Effects of continuous positive airway pressure treatment on sleep architecture in adults with obstructive sleep apnea and type 2 diabetes

Obstructive sleep apnea (OSA) severely impacts sleep and has long-term health consequences. Treating sleep apnea with continuous positive airway pressure (CPAP) not only relieves obstructed breathing, but also improves sleep. CPAP improves sleep by reducing apnea-induced awakenings. CPAP may also improve sleep by enhancing features of sleep architecture assessed with electroencephalography (EEG) that maximize sleep depth and neuronal homeostasis, such as the slow oscillation and spindle EEG activity, and by reducing neurophysiological arousal during sleep (i.e., beta EEG activity). We examined cross-sectional differences in quantitative EEG characteristics of sleep, assessed with power spectral analysis, in 29 adults with type 2 diabetes treated with CPAP and 24 adults undergoing SHAM CPAP treatment (total n = 53). We then examined changes in spectral characteristics of sleep as the SHAM group crossed over to active CPAP treatment (n = 19). Polysomnography (PSG) from the CPAP titration night was used for the current analyses. Analyses focused on EEG frequencies associated with sleep maintenance and arousal. These included the slow oscillation (0.5–1 Hz), sigma activity (12–16 Hz, spindle activity), and beta activity (16–20 Hz) in F3, F4, C3, and C4 EEG channels. Whole night non-rapid eye movement (NREM) sleep and the first period of NREM spectral activity were examined. Age and sex were included as covariates. There were no group differences between CPAP and SHAM in spectral characteristics of sleep architecture. However, SHAM cross-over to active CPAP was associated with an increase in relative 12–16 Hz sigma activity across the whole night and a decrease in average beta activity across the whole night. Relative slow oscillation power within the first NREM period decreased with CPAP, particularly for frontal channels. Sigma and beta activity effects did not differ by channel. These findings suggest that CPAP may preferentially enhance spindle activity and mitigate neurophysiological arousal. These findings inform the neurophysiological mechanisms of improved sleep with CPAP and the utility of quantitative EEG measures of sleep as a treatment probe of improvements in neurological and physical health with CPAP.

Metabolic outcomes in adults with type 2 diabetes and sleep disorders

PURPOSE

Insomnia is frequently co-morbid with obstructive sleep apnea (OSA); the effect of insomnia or co-morbid insomnia and OSA (OSA + I) on associated metabolic outcomes in adults with type 2 diabetes (T2D) remains unclear. This study in adults with T2D compared metabolic outcomes among persons with OSA, insomnia, or OSA + I.

METHODS

This study analyzed baseline data from the Diabetes Sleep Treatment Trial of persons recruited for symptoms of OSA or poor sleep quality. Home sleep studies determined OSA presence and severity. Insomnia was evaluated using the Insomnia Severity Index. Height and weight to calculate body mass index (BMI) and blood for laboratory values were obtained. Multivariate general linear models were used to examine the impact of the type of sleep disorder and sociodemographic, lifestyle, and sleep risk factors on metabolic outcomes.

RESULTS

Participants (N = 253) were middle-aged (56.3 ± 10.5 years), white (60.5%), obese (mean BMI of 35.3 ± 7.1 kg/m²), and male (51.4%) with poor glucose control (mean HbA1c of 8.0 ± 1.8%). Most participants had OSA + I (42.7%) or insomnia only (41.0%). HbA1c and BMI differed among the sleep disorder groups. In addition, in the adjusted models, having insomnia only, compared to OSA only, was associated on average with higher HbA1c levels (b = 1.08 ± 0.40, p < 0.007) and lower BMI (b =  - 7.03 ± 1.43, p < 0.001).

CONCLUSIONS

Findings suggest that insomnia frequently co-exists with OSA, is independently associated with metabolic outcomes in adults with T2D, and should be considered in investigations of the effects of OSA in persons with T2D.

TRIAL REGISTRATION

Diabetes-Obstructive Sleep Apnea Treatment Trial (NCT01901055), https: Clinicaltrials.gov/ct2/show/NCT01901055; Registration date: July 17, 2013.

Comorbid obstructive sleep apnea and insomnia and its associations with mood and diabetes-related distress in type 2 diabetes mellitus

STUDY OBJECTIVES

Previous research suggests that obstructive sleep apnea (OSA) and insomnia frequently co-exist and are prevalent in persons with type 2 diabetes mellitus (T2DM). This study compared mood and diabetes-related distress among OSA, insomnia, and comorbid OSA and insomnia (OSA+I) groups in persons with T2DM.

METHODS

A secondary analysis was conducted with baseline data from two independent randomized controlled trials evaluating the efficacy of OSA and insomnia treatment. The pooled sample (N=224) included participants with OSA only (n=68 [30.4%]), insomnia only (n=107 [47.8%]), and OSA and insomnia (OSA+I; n=49 [21.9%]). OSA was defined as an apnea-hypopnea index ≥ 15 events per hour; insomnia defined as an Insomnia Severity Index score ≥ 15. Mood was measured by the Profile of Mood States total and subscale scores; diabetes-related distress was assessed by the Problem Areas in Diabetes. One-way analysis of covariance and multivariate analysis of covariance were conducted, controlling for demographic characteristics and restless leg syndrome.

RESULTS

The insomnia group had on average significantly higher scores for total mood disturbance (insomnia vs. OSA= 45.32 vs. 32.15, p=.049), tension-anxiety (insomnia vs. OSA= 12.64 vs. 9.47, p=.008), and confusion-bewilderment (insomnia vs. OSA= 9.45 vs. 7.46, p=.036) than OSA group. The OSA+I group had on average significantly greater diabetes-related distress than OSA group (OSA+I vs. OSA= 40.61 vs. 30.97, p=.036).

CONCLUSIONS

Insomnia may have greater impact on mood disturbance and diabetes-related distress than OSA in persons with T2DM. In particular, comorbid insomnia may contribute to greater diabetes-related distress in persons with T2DM and OSA.

Age-Related Differences in Mood, Diabetes-Related Distress, and Functional Outcomes in Adults With Type 2 Diabetes Mellitus and Comorbid Obstructive Sleep Apnea and Insomnia

PURPOSE

The purpose of this study was to examine age-related differences in mood, diabetes-related distress, and functional outcomes in activities sensitive to impaired sleep in adults with type 2 diabetes mellitus (T2DM) and comorbid obstructive sleep apnea (OSA) and insomnia. This study also evaluated the associations of age, insomnia severity, and OSA severity on outcome variables.

METHODS

This study was a secondary analysis of pooled baseline data from 2 randomized controlled trials among adults with T2DM with symptoms of sleep disorders (N = 145,109 younger adults, 36 older adults; 46.2% male; 67.6% white). Comorbid OSA and insomnia was defined as Apnea-Hypopnea Index ≥5 events per hour and Insomnia Severity Index ≥10. Outcome variables included mood, diabetes-related distress, and functional outcomes.

RESULTS

Older adults reported better mood, lower diabetes-related distress, and higher functional outcomes relative to younger adults (all Ps < .05). Insomnia severity was associated with worse mood (b = 2.59, P < .001) and diabetes-related distress (b = 1.40, P < .001) and lower functional outcome (b = -0.22, P < .001). Older age was associated with lower diabetes-related distress (b = -0.44, P = .040).

CONCLUSION

Older age was a protective factor of mood disturbance, diabetes-related distress, and functional impairment in adults with T2DM and comorbid OSA and insomnia. Insomnia severity was associated with greater mood disturbance, diabetes-related distress, and functional impairment when OSA and insomnia coexist. The results suggest that diabetes care and education specialists should assess patients for impaired sleep.

Sex differences in subjectively reported symptoms of obstructive sleep apnea in community-dwelling adults with type 2 diabetes

BACKGROUND

Reports of sex differences in self-reported mood, sleep quality, daytime function, and excessive daytime sleepiness in people with obstructive sleep apnea (OSA) have been inconsistent. The purpose of this study was to investigate sex differences in these subjective sleep outcomes in participants with type 2 diabetes (T2D) either at high risk for OSA or diagnosed with OSA.

METHODS

Measures included OSA severity by apnea-hypopnea index (AHI) and self-reported questionnaires: Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), functional outcomes of sleep quality questionnaire (FOSQ), and the profile of mood states (POMS). Relevant individual, social, and health determinants were included as covariates.

RESULTS

A total of 350 participants with T2D [Mean A1C 8.0% (SD ±1.8)] had mean age 56.5 (SD ±10.5) and were balanced by sex (51% men) and race (60% white, 40% non-white). Reports of sleep quality and daytime function were worse in women than in men (p <0.05), whereas men had more severe OSA than women (p <0.05). In fully adjusted models, there was no moderation by sex in the relations between AHI and the sleep outcome measures. AHI showed a significant association with ESS but not PSQI, FOSQ, or POMS.

CONCLUSION

In participants with T2D at high risk for or diagnosed with OSA, excessive daytime sleepiness was independently associated with OSA severity, but not self-reported sleep quality, daytime function, or mood. While women reported worse outcomes associated with sleep, these outcomes were not associated with OSA severity.

