Effect of one week of CPAP treatment of obstructive sleep apnoea on 24-hour profiles of glucose, insulin and counter-regulatory hormones in type 2 diabetes

The benefits of hypoglycemic therapy for patients with obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) is often associated with glycemic abnormalities. This study is conducted to investigate the effects of hypoglycemic therapy on OSA-related indicators.

METHOD

We systematically searched Web of Science, PubMed, Embase, and the Cochrane Library for articles on OSA patients receiving any hypoglycemic drugs, published until December 25, 2022. Seven original studies were finally included. The proposal was registered with PROSPERO (CRD42022351206).

RESULTS

In summary, in addition to reduced glycosylated hemoglobin A1c (HbA1c), we found that hypoglycemic treatment can lower the apnea-hypopnea index (AHI) by 7.07/h (p = 0.0001). Although long-term treatment (> 12 weeks) achieved a more significant reduction in HbA1c (- 1.57% vs. - 0.30%) compared to short-term treatment (≤ 12 weeks), there was no significant difference between the two in terms of AHI (intergroup p-value = 0.27). We also found that patients using sodium glucose cotransporter 2 inhibitors (SGLT2i) experienced a greater reduction in AHI (- 11.00/h, p < 0.00001). Additionally, hypoglycemic treatment also showed certain improvements in related indicators like Epworth Sleepiness Scale, body mass index, and blood pressure.

CONCLUSIONS

Our results affirm the benefits of hypoglycemic treatment for OSA patients and highlight the notable effect of SGLT2i. Further researches are needed to help doctors gain a comprehensive understanding of the interaction between OSA and glycemic abnormalities.

[Relationship between obstructive sleep apnea and type 2 diabetes mellitus]

INTRODUCTION

The association between obstructive sleep apnea (OSA) and glucose metabolism remains controversial. This study investigates the relationship between OSA and incident type 2 diabetes (DM) and prediabetes (preDM), as well as the effect of long-term CPAP (continuous positive airway pressure) treatment.

METHODS

Follow-up study in a retrospective clinical cohort of patients with OSA and randomly selected controls. Data on incident DM and preDM as well as CPAP were obtained from hospital records. The relationship between baseline OSA and incident DM was examined using COX regression models.

RESULTS

Three hundred and fifty-six patients, 169 with OSA and 187 controls were followed for a median of 98 months; 47 patients (13.2%) developed DM and 43 (12.1%) developed preDM. The 5-year cumulative incidence of DM was 10.7% (6.5-13.9%). 87% of subjects with preDM in the baseline sample progressed to incident DM. It is shown that body mass index (BMI), nocturnal hypoxia and apnea hypopnea index (AHI) are risk factors for the development of DM and that CPAP reduces this risk.

CONCLUSIONS

Patients with OSA have a higher risk of developing DM. The risk factors involved are BMI, nocturnal hypoxia and AHI. Regular long-term CPAP use was associated with a decreased risk.

Veterans' Experiences of Support in Managing Comorbid Sleep Apnea and Type 2 Diabetes

BACKGROUND

Obstructive sleep apnea (OSA) is highly prevalent in patients with Type 2 diabetes, more so in veterans compared with nonveterans. Positive airway pressure is the recommended first-line treatment for OSA. However, adherence to both positive airway pressure and diabetes management regimens can be challenging for older adults. Support from family or friends may improve glucose control or sleep-apnea-related symptoms, yet the evidence is limited when both conditions coexist.

OBJECTIVES

This study aimed to describe veterans' experiences of support from family and friends with managing comorbid sleep apnea and Type 2 diabetes.

METHODS

We conducted a postal survey of older veterans with OSA and Type 2 diabetes from one healthcare system. Questions include demographic and health-related information, information about sleep apnea and diabetes treatment and education received, related support from family or a friend, perceived benefits of regular positive airway pressure device use on improving sleep health, and perceived benefits of education for family or a friend on sleep apnea and diabetes. Descriptive and bivariate analyses were performed.

RESULTS

Of 145 respondents (mean age = 72 years), 43% reported receiving help for Type 2 diabetes from family or a friend. Almost two thirds of the respondents were currently using a positive airway pressure device, of whom 27% received support with device use from family or friends. About one third of veterans perceived family and friends receiving education on treating sleep apnea and diabetes to be very or extremely helpful. Such perceived benefit was higher among those who were married or identified as non-White. Veterans using a positive airway pressure device had lower hemoglobin A1c levels than nonusers.

DISCUSSION

Veterans perceived that additional education for the individuals providing support would be beneficial. Future studies could address interventions to increase sleep apnea and Type 2 diabetes knowledge among families and friends of veterans with these comorbid conditions. In addition, patients' adherence to positive airway pressure may be enhanced by support from family and friends.

Role of chemosensitivity: Possible pathophysiological mediator of obstructive sleep apnea and type 2 diabetes

Obstructive sleep apnea (OSA) and type 2 diabetes show some mutual promotion of disease development. Variation in chemosensitivity is a key contributor to the pathophysiological mechanisms causing OSA and type 2 diabetes. According to studies conducted thus far, people with OSA or type 2 diabetes may have higher chemoreflex levels, but it is challenging to identify the precise changes because of variations in participant characteristics, the severity of the disease at the time of recruitment, and the small sample sizes in each study. Lowering chemosensitivity may also be viewed as a new issue for individuals with OSA and type 2 diabetes who require personalized care. The purpose of this review was to give an overview of chemosensitivity changes in OSA and glucose metabolism, as well as prospective therapeutic treatments for patients with OSA and type 2 diabetes.

Circadian clock, diurnal glucose metabolic rhythm, and dawn phenomenon

The circadian clock provides cue-independent anticipatory signals for diurnal rhythms of baseline glucose levels and glucose tolerance. The central circadian clock is located in the hypothalamic suprachiasmatic nucleus (SCN), which comprises primarily GABAergic neurons. The SCN clock regulates physiological diurnal rhythms of endogenous glucose production (EGP) and hepatic insulin sensitivity through neurohumoral mechanisms. Disruption of the molecular circadian clock is associated with the extended dawn phenomenon (DP) in type 2 diabetes (T2D), referring to hyperglycemia in the early morning without nocturnal hypoglycemia. The DP affects nearly half of patients with diabetes, with poorly defined etiology and a lack of targeted therapy. Here we review neural and secreted factors in physiological diurnal rhythms of glucose metabolism and their pathological implications for the DP.

Changes of circulating biomarkers of inflammation and glycolipid metabolism by CPAP in OSA patients: a meta-analysis of time-dependent profiles

Background:

Continuous positive airway pressure (CPAP) is the first-line therapy for moderate-to-severe obstructive sleep apnea (OSA). Specifying timing of CPAP benefits on OSA-related biomarkers will help to assess the effectiveness of CPAP and to optimize the treatment strategies.

