The impact of effective continuous positive airway pressure on homeostasis model assessment insulin resistance in non-diabetic patients with moderate to severe obstructive sleep apnea

Characteristics of obstructive sleep apnea related to insulin resistance

BACKGROUND

Obstructive sleep apnea (OSA) is associated with multiple comorbidities, including diabetes. Its development is preceded by alterations in the initial phase of carbohydrate metabolism characterized by insulin resistance. This study aims to evaluate the role of intermittent hypoxia and sleep fragmentation characteristic of OSA on the risk of insulin resistance among apneic patients without diabetes.

METHODOLOGY

92 consecutive patients with OSA without evidence of diabetes were recruited. Overnight video polysomnography was performed and, the following morning, fasting blood glucose, insulin and glycosylated hemoglobin were determined. Insulin resistance was measured using the HOMA-IR index.

RESULTS

Insulin resistance was present in 52.2% of OSA patients. In these subjects, insulin resistance was independently associated to the apnea index during REM sleep (adjusted odds ratio [aOR] 1.09; 95% CI, 1.03 to 1.16; p = 0.004), desaturation index (aOR 1.08; 95% CI: 1.04 to 1.13; p = 0.027), and sleep time with oxygen saturation below 90% (aOR 1.04; 95% CI 1.00 to 1.08; p = 0.049). Furthermore, the HOMA-IR level was also directly related to the desaturation index (standardized regression coefficient [B] = 0.514, p < 0.001) and to the apnea index during REM sleep (B = 0.344, p = 0.002).

CONCLUSIONS

Intermittent hypoxia and disturbances in REM sleep emerge as main contributors to insulin resistance in OSA patients yet to experience diabetes onset.

Effects of continuous positive airway pressure on cardiac events and metabolic components in patients with moderate to severe obstructive sleep apnea and coronary artery disease: a meta-analysis

STUDY OBJECTIVES

This meta-analysis aimed to systematically assess the effects of continuous positive airway pressure (CPAP) in secondary prevention of major cardiovascular events (MACEs) in patients with moderate-to-severe obstructive sleep apnea and coronary artery disease.

METHODS

PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov were searched for observational studies and randomized controlled trials that compared CPAP with usual care in patients with moderate-to-severe obstructive sleep apnea with coronary artery disease. The primary outcomes were MACEs, all-cause death, acute coronary syndrome, rehospitalization for heart failure, repeat revascularization, and arrhythmia.

RESULTS

A total of 11 studies (5 randomized controlled trials and 6 observational studies) with 5,410 patients reported outcomes of MACEs. Treatment with CPAP was associated with a modest risk reduction in MACEs (risk ratio [RR] 0.87, 95% confidence interval [CI] 0.78 to 0.98; P = .02). Similarly, CPAP significantly reduced the risk of all-cause and cardiovascular death by 23% (RR 0.77, 95% CI 0.60 to 0.99; P = .04; I2 = 0%). Subgroup analysis revealed that CPAP adherence time ≥ 4 hours/night had a greater benefit on MACEs by 42% (RR 0.58, 95% CI 0.42 to 0.79; P < .001; I2 = 0%) and repeat revascularization by 44% (RR 0.56, 95% CI 0.34 to 0.92; P = .02; I2 = 0%). Also, CPAP had a positive effect on systolic and diastolic blood pressure.

CONCLUSIONS

CPAP therapy might prevent subsequent MACEs and all-cause death among patients with moderate to severe obstructive sleep apnea and concomitant coronary artery disease. CPAP use exceeding 4 hours/night may add more benefits on MACEs, repeat revascularization, and blood pressure.

CLINICAL TRIAL REGISTRATION

Registry: PROSPERO database; Name: Effects of Continuous Positive Airway Pressure on Cardiovascular Events and Metabolic Components in Patients with Obstructive Sleep Apnea and Coronary Artery Disease; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID= CRD42020213546; Identifier: CRD42020213546.

CITATION

Yang D, Li L, Dong J, Yang W, Liu Z. Effects of continuous positive airway pressure on cardiac events and metabolic components in patients with moderate to severe obstructive sleep apnea and coronary artery disease: a meta-analysis. J Clin Sleep Med. 2023;19(12):2015-2025.