HMGB1/TLR4 promotes apoptosis and reduces autophagy of hippocampal neurons in diabetes combined with OSA

AIMS

Obstructive sleep apnea (OSA) combined with type 2 diabetes (T2DM) may lead to cognitive dysfunction. We previously reported that cognitive impairment is exacerbated in KKAy mice exposed to intermittent hypoxia (IH), during which the DNA binding protein HMGB1 mediates hippocampal neuronal apoptosis by maintaining microglia-associated neuroinflammation, but the underlying mechanism remains largely unknown.

MATERIALS AND METHODS

We performed immunofluorescence, Western blotting, and immunohistochemistry experiments in mouse hippocampal tissues and HT22 cells. KKAy type 2 diabetes model mice and normal C57BL/6J mice were exposed to IH or intermittent normoxia. HT22 cells were cultured in high glucose medium and exposed to IH or intermittent normoxia. We transfected HMGB1 siRNA into HT22 cells and then treated them with high glucose combined with intermittent hypoxia.

KEY FINDINGS

In conclusion, IH aggravated apoptosis and autophagy defects in T2DM mice, and increased the protein expression of HMGB1 and TLR4. This was also confirmed in HG + IH-treated hippocampal HT22 cells. HMGB1 siRNA can significantly reduce the protein expression of HMGB1 and TLR4, reverse neuronal apoptosis and enhance autophagy.

SIGNIFICANCE

We believe that HMGB1 is a key factor in the regulation of hippocampal neuronal apoptosis and autophagy defects in T2DM combined with OSA. Targeting HMGB1/TLR4 signaling as a novel approach may delay or prevent the increased apoptosis and decreased autophagy induced by T2DM combined with OSA, and may ultimately improve cognitive dysfunction.

Current Smoking: An Independent Predictor of Elevated A1C in Persons With Type 2 Diabetes

Purpose

The purpose of this study is to examine the association of current smoking as one of several potential predictors of elevated A1C in adults with type 2 diabetes (T2D).

Methods

Using a cross-sectional design, baseline data (N = 282) were analyzed from a randomized clinical trial examining treatment of obstructive sleep apnea in persons with T2D. Sociodemographic, clinical, and behavioral data were collected using questionnaires and physical examinations. Physical activity (mean daily steps walked) was measured with the BodyMedia Armband. Participants were asked if they never smoked, had previously smoked, or currently smoke. The sample distributions of demographic and clinical characteristics were examined using descriptive statistics. Continuous variables were described using means and standard deviations; categorical variables were described as numbers and percentages. Multiple linear regression analysis with backward selection was conducted to develop a parsimonious predictive model for the dependent variable A1C.

Results

Participants were generally middle-aged and, on average, obese with suboptimal blood glucose control; almost 1 of every 5 participants currently smoked. After controlling for age, race, education, financial difficulty, diabetes education, physical activity, and diabetes knowledge, 4 variables were found in the final model to be independently associated with higher A1C: (1) current smoking status, (2) younger age, (3) longer diabetes duration, and (4) higher diabetes-related distress.

Conclusions

The study found that not only is smoking prevalent among persons with T2D with self-reported sleep problems but smoking is also an independent predictor of elevated A1C. The results highlight the vital role diabetes educators have in promoting risk reduction through education and support for smoking cessation.

DNA methylation changes and improved sleep quality in adults with obstructive sleep apnea and diabetes

OBJECTIVE

Obstructive sleep apnea (OSA) is common among adults with diabetes. However, little is known about the impact of OSA treatment on DNA methylation levels. The purpose of this study is to explore changes in DNA methylation levels among adults with these conditions enrolled in a randomized controlled trial.

RESEARCH DESIGN AND METHODS

Participants were randomized to continuous positive airway pressure (CPAP) treatment or sham-CPAP placebo for 12 weeks. All participants received diabetes education and counseling. At baseline and 12 weeks, white blood cell DNA methylation levels for five candidate genes (ANGPTL4, DAPK3, KAT5, PER1, and TNFAIP3) and hemoglobin A1C (A1C) levels were obtained from blood. The Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS) assessed sleep quality and daytime sleepiness, respectively. T-tests examined within-subject changes from baseline to 12 weeks. Regression analyses explored associations between DNA methylation changes and baseline variables, minutes of therapeutic CPAP use, and changes in A1C levels, PSQI scores, and ESS scores.

RESULTS

Participants (n=10) were 70% female, 80% white, and 61.7±7.9 years old. Among all participants from baseline and 12 weeks, TNFAIP3 and PER1 DNA methylation levels decreased. At baseline, PER1 methylation levels were significantly higher in males and sex-based difference in methylation level changes was observed from baseline to 12 weeks. Changes in DNA methylation levels were not associated with minutes of therapeutic CPAP use or changes in A1C, PSQI scores, and ESS scores.

CONCLUSIONS

While DNA methylation level changes were observed in the study, the causal mechanism is unclear and additional work is needed. Although the methylation changes were small, the long-term effects are unknown.