Purpose:

To explore the time-dependent changes of circulating biomarkers to CPAP treatment in patients with OSA, including inflammatory biomarkers [C-reactive protein (CRP) and tumor necrosis factor–α (TNF-α)] and glycolipid metabolic biomarkers [fasting blood glucose (FBG), fasting insulin (FINS), low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), and triglyceride (TG)].

Methods:

Searches of PubMed and Embase database were completed. Two independent reviewers extracted data from 68 included studies. A meta-analysis was conducted using a random-effect (or fixed-effect) model and standardized mean difference (SMD) model. The timing profiles of circulating biomarkers changes of inflammation and glycolipid metabolism were analyzed based on different CPAP duration, that is, short-term (<3 months), mid-term (3–6 months), and long-term (⩾6 months).

Results:

Those first improved by short-term treatment include CRP [SMD: 0.73, 95% confidence interval (CI): 0.15–1.31; p = 0.014], TNF-α [SMD: 0.48 (95% CI: 0.10–0.86; p = 0.014)], FBG [SMD: 0.32 (95% CI: 0.07–0.57; p = 0.011)], and LDL [SMD: 0.40 (95% CI: 0.18–0.62; p = 0.000)]. Those first improved by the mid-term or long-term treatment include HDL [SMD: –0.20 (95% CI: –0.36 to –0.03; p = 0.018)] and TC [SMD: 0.20 (95% CI: 0.05–0.34; p = 0.007)]. There were insignificant changes for TG and FINS after short or long CPAP.

Conclusion:

Our results imply that changes of circulating biomarkers for patients with OSA under CPAP treatment have a time-dependent profile.

A Review of the Associations Between Obstructive Sleep Apnea and Gestational Diabetes Mellitus and Possible Mechanisms of Disease

Obstructive sleep apnea (OSA) usually leads to the occurrence of diabetes. Gestational diabetes mellitus (GDM) is a common gestational complication associated with adverse maternal and fetal outcomes. Increasing studies suggest that women with OSA during pregnancy may be at a significantly greater risk of developing GDM. It is crucial to explore the association between OSA and GDM and the mechanisms underlying this association. In this review, we presented a comprehensive literature review of the following: the association between OSA and GDM, the possible mechanisms of this association, and the effects of continuous positive airway pressure (CPAP) on OSA with GDM. The results showed that most authors suggested that there was an association between OSA and GDM. The intermittent hypoxemia (IH) and reduction of slow-wave sleep (SWS) may be the key to this association. IH induces the products of oxidative stress and inflammation as well as dysregulation of the hypothalamic-pituitary-adrenal, which lead to diabetes. In addition, SWS reduction in OSA enhances the inflammation by increasing the inflammatory cytokines, increases the sympathetic activation, and causes changes in leptin level, which result in the development of GDM. Additionally, whether CPAP is beneficial to GDM remains still unclear.

Usefulness of Aerobic Exercise for Home Blood Pressure Control in Patients with Diabetes: Randomized Crossover Trial

Hypertension usually coexists with diabetes mellitus and significantly increases the risk of macrovascular complications. Blood pressure measured at home, especially nocturnal blood pressure, is particularly important because it is more strongly associated with target organ damage than clinical blood pressure measurements. Regular moderate aerobic exercise has been shown to have anti-hypertensive effects. This study aimed to investigate the effects of aerobic exercise on home blood pressure in patients with diabetes. This randomized crossover trial was based on outpatient treatment at a university hospital. In this randomized crossover trial, 124 patients with type 2 diabetes were randomly assigned to two groups over 56 days: an exercise preceding group (exercise intervention for 28 days and then no exercise intervention for the following 28 days) and an exercise lagging group (no exercise intervention for 28 days and then exercise intervention for the following 28 days). The associations between the nocturnal blood pressure and exercise intervention were assessed accordingly. A decrease in blood pressure was observed in the morning and evening, at 2 a.m. and 3 a.m. after exercise intervention; however, there was no significant difference between groups. Moderate exercise was not effective in lowering nocturnal blood pressure in this study.

Changes in cortisol levels by continuous positive airway pressure in patients with obstructive sleep apnoea: Meta-analysis of 637 individuals

BACKGROUND

Obesity, obstructive sleep apnoea (OSA) and hypertension frequently coexist and are associated with elevated cortisol levels. Identification and treatment of such patients is important when investigating for suspected Cushing's syndrome and hypertension. Studies of the impact of continuous positive airway pressure (CPAP) on cortisol and blood pressure are limited by the small sample size and show conflicting findings. We conducted a meta-analysis to document changes in the levels of cortisol and blood pressure in response to CPAP treatment of OSA.

METHODS

Meta-analysis was conducted using RevMan (v5.3) and expressed in standardized mean difference (SMD) for catecholamines and mean difference for systolic (SBP) and diastolic blood pressure (DBP). The quality of the studies was evaluated using standard tools for assessing the risk of bias.

RESULTS

A total of 22 studies met our search criteria; they consisted of 16 prospective cohort studies (PCS) that recruited 385 participants and six randomized control trials (RCT) totalling 252 participants. The range of mean age was 41-62 years and BMI 27.2-35.1 kg/m² . CPAP treatment reduced plasma cortisol levels in PCS: SMD = -0.28 [95% confidence interval (95% CI) = -0.45 to -0.12], I²  = 0%, p = .79 and in RCT: SMD = -0.39 (95% CI = -0.75 to -0.03), I²  = 28.3%, p = .25. CPAP treatment reduced SBP by 5.4 mmHg (95% CI = 1.7-9.1) and DBP by 3.3 mmHg (95% CI = 1.0-5.7). Interstudy heterogeneity was low for all studies. Bias in most RCT arose from the lack of blinding of participants and personnel.

CONCLUSION

CPAP treatment in individuals with OSA reduces cortisol levels and blood pressure.

Obstructive sleep apnoea and 12-month weight loss in adults with class 3 obesity attending a multidisciplinary weight management program

BACKGROUND

Although there is a strong association between obesity and obstructive sleep apnoea (OSA), the effects of OSA and CPAP therapy on weight loss are less well known. The aim of this study in adults with class 3 obesity attending a multidisciplinary weight management program was to assess the relationship between OSA and CPAP usage, and 12-month weight change.

METHODS

A retrospective cohort study of all patients commencing an intensive multidisciplinary publicly funded weight management program in Sydney, Australia, between March 2018 and March 2019. OSA was diagnosed using laboratory overnight sleep studies. Demographic and clinical data, and use of CPAP therapy was collected at baseline and 12 months. CPAP use was confirmed if used ≥4 h on average per night on download.