Understanding the pathophysiological mechanisms of cardiometabolic complications in obstructive sleep apnoea: towards personalised treatment approaches

In January 2019, a European Respiratory Society research seminar entitled "Targeting the detrimental effects of sleep disturbances and disorders" was held in Dublin, Ireland. It provided the opportunity to critically review the current evidence of pathophysiological responses of sleep disturbances, such as sleep deprivation, sleep fragmentation or circadian misalignment and of abnormalities in physiological gases such as oxygen and carbon dioxide, which occur frequently in respiratory conditions during sleep. A specific emphasis of the seminar was placed on the evaluation of the current state of knowledge of the pathophysiology of cardiovascular and metabolic diseases in obstructive sleep apnoea (OSA). Identification of the detailed mechanisms of these processes is of major importance to the field and this seminar offered an ideal platform to exchange knowledge, and to discuss pitfalls of current models and the design of future collaborative studies. In addition, we debated the limitations of current treatment strategies for cardiometabolic complications in OSA and discussed potentially valuable alternative approaches.

Pro: should asymptomatic patients with moderate-to-severe OSA be treated?

Substantial evidence points to a benefit with CPAP on cardiovascular and metabolic outcomes in asymptomatic patients with moderate-to-severe obstructive sleep apnoea http://ow.ly/FUxN30nkTqU.

Sleep apnea and type 2 diabetes

The aim of the present review was to clarify the association between obstructive sleep apnea (OSA) and type 2 diabetes, and discuss the therapeutic role of continuous positive airway pressure (CPAP) in type 2 diabetes. OSA patients are more likely than non-OSA populations to develop type 2 diabetes, while more than half of type 2 diabetes patients suffer from OSA. Similar to Western countries, in the East Asian population, the association between these two disorders has also been reported. CPAP is the primary treatment for OSA, but the effect of CPAP on comorbid diabetes has not been established. CPAP improved glucose metabolism determined by the oral glucose tolerance test in OSA patients, and several studies have shown that CPAP improves insulin resistance, particularly in obese populations undergoing long-term CPAP. Diabetes is associated with other sleep-related manifestations as well, such as snoring and excessive daytime sleepiness. Snoring is associated with the development of diabetes, and excessive daytime sleepiness appears to modify insulin resistance. Well-designed studies are required to clarify the therapeutic effect of CPAP on diabetes. As both diabetes and OSA lead to cardiovascular disease, clinicians and healthcare professionals should be aware of the association between diabetes and OSA, and should take CPAP and health-related behaviors into consideration when treating patients with diabetes and/or OSA.

Effect of CPAP therapy on liver disease in patients with OSA: a review

Obstructive sleep apnea (OSA) may play an important role in the progression of nonalcoholic fatty liver disease (NAFLD).The effect of continuous positive airway pressure (CPAP) treatment, the first-line therapy for OSA, on liver disease in OSA patients is still debated. We provide this review of previous studies to summarize the effects of CPAP treatment on liver disease in OSA patients in aspects of liver function, liver steatosis, fibrosis, and incidence of liver disease. CPAP treatment may be beneficial to liver disease in subjects with OSA independent of metabolic risk factors, but a sufficiently long therapeutic duration (perhaps greater than 3 months) may be needed to achieve these positive effects. Though the mechanism of impact of CPAP treatment on liver in OSA patients is unclear, the influence of CPAP treatment on the factors of the "Two-hit" hypothesis (insulin resistance, fatty acids dysregulation, oxidative stress, and inflammation) may be a reasonable explanation.

Obstructive sleep apnoea and polycystic ovary syndrome: A comprehensive review of clinical interactions and underlying pathophysiology

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine disorder in women of reproductive age. PCOS is associated with multiple comorbidities including, obesity, insulin resistance and type 2 diabetes, as well as mood disorders and impaired quality of life (QoL). Obstructive sleep apnoea (OSA) is also a common medical condition that is often undiagnosed, particularly in women. OSA is associated with a similar spectrum of comorbidities to that observed in PCOS, including manifestations of the metabolic syndrome and impaired QoL, whilst obesity frequently constitutes a common denominator in the pathophysiology of both OSA and PCOS. Hence, it is not surprising that OSA and PCOS may coexist in women of reproductive age, and the current clinical guidelines on the management of PCOS recommend screening for OSA symptoms in overweight/obese women with PCOS. In this review, we examine the relationship between OSA and PCOS and explore the potential underlying mechanisms that link these two conditions.

