Effect of continuous positive airway pressure on glucose metabolism in adults with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Association of poor sleep and HbA1c in metformin-treated patients with type 2 diabetes: Findings from the UK Biobank cohort study

The American Diabetes Association recommends a glycated haemoglobin target of less than 7% for treating type 2 diabetes mellitus. However, it is still being determined if poor sleep affects this therapeutic goal, despite being treated with the blood-glucose-lowering medication metformin. Thus, we used data from 5703 patients on metformin monotherapy participating in the UK Biobank baseline investigation between 2006 and 2010. We combined self-reported chronotype, daily sleep duration, insomnia, daytime sleepiness and snoring into a multidimensional poor sleep score ranging from 0 to 5, with higher scores indicating a less healthy sleep pattern. With each point increase on the poor sleep score scale, the odds of patients having an glycated haemoglobin of ≥ 7% increased by 6% (odds ratio [95% confidence interval], 1.06 [1.01, 1.11], p = 0.021). When examining the components of the poor sleep score separately, snoring was specifically associated with a glycated haemoglobin of ≥ 7% (1.12 [1.01, 1.25] versus no snoring, p = 0.038). However, adjusting for health and lifestyle conditions, such as body mass index, weekly physical activity level and hypertension status, eliminated the significant associations between the poor sleep score and snoring with glycated haemoglobin of ≥ 7%. Our findings suggest that poor sleep, specifically snoring, a symptom of obstructive sleep apnea, may interfere with the therapeutic goal of achieving a glycated haemoglobin below 7%. However, other factors known to be promoted by poor sleep, such as high body mass index, low physical activity and hypertension, may also contribute to the link between poor sleep and higher glycated haemoglobin levels.

Effects of continuous positive airway pressure therapy on glucose metabolism in patients with obstructive sleep apnoea and type 2 diabetes: a systematic review and meta-analysis

Obstructive sleep apnoea is a highly prevalent chronic disorder and has been shown to be associated with disturbed glucose metabolism and type 2 diabetes. However, the evidence from individual clinical trials on the effect of continuous positive airway pressure (CPAP) treatment on glycaemic control in patients with co-existing obstructive sleep apnoea and type 2 diabetes remains controversial. A systematic review of randomised controlled trials assessing the effect of CPAP on glycaemic control in patients with obstructive sleep apnoea and type 2 diabetes was conducted using the databases MEDLINE, Embase, Cochrane and Scopus up to December 2022. Meta-analysis using a random-effect model was performed for outcomes that were reported in at least two randomised controlled trials. From 3031 records screened, 11 RCTs with a total of 964 patients were included for analysis. CPAP treatment led to a significant reduction in haemoglobin A1c (HbA1c) (mean difference -0.24%, 95% CI -0.43- -0.06%, p=0.001) compared to inactive control groups. Meta-regression showed a significant association between reduction in HbA1c and hours of nightly CPAP usage. CPAP therapy seems to significantly improve HbA1c and thus long-term glycaemic control in patients with type 2 diabetes and obstructive sleep apnoea. The amount of improvement is dependent on the hours of usage of CPAP and thus optimal adherence to CPAP should be a primary goal in these patients.

Association between positive airway pressure therapy adherence and health care resource utilization in patients with obstructive sleep apnea and type 2 diabetes in the United States

STUDY OBJECTIVES

There is a complex interplay between obstructive sleep apnea (OSA) and type 2 diabetes. There are minimal data regarding the effects of treating OSA with positive airway pressure (PAP) therapy on outcomes and health care resource utilization (HCRU) in patients with OSA and type 2 diabetes. We investigated the impact of PAP adherence on HCRU and costs in this population.

METHODS

A retrospective analysis was conducted with a cohort of OSA patient from a US administrative claims dataset linked to objective device data (AirView, ResMed Corp., San Diego, California). Propensity score matching was used to control for potential imbalance in baseline covariates between PAP-adherent and -nonadherent patients. Newly diagnosed patients with OSA aged ≥ 18 years with type 2 diabetes were included. PAP adherence was defined as meeting Centers for Medicare and Medicaid Services compliance criteria in all 8 90-day periods over 2 years. HCRU was based on the number of all-cause doctor visits, emergency room visits, inpatient hospitalizations, and PAP equipment and supplies.

