Autonomic neuropathy increases the risk of obstructive sleep apnea in obese diabetics

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.

Potential Therapeutic Targets in Obesity, Sleep Apnea, Diabetes, and Fatty Liver Disease

Obesity and metabolic syndrome affect the majority of the US population. Patients with obesity are at increased risk of developing type 2 diabetes (T2DM), obstructive sleep apnea (OSA), and metabolic dysfunction-associated steatotic liver disease (MASLD), each of which carry the risk of further complications if left untreated and lead to adverse outcomes. The rising prevalence of obesity and its comorbidities has led to increased mortality, decreased quality of life, and rising healthcare expenditures. This phenomenon has resulted in the intensive investigation of exciting therapies for obesity over the past decade, including more treatments that are still in the pipeline. In our present report, we aim to solidify the relationships among obesity, T2DM, OSA, and MASLD through a comprehensive review of current research. We also provide an overview of the surgical and pharmacologic treatment classes that target these relationships, namely bariatric surgery, the glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon receptor agonists.

Identifying clusters of patient comorbidities associated with obstructive sleep apnea using electronic health records

STUDY OBJECTIVES

The objectives of this study were to understand the relative comorbidity burden of obstructive sleep apnea (OSA), determine whether these relationships were modified by sex or age, and identify patient subtypes defined by common comorbidities.

METHODS

Cases with OSA and noncases (controls) were defined using a validated electronic health record (EHR)-based phenotype and matched for age, sex, and time period of follow-up in the EHR. We compared prevalence of the 20 most common comorbidities between matched cases and controls using conditional logistic regression with and without controlling for body mass index. Latent class analysis was used to identify subtypes of OSA cases defined by combinations of these comorbidities.

RESULTS

In total, 60,586 OSA cases were matched to 60,586 controls (from 1,226,755 total controls). Patients with OSA were more likely to have each of the 20 most common comorbidities compared with controls, with odds ratios ranging from 3.1 to 30.8 in the full matched set and 1.3 to 10.2 after body mass index adjustment. Associations between OSA and these comorbidities were generally stronger in females and patients with younger age at diagnosis. We identified 5 distinct subgroups based on EHR-defined comorbidities: High Comorbidity Burden, Low Comorbidity Burden, Cardiovascular Comorbidities, Inflammatory Conditions and Less Obesity, and Inflammatory Conditions and Obesity.

CONCLUSIONS

Our study demonstrates the power of leveraging the EHR to understand the relative health burden of OSA, as well as heterogeneity in these relationships based on age and sex. In addition to enrichment for comorbidities, we identified 5 novel OSA subtypes defined by combinations of comorbidities in the EHR, which may be informative for understanding disease outcomes and improving prevention and clinical care. Overall, this study adds more evidence that OSA is heterogeneous and requires personalized management.

CITATION

Te TT, Keenan BT, Veatch OJ, Boland MR, Hubbard RA, Pack AI. Identifying clusters of patient comorbidities associated with obstructive sleep apnea using electronic health records. J Clin Sleep Med. 2024;20(4):521-533.

Obstructive sleep apnoea-hypopnoea syndrome

Obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is a common disorder characterised by repetitive episodes of the complete or partial collapse of the pharyngeal airway during sleep. This results in cessation (apnoea) or reduction (hypopnoea) of airflow, leading to oxygen desaturation and sleep fragmentation. An individual's disposition to develop OSAHS depends on the collapsibility of a segment of the upper airway. The degree of collapsibility can be quantified by the balance between occluding or extraluminal pressures of the surrounding tissues. Patients can experience snoring, unrefreshing sleep, witnessed apnoeas, waking with a choking sensation and excessive daytime sleepiness. OSAHS has a broad range of consequences, including cardiovascular, metabolic, and neurocognitive sequelae. Treatment options include lifestyle measures, in particular weight loss, and strategies to maintain upper airway patency overnight, including continuous positive airway pressure, mandibular advancement devices and positional modifiers.

Shorter respiratory event duration is related to prevalence of type 2 diabetes

BACKGROUND

Obstructive sleep apnea (OSA) is a heterogeneous sleep disorder often comorbid with metabolic diseases, and type 2 diabetes (T2DM) is one of them. Although apnea hypopnea index (AHI) is currently the diagnostic criteria for OSA severity, a controversial relationship between AHI and T2DM has been found. On the other hand, the duration of apnea-hypopnea events has been shown to be a useful metric for predicting mortality. This study aimed to test whether average respiratory event duration was associated with prevalence of T2DM.