Insulin Resistance and Hypertension in Obese Youth With Sleep-Disordered Breathing Treated With Positive Airway Pressure: A Prospective Multicenter Study

STUDY OBJECTIVES

There is evidence that cardiometabolic disease associated with obesity and sleep-disordered breathing (SDB) in adults is present in youth. SDB is often treated with positive airway pressure (PAP) in youth with obesity. Our aims were to determine: (1) the prevalence of cardiometabolic disease and (2) whether PAP improves markers of cardiometabolic disease, in youth with obesity and newly diagnosed moderate-severe SDB.

METHODS

A prospective multicenter cohort study was conducted in youth (8 to 16 years old) with obesity, prescribed PAP therapy for newly diagnosed moderate-severe SDB. Assessments occurred at baseline and at 6 and 12 months. Outcomes included markers of insulin resistance (change in homeostasis model assessment of insulin resistance (HOMA-IR) at 6 months = primary outcome), hypertension (24-hour ambulatory/blood pressure) and inflammation (high-sensitivity C-reactive protein: hs-CRP).

RESULTS

Twenty-seven participants were enrolled. Of those with baseline testing available, 10/25 (40%) had HOMA-IR above the 97th percentile, 10/23 (44%) were hypertensive, 16/23 (70%) had loss of nocturnal blood pressure dip and hs-CRP was elevated in 16/27 (64%). There were no significant changes over time in markers of metabolic dysfunction or blood pressure, nor between PAP-adherent and non-adherent subgroups.

CONCLUSIONS

In youth with obesity and SDB, metabolic dysfunction and hypertension were highly prevalent. There were no statistically significant improvements in cardiometabolic markers 1 year after the prescription of PAP therapy, although clinically relevant improvements were seen in insulin resistance and systolic blood pressure load, important predictors of future risk of cardiovascular disease. Larger, longer-term studies are needed to determine whether PAP improves cardiometabolic outcomes in obese youth.

COMMENTARY

A commentary on this article appears in this issue on page 1025.

Continuous positive airway pressure and diabetes risk in sleep apnea patients: A systemic review and meta-analysis

BACKGROUND

The study assessed the effect of continuous positive airway pressure (CPAP) therapy on the risk of developing type 2 diabetes by evaluating change in the homeostasis model assessment of insulin resistance (HOMA-IR) fasting blood glucose (FBG) and fasting insulin following CPAP treatment in non-diabetic patients and pre-diabetic with obstructive sleep apnea (OSA).

METHODS

Medline, PubMed, Cochrane, and EMBASE databases were searched until August 24, 2015. The analysis included randomized controlled trials (RCTs), two arm prospective studies, cohort studies, and retrospective studies. The primary outcome measure was change of HOMA-IR in pre-diabetic patients receiving CPAP treatment.

RESULTS

Twenty-three studies were included with 965 patients who had OSA. Nineteen studies were prospective studies and four were RCTs. CPAP therapy resulted in a significant reduction in the pooled standard difference in means of HOMA-IR (-0.442, P=0.001) from baseline levels compared with the control group. Change in FBG and fasting insulin from baseline levels was similar for the CPAP and control groups. For RCT studies (n=4), there was no difference in change in HOMA-IR or FBG levels from baseline between CPAP and control groups. The combined effect of RCTs showed that CPAP was associated with a significant reduction in change from baseline in fasting insulin than the control group (standardized diff. in means between groups=-0.479, P value=0.003).

CONCLUSION

These findings support the use of CPAP in non-diabetic and pre-diabetic patients with OSA to reduce change of HOMA-IR and possibly reduce the risk of developing type 2 diabetes in this patient population.

Glucose tolerance and cardiovascular risk biomarkers in non-diabetic non-obese obstructive sleep apnea patients: Effects of long-term continuous positive airway pressure

BACKGROUND

Insulin resistance, glucose dyshomeostasis and oxidative stress are associated to the cardiovascular consequences of obstructive sleep apnea (OSA). The effects of a long-term continuous positive airway pressure (LT-CPAP) treatment on such mechanisms still remain conflicting.

OBJECTIVE

To investigate the effect of LT-CPAP on glucose tolerance, insulin sensitivity, oxidative stress and cardiovascular biomarkers in non-obese non-diabetic OSA patients.

PATIENTS & METHODS

Twenty-eight apneic, otherwise healthy, men suffering from OSA (mean age = 48.9 ± 9.4 years; apnea-hypopnea index = 41.1 ± 16.1 events/h; BMI = 26.6 ± 2.8 kg/m(2); fasting glucose = 4.98 ± 0.37 mmol/L) were evaluated before and after LT-CPAP by an oral glucose tolerance test (OGTT), measuring plasma glucose, insulin and proinsulin. Glycated hemoglobin, homeostasis model assessment resistance insulin, blood lipids, oxidative stress, homocysteine and NT-pro-brain natriuretic peptide (NT-proBNP) were also measured.

RESULTS

LT-CPAP treatment lasted 13.9 ± 6.5 months. At baseline, the time spent at SaO2<90%, minimal and mean SaO2 were associated with insulin area under the curve during OGTT (r = 0.448, P = 0.011; r = -0.382; P = 0.047 and r = -0.424; P = 0.028, respectively) and most other glucose/insulin homeostasis biomarkers, as well as with homocysteine (r = 0.531, P = 0.006; r = -0.487; P = 0.011 and r = -0.409; P = 0.034, respectively). LT-CPAP had no effect on all the OGTT-related measurements, but increased plasma total antioxidant status (+7.74%; P = 0.035) in a duration-dependent manner (r = 0.607; P < 0.001), and decreased both homocysteine (-15.2%; P = 0.002) and NT-proBNP levels (-39.3%; P = 0.002).

CONCLUSIONS

In non-obese non-diabetic OSA patients, nocturnal oxygen desaturation is strongly associated to insulin resistance. LT-CPAP does not improve glucose homeostasis nor insulin sensitivity but has a favorable effect on antioxidant capacity and cardiovascular risk biomarkers.

Insulin resistance, glucose intolerance and diabetes mellitus in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a highly prevalent disorder, which conveys an increased risk of cardiovascular disease and death. Type 2 diabetes mellitus (T2DM), glucose intolerance and insulin resistance (IR) are common in subjects with OSA, but a shared intimate relationship with obesity makes discerning an independent link challenging. Nonetheless, mechanistic studies suggest that OSA could contribute to impaired glucose metabolism via the effects of sleep fragmentation, sympathetic excitation and intermittent hypoxia (IH) on pancreatic B-cell function, insulin sensitivity, and systemic inflammation. In particular, emerging data suggest that IH may have an important detrimental effect on adipose tissue function and inflammation. Similarly, data from population-and clinic-level studies suggest that OSA is independently related with the prevalence and incidence of T2DM and IR, and may also lead to worse glycaemic control in diabetics. However, the ability of continuous positive airway pressure (CPAP) therapy to make a meaningful impact on T2DM or IR remains uncertain. In this review we explore the available evidence linking OSA with IR, glucose intolerance and T2DM, and discuss potential pathobiological mechanisms by which sleep disordered breathing can affect metabolic health.

Obstructive Sleep Apnoea and Vascular Disease in Patients with Type 2 Diabetes

Obstructive sleep apnoea (OSA) is common and is associated with many vascular risk factors, such as hypertension, insulin resistance, albuminuria, dyslipidaemia, increased inflammation and endothelial dysfunction. Epidemiological studies have shown that OSA is associated with increased cardiovascular disease (CVD) and that continuous positive airway pressure (CPAP) might reduce CVD events in patients with OSA. In addition, OSA has also been shown to be associated with albuminuria, chronic kidney disease, a wide range of ocular diseases and peripheral neuropathy. Considering that CVD and microvascular complications are major contributors to the morbidity, mortality and the economic burden of diabetes and that OSA is common in patients with type 2 diabetes (T2D), it is important to understand the role of OSA in the development and/or progression of vascular disease in patients with T2D and to explore the impact of CPAP on diabetes-related vascular outcomes. The purpose of this article is to review the evidence for the relationship and impact of OSA on vascular disease and vascular risk factors particularly in patients with T2D.

Obstructive Sleep Apnea Risk, Asthma Burden, and Lower Airway Inflammation in Adults in the Severe Asthma Research Program (SARP) II

BACKGROUND

Obstructive sleep apnea (OSA) may worsen asthma, but large studies are lacking and the underlying mechanisms are unknown.