RESULTS

In years 1 and 2 of PAP therapy, HCRU was significantly lower in adherent vs nonadherent patients (number/patient for emergency room visits 0.68 ± 1.47 vs 0.99 ± 1.91 [year 1], 0.69 ± 1.43 vs 0.95 ± 1.89 [year 2]; for hospitalizations 0.16 ± 0.58 vs 0.22 ± 0.62 [year 1], 0.15 ± 0.51 vs 0.21 ± 0.74 [year 2]; all P < .001). Changes in estimated total 24-month payments were higher for nonadherent patients ($2,282, 95% confidence interval: $1,368, $3,205).

CONCLUSIONS

Consistent use of PAP therapy over 2 years was associated with decreased HCRU in patients with OSA and type 2 diabetes, strongly suggesting a role for screening and treating OSA in type 2 diabetes.

CITATION

Sterling KL, Cistulli PA, Linde-Zwirble W, et al. Association between positive airway pressure therapy adherence and health care resource utilization in patients with obstructive sleep apnea and type 2 diabetes in the United States. J Clin Sleep Med. 2023;19(3):563-571.

Effect of Continuous Positive Airway Pressure on Glucose and Lipid Profiles in Patients With Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIM

Continuous Positive Airway Pressure (CPAP) is the most effective therapy for symptomatic obstructive sleep apnoea (OSA). However, uncertainty remains about the effectiveness of CPAP in improving OSA-related metabolic dysregulation. This meta-analysis of randomized controlled trials (RCTs) aimed to investigate whether CPAP, compared to other control treatments, could improve glucose or lipid metabolism in OSA patients.

METHODS

Relevant articles were searched in three different databases (MEDLINE, EMBASE and Web of Science) from inception to 6th Feb 2022 through specific search terms and selection criteria.

RESULTS

From a total of 5553 articles, 31 RCTs were included. CPAP modestly improved insulin sensitivity as determined by mean fasting plasma insulin and Homeostasis Model Assessment of Insulin Resistance reduction of 1.33mU/L and 0.287, respectively. In subgroup analyses pre-diabetic/type 2 diabetic patients as well as those with sleepy OSA showed a greater response to CPAP. Regarding lipid metabolism, CPAP was associated with a mean total cholesterol reduction of 0.064mmol/L. In subgroup analyses, the benefit was higher in patients that showed more severe OSA and oxygen desaturations at the baseline sleep study as well as in younger and obese subjects. Neither glycated haemoglobin nor triglycerides, HDL- and LDL-cholesterol were reduced by CPAP.

CONCLUSION

CPAP treatment may improve insulin sensitivity and total cholesterol levels in OSA patients but with low effect size. Our results suggest that CPAP does not substantially improve metabolic derangements in an unselected OSA population, but the effect may be higher in specific subgroups of OSA patients.

Insulin Resistance, Hyperglycemia, and Risk of Developing Obstructive Sleep Apnea in Men and Women in the United States

Rationale: Recent prospective studies suggest diabetes as a risk factor for the development of obstructive sleep apnea (OSA). However, the extent to which diabetes-related traits, such as hyperglycemia and insulin resistance, are related to OSA risk remains uncertain. Objectives: To examine the risk of developing OSA according to baseline concentrations of fasting insulin and hemoglobin A1c (HbA1c). Methods: Participants from four prospective U.S. cohorts were included: NHS (Nurses' Health Study; 2002-2012), NHSII (Nurses' Health Study II; 1995-2013), HPFS (Health Professionals Follow-up Study; 1996-2012), and MESA (Multi-Ethnic Study of Atherosclerosis; 2000-2012). OSA was assessed by self-reported clinical diagnosis in NHS/NHSII/HPFS and at-home polysomnography in MESA (defined as Apnea-Hypopnea Index ⩾30). Results: Of 9,283 participants with fasting insulin data, 790 (8.5%) developed OSA over 10 to 18 years of follow-up. After adjusting for sociodemographic, lifestyle, and comorbidity factors, the odds ratio for incident OSA comparing the extreme quintiles of fasting insulin was 3.59 (95% confidence interval, 2.67-4.82; P-trend < 0.0001). Of 6,342 participants with HbA1c data, 715 (11.3%) developed OSA. The comparable odds ratio for HbA1c was 2.21 (95% confidence interval, 1.69-2.89; P-trend < 0.0001). Additional adjustment for body mass index and waist circumference attenuated the associations for fasting insulin (P-trend = 0.005) and HbA1c (P-trend = 0.03). In the fully adjusted model simultaneously including both biomarkers, only fasting insulin but not HbA1c was associated with OSA risk. Conclusions: Independent of obesity, insulin resistance may play a more important role than hyperglycemia in the pathogenesis of OSA. Given the limitation of using self-reported diagnosis to exclude baseline prevalent OSA cases, additional studies are needed to further establish the temporal relationship and assess whether improving insulin resistance may reduce OSA risk.

Obesity and Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is characterized by upper airway collapse during sleep. Chronic intermittent hypoxia, sleep fragmentation, and inflammatory activation are the main pathophysiological mechanisms of OSA. OSA is highly prevalent in obese patients and may contribute to cardiometabolic risk by exerting detrimental effects on adipose tissue metabolism and potentiating the adipose tissue dysfunction typically found in obesity. This chapter will provide an update on: (a) the epidemiological studies linking obesity and OSA; (b) the studies exploring the effects of intermittent hypoxia and sleep fragmentation on the adipose tissue; (c) the effects of OSA treatment with continuous positive airway pressure (CPAP) on metabolic derangements; and (d) current research on new anti-diabetic drugs that could be useful in the treatment of obese OSA patients.

Diabetes mellitus and cardiovascular risk: an update of the recommendations of the Diabetes and Cardiovascular Disease Working Group of the Spanish Society of Diabetes (SED, 2021)

This document is an update to the clinical practice recommendations for the management of cardiovascular risk factors (CVRF) in diabetes mellitus. The consensus has been developed by a multidisciplinary team made up of members of the Cardiovascular Risk Group of the Spanish Diabetes Society (SED). The work is a necessary update as, since the last review three years ago, there have been many clinical trials that have studied the cardiovascular outcomes of numerous drugs in the diabetic population. We believe that this guideline update may be of interest to all clinicians treating patients with diabetes.

Long-Term Weight Change and Glycemic Control in Patients With Type 2 Diabetes Mellitus and Treated vs. Untreated Sleep-Disordered Breathing-Analysis From the DIAbetes COhoRtE

Hypothesis: Positive airway pressure (PAP) is the standard treatment for sleep-disordered breathing (SDB), a prevalent condition in patients with type 2 diabetes mellitus (DM2). Recent studies showed that short-term PAP treatment may cause weight gain. However, long-term data for patients with DM2 are scarce. Therefore, the aim of the present analysis was to assess changes in weight and glycemic control in patients with DM2 and treated vs. untreated SDB.

Methods: The DIAbetes COhoRtE (DIACORE) study is a prospective population-based cohort study in patients with DM2. At baseline, patients of the DIACORE-SDB sub-study were tested for SDB [defined as apnea-hypopnea-index (AHI) ≥ 15/h] using a two-channel ambulatory SDB-monitoring device. In this observational study, PAP treatment was initiated in a subgroup of patients with SDB (SDB PAP) within clinical routine between the baseline and first follow-up visit [median observation period of 2.3 (2.2; 2.4) years], whereas the other patients with SDB did not receive PAP (SDB untreated). At baseline and first follow-up visit, weight and HbA1c were assessed.

Results: Of the 346 patients with SDB [mean age 68 years, 71% male, body-mass index (BMI) 31.9 kg/m²], 17% were in the SDB PAP and 83% in the SDB untreated group. Weight change within the observation period was similar in both groups (−0.2 and −0.9 kg; p = 0.322). The percentage of patients with severe weight gain (≥ 5 kg) within the observation period was significantly higher in the SDB PAP group compared to the SDB untreated group (15.0 vs. 5.6%; p = 0.011). Multivariable regression analysis, accounting for baseline HbA1c, insulin substitution, BMI, waist-to-hip ratio (WHR), physical activity, and AHI, showed that PAP treatment was significantly associated with a weight gain ≥ 5 kg [odds ratio (OR) = 3.497; 95% CI (1.343; 9.106); p = 0.010] and an increase in HbA1c [B = 2.410; 95% CI (0.118; 4.702); p = 0.039].

Conclusion: Median weight change was similar in patients with SDB with and without PAP treatment. However, patients with DM2 and PAP treatment have an increased risk of severe long-term weight gain and an increase in HbA1c.

Clinical Trial registration: DRKS00010498

ATS Core Curriculum 2021. Adult Sleep Medicine: Sleep Apnea

The American Thoracic Society Sleep Core Curriculum updates clinicians on important sleep topics, presented during the annual meeting, and appearing in summary here. This year’s sleep core theme is sleep-disordered breathing and its management. Topics range from pathophysiological mechanisms for the association of obstructive sleep apnea (OSA) and metabolic syndrome, surgical modalities of OSA treatment, comorbid insomnia and OSA, central sleep apnea, and sleep practices during a pandemic. OSA has been associated with metabolic syndrome, independent of the role of obesity, and the pathophysiology suggests a role for sleep fragmentation and intermittent hypoxia in observed metabolic outcomes. In specific patient populations, surgical treatment modalities for OSA have demonstrated large reductions in objective disease severity compared with no treatment and may facilitate adherence to positive airway pressure treatment. Patient-centered approaches to comorbid insomnia and sleep apnea include evaluating for both OSA and insomnia simultaneously and using shared-decision making to determine the order and timing of positive airway pressure therapy and cognitive behavioral therapy for insomnia. The pathophysiology of central sleep apnea is complex and may be due to the loss of drive to breathe or instability in the regulatory pathways that control ventilation. Pandemic-era sleep practices have evolved rapidly to balance safety and sustainability of care for patients with sleep-disordered breathing.

Sleep interventions and glucose metabolism: systematic review and meta-analysis

OBJECTIVE

Sleep disturbances (insufficient or poor sleep quality) have been linked to abnormal glucose metabolism. This systematic review and meta-analysis aimed to explore the effects of behavioral and pharmacological sleep interventions on glucose metabolism.

METHODS

Medline and Embase were used for systematic search. Studies reporting behavioral or pharmacological interventions in population with sleep disturbances, with measured outcomes of glucose metabolism and sleep parameters were selected.

RESULTS

Twenty two studies were eligible for review (eight were conducted in people with type 2 diabetes). Studies were grouped into three types of intervention: sleep extension (n = 6), sleep education or cognitive behavioral therapy for insomnia (CBT-I, n = 6) and pharmacological interventions (n = 10). CBT-I and sleep education resulted in significantly improved self-reported sleep quality (Pittsburgh Sleep Quality Index, mean difference, MD, -1.31, 95% confidence interval (CI) -1.83, -0.80), non-significant reduction in hemoglobin A1c level (MD -0.35%, 95% CI -0.84, 0.13), and non-significant reduction in fasting glucose levels (MD -4.76 mg/dL, 95% CI -14.19, 4.67). Other studies were not eligible for meta-analysis due to heterogeneity of interventions or outcomes. Sleep extension was able to increase sleep duration by varying degrees in short sleepers, and five of six studies demonstrated relationships between the intervention and measures of insulin resistance. A majority of pharmacological intervention studies showed improved sleep but the effects on glucose metabolism were mixed.

CONCLUSIONS

Available sleep interventions were effective in improving sleep but the effects on glucose metabolism were inconclusive. Larger randomized studies with consistent outcome measurements are needed to demonstrate this potential causal relationship.

Systematic review of clinical practice guidelines to identify recommendations for sleep in type 2 diabetes mellitus management

INTRODUCTION

Sleep quality, quantity and timing have been shown to impact glycaemic control, with a role in insulin sensitivity, glucose tolerance and HbA1C levels, in both diabetic and non-diabetic populations. The aim of this study was to identify recommendations for sleep assessment and management in international clinical practice guidelines focused on type 2 diabetes mellitus management in adults.

STUDY DESIGN

Systematic Review.

METHODOLOGY

Clinical practice guidelines which focused on the management of type 2 diabetes mellitus in adults were included (n = 35). Two independent reviewers utilised the Appraisal of Guidelines for Research and Evaluation tool (AGREE) II and a third reviewer resolved any disagreements. Included guidelines were assessed for recommendations about sleep in diabetes management (n = 14). Data were extracted on sleep recommendations ,themes were generated from the extracted data and narrative syntheses were created.

RESULTS

From 1114 identified papers, 35 guidelines met the inclusion criteria. Fourteen of these guidelines included recommendations pertaining to sleep, which broadly fell into five categories; sleep assessment, sleep as a therapeutic target, sleep and co-morbidities of type 2 diabetes mellitus, shift work and sleep and driving. Recommendations varied across guidelines.

CONCLUSION

Few guidelines provided recommendations relating to assessment and management of sleep in type 2 diabetes care. Most of the recommendations were related to obstructive sleep apnoea. However, few guidelines discussed sleep as a therapeutic intervention for diabetes mellitus or described the potential importance of sleep quality and duration in glycaemic control. Prospero registration number: CRD42020142136.

Does non-invasive ventilation change metabolic markers in children with obstructive sleep apnoea? A systematic review and meta-analysis study protocol

INTRODUCTION

Obstructive sleep apnoea (OSA) is not only common within paediatrics but is associated with critical childhood metabolic morbidity such as obesity, cardiovascular disease and glucose tolerance impairment. Increasing evidence suggests an association between childhood OSA and metabolic syndrome such as markers of cardiovascular disease, systemic hypertension, glucose intoleranceand increased lipid profile. Recent studies have targeted changes in metabolic markers in children using non-invasive ventilation (NIV) but no systematic reviews are available to summarise this emerging evidence. The purpose of this systematic review is to provide systematic synthesis of the evidence on the effect of NIV use on metabolic markers in children with OSA.

METHODS AND ANALYSIS

A systematic search of electronic databases and grey literature will include paediatric interventional studies (random controlled trials, cohort studies) with and without a comparison group. Two reviewers will independently undertake the two step process of title/abstract and full-text screening. Data will be extracted and assessed, with aggregate data being reported. When the data allow, meta-analysis will be performed.

ETHICS AND DISSEMINATION

There are no ethical concerns with this systematic review, as data have previously been published. This review will inform clinicians taking care of children with OSA and obesity/metabolic syndrome about the potential effects of NIV therapies on metabolic markers and has the potential to change the approach to childhood OSA and obesity. Results of this systematic review will be submitted for dissemination in abstract and manuscript form.

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.

Medication of comorbidities in females with sleep-disordered breathing during long-term CPAP therapy

BACKGROUND

Treating sleep disordered breathing (SDB) with nasal continuous positive airway pressure (CPAP) may reduce mortality, but the studies on the effect on medication use are few. Women tend to have more mild sleep apnoea and partial airway obstruction and are therefore expected to have less co-morbidity. The purpose of this study was to evaluate the effect of CPAP therapy on medication use in women as overall medication, and in different subcategories of diseases, and to evaluate the impact of nocturnal airway obstruction type as partial or complete.

METHODS

From the database of the Department of Pulmonary Diseases in Turku University Hospital from 1994 to 1998, 601 consecutive females with SDB were enrolled, and the type of SDB was evaluated. All were offered CPAP therapy. The medication use measured as defined daily doses (DDD) in overall medication and in nine subcategories were collected three years before and three years after CPAP initiation.

RESULTS

In final analyses, 182 women were included. In CPAP users (n = 66), comorbidities were more frequent and DDDs higher overall, in asthma, in chronic obstructive pulmonary disease, and in severe mental disorders, both before and after CPAP initiation. The medication use was similar regardless of the type of SDB. The change in medication use was similar as in controls.

CONCLUSIONS

CPAP therapy did not decrease medication use in three-year follow-up. However, possibly continuous rise in medication use was prevented, as the change in medication use was similar in controls. Complete and partial obstruction had similar effects.

Effect of Glucose Improvement on Nocturnal Sleep Breathing Parameters in Patients with Type 2 Diabetes: The Candy Dreams Study

Type 2 diabetes exerts a negative impact on sleep breathing. It is unknown whether a long-term improvement in glycemic control ameliorates this effect. We conducted an interventional study with 35 patients with type 2 diabetes and obstructive sleep apnea (OSA) to explore this. At home, sleep breathing parameters were assessed at baseline and after a 4-month period in which antidiabetic therapy was intensified. Patients who decreased their body mass index ≥2kg/m² were excluded. Those with an HbA1c reduction ≥0.5% were considered good responders (n = 24). After the follow-up, good responders exhibited an improvement in the apnea–hypopnea index (AHI: 26-1 (95% IC: 8.6–95.0) vs. 20.0 (4.0–62.4) events/hour, p = 0.002) and in time with oxygen saturation below 90% (CT90: 13.3 (0.4–69.0) vs. 8.1 (0.4–71.2) %, p = 0.002). No changes were observed in the group of non–responders (p = 0.722 and p = 0.138, respectively). The percentage of moderate and severe OSA decreased among good responders (p = 0.040). In the wider population, the change in HbA1c correlated positively to decreases in AHI (r = 0.358, p = 0.035) and negatively to increases in the minimum arterial oxygen saturation (r = −0.386, p = 0.039). Stepwise multivariate regression analysis showed that baseline AHI and the absolute change in HbA1c independently predicted decreased AHI (R² = 0.496). The improvement of glycemic control exerts beneficial effects on sleep breathing parameters in type 2 diabetes, which cannot be attributed merely to weight loss.

Association between body mass index and effectiveness of continuous positive airway pressure in patients with obstructive sleep apnea: a retrospective study

PURPOSE

Ineffective use of continuous positive airway pressure (CPAP) therapy can result in inconvenience and additional costs in patients with obstructive sleep apnea (OSA). This study investigated the predictive value of body mass index (BMI) to assess the efficacy of CPAP in patients with OSA.

METHODS

Data were extracted from a retrospective study performed in Silkeborg Hospital. The primary outcome was the improvement of Apnea-Hypopnea Index (AHI) after CPAP treatment. Association between BMI and improvement of AHI was assessed by multivariable linear regression. Interactions between BMI, baseline AHI severity (≥ 30 or < 30), and diabetes were also evaluated.

RESULTS

Four hundred eighty-one patients were included in the study. After adjusting for confounders, high BMI (coefficient [coef], 0.80; 95% confidence interval [CI], 0.59-1.00; p < 0.001) and high AHI severity (AHI ≥ 30) (coef, 29.2; 95% CI, 26.7-31.7; p < 0.001) were associated with greater improvement of AHI after CPAP treatment, while diabetes was associated with less improvement of AHI (coef, - 4.91; 95% CI, - 9.40 to - 0.42; p = 0.032). Baseline AHI severity, diabetes, and BMI showed significant interactions (p < 0.001). On subgroup analysis, the association between BMI and improvement of AHI remained significant only in patients belonging to high AHI severity subgroup (coef, 1.18; 95% CI, 0.8-1.49; p < 0.001) and that without diabetes (coef, 1.42; 95% CI, 1.11-1.72; p < 0.001).

CONCLUSIONS

Patients with OSA having high BMI, without diabetes, are more likely to benefit from CPAP therapy. Future studies should explore the predictors of the efficacy of CPAP in more depth.

Obstructive Sleep Apnea, Sleepiness, and Glycemic Control in Type 2 Diabetes

STUDY OBJECTIVES

Self-reported sleepiness is common in patients with obstructive sleep apnea (OSA) and is being increasingly recognized as an effect modifier of the association between OSA and cardiovascular outcomes. However, data on whether sleepiness modifies the association between OSA and glycemic outcomes are lacking. The current study sought to characterize the association between glycemic control and sleepiness in people with OSA and type 2 diabetes.

METHODS

Adults with non-insulin requiring type 2 diabetes and undiagnosed moderate to severe OSA were recruited from the community. Demographic data, Epworth Sleepiness Scale (ESS), hemoglobin A1c (HbA1c), as well a type III home sleep test were obtained. The association between self-reported sleepiness and glycemic control was examined using quantile regression.

RESULTS

The study cohort included 311 participants with 56% of the sample being men. Stratified analyses by sex demonstrated that self-reported sleepiness was associated with a higher HbA1c level, but this association was present only in men with a body mass index (BMI) < 35 kg/m². Mean HbA1c levels were higher by 0.57% (95% confidence interval: 0.11, 1.02) in men with an ESS ≥ 11 compared to men with an ESS < 11. No such association was observed in men with a BMI ≥ 35 kg/m² or in women of any BMI category.

CONCLUSIONS

The association between self-reported sleepiness and glycemic control in people with type 2 diabetes and moderate to severe OSA varies a function of BMI and sex. The noted differences in association should be considered when assessing possible treatment effects of therapy for OSA on metabolic outcomes.

Obstructive sleep apnea and comorbidities: a dangerous liaison

Obstructive sleep apnea (OSA) is a highly prevalent disease, and is traditionally associated with increased cardiovascular risk. The role of comorbidities in OSA patients has emerged recently, and new conditions significantly associated with OSA are increasingly reported. A high comorbidity burden worsens prognosis, but some data suggest that CPAP might be protective especially in patients with comorbidities. Aim of this narrative review is to provide an update on recent studies, with special attention to cardiovascular and cerebrovascular comorbidities, the metabolic syndrome and type 2 diabetes, asthma, COPD and cancer. Better phenotypic characterization of OSA patients, including comorbidities, will help to provide better individualized care. The unsatisfactory adherence to CPAP in patients without daytime sleepiness should prompt clinicians to examine the overall risk profile of each patient in order to identify subjects at high risk for worse prognosis and provide the optimal treatment not only for OSA, but also for comorbidities.

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.

Sleep-Disordered Breathing Is Associated with Metabolic Syndrome in Outpatients with Diabetes Mellitus Type 2

BACKGROUND

Metabolic syndrome (MS) and sleep-disordered breathing (SDB) are highly prevalent in patients with diabetes mellitus type 2 (DM2). The present study examined whether there is an independent association between SDB and MS in a sample of outpatients with DM2.

METHODS

MS was determined in 679 patients of the DIACORE-SDB substudy, a study of outpatients with DM2. According to the National Cholesterol Education Program (NCEP) criteria, MS is defined by at least three of the following five criteria: waist circumference of >102 cm (men)/>88 cm (women), blood pressure of ≥130/85 mmHg, a fasting triglyceride level of >150 mg/dl, high-density lipoprotein (HDL) of <40 mg/dl (men)/<50 mg/dl (women), and a fasting glucose level of ≥110 mg/dl. The apnea-hypopnea index (AHI) was assessed with a 2-channel ambulatory monitoring device and used to define the severity of SDB (AHI < 15.0: no/mild SDB; AHI 15.0-29.9: moderate SDB; AHI ≥ 30.0: severe SDB).

RESULTS

228 (34%) of the 679 participants (mean age 66 years, mean body mass index (BMI) 31.2 kg/m², and mean AHI 14/hour) had SDB. MS was significantly more frequent in patients with more severe SDB (no/mild SDB vs. moderate SDB vs. severe SDB: 72% vs. 79% vs. 85%, respectively, p = 0.038). Logistic regression analysis adjusted for sex, age, obesity (BMI ≥ 30 kg/m²), and the HOMA index showed a significant association between the AHI and the presence of MS (OR (95%CI) = 1.039 (1.011; 1.068); p = 0.007). Further, male sex, obesity, and the HOMA index were significantly associated with MS.

CONCLUSION

SDB is significantly and independently associated with MS in outpatients with DM2.

"Mind" in Betel-quid Use and Related Disorders

Oral squamous cell carcinoma is characterized by a unique predisposing state called oral potentially malignant disorders (OPMDs). Wide variety of carcinogenic insult in the form of detrimental habits can contribute to the causation of variety of OPMDs.1,2.