METHODS

Patients referred to the sleep clinic were recruited in the study. Baseline clinical characteristics and polysomnography parameters including average respiratory event duration were collected. The association of average respiratory event duration with the prevalence of T2DM was evaluated by univariate and multivariate logistic regression analyses.

RESULTS

A total of 260 participants were enrolled, and 92 (35.4%) had T2DM. Univariate analysis revealed that age, body mass index (BMI), total sleep time, sleep efficiency, history of hypertension, and shorter average respiratory event duration were associated with T2DM. In multivariate analysis, only age and BMI remained significant. While average respiratory event duration was insignificant in multivariate analysis, subtype event analysis showed that shorter average apnea duration was both significant in univariate (OR, 0.95; 95% CI, 0.92-0.98) and multivariate analyses (OR, 0.95; 95% CI, 0.91-0.99). Neither average hypopnea duration nor AHI was associated with T2DM. Significant association (OR, 1.19; 95% CI, 1.12-1.25) was observed between shorter average apnea duration and lower respiratory arousal threshold after multivariate adjustment. However, causal mediation analysis revealed no mediating effect of arousal threshold on average apnea duration and T2DM.

CONCLUSION

The average apnea duration may be a useful metric in the diagnosis of OSA comorbidity. Shorter average apnea duration indicating poor sleep quality and augmented autonomic nervous system responses might be the potential pathological mechanisms leading to T2DM.

Endocrine disorders in obstructive sleep apnoea syndrome: A bidirectional relationship

Obstructive sleep apnoea (OSA) is a common disorder characterized by recurrent episodes of apnoea or hypopnea due to total or partial pharyngeal collapse and temporary upper airway obstruction during sleep. The prevalence of OSA is increasing and currently affects about 30% of men and 13% of women in Europe. Intermittent hypoxia, oxidative stress, systemic inflammation, and sleep fragmentation resulting from OSA can provoke subsequent cardiometabolic disorders. The relationships between endocrine disorders and OSA are complex and bidirectional. Indeed, several endocrine disorders are risk factors for OSA. Compared with the general population, the prevalence of OSA is increased in patients with obesity, hypothyroidism, acromegaly, Cushing syndrome, and type 1 and 2 diabetes. In some cases, treatment of the underlying endocrine disorder can improve, and occasionally cure, OSA. On the other hand, OSA can also induce endocrine disorders, particularly glucose metabolism abnormalities. Whether continuous positive airway pressure (CPAP) treatment for OSA can improve these endocrine disturbances remains unclear due to the presence of several confounding factors. In this review, we discuss the current state-of-the-art based on the review of the current medical literature for key articles focusing on the bidirectional relationship between endocrine disorders and OSA and the effects of treatment. Screening of OSA in endocrine patients is also discussed, as it remains a subject of debate.

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.

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.

Effect of nocturnal hypoxemia on glycemic control among diabetic Saudi patients presenting with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a prevalent disease that is associated with an increased incidence of type II diabetes mellitus (DM) if left untreated. We aimed to determine the association between glycosylated hemoglobin (HbA1c) levels and both nocturnal hypoxemia and apnea-hypopnea index (AHI) among a Saudi patients with OSA.

METHODS

A cross-sectional study that enrolled 103 adult patients diagnosed with DM and confirmed to have OSA by full night attended polysomnography between 2018 and 2021. Those who presented with acute illness, chronic obstructive pulmonary disease (COPD)/restrictive lung diseases causing sleep-related hypoxemia, or no available HbA1c level within 6 months before polysomnography were excluded from the study. Univariate and multivariate linear regression analyses between HbA1c levels and parameters of interest were tested.

RESULTS

Sixty-seven (65%) of the studied population had uncontrolled DM (HbA1c ≥7%). In univariate regression analysis, there was a significant positive association between HbA1c, and sleep time spent with an oxygen saturation below 90% (T90), female gender, and body mass index (BMI) (p<0.05) but not AHI, or associated comorbidities (p>0.05). In the multivariate analysis, HbA1c was positively associated with increasing T90 (p<0.05), and ODI (p<0.05), but not with AHI (p>0.05).

CONCLUSION

Nocturnal hypoxemia could be an important factor affecting glycemic control in patients with OSA suffering from DM irrespective of the severity of both diseases.

The Association Between Obstructive Sleep Apnea and Cotton-Wool Spots in Nonproliferative Diabetic Retinopathy

Purpose:

This work reports the association of obstructive sleep apnea (OSA) and cotton-wool spots (CWS) seen in patients with nonproliferative diabetic retinopathy (DR).

Methods:

A random sample of patients diagnosed with DR between January 1, 2015 and December 31, 2018, were selected from medical-billing codes. Dilated funduscopic examination findings and medical history were analyzed by reviewing medical records.

Results:

CWS were present in 12 of 118 patients without OSA, compared with 11 of 32 patients with OSA (10.2% vs 34.4%, respectively; P = .002). OSA was more common in men (68.8%, P = .03) and associated with a higher body mass index (30.0 ± 5.0 without OSA vs 33.6 ± 5.5 with OSA, P < .001). When comparing those with and without OSA, there was no association with age; glycated hemoglobin A1c; stage of DR; insulin dependence; presence of diabetic macular edema; smoking status; or a history of hypertension, hyperlipidemia, cardiovascular disease, or other breathing disorder.

Conclusions:

The presence of OSA is associated with CWS in patients with DR, as well as male sex and a higher body mass index. Further research is needed to determine the ophthalmologist’s role in the timely referral of patients with CWS for OSA evaluation.

Bidirectional association between chronic kidney disease and sleep apnea: a systematic review and meta-analysis

BACKGROUND

Previous data have suggested a link between chronic kidney disease (CKD) and sleep apnea (SA). However, the prevalence and risk association of both disease entities are not uniformly described.

METHODS

Ovid MEDLINE, EMBASE, and the Cochrane Library were searched for eligible publications that included patients aged ≥ 18 years diagnosed with CKD or SA. Included studies were divided into two cohorts: (1) a cohort of CKD or end-stage kidney disease (ESKD) patients reporting the prevalence of SA or odds ratio (OR) for SA (CKD cohort) and (2) a cohort of SA patients reporting the prevalence of CKD/ESKD or OR for CKD/ESKD (SA cohort).

RESULTS

CKD cohort: Of 16 studies (n = 340,587), the pooled estimated prevalence of SA among CKD/ESKD patients was 47.5% (95% CI 28.8-66.9). The pooled adjusted OR for SA among CKD/ESKD patients was 1.961 (95% CI 1.702-2.260). Male sex, history of diabetes, and lower BMI were associated with increased prevalence of SA. SA cohort: Of 12 studies (n = 3,103,074), the pooled prevalence of CKD/ESKD among patients with SA was 8.2% (95% CI 4.7-13.7), whereas the pooled adjusted OR for CKD/ESKD among patients with SA was 2.088 (95% CI 1.777-2.452). Increasing age, higher BMI, male sex, white race, and history of diabetes were associated with higher prevalence of CKD/ESKD.

CONCLUSION

There was a bidirectional association between CKD/ESKD and SA. Interventions aiming to prevent the progression of either CKD or SA are important.

Impact of sleep apnoea-hypopnoea syndrome on diabetic neuropathy. A systematic review

INTRODUCTION

Diabetes mellitus and sleep apnoea-hypopnoea syndrome appear to be related, but it is not well defined whether there is an increased risk of peripheral neuropathy in patients with both diseases. For this reason, we conducted a systematic review.

METHODS

Bibliographic search in 3 electronic databases using a predefined strategy and the PRISMA methodology. Only original studies (any type of design) published from 2000 onwards in English, French, Portuguese or Spanish were included. A study quality scale was established.

RESULTS

Twelve articles were selected, of which six studied type 2 diabetic patients. The overall prevalence of sleep apnoea-hypopnoea syndrome was 43.7% (1,559/3,564 patients). Diabetic neuropathy was more frequent in patients with sleep apnoea-hypopnoea syndrome in nine studies, although significantly only in four (60% vs 27%, P<.001; 64.5% vs 36%, P=.03; 37% vs 23.4%, P<.02; 66.6% vs 0%, P=.007). In one study, diabetic neuropathy was more frequent in patients without sleep apnoea-hypopnoea syndrome (although not statistically significant) and in 2 no comparison was made between patients with/without sleep apnoea/hypopnoea syndrome.

CONCLUSIONS

The observed results suggest a relationship between diabetes mellitus and sleep apnoea-hypopnoea syndrome in the occurrence of diabetic neuropathy.

Sleep Apnea, Obesity, and Disturbed Glucose Homeostasis: Epidemiologic Evidence, Biologic Insights, and Therapeutic Strategies

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA), obesity, and disturbed glucose homeostasis are usually considered distinct clinical condition, although they are tightly related to each other. The aim of our manuscript is to provide an overview of the current evidence on OSA, obesity, and disturbed glucose homeostasis providing epidemiologic evidence, biological insights, and therapeutic strategies.

RECENT FINDINGS

The mechanisms hypothesized to be involved in this complex interplay are the following: (1) "direct weight-dependent" mechanisms, according to which fat excess compromises respiratory mechanics, and (2) "indirect weight-dependent" mechanisms such as hyperglycemia, insulin resistance and secondary hyperinsulinemia, leptin resistance and other hormonal dysregulations frequently found in subjects with obesity, type 2 diabetes, and/or sleep disorders. Moreover, the treatment of each of these clinical conditions, through weight loss induced by diet or bariatric surgery, the use of anti-obesity or antidiabetic drugs, and continuous positive airway pressure (CPAP), seems to positively influence the others. These recent data suggest not only that there are multiple connections among these diseases but also that treating one of them may result in an improvement of the others.

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.

Metabolic Consequences of Obstructive Sleep Apnea Especially Pertaining to Diabetes Mellitus and Insulin Sensitivity

Obstructive sleep apnea (OSA) and diabetes has been known to be closely related to each other and both diseases impact highly on the public health. There are many evidence of reports that OSA is associated with diabetes with a bidirectional correlation. A possible causal mechanism of OSA to diabetes is intermittent hypoxemia and diabetes to OSA is microvascular complication. However, OSA and diabetes have a high prevalence rate in public and shares the common overlap characteristic and risk factors such as age, obesity, and metabolic syndrome that make it difficult to establish the exact pathophysiologic mechanism between them. In addition, studies demonstrating that treatment of OSA may help prevent diabetes or improve glycemic control have not shown convincing result but have become a great field of interest research. This review outlines the bidirectional correlation between OSA and diabetes and explore the pathophysiologic mechanisms by approaching their basic etiologies.

Clinical significance of obstructive sleep apnea in patients with acute coronary syndrome in relation to diabetes status

OBJECTIVE

The prognostic significance of obstructive sleep apnea (OSA) in patients with acute coronary syndrome (ACS) according to diabetes mellitus (DM) status remains unclear. We aimed to elucidate the association of OSA with subsequent cardiovascular events in patients with ACS with or without DM.

RESEARCH DESIGN AND METHODS

In this prospective cohort study, consecutive eligible patients with ACS underwent cardiorespiratory polygraphy between June 2015 and May 2017. OSA was defined as an Apnea Hypopnea Index ≥15 events/hour. The primary end point was major adverse cardiovascular and cerebrovascular events (MACCEs), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure.

RESULTS

Among 804 patients, 248 (30.8%) had DM and 403 (50.1%) had OSA. OSA was associated with 2.5 times the risk of 1 year MACCE in patients with DM (22.3% vs 7.1% in the non-OSA group; adjusted HR (HR)=2.49, 95% CI 1.16 to 5.35, p=0.019), but not in patients without DM (8.5% vs 7.7% in the non-OSA group, adjusted HR=0.94, 95% CI 0.51 to 1.75, p=0.85). Patients with DM without OSA had a similar 1 year MACCE rate as patients without DM. The increased risk of events was predominately isolated to patients with OSA with baseline glucose or hemoglobin A1c levels above the median. Combined OSA and longer hypoxia duration (time with arterial oxygen saturation <90%>22 min) further increased the MACCE rate to 31.0% in patients with DM.

CONCLUSIONS

OSA was associated with increased risk of 1 year MACCE following ACS in patients with DM, but not in non-DM patients. Further trials exploring the efficacy of OSA treatment in high-risk patients with ACS and DM are warranted.

The correlation between obstructive sleep apnea and diabetic neuropathy: A meta-analysis

BACKGROUND

The aim of this study was to explore the correlation between obstructive sleep apnea (OSA) and diabetic neuropathy.

MATERIALS AND METHODS

After working out searching strategy, literatures were screened from the electronic databases: PubMed, Embase, and the Cochrane library. R 3.12 was utilized to perform meta-analysis, and odds ratio (OR) and its 95% confidence interval (CI) were used to present effect size. Heterogeneity was assessed by χ²-based Q test and I² statistics. Publication bias was estimated by Egger's test and sensitivity was evaluated by leave one out methods.

RESULTS

According to the criteria, a total of 11 studies with 1842 patients were enrolled in this study. With a significant heterogeneity (Q=31.83, I²=68.60%), the random effects model was utilized to assess the effect size of pooled data. A remarkable correlation was identified OSA and diabetic neuropathy (OR=1.84, 95% CI: 1.18-2.87) without publication bias (t=1.68, P=0.13). Meanwhile, the result of leave one out performed a well sensitivity. Moreover, the subgroup analyses presented that OSA was significantly correlated with type 1 diabetic neuropathy (OR=1.97, 95% CI: 1.19-3.25), but no remarkable correlation was identified between OSA and type 1 (OR=1.84, 95% CI: 0.86-3.93) or 1+2 (OR=1.30, 95% CI: 0.43-3.92) diabetic neuropathy.

CONCLUSION

OSA was significantly correlated with neuropathy in type 1 diabetes, but not in type 2 and type 1+2 diabetes.

Health-related quality of life in type 2 diabetes mellitus patients with different risk for obstructive sleep apnea

PURPOSE

Our study primarily aimed to investigate health-related quality of life (HRQoL) in type 2 diabetes mellitus (T2DM) patients with different risk for obstructive sleep apnea (OSA).

PATIENTS AND METHODS

This cross-sectional, questionnaire-based study included 466 adult patients with T2DM on regular visit to Center for Diabetes of University Hospital of Split from April to September 2017. All subjects underwent detailed anamnestical evaluation and physical examination with anthropometric measurements. Additionally, all subjects completed STOP (Snoring, Tiredness, Observed apnea, and high blood Pressure) questionnaire to assess risk for OSA, Epworth Sleepiness Scale to assess daytime sleepiness, and Medical Outcomes Study Short Form-36 (SF-36) instrument to evaluate HRQoL.

RESULTS

Most subjects (N=312, 67.0%) represented high-risk OSA group based on STOP questionnaire (STOP score ≥2). Statistically significantly lower HRQoL scores in all SF-36 dimensions were found in T2DM patients with high risk for OSA compared to low-risk group (P<0.001). STOP score showed statistically significant negative correlation with all SF-36 dimensions (P<0.001). In multiple linear regression analysis, STOP score was confirmed as statistically significant independent predictor for all SF-36 components, adjusted for body mass index, age, glycated hemoglobin, and T2DM duration (P<0.001).

CONCLUSION

Our study found that high proportion of patients with T2DM are at high risk for OSA. Furthermore, we showed that group of T2DM patients with high risk for OSA has lower HRQoL in all SF-36 dimensions compared to low-risk patients.

Interactions between and Shared Molecular Mechanisms of Diabetic Peripheral Neuropathy and Obstructive Sleep Apnea in Type 2 Diabetes Patients

Type 2 diabetes (T2D) accounts for about 90% of all diabetes patients and incurs a heavy global public health burden. Up to 50% of T2D patients will eventually develop neuropathy as T2D progresses. Diabetic peripheral neuropathy (DPN) is a common diabetic complication and one of the main causes of increased morbidity and mortality of T2D patients. Obstructive sleep apnea (OSA) affects over 15% of the general population and is associated with a higher prevalence of T2D. Growing evidence also indicates that OSA is highly prevalent in T2D patients probably due to diabetic peripheral neuropathy. However, the interrelations among diabetic peripheral neuropathy, OSA, and T2D hitherto have not been clearly elucidated. Numerous molecular mechanisms have been documented that underlie diabetic peripheral neuropathy and OSA, including oxidative stress, inflammation, endothelin-1, vascular endothelial growth factor (VEGF), accumulation of advanced glycation end products, protein kinase C (PKC) signaling, poly ADP ribose polymerase (PARP), nitrosative stress, plasminogen activator inhibitor-1, and vitamin D deficiency. In this review, we seek to illuminate the relationships among T2D, diabetic peripheral neuropathy, and OSA and how they interact with one another. In addition, we summarize and explain the shared molecular mechanisms involved in diabetic peripheral neuropathy and OSA for further mechanistic investigations and novel therapeutic strategies for attenuating and preventing the development and progression of diabetic peripheral neuropathy and OSA in T2D.

Relationship of Obstructive Sleep Apnoea with Diabetic Retinopathy: A Meta-Analysis

Until now, the relationship of obstructive sleep apnoea (OSA) with diabetic retinopathy (DR) was controversial. This meta-analysis was performed to obtain definitive conclusion on this topic. Relevant articles were searched on databases of Pubmed, Google Scholar, and Chinese National Knowledge Infrastructure (CNKI). The articles were selected according to inclusion and exclusion criteria. Odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the relationship of OSA with risk of DR. I2 and P value were used to assess the presence of heterogeneity. I2 ≥ 50% or P < 0.05 indicated significant heterogeneity. Sensitivity analysis was performed to evaluate the robustness of pooled results. Begg's funnel plot and Egger's regression analysis were adopted to assess publication bias. 6 eligible studies were selected in the present meta-analysis. The pooled results indicated that OSA was significantly associated with increased risk of DR (OR = 2.01, 95% CI = 1.49-2.72). Subgroup analysis based on type of diabetes mellitus suggested that OSA was related to DR in both Type 1 and Type 2 diabetes mellitus. Sensitivity analysis demonstrated that pooled results were robust. No significant publication bias was observed (P = 0.128). The results indicate that OSA is related to increased risk of DR.

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.

Effect of obstructive sleep apnoea on diabetic retinopathy and maculopathy: a systematic review and meta-analysis

AIMS

To summarize the association between obstructive sleep apnoea and diabetic retinopathy and diabetic maculopathy, and to examine the effects of oxygen desaturation index, mean and minimum oxygen saturation and time spent with < 90% oxygen saturation on diabetic retinopathy and diabetic maculopathy.

METHODS

A systematic search was performed for papers published from inception to January 2014 in MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews using indexed terms and free text. Additional searches were carried out for grey literature. Two authors conducted the study selection and quality assessment. Data extraction was performed by the main author and checked by the other authors.

RESULTS

One cohort study and 15 cross-sectional studies were included for narrative synthesis and three for meta-analyses. There was no convincing evidence that obstructive sleep apnoea was associated with diabetic retinopathy, although some evidence suggested that obstructive sleep apnoea was associated with greater severity of diabetic retinopathy and advanced diabetic retinopathy in people with Type 2 diabetes. Only six studies examined the impact of obstructive sleep apnoea on diabetic maculopathy and our narrative review suggests there is an association in Type 2 diabetes. Oxygen desaturation index, mean oxygen saturation or time spent with < 90% oxygen saturation were not associated with diabetic retinopathy, and insufficient evidence was available to draw conclusions on their effects on diabetic maculopathy; however, there was evidence from both narrative synthesis and meta-analysis that minimum oxygen saturation had an impact on diabetic retinopathy (pooled odds ratio 0.91, 95% CI 0.87-0.95; I(2) = 0%).

CONCLUSIONS

There is a need for large cohort studies with long-term follow-up data to examine the long-term effects of obstructive sleep apnoea and other sleep variables on advanced retinal disease in diabetes.

The Association between Obstructive Sleep Apnea on Diabetic Kidney Disease: A Systematic Review and Meta-Analysis

STUDY OBJECTIVE

This systematic review aims to investigate the association between obstructive sleep apnea (OSA) and diabetic kidney disease (DKD).

METHODS

MeSH terms and free text searches were performed on MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from inception to April 2015. Zetoc and OpenGrey databases were queried for grey literature, and lastly, hand searches were carried out. Study selection and quality assessment were conducted by two authors. One author carried out data extraction, which was checked by other authors. The relationships between apneahypopnea index (AHI), oxygen desaturation index (ODI), time spent under 90% oxygen saturation (%TST < 90), and minimum and mean oxygen saturