Association between severity of obstructive sleep apnea and glycated hemoglobin level in Japanese individuals with and without diabetes

Effects of Positive Airway Pressure Therapy on Glycemic Variability in Patients With Type 2 Diabetes and OSA: A Randomized Controlled Trial

BACKGROUND

Glycemic variability is associated with increased risk for cardiovascular disease in patients with type 2 diabetes independent of glycosylated hemoglobin A1c (HbA1c) levels. Given the conflicting evidence on the effect of positive airway pressure (PAP) therapy for OSA on HbA1c, elucidating its effect on glycemic variability has value.

RESEARCH QUESTION

Does the use of PAP therapy for OSA improve glycemic variability in patients with type 2 diabetes?

STUDY DESIGN AND METHODS

A randomized controlled trial was conducted in 184 patients with type 2 diabetes and moderate-to-severe OSA. Participants received either 3 months of PAP therapy with lifestyle counseling or lifestyle counseling alone. End points included the SD of glucose levels along with other metrics derived from continuous glucose monitoring and self-monitoring of blood glucose.

RESULTS

No differences were noted in either primary or secondary continuous glucose monitoring end points between the two groups. Average use of PAP therapy was 5.4 h/night (SD, 1.6). Exploratory analyses by sex showed significant differences in the primary and secondary outcomes. In female participants, PAP therapy was associated with improvement in the SD of glucose levels, with a mean difference in change between intervention and control groups of 3.5 mg/dL (P = .02). PAP therapy was also associated with lower post-dinner and bedtime glucose levels: 20.1 mg/dL (P < .01) and 34.6 mg/dL (P < .01), respectively.

INTERPRETATION

PAP therapy did not improve glycemic control or variability in patients with moderate-to-severe OSA and type 2 diabetes. Exploratory analyses suggested that PAP therapy may improve glucose variability in female participants. Post-dinner and bedtime glucose levels were higher in those who did not receive PAP therapy.

TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02454153; URL: www.

CLINICALTRIALS

gov.

CGMap: Characterizing continuous glucose monitor data in thousands of non-diabetic individuals

Despite its rising prevalence, diabetes diagnosis still relies on measures from blood tests. Technological advances in continuous glucose monitoring (CGM) devices introduce a potential tool to expand our understanding of glucose control and variability in people with and without diabetes. Yet CGM data have not been characterized in large-scale healthy cohorts, creating a lack of reference for CGM data research. Here we present CGMap, a characterization of CGM data collected from over 7,000 non-diabetic individuals, aged 40-70 years, between 2019 and 2022. We provide reference values of key CGM-derived clinical measures that can serve as a tool for future CGM research. We further explored the relationship between CGM-derived measures and diabetes-related clinical parameters, uncovering several significant relationships, including associations of mean blood glucose with measures from fundus imaging and sleep monitoring. These findings offer novel research directions for understanding the influence of glucose levels on various aspects of human health.

Investigating the Relationship between Obstructive Sleep Apnoea, Inflammation and Cardio-Metabolic Diseases

Obstructive sleep apnoea (OSA) is a prevalent underdiagnosed disorder whose incidence increases with age and weight. Uniquely characterised by frequent breathing interruptions during sleep-known as intermittent hypoxia (IH)-OSA disrupts the circadian rhythm. Patients with OSA have repeated episodes of hypoxia and reoxygenation, leading to systemic consequences. OSA consequences range from apparent symptoms like excessive daytime sleepiness, neurocognitive deterioration and decreased quality of life to pathological complications characterised by elevated biomarkers linked to endocrine-metabolic and cardiovascular changes. OSA is a well-recognized risk factor for cardiovascular and cerebrovascular diseases. Furthermore, OSA is linked to other conditions that worsen cardiovascular outcomes, such as obesity. The relationship between OSA and obesity is complex and reciprocal, involving interaction between biological and lifestyle factors. The pathogenesis of both OSA and obesity involve oxidative stress, inflammation and metabolic dysregulation. The current medical practice uses continuous positive airway pressure (CPAP) as the gold standard tool to manage OSA. It has been shown to improve symptoms and cardiac function, reduce cardiovascular risk and normalise biomarkers. Nonetheless, a full understanding of the factors involved in the deleterious effects of OSA and the best methods to eliminate their occurrence are still poorly understood. In this review, we present the factors and evidence linking OSA to increased risk of cardiovascular conditions.

Effect of CPAP on blood glucose fluctuation in patients with type 2 diabetes mellitus and obstructive sleep apnea

Purpose

This study aimed to investigate the effect of continuous positive airway pressure (CPAP) on blood glucose fluctuation in patients with type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA).

Methods

Patients with T2DM and OSA were divided into an intervention group and a control group. All patients were treatment naïve. The intervention group was given CPAP therapy. The subjects were monitored using a continuous glucose monitoring system (CGMS) for 2 weeks.

Results

Of 60 patients, 30 were selected to receive CPAP intervention while 30 without CPAP served as controls. The CPAP tolerance of the intervention group was good, with average time on CPAP therapy of 55.2 ± 4.3 days, and average daily time on CPAP therapy of 8.3 ± 2.8 h. The postprandial blood glucose (PBG), fasting blood glucose (FBG), and HbA1c levels in the intervention group decreased significantly (P < 0.05). Significant variations in 24-h mean blood glucose and night-time mean blood glucose were significantly lower with CPAP therapy than without therapy (P < 0.05, respectively). The mean of daily differences and mean ambulatory glucose excursions were both considerably lower with treatment than without (P < 0.05, respectively). There was also a significant difference in time in range and time above range (P < 0.05, respectively).

Conclusion

CPAP treatment may significantly improve the blood glucose level and blood glucose stability in patients with T2DM and OSA. CPAP is an effective treatment method beyond lifestyle intervention and drug therapy.

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.

Relationship between obstructive sleep apnoea during rapid eye movement sleep and metabolic syndrome parameters in patients with type 2 diabetes mellitus

PURPOSE

Sleep-disordered breathing (SDB) is associated with hypertension, poor glycemic control and dyslipidemia. Usually, apnoea events tend to be more prominent during rapid eye movement (REM) sleep than non-REM (NREM) sleep. We examined which SDB parameters are associated with blood pressure (BP), HbA1c and lipid profile in patients with type 2 diabetes (T2D).

METHODS

A total of 185 patients with T2D who underwent polysomnography were analysed. Exclusion criteria were: the presence of pulmonary diseases, central sleep apnoea, treated SDB, or REM sleep < 30 min. To predict BP, HbA1c, and lipid profiles, we performed multiple linear regression analyses adjusted for known risk factors. Subsequently, we performed multivariable logistic regression analyses.

RESULTS

Patient characteristics (mean ± standard deviation/median) were as follows: age 58.0 ± 11.8 years, body mass index 26.0 kg/m2 (24.1-28.9 kg/m2 ), systolic BP 134 ± 19 mmHg, mean BP 98 ± 14 mmHg, HbA1c 7.4% (6.8-8.4%), triglyceride 143 mg/dL (97-195 mg/dL), non-high density lipoprotein (non-HDL) cholesterol 143 mg/dL (120-163 mg/dL), REM-apnoea-hypopnea index (AHI) 35.1/h (21.1-53.1/h). The analyses revealed that REM-AHI was independently associated with systolic and mean BP, whereas NREM-AHI was not. A statistically significant association was not observed between REM-AHI and HbA1c or lipid profile.

CONCLUSION

In patients with T2D, REM-AHI was associated with systolic and mean BP. The alteration of BP, associated with SDB during REM sleep, may be an important pathophysiological link between SDB and cardiovascular diseases.

The relationship between coffee intake, obstructive sleep apnea risk, and type 2 diabetes glycemic control, in Tabuk City, The Kingdom of Saudi Arabia: a case-control study

Objectives

The study aimed to assess the relationship between coffee intake, obstructive sleep apnea risk (OSA), and glycemic control among patients with diabetes mellitus.

Results

There were 110 patients with diabetes and 96 healthy control subjects (matched for age and sex) attending a diabetes center زinTabuk, Saudi Arabia during the period from June 2018–October 2019. Stop-Bang questionnaire was used to assess OSA risk, and Epworth Sleepiness Scale to investigate daytime sleepiness. OSA risk and daytime sleepiness were higher among patients with diabetes compared to controls (4.34 ± 1.61 vs. 2.86 ± 1.24, and 8.31 ± 4.40 vs. 6.39 ± 3.70 respectively, P < 0.5), while coffee consumption was not (4.64 ± 3.95 vs. 3.45 ± 3.06, P > 0.05). Women with diabetes were younger with short duration since the diagnosis of diabetes and consumed less coffee compared to men, P < 0.5. A negative correlation was found between coffee consumption and the duration of diabetes, while no correlation was found between coffee intake, the glycated hemoglobin, OSA risk, sex, and daytime sleepiness. Daytime sleepiness and OSA risk were commoners among patients with diabetes, they were not correlated with coffee consumption which was negatively correlated with the duration since diabetes diagnosis. Further larger multi-center studies investigating coffee intake among patients newly diagnosed with diabetes are recommended.

Improving obesity and blood pressure

Obesity-associated hypertension is a serious public health concern. Sympathetic nervous system (SNS) overactivity, especially in the kidneys, is an important mechanism linking obesity to hypertension. Some adipokines play important roles in elevating blood pressure (BP). Hyperinsulinemia caused by insulin resistance stimulates sodium reabsorption, enhances sodium retention, and increases circulating plasma volume. Hyperinsulinemia also stimulates both the renin-angiotensin-aldosterone system (RAAS) and the SNS, resulting in the acceleration of atherosclerosis through the hypertrophy of vascular smooth muscle cells, which contributes to increased peripheral vascular resistance. Obesity is associated with increased RAAS activity despite volume overload, as the tissue RAASs are stimulated in obese hypertensive individuals. Mineralocorticoid receptor-associated hypertension must also be considered in obese patients with resistant hypertension. Obstructive sleep apnea syndrome (OSAS) is the most common cause of secondary hypertension. Some components of the gut microbiota contribute to BP control; therefore, gut dysbiosis caused by obesity might lead to increased BP. The ratio of visceral fat to subcutaneous fat is higher in Japanese patients than in Caucasian patients, which may explain why Japanese patients are more susceptible to metabolic disorders even though they are less obese than Caucasian individuals. Obesity-associated kidney dysfunction directly increases BP, leading to further deterioration of kidney function. A bodyweight reduction of more than 3% or 5 kg significantly lowers BP. Gastrointestinal bypass surgery is an effective treatment for morbid obesity and its related metabolic disorders, including hypertension. Because both obesity and hypertension are representative lifestyle-related disorders, lifestyle modification, especially to improve obesity, should be performed first as a treatment for hypertension.

Effects of CPAP on the transcriptional signatures in patients with obstructive sleep apnea via coexpression network analysis

A growing number of studies provide epidemiological evidence linking obstructive sleep apnea (OSA) with a number of chronic disorders. Transcriptional analyses have been conducted to analyze the gene expression data. However, the weighted gene coexpression network analysis (WGCNA) method has not been applied to determine the transcriptional consequence of continuous positive airway pressure (CPAP) therapy in patients with severe OSA. The aim of this study was to identify key pathways and genes in patients with OSA that are influenced by CPAP treatment and uncover/unveil potential molecular mechanisms using WGCNA. We analyzed the microarray data of OSA (GSE 49800) listed in the Gene Expression Omnibus database. Coexpression modules were constructed using WGCNA. In addition, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were also conducted. After the initial data processing, 5101 expressed gene profiles were identified. Next, a weighted gene coexpression network was established and 16 modules of coexpressed genes were identified. The interaction analysis demonstrated a relative independence of gene expression in these modules. The black module, tan module, midnightblue module, pink module, and greenyellow module were significantly associated with the alterations in circulating leukocyte gene expression at baseline and after exposure to CPAP. The five hub genes were considered to be candidate OSA-related genes after CPAP treatment. Functional enrichment analysis revealed that steroid biosynthesis, amino sugar and nucleotide sugar metabolism, protein processing in the endoplasmic reticulum, and the insulin signaling pathway play critical roles in the development of OSA in circulating leukocyte gene expression at baseline and after exposure to CPAP. Using this new systems biology approach, we identified several genes and pathways that appear to be critical to OSA after CPAP treatment, and these findings provide a better understanding of OSA pathogenesis.

Evaluation of obstructive sleep apnea in metabolic syndrome

Background:

Metabolic syndrome has become one of the most important public health problems with a growing prevalence in both developed and developing countries. Obesity is a major risk factor for obstructive sleep apnea (OSA), which is associated with significant cardiorespiratory morbidity.

Aims:

The aims of this study were to find out the prevalence of OSA in patients with metabolic syndrome and to highlight the importance of assessment of OSA in these patients.

Methods:

This cross-sectional analytical study was conducted on 100 subjects aged 30–60 years, comprising 50 cases of metabolic syndrome and 50 controls without metabolic syndrome. Overnight polysomnography was done in all the subjects. Prevalence and severity of OSA were assessed and compared between the two groups.

Results:

Prevalence of OSA was significantly higher (66%) in patients with metabolic syndrome than in subjects without metabolic syndrome (12%). Out of 33 (66%) OSA patients with metabolic syndrome, 8 (16%) had mild OSA, 11 (22%) had moderate OSA, and 14 (28%) had severe OSA. Increasing severity of OSA was associated with higher mean levels of all the metabolic syndrome parameters except serum high density lipoprotein (HDL).

Conclusions:

OSA is highly prevalent in patients with metabolic syndrome. Also, the increasing severity of OSA is associated with poorer control of diabetes, hypertension, and dyslipidemia, which are all components of metabolic syndrome. Therefore, effective treatment of metabolic syndrome can prevent and control OSA in these patients. Similarly, reducing the severity of OSA (by early diagnosis and treatment) in patients with metabolic syndrome might help to optimize control of blood sugar, blood pressure, and serum lipids, thereby reducing the risk of cardiovascular disease. Therefore, the need for screening metabolic syndrome patients for OSA has been reinforced by this study.