RESULTS

Of the 178 patients who joined the program, 111 (62.4 %) completed 12 months in the program. At baseline, 63.1 % (n=70) of patients had OSA, of whom 54.3 % (n=38) were using CPAP. The non-OSA group had more females compared to the OSA with CPAP group and OSA without CPAP group (90.2 % vs. 57.9 % and 62.5 %, respectively; p=0.003), but there were no significant baseline differences in BMI (50.4±9.3 vs. 52.1±8.7 and 50.3±9.5 kg/m², respectively; p=0.636). There was significant weight loss across all three groups at 12 months. However, there were no statistically significant differences across groups in the percentage of body weight loss (OSA with CPAP: 6.3±5.6 %, OSA without CPAP: 6.8±6.9 %, non-OSA: 7.2±6.5 %; p=0.844), or the proportion of patients who achieved ≥5 % body weight loss (OSA with CPAP: 57.9 %, OSA without CPAP: 59.4 %, non-OSA: 65.9 %; p=0.743). In patients with T2DM, there was a significant reduction in HbA1c from baseline to 12 months (7.8±1.7 % to 7.3±1.4 %, p=0.03), with no difference between groups (p=0.997).

CONCLUSIONS

This multidisciplinary weight management program resulted in significant weight loss at 12 months, regardless of OSA diagnosis or CPAP use in adults with class 3 obesity. Larger studies are needed to further investigate the effects of severity of OSA status and CPAP use in weight management programs. Until completed, this study suggests that the focus should remain on implementing lifestyle changes and weight management regardless of OSA status.

Blood glucose dynamics during sleep in patients with obstructive sleep apnea and normal glucose tolerance: effects of CPAP therapy

Purpose

Glycemic variability (GV) and hypoglycemia during nighttime are presumed to be associated with fatal bradycardia. The aim of this prospective study was to evaluate blood glucose dynamics during sleep in patients with obstructive sleep apnea syndrome (OSA) and normal glucose tolerance.

Methods

Patients with OSA and no diabetes who underwent type 1 overnight polysomnography from December 2018 to May 2020 participated in this study. GV was evaluated in all participants for 14 days using a flash glucose monitoring device. Correlations were examined between GV indexes and indexes related to sleep breathing disorders, the effects of treatment with continuous positive airway pressure (CPAP) on these GV indexes, and the characteristics of glucose dynamics in different OSA subtypes classified by sleep stage.

Results

Among 42 patients with OSA and no diabetes, the standard deviation of GV during sleep correlated significantly with sleep time spent with oxygen saturation <90% (r=0.591, p=0.008). High blood glucose index during sleep correlated significantly with stage N1% (r=0.491, p=0.032) and negatively with stage N2% (r=−0.479, p=0.038). High blood glucose index correlated significantly with sleep time spent with oxygen saturation <90% (r=0.640, p=0.003). The rapid eye movement–related OSA group had a higher incidence of hypoglycemia. One-week with CPAP treatment significantly improved GV during sleep, standard deviation of GV (from 12.1 to 9.0 mg/dL, p<0.001), and high blood glucose index (from 0.7 to 0.4, p=0.006).

Conclusions

To evaluate GV during sleep in patients with OSA may be useful for clinical risk management. CPAP treatment for 1 week may have an improving GV and high blood glucose index.

Clinical trial registration

UMIN000038489 2019/11/04, UMIN 000025433 2016/12/27

Supplementary Information

The online version contains supplementary material available at 10.1007/s11325-021-02442-9.

Association between nocturnal activity of the sympathetic nervous system and cognitive dysfunction in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is associated with repetitive breathing obstructions during sleep. These episodes of hypoxia and associated arousals from sleep induce physiological stress and nocturnal over-activation of the sympathetic nervous system (SNS). One consequence of OSA is impairment in a range of cognitive domains. Previous research into cognitive impairment in OSA have focussed on intermittent hypoxia and disrupted sleep, but not nocturnal over-activation of the SNS. Therefore, we investigated whether nocturnal over-activity of the SNS was associated with cognitive impairments in OSA. The extent of nocturnal SNS activation was estimated from heart rate variability (HRV), pulse wave amplitude (PWA) and stress response biomarkers (cortisol and glucose levels). OSA severity was significantly associated with PWA indices and the HRV low frequency/ high frequency ratio (p < 0.05). Morning blood glucose levels were significantly associated with the duration of a blood oxygen saturation (SaO₂) < 90% (p < 0.01). PWA and HRV were significantly associated with the time taken to perform a task involving visuospatial functioning (p < 0.05), but not with impairments in sustained attention, reaction time or autobiographical memory. These results suggest that the visuospatial dysfunction observed in people with OSA is associated with increased nocturnal activity of the SNS.

Obstructive Sleep Apnea, Glucose Tolerance, and β-Cell Function in Adults With Prediabetes or Untreated Type 2 Diabetes in the Restoring Insulin Secretion (RISE) Study

OBJECTIVE

Obstructive sleep apnea (OSA) is associated with insulin resistance and has been described as a risk factor for type 2 diabetes. Whether OSA adversely impacts pancreatic islet β-cell function remains unclear. We aimed to investigate the association of OSA and short sleep duration with β-cell function in overweight/obese adults with prediabetes or recently diagnosed, treatment-naive type 2 diabetes.

RESEARCH DESIGN AND METHODS

Two hundred twenty-one adults (57.5% men, age 54.5 ± 8.7 years, BMI 35.1 ± 5.5 kg/m²) completed 1 week of wrist actigraphy and 1 night of polysomnography before undergoing a 3-h oral glucose tolerance test (OGTT) and a two-step hyperglycemic clamp. Associations of measures of OSA and actigraphy-derived sleep duration with HbA_1c, OGTT-derived outcomes, and clamp-derived outcomes were evaluated with adjusted regression models.

RESULTS

Mean ± SD objective sleep duration by actigraphy was 6.6 ± 1.0 h/night. OSA, defined as an apnea-hypopnea index (AHI) of five or more events per hour, was present in 89% of the participants (20% mild, 28% moderate, 41% severe). Higher AHI was associated with higher HbA_1c (P = 0.007). However, OSA severity, measured either by AHI as a continuous variable or by categories of OSA severity, and sleep duration (continuous or <6 vs. ≥6 h) were not associated with fasting glucose, 2-h glucose, insulin sensitivity, or β-cell responses.

CONCLUSIONS

In this baseline cross-sectional analysis of the RISE clinical trial of adults with prediabetes or recently diagnosed, untreated type 2 diabetes, the prevalence of OSA was high. Although some measures of OSA severity were associated with HbA_1c, OSA severity and sleep duration were not associated with measures of insulin sensitivity or β-cell responses.

Effect of 12-week continuous positive airway pressure therapy on glucose levels assessed by continuous glucose monitoring in people with type 2 diabetes and obstructive sleep apnoea; a randomized controlled trial

Aim

Obstructive sleep apnoea (OSA) is frequent in type 2 diabetes (T2D). The aim was to investigate the effect of a 12-week treatment with continuous positive airway pressure (CPAP) on glycaemic control assessed by continuous glucose monitoring (CGM), HbA1c and fasting blood glucose in patients with T2D and newly detected OSA.

Methods

In a randomized controlled multicentre study, 72 participants with T2D and moderate to severe OSA (78% male, age 62 ± 7, AHI 35 ± 15) were recruited from outpatient clinics in three Danish hospitals and were randomized to CPAP intervention or control. The main outcome was glycaemic control assessed by 6 days CGM at baseline and after 12-week therapy, as well as by HbA1c and fasting blood glucose.

Results

No significant changes were found in average glucose levels, time in glucose range, time with hypoglycaemia, time with hyperglycaemia or coefficient of variability. HbA1c decreased 0.7 mmol/mol (0.07%; P = .8) in the CPAP group and increased 0.8 mmol/mol (0.08%; P = .6) in the control group (intergroup difference, P = .6). Fasting blood glucose increased by 0.2 mmol/L (P = .02) in the CPAP group and by 0.4 mmol/L (P = .01) in the control group (intergroup difference, P = .7). In a prespecified subgroup analysis comparing participants with high adherence (minimum usage of four hours/night for 70% of all nights) to CPAP to the control group, no significant changes were observed either, although these participants had a tendency towards better glycaemic indices.

Conclusions

CPAP treatment for 12 weeks does not significantly change glycaemic control in patients with type 2 diabetes and OSA.

Obstructive sleep apnea during rapid eye movement sleep in patients with diabetic kidney disease

STUDY OBJECTIVES

Although recent studies suggest that obstructive sleep apnea during rapid eye movement (REM) is associated with different cardiometabolic and neurocognitive risks compared with non-REM (NREM) sleep, there is no information on whether obstructive sleep apnea during REM and/or NREM sleep is independently associated with diabetic kidney disease (DKD).

METHODS

In this cross-sectional study, 303 patients with type 2 diabetes who were followed up at our diabetes outpatient clinic underwent all-night polysomnography. Logistic regression analysis was performed to determine the separate effects of obstructive sleep apnea during REM and/or NREM sleep (REM and/or NREM-apnea-hypopnea index [AHI]) and several other polysomnography parameters on DKD after adjustment for several known risk factors for DKD.

RESULTS

The median (interquartile range) AHI, REM-AHI, and NREM-AHI of the patients (age 57.8 ± 11.8 years, male sex 86.8%, hypertension 64.3%, and DKD 35.2%) were 29.8 (18.0-45.4), 35.4 (21.1-53.3), and 29.1 (16.3-45.4) events/h, respectively. REM-AHI quartiles, but not NREM-AHI quartiles, correlated independently and significantly with DKD (P = .03 for linear trend, odds ratio (OR), and 95% confidence interval for Q2: 3.14 (1.10-8.98), Q3: 3.83 (1.26-11.60), Q4: 4.97 (1.60-15.46), compared with Q1). In addition, categorical AHI (P = .01, OR, and 95% confidence interval for ≥ 15 to < 30: 1.54 (0.64-3.71), ≥ 30: 3.08 (1.36-6.94) compared with < 15), quartiles of AHI (P = .01), quartiles of lowest arterial oxyhemoglobin saturation (P < .01), quartiles of percentage of time spent with arterial oxyhemoglobin saturation < 90 (P < .01), and quartiles of mean arterial oxyhemoglobin saturation were independently associated with DKD.

CONCLUSIONS

Obstructive sleep apnea, especially during REM sleep, is a potential risk factor for DKD.

Personalized and Patient-Centered Strategies to Improve Positive Airway Pressure Adherence in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA), a common sleep disorder characterized by repeated pauses in breathing during sleep, is effectively treated with positive airway pressure (PAP) therapy. The magnitude of improvements in daily functioning and reduced negative health risks are dependent on maintaining PAP adherence, which is a significant challenge. Evidence-based interventions to improve PAP use are not easily translated to clinical practice because they are labor-intensive and require specialty expertise. Further, to date, individualized care, inclusive of personalized medicine and patient- and person-centered care have been marginally incorporated in the field's understanding of OSA and PAP adherence. This integrative review describes current PAP adherence assessment processes, interventions to improve adherence, and outlines future opportunities to advance the field, particularly as it relates to individualizing care and the use of implementation science to apply evidence to practice.

Rationale and design of the Hyperglycemic Profiles in Obstructive Sleep Apnea (HYPNOS) trial

The Hyperglycemic Profiles in Obstructive Sleep Apnea (HYPNOS) randomized clinical trial was conducted in adults with type 2 diabetes and moderate-to-severe obstructive sleep apnea (OSA) to determine whether treatment with positive airway pressure (PAP) therapy is associated with improvements in glycemic measures. Participants were randomly assigned to PAP therapy with lifestyle counseling or lifestyle counseling alone. While observational and experimental evidence indicate that intermittent hypoxemia and recurrent arousals in OSA may alter glucose metabolism and worsen glycemic measures, the effect of treating OSA with PAP therapy on these measures in type 2 diabetes is uncertain. Adequately powered randomized clinical trials have yet to be performed to demonstrate whether PAP therapy for OSA in patients with type 2 diabetes can improve glycemic measures. The HYPNOS trial was designed to determine whether PAP therapy for OSA in patients with type 2 diabetes over 3 months leads to improvements in glycemic measures including glycemic variability (standard deviation) based on Dexcom G4 Platinum continuous glucose monitoring. Secondary objectives were to assess the effects of PAP therapy for OSA on measures of: (1) glycemic variability based on Abbott Freestyle Pro Libre continuous glucose monitoring; (2) point-of-care hemoglobin A1c (HbA1c); (3) degree of post-prandial hyperglycemia as determined by 7-point self-monitoring of blood glucose; (4) clinic and ambulatory blood pressure; and (5) endothelial function. The HYPNOS trial was designed to address gaps in our understanding of the effects of PAP therapy on glucose metabolism in adults with type 2 diabetes and moderate-to-severe OSA. Trial Registration: ClinicalTrials.gov Identifier NCT02454153.

Meta-analysis of changes in the levels of catecholamines and blood pressure with continuous positive airway pressure therapy in obstructive sleep apnea

Stress from obstructive sleep apnea (OSA) stimulates catecholamine release consequently exacerbating hypertension. However, different studies have shown a conflicting impact of continuous positive airway pressure (CPAP) treatment in patients with OSA on catecholamine levels and blood pressure. We aimed to examine changes to catecholamine levels and blood pressure in response to CPAP treatment. We conducted a meta‐analysis of data published up to May 2020. The quality of the studies was evaluated using standard tools for assessing the risk of bias. Meta‐analysis was conducted using RevMan (v5.3) and expressed in standardized mean difference (SMD) for catecholamines and mean difference (MD) for systolic (SBP) and diastolic blood pressure (DBP). A total of 38 studies met our search criteria; they consisted of 14 randomized control trials (RCT) totaling 576 participants and 24 prospective cohort studies (PCS) of 547 participants. Mean age ranged between 41 and 62 year and body mass index between 27.2 and 35.1 kg/m². CPAP treatment reduced 24‐hour urinary noradrenaline levels both in RCT (SMD = −1.1; 95% confidence interval (CI): −1.63 to − 0.56) and in PCS (SMD = 0.38 (CI: 0.24 to 0.53). SBP was also reduced by CPAP treatment in RCT (4.8 mmHg; CI: 2.0‐7.7) and in PCS (7.5 mmHg; CI: 3.3‐11.7). DBP was similarly reduced (3.0 mmHg; CI: 1.4‐4.6) and in PCS (5.1 mmHg; CI: 2.3‐8.0). In conclusion, CPAP treatment in patients with OSA reduces catecholamine levels and blood pressure. This suggests that sympathetic activity plays an intermediary role in hypertension associated with OSA‐related stress.

Continuous Positive Airway Pressure Treatment, Glycemia, and Diabetes Risk in Obstructive Sleep Apnea and Comorbid Cardiovascular Disease

OBJECTIVE

Despite evidence of a relationship among obstructive sleep apnea (OSA), metabolic dysregulation, and diabetes, it is uncertain whether OSA treatment can improve metabolic parameters. We sought to determine effects of long-term continuous positive airway pressure (CPAP) treatment on glycemic control and diabetes risk in patients with cardiovascular disease (CVD) and OSA.

RESEARCH DESIGN AND METHODS

Blood, medical history, and personal data were collected in a substudy of 888 participants in the Sleep Apnea cardioVascular Endpoints (SAVE) trial in which patients with OSA and stable CVD were randomized to receive CPAP plus usual care, or usual care alone. Serum glucose and glycated hemoglobin A_1c (HbA_1c) were measured at baseline, 6 months, and 2 and 4 years and incident diabetes diagnoses recorded.

RESULTS

Median follow-up was 4.3 years. In those with preexisting diabetes (n = 274), there was no significant difference between the CPAP and usual care groups in serum glucose, HbA_1c, or antidiabetic medications during follow-up. There were also no significant between-group differences in participants with prediabetes (n = 452) or new diagnoses of diabetes. Interaction testing suggested that women with diabetes did poorly in the usual care group, while their counterparts on CPAP therapy remained stable.

CONCLUSIONS

Among patients with established CVD and OSA, we found no evidence that CPAP therapy over several years affects glycemic control in those with diabetes or prediabetes or diabetes risk over standard-of-care treatment. The potential differential effect according to sex deserves further investigation.

Sleep disturbances: one of the culprits of obesity-related cardiovascular risk?

Growing evidence suggested that Sleep Disorders (SD) could increase the risk of developing obesity and could contribute to worsen obesity-related cardiovascular risk. Further, obesity per se has been reported to blunt sleep homeostasis. This happens through several mechanisms. First of all, the excessive adipose tissue at neck and chest levels could represent a mechanical obstacle to breathe. Moreover, the visceral adipose tissue is known to release cytokines contributing to low-grade chronic inflammation that could impair the circadian rhythm. Also, nutrition plays an important role in sleep homeostasis. High fat and/or high carbohydrate diets are known to have a negative impact on both sleep quality and duration. In addition, obesity predisposes to a condition called "obstructive sleep apnea" that has a detrimental effect on sleep. SD could increase the risk and/or could contribute to worsen cardiovascular risk usually associated with obesity. The chronic low grade inflammation associated with obesity has been reported to increase the risk of developing hypertension, type 2 diabetes and dyslipidemia. In turn, improving quality of sleep has been reported to improve the management of these cardiovascular risk factors. Thus, the aim of this manuscript is to provide evidence on the association of obesity and SD and on how they could contribute to the risk of developing cardiovascular risk factors such as hypertension, dyslipidemia and type 2 diabetes in obesity.

Maternal Sleep-Disordered Breathing in Pregnancy and Increased Nocturnal Glucose Levels in Women with Gestational Diabetes Mellitus

BACKGROUND

Women with hyperglycemia during pregnancy are at high risk for adverse perinatal outcomes. Maternal sleep-disordered breathing (SDB) during pregnancy is common and is a risk factor for gestational diabetes mellitus (GDM). However, the relationship between SDB severity and glucose control is unknown.

RESEARCH QUESTION

Is there an association between SDB severity and glucose levels as assessed by continuous glucose monitoring in GDM?

STUDY DESIGN AND METHODS

Women with GDM underwent sleep recordings and 72-hour continuous glucose monitoring. Linear mixed models were used to estimate the association of the apnea-hypopnea index (AHI), rapid eye movement (REM)-AHI, and non-REM-AHI with mean glucose levels during nighttime (two periods: 11 pm to 3 am and 3 am to 6 am), daytime (8 am to 9 pm), and 24-hours. Models were adjusted for BMI and antihyperglycemic medications.

RESULTS

In 65 participants who were 35 ± 5 (mean ± SD) years of age with BMI of 33 ± 7 kg/m², 31% were undergoing insulin and/or metformin therapy. A ten-unit increase in AHI was associated with elevated nocturnal glucose levels (11 pm to 3 am: 0.20 mmol/L [95% CI, 0.04-0.40]) with persistent elevations into the morning (8 am: 0.26 mmol/L [95% CI, 0.08-0.4]) when adjusted for BMI and medications. REM-AHI was also associated with higher nocturnal and morning glucose levels, whereas non-REM was not. AHI was not associated with either mean daytime or 24-hour glucose levels.

INTERPRETATION

Greater severity of SDB was associated with higher nocturnal and morning glucose levels in women with GDM.

Associations of apnea hypopnea index and educational attainments with microvascular complications in patients with T2DM

PURPOSE

The relationship between obstructive sleep apnea (OSA) and diabetic microvascular complications (DMC) are controversial. Whether low education is associated with increased risk of DMC independently of poor lifestyles are currently unknown. The aim of this study is to explore the independent associations of different PSG index and educational attainment with risks of DR, DKD, and DPN.

METHODS

A cross-sectional study of 330 patients with T2DM who underwent overnight polysomnography (PSG) tests. Multivariable logistic regression analysis was performed to determine the associations of PSG index and educational attainments with DR, DKD, and DPN.

RESULTS

The prevalence rates of DMC were 30.6% for DR, 24.9% for DKD, and 64.6% for DPN. All PSG index (AHI, REM-AHI, NREM-AHI, the severity of OSAS, ODI, MAI, and lowest SaO₂) were not significantly associated with risks of DR, DKD, or DPN with adjustment for potential confounding factors. Subjects with increasing educational attainments showed significantly decreased prevalence rates of DR (42.6, 27.3, and 21.3%, p = 0.005), DKD (31.7, 25.3, and 14.7%, p = 0.035) and DPN (74.3, 63.6, and 53.3%, p = 0.015), respectively. Logistic regression analyses showed that educational attainment of primary or below showed significantly increased risks of DR (OR (95% CIs): 3.596 (1.453-8.899, p = 0.006)) and DKD (OR (95% CIs): 3.201 (1.244-8.242, p = 0.016)) as compared with that of college or above. There were significant trends of lower educational attainment with increased risks of DR and DKD (p values < 0.05).

CONCLUSION

PSG index were not significantly associated with DMC. But lower education was significantly associated with increased risks of DR and DKD, and strategies to prevent DMC for those with low education should be strengthened.

The fluctuation in sympathetic nerve activity around wake-up time was positively associated with not only morning but also daily glycemic variability in subjects with type 2 diabetes

AIMS

It is known that autonomic nerve activity (ANA) affects glucose metabolism by regulating the secretion of insulin and glucagon. Sympathetic nerve stimulation results in increased blood glucose levels. ANA also showed a circadian variation, and sympathetic nerve activity was minimal at night and began to rise at arousal. Therefore, a drastic alteration in ANA around wake-up would be associated with glycemic variability (GV) known risk factor for cardiovascular disease. We investigated the relation between ANA around wake-up and either morning or daily GV.

METHODS

We simultaneously performed Holter ECG and continuous glucose monitoring system in 41 patients with type 2 diabetes (T2D). ANA was assessed by heart rate variability (HRV) analysis. Delta (Δ) wake-up was defined as the difference between the maximum and minimum value during 1 h before and after wake-up time, before breakfast.

RESULTS

Δ of low frequency/high frequency (LF/HF) around wake-up time (Δ LF/HF _wake-up) was positively associated with Δ glucose _wake-up, standard deviation (SD) glucose _wake-up, the mean amplitude of glucose excursions (MAGE_24h), and SD glucose_24h after adjustment for age, sex, BMI, the duration of diabetes, and the prevalence of diabetic polyneuropathy (β = 0.47, p = 0.011, β = 0.48, p = 0.009, β = 0.54, p = 0.002 and β = 0.41, p = 0.0025, respectively). No association was found between Δ LF/HF_wake-up and either mean blood glucose for 24 h, or HbA1c as parameters of chronic hyperglycemia.

CONCLUSIONS

In T2D, the fluctuation in fasting sympathetic nerve activity around wake-up was positively associated with not only morning but also daily GV.

Apnea Hypopnea Index During Rapid Eye Movement Sleep With Diabetic Retinopathy in Patients With Type 2 Diabetes

CONTEXT

Recent studies based on home sleep apnea testing (HSAT) reported the potential association of sleep disordered breathing, such as obstructive sleep apnea (OSA), with diabetic retinopathy (DR). A few studies showed that the apnea-hypopnea index (AHI) during rapid eye movement (REM) sleep (REM-AHI) is associated with glycated hemoglobin and hypertension, two known risk factors for DR. However, there are no studies that have evaluated the association of REM-AHI with DR because previous studies were based on HSAT.

OBJECTIVE

To determine the association of REM-AHI with DR.

DESIGN, SETTING, AND PATIENTS

The study subjects were 131 patients with type 2 diabetes mellitus who underwent all-night polysomnography with ≥30 minutes of REM sleep and were free of heart failure or active lung disease and had not yet been treated for OSA. Logistic regression analysis was performed to determine the effect of REM-AHI on the prevalence of DR adjusted by several known risk factors for DR.

RESULTS

Quartile of REM-AHI was independently associated with DR (P = 0.024) (Q2: OR, 3.887; 95% CI, 0.737 to 20.495; Q3: OR, 9.467; 95% CI, 1.883 to 47.588; Q4: OR, 12.898; 95% CI, 2.008 to 82.823 relative to Q1), whereas quartile of non-REM (NREM)-AHI was not (P = 0.119). Similarly, continuous REM-AHI (OR, 2.875; 95% CI, 1.224 to 6.752; P = 0.015) was independently associated with DR, whereas NREM-AHI was not (P = 0.107). In addition, AHI was independently associated with DR when controlling for several known risk factors for DR (P = 0.043).

CONCLUSION

REM-AHI was independently associated with DR. REM-AHI could be a potential risk factor for DR.

Obstructive sleep apnoea and comorbidity - an overview of the association and impact of continuous positive airway pressure therapy

INTRODUCTION

Obstructive sleep apnoea (OSA) is highly prevalent and there is considerable evidence supporting an independent association with a wide range of co-morbidities including cardiovascular, endocrine and metabolic, neuropsychiatric, pulmonary, and renal. Areas covered: A PubMed search of all the recent literature relating to OSA and co-morbidities was undertaken to critically evaluate the potential relationships and possible benefit of continuous positive airway pressure (CPAP) therapy. Expert commentary: The evidence supporting an independent association is stronger for some co-morbidities than others and in cardiovascular diseases is strongest for hypertension and atrial fibrillation. Potential mechanisms include intermittent hypoxia, fluctuating intrathoracic pressure, and recurring micro-arousals that trigger cell and molecular consequences including sympathetic excitation, systemic inflammation and oxidative stress, in addition to metabolic and endothelial dysfunction. Different mechanisms may predominate in individual co-morbidities. Recent long term randomised controlled trials have cast doubt on benefits to co-morbidities from CPAP therapy of OSA, especially where co-morbidities are already established. However, benefits may result in patients who are compliant with therapy and further research is required to clearly establish the role of OSA therapy in both primary and secondary prevention of co-morbidities.

Circadian clocks and insulin resistance

Insulin resistance is a main determinant in the development of type 2 diabetes mellitus and a major cause of morbidity and mortality. The circadian timing system consists of a central brain clock in the hypothalamic suprachiasmatic nucleus and various peripheral tissue clocks. The circadian timing system is responsible for the coordination of many daily processes, including the daily rhythm in human glucose metabolism. The central clock regulates food intake, energy expenditure and whole-body insulin sensitivity, and these actions are further fine-tuned by local peripheral clocks. For instance, the peripheral clock in the gut regulates glucose absorption, peripheral clocks in muscle, adipose tissue and liver regulate local insulin sensitivity, and the peripheral clock in the pancreas regulates insulin secretion. Misalignment between different components of the circadian timing system and daily rhythms of sleep-wake behaviour or food intake as a result of genetic, environmental or behavioural factors might be an important contributor to the development of insulin resistance. Specifically, clock gene mutations, exposure to artificial light-dark cycles, disturbed sleep, shift work and social jet lag are factors that might contribute to circadian disruption. Here, we review the physiological links between circadian clocks, glucose metabolism and insulin sensitivity, and present current evidence for a relationship between circadian disruption and insulin resistance. We conclude by proposing several strategies that aim to use chronobiological knowledge to improve human metabolic health.

A Population-Based Study of the Bidirectional Association Between Obstructive Sleep Apnea and Type 2 Diabetes in Three Prospective U.S. Cohorts

OBJECTIVE

Multiple lines of evidence support a complex relationship between obstructive sleep apnea (OSA) and diabetes. However, no population-based study has evaluated the potential bidirectional association between these two highly prevalent disorders.

RESEARCH DESIGN AND METHODS

We followed 146,519 participants from the Nurses' Health Study (NHS; 2002-2012), Nurses' Health Study II (NHSII; 1995-2013), and Health Professionals Follow-up Study (HPFS; 1996-2012) who were free of diabetes, cardiovascular disease, and cancer at baseline. Cox proportional hazards models were used to estimate hazard ratios (HRs) for developing diabetes according to OSA status. In parallel, we used similar approaches to estimate risk of developing OSA according to diabetes status among 151,194 participants free of OSA, cardiovascular disease, and cancer at baseline. In all three cohorts, diagnoses of diabetes and OSA were identified by validated self-reports.

RESULTS

Similar results were observed across the three cohorts. In the pooled analysis, 9,029 incident diabetes cases were identified during follow-up. After accounting for potential confounders, the HR (95% CI) for diabetes was 2.06 (1.86, 2.28) comparing those with versus without OSA. The association was attenuated but remained statistically significant after further adjusting for waist circumference and BMI (HR 1.37 [95% CI 1.24, 1.53]), with the highest diabetes risk observed for OSA concomitant with sleepiness (1.78 [1.13, 2.82]). In the second analysis, we documented 9,364 incident OSA cases during follow-up. Compared with those without diabetes, the multivariable HR (95% CI) for OSA was 1.53 (1.32, 1.77) in individuals with diabetes. Adjustment for BMI and waist circumference attenuated the association (1.08 [1.00, 1.16]); however, an increased risk was observed among those with diabetes who used insulin compared with those without diabetes (1.43 [1.11, 1.83]), particularly among women (1.60 [1.34, 1.89]).

CONCLUSIONS

OSA is independently associated with an increased risk of diabetes, whereas insulin-treated diabetes is independently associated with a higher risk of OSA, particularly in women. Clinical awareness of this bidirectional association may improve prevention and treatment of both diseases. Future research aimed at elucidating the mechanisms that underlie each association may identify novel intervention targets.

The Epidemiology of Sleep and Diabetes

PURPOSE OF REVIEW

To provide an overview of the mechanistic and epidemiologic evidence linking sleep-related exposures, such as short sleep duration, obstructive sleep apnea, shift work, and insomnia, with type 2 diabetes risk in adults.

RECENT FINDINGS

Both poor sleep habits and sleep disorders are highly prevalent among adults with type 2 diabetes. In observational studies, short sleep duration, obstructive sleep apnea, shift work, and insomnia are all associated with higher risk of incident type 2 diabetes and may predict worse outcomes in those with existing diabetes. However, interventional studies addressing sleep abnormalities in populations with or at high risk for type 2 diabetes are scarce. Although common sleep abnormalities are associated with risk of incident type 2 diabetes and worse prognosis in those with established diabetes, there are few randomized trials evaluating the impact of sleep-focused interventions on diabetes, making it difficult to determine whether the relationship is causal.

Disturbed sleep and diabetes: A potential nexus of dementia risk

Type 2 diabetes (T2D) and sleep disturbance (e.g., insomnia, sleep-disordered breathing) are prevalent conditions among older adults that are associated with cognitive decline and dementia, including Alzheimer's disease (AD). Importantly, disturbed sleep is associated with alterations in insulin sensitivity and glucose metabolism, and may increase the risk of T2D, and T2D-related complications (e.g., pain, nocturia) can negatively affect sleep. Despite these associations, little is known about how interactions between T2D and sleep disturbance might alter cognitive trajectories or the pathological changes that underlie dementia. Here, we review links among T2D, sleep disturbance, cognitive decline and dementia-including preclinical and clinical AD-and identify gaps in the literature, that if addressed, could have significant implications for the prevention of poor cognitive outcomes.

Continuous Positive Airway Pressure Therapy in Gestational Diabetes With Obstructive Sleep Apnea: A Randomized Controlled Trial

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is associated with gestational diabetes mellitus (GDM). This study assessed the effects of continuous positive airway pressure (CPAP) in obese pregnant females with GDM and OSA.

METHODS

A randomized controlled trial was conducted (April 2014 - June 2016). Obese females at 24 to 34 weeks gestation and with diet-controlled GDM were screened for OSA. Those with OSA were randomly assigned to receive 2 weeks nightly CPAP or be part of a waitlist control group. After 2 weeks, all patients were offered CPAP. The primary outcome was glucose metabolism, obtained from an oral meal tolerance test (MTT) at baseline and 2 weeks. Pregnancy outcomes were collected.

RESULTS

Eighteen patients were randomized to CPAP and 18 to control groups. There were no significant changes between groups in fasting glucose, glucose response to MTT, and insulin sensitivity or secretion after 2 weeks. Those adherent to CPAP had significantly improved insulin secretion (P = .016) compared to the control group. When a counterfactual instrumental variable approach was applied to deal with nonadherence, the CPAP group had significantly improved insulin secretion (P = .002) and insulin sensitivity (P = .015). Lower rates of preterm delivery (P = .002), unplanned cesarean section (P = .005), and neonatal intensive care unit admissions (P < .001) were observed among those who used CPAP longer than 2 weeks.

CONCLUSIONS

Two weeks of CPAP in females with GDM and OSA did not result in improved glucose levels, but insulin secretion improved in those adherent to CPAP. Continued CPAP use was possibly associated with improved pregnancy outcomes.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Obstructive Sleep Apnea and Gestational Diabetes: Incidence and Effects of Continuous Positive Airway Pressure Treatment on Glucose Metabolism; Identifier: NCT02108197; URL: https://clinicaltrials.gov/ct2/show/NCT02108197.

[Sleep apneas, metabolic syndrome and cardiovascular risk: Data from the Pays de la Loire sleep cohort]

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a prevalent disease characterized by recurrent episodes of partial or complete obstruction of upper airway during sleep. Untreated moderate to severe OSAHS is recognized as a cardiovascular (CV) risk factor. Data from the Pays de la Loire sleep cohort and other clinic- or population-based cohorts demonstrate a strong association between OSAHS and the different components of the metabolic syndrome including systemic hypertension, diabetes and impaired lipid metabolism. Beside sleep-disordered breathing severity, these factors contribute to increase the risk of CV events in OSAHS patients. Continuous positive airway pressure (CPAP) therapy of OSAHS is associated with a modest but clinically significant blood pressure reduction. Conversely, there is no clear evidence in support of a metabolic impact of CPAP in OSAHS patients. Considering the multifactorial pathophysiology of CV risk in OSAHS patients and the beneficial impact of various lifestyle and pharmacologic interventions on blood pressure and metabolic dysfunction, combined modality therapy is a promising strategy to improve CV outcomes in individuals with OSAHS.

Current child, but not maternal, snoring is bi-directionally related to adiposity and cardiometabolic risk markers: A cross-sectional and a prospective cohort analysis

PURPOSE

Obstructive sleep apnea (OSA), typically manifested as snoring, is closely associated with obesity. However, the directionality of associations of OSA with cardiometabolic risk markers is unclear, as obesity increases risk for OSA, and OSA results in excess weight gain and its metabolic consequences. Less is known about how obesity and OSA may relate in children and adolescents and whether maternal OSA may influence the development of obesity and cardiometabolic dysfunction in offspring.

BASIC PROCEDURES

Among 1078 children from the Project Viva cohort, we examined cross-sectionally and prospectively associations of parent-reported child or maternal snoring with cardiometabolic outcomes, including adiposity, adipokines, and insulin resistance.

MAIN FINDINGS

Cross-sectionally, child snoring was related to adiposity and metabolic risk, particularly body mass index (BMI; β 0.61kg/m2, 95% CI 0.33, 0.89; p<0.001), trunk fat mass index (β 0.23kg/m2, CI 0.12, 0.34; p<0.001), high-density lipoprotein cholesterol (β -1.47mg/dL, CI -2.69, -0.25; p=0.02), and metabolic risk z-score (β 0.08, CI 0.02, 0.14; p=0.01) after correction for covariates. Prospectively, adiposity (BMI, trunk fat, fat mass, and waist circumference) and cardiometabolic (leptin, HOMA-IR, CRP, and global metabolic risk) measures at mid-childhood (~7y) were associated with child snoring at the early teen visit (~12y) after correction for covariates. Child snoring at ~9y was related to changes in adiposity between mid-childhood and early teen visits.

CONCLUSIONS

Child but not maternal snoring, was related to child adiposity and cardiometabolic outcomes. Adiposity and child snoring are associated with each other cross-sectionally and are each predictive of the other among children/adolescents prospectively. These results suggest similar mechanisms in pediatric/adolescent populations as in adults for the development of sleep-disordered breathing and sleep apnea that will need to be confirmed in randomized clinical trials. Importantly, this research points to the need to target both sleep and obesity in order to break this vicious cycle.

Obstructive Sleep Apnea Dynamically Increases Nocturnal Plasma Free Fatty Acids, Glucose, and Cortisol During Sleep

CONTEXT

Obstructive sleep apnea (OSA) is associated with diabetes and cardiovascular disease. This association may be related to metabolic changes that transpire during sleep in OSA.

OBJECTIVE

To examine the impact of OSA, elicited by cessation of continuous positive airway pressure (CPAP), on frequently sampled nocturnal metabolic markers including plasma free fatty acids (FFAs), glucose, insulin, triglycerides (TGs), cortisol, and lactate, as well as glucose production, oral glucose tolerance, blood pressure (BP), endothelial function, cholesterol, and high-sensitivity C-reactive protein (hsCRP).

DESIGN AND SETTING

Randomized crossover trial of CPAP vs CPAP withdrawal.

PATIENTS

Thirty-one patients with moderate to severe OSA acclimated to CPAP.

INTERVENTION

Patients underwent attended polysomnography while sleeping with therapeutic CPAP, or after CPAP withdrawal, in random order. Venous blood was sampled at ∼20-minute intervals on both nights. In 11 patients, we assessed glucose kinetics with an infusion of 6,6-[2H2]glucose.

RESULTS

CPAP withdrawal caused recurrence of OSA associated with hypoxemia, sleep disruption, and heart rate (HR) elevation. CPAP withdrawal dynamically increased nocturnal FFA (P = 0.007), glucose (P = 0.028), and cortisol (P = 0.037), in proportion to respiratory event frequency, HR elevation, or sleep fragmentation. Diabetes predisposed to glucose elevation. CPAP withdrawal also increased systolic BP (P = 0.017) and augmentation index (P = 0.008), but did not affect insulin, TGs, glucose production, oral glucose tolerance, cholesterol, or hsCRP.

CONCLUSION

OSA recurrence during CPAP withdrawal increases FFA and glucose during sleep, associated with sympathetic and adrenocortical activation. Recurring exposure to these metabolic changes may foster diabetes and cardiovascular disease.

Obstructive Sleep Apnea and Diabetes: A State of the Art Review

OSA is a chronic treatable sleep disorder and a frequent comorbidity in patients with type 2 diabetes. Cardinal features of OSA, including intermittent hypoxemia and sleep fragmentation, have been linked to abnormal glucose metabolism in laboratory-based experiments. OSA has also been linked to the development of incident type 2 diabetes. The relationship between OSA and type 2 diabetes may be bidirectional in nature given that diabetic neuropathy can affect central control of respiration and upper airway neural reflexes, promoting sleep-disordered breathing. Despite the strong association between OSA and type 2 diabetes, the effect of treatment with CPAP on markers of glucose metabolism has been conflicting. Variability with CPAP adherence may be one of the key factors behind these conflicting results. Finally, accumulating data suggest an association between OSA and type 1 diabetes as well as gestational diabetes. This review explores the role of OSA in the pathogenesis of type 2 diabetes, glucose metabolism dysregulation, and the impact of OSA treatment on glucose metabolism. The association between OSA and diabetic complications as well as gestational diabetes is also reviewed.

Obesity, Cardiovascular Disease and Sleep Disorders: Insights into the Rising Epidemic

Cardiovascular disease (CVD) is the main cause of death among adult men and women in the USA and impacts millions around the globe. Traditional risk factors for CVD include obesity, diabetes, hypertension and dyslipidemia. The modern-day epidemic of obesity not only increased the rate of CVD but also ushered in an additional CVD risk factor to be added to the list; that is obstructive sleep apnea (OSA). In this review, we discuss the growing epidemic of obesity and OSA, highlighting the common pathogenic hypotheses linking these risk factors to CVD. We will also highlight the therapeutic rationale of OSA as a way to reduce CVD risk.

Obstructive sleep apnea in adults with type 1 and type 2 diabetes: perspectives from a quality improvement initiative in a university-based diabetes center

OBJECTIVE

Obstructive sleep apnea (OSA) and diabetes are frequent comorbid conditions. Screening for OSA in patients with diabetes is recommended but the frequency with which this is done in clinical practice is unknown. The objectives of this quality improvement initiative were to identify clinician and patient perceptions regarding OSA and to identify the prevalence of patients at high risk for OSA (HROSA).

METHODS

A quality improvement initiative was conducted to query clinicians and patients attending a specialty diabetes clinic regarding attitudes and beliefs related to OSA. The Berlin Questionnaire was embedded in patient questionnaires to identify patients as low risk for OSA (LROSA) or HROSA.

RESULTS

35 clinicians completed questionnaires with >80% agreement that OSA contributed to blood pressure (BP), glycemic control, and diabetes complications and that screening is a shared responsibility with other physicians; but only 17% indicated regular screening due predominantly to insufficient time. Of 107 patients (26 type 1 diabetes mellitus (T1DM) and 81 type 2 diabetes mellitus (T2DM)), 30% were aware that OSA could affect diabetes outcomes. The prevalence of known OSA, LROSA, and HROSA was similar in T1DM (15%, 50%, 35%) and T2DM (36%, 33%, 31%, respectively) (p=0.21). 59% of all HROSA patients indicated that OSA screening had never been discussed with them.

CONCLUSIONS

These results demonstrate that providers, but not patients, are knowledgeable about the importance of OSA screening, but insufficient time is a major barrier to wider screening. Approximately, 30% of patients with T1DM and T2DM were identified as HROSA supporting the need for procedures that improve detection and treatment.