OBJECTIVE

The objective of this study was to determine the prevalence of OSA risk among patients with asthma of different severity compared with normal controls (NC), and among asthmatics, to test the relationship of OSA risk with asthma burden and airway inflammation.

METHODS

Subjects with severe (SA, n = 94) and nonsevere asthma (NSA, n = 161), and NC (n = 146) were recruited in an add-on substudy, to the observational Severe Asthma Research Program (SARP) II; subjects completed sleep quality, sleepiness and OSA risk (Sleep Apnea scale of the Sleep Disorders Questionnaire [SA-SDQ]) questionnaires, and clinical assessments. Sputum was induced in a subset of asthmatics.

RESULTS

Relative to NC, despite similar sleep duration, the subjects with SA and NSA had worse sleep quality, were sleepier, and had higher SA-SDQ scores. Among asthmatics, higher SA-SDQ was associated with increased asthma symptoms, β-agonist use, health care utilization, and worse asthma quality of life. A significant association of SA-SDQ with sputum polymorphonuclear cells% was noted: each increase in SA-SDQ by its standard deviation (6.85 units) was associated with a rise in % sputum neutrophils of 7.78 (95% CI 2.33-13.22, P = .0006), independent of obesity and other confounders.

CONCLUSIONS

OSA symptoms are more prevalent among asthmatics, in whom they are associated with higher disease burden. OSA risk is associated with a neutrophilic airway inflammation in asthma, which suggests that OSA may be an important contributor to the neutrophilic asthma. Further studies are necessary to confirm these findings and better understand the mechanistic underpinnings of this relationship.

Meta-analyses of the Association of Sleep Apnea with Insulin Resistance, and the Effects of CPAP on HOMA-IR, Adiponectin, and Visceral Adipose Fat

OBJECTIVE

We sought to conduct an updated meta-analysis of randomized controlled trials (RCTs) on the effect of continuous positive airway pressure (CPAP) on insulin resistance, as measured by homeostasis model assessment of insulin resistance (HOMA-IR), visceral abdominal fat (VAF), and adiponectin. Additionally, we performed a separate meta-analysis and meta-regression of studies on the association of insulin resistance and obstructive sleep apnea (OSA).

METHODS

All included studies were searched from PubMed (from conception to March 15, 2014). Data were pooled across all included RCTs as the mean difference in HOMA-IR and VAF, and as the standardized mean difference in the case of adiponectin analysis. From the included case-control studies, data on the difference of HOMA-IR between cases and controls were pooled across all studies, as the standardized mean difference (SMD).

RESULTS

There was a significant difference in HOMA-IR (-0.43 [95% CIs: -0.75 to -0.11], p = 0.008) between CPAP treated and non CPAP treated participants. However, there was no significant difference in VAF or adiponectin; (-47.93 [95% CI: -112.58 to 16.72], p = 0.14) and (-0.06 [95% CI: -0.28 to 0.15], p = 0.56), respectively. Meta-analysis of 16 case-control studies showed a pooled SMD in HOMA-IR of 0.51 (95% CI: 0.28 to 0.75), p ≤ 0.001, between cases and controls.

CONCLUSIONS

The results of our meta-analyses show that CPAP has a favorable effect on insulin resistance. This effect is not associated with any significant changes in total adiponectin levels or amount of VAF. Our findings also confirm a significant association between OSA and insulin resistance.

Novel therapeutics for type 2 diabetes: insulin resistance

Insulin resistance (IR) plays an important role in the pathogenesis of type 2 diabetes (T2D) and cardiovascular disease. Hence improving IR is a major target of treatment in patients with T2D. Obesity and lack of exercise are major causes of IR. However, recent evidence implicates sleep disorders and disorders of the circadian rhythm in the pathogenesis of IR. Weight loss and lifestyle changes are the cornerstone and most effective treatments of IR, but adherence and patient's acceptability are poor. Bariatric surgery results in significant and sustainable long-term weight loss associated with beneficial impact on IR and glucose metabolism, making this an attractive treatment option for patients with T2D. Currently available pharmacological options targeting IR (such as metformin and thiazolidinediones) do not maintain glycaemic measures within targets long term and can be associated with significant side effects. Over the last two decades, many pharmacological agents targeting different aspects of the insulin signalling pathway were developed to improve IR, but only a minority reached clinical trials. Such treatments need to be specific and reversible as many of the components of the insulin signalling pathway are involved in other cellular functions such as apoptosis. Recent evidence highlighted the role of circadian rhythm and sleep-related disorders in the pathogenesis of IR. In this article, we review the latest developments in the pharmacological and non-pharmacological interventions targeting IR including bariatric surgery. We will also review the role of circadian rhythm and sleep-related disorders in the development and treatment of IR.

Obstructive sleep apnoea and diabetes: an update

PURPOSE OF REVIEW

The relationship between obstructive sleep apnoea (OSA) and dysglycaemia is well established. However, uncertainty remains as to the extent that obesity mediates this relationship. The impact of OSA treatment on glucose metabolism and the consequences of having OSA in patients with diabetes is unclear. This review aims to summarize the latest evidence regarding the links between OSA and dysglycaemia.

RECENT FINDINGS

OSA is associated with insulin resistance in lean individuals and predicts insulin resistance worsening longitudinally. Continuous positive airway pressure (CPAP) lowers insulin resistance in CPAP-compliant patients. OSA is associated with impaired β-cell function. In patients with type 2 diabetes (T2D), the association between OSA and glycosylated haemoglobin (HbA1c) is related to nocturnal hypoxaemia. Apnoea hypopnoea index (AHI) during rapid eye movement (REM) (not non-REM) sleep is associated with HbA1c. In-laboratory, supervised CPAP improves glycaemia. OSA is associated with and predicts the progression of some diabetic vascular complications. Intensive lifestyle intervention in patients with T2D improves OSA independent of weight loss.

SUMMARY

OSA is associated with insulin resistance and β-cell dysfunction independent of obesity. OSA is associated with HbA1c and vascular complications in patients with T2D. CPAP might improve insulin resistance and glycaemic measures. Lifestyle intervention has a significant impact on AHI in patients with T2D.

Effect of continuous positive airway pressure on lipid profile in patients with obstructive sleep apnea syndrome: a meta-analysis of randomized controlled trials

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for development of dyslipidemia. Continuous positive airway pressure (CPAP) is the first-line treatment for OSAS. However, it is unclear whether CPAP improves lipid metabolism.

OBJECTIVES

To review the effect of CPAP on lipid profile of patients with OSAS.

METHODS

We searched PubMed, Embase, and the Cochrane Library to identify eligible articles published prior to October 30, 2013. Six randomized controlled trials (RCTs) were subjected to meta-analysis using Comprehensive Meta-Analysis software.

RESULTS

Six RCTs meeting the inclusion criteria were enrolled. The total numbers of measurements of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol, in CPAP intervention patients and sham/control groups, were 370 and 371, 330 and 328, 276 and 274, and 269 and 266 respectively. The pooled estimate of the difference in the mean TC level between the CPAP and sham CPAP/control groups was significantly different (-0.15 [95% confidence interval, -0.27 to -0.03]; p = 0.01). Subgroup analysis revealed that OSAS patients of younger age, who were more obese, and who had been treated via CPAP for a longer duration, showed a significant decrease in TC levels (the differences in the means were -0.27, -0.24, and -0.20; and the p values 0.001, 0.01, and 0.04, respectively).

CONCLUSION

We confirmed that CPAP decreases the TC level, especially in OSAS patients who are younger, more obese, and who use CPAP for a longer period. CPAP did not alter TG, LDL, or HDL levels, suggesting that CPAP may have no clinically important effect on lipid metabolism.

Obstructive Sleep Apnoea and Type 2 Diabetes

With the growing prevalence of obesity, the burden of type 2 diabetes is increasing. Obstructive sleep apnoea (OSA) is a very common medical condition that is associated with increased risk of cardiovascular disease and mortality. Obesity is a common risk factor for OSA and type 2 diabetes and hence it is not surprising that OSA and type 2 diabetes are interlinked. OSA has been shown to be an independent risk factor for the development of incident pre-diabetes/type 2 diabetes. OSA is also associated with worse glycaemic control and vascular disease in patients with type 2 diabetes. However, evidence for the benefits of OSA treatment in patients with type 2 diabetes is still lacking. The aim of this article is to provide an overview of OSA, the relationships between OSA and dysglycaemia and the impact of OSA in patients with type 2 diabetes, highlighting recent advances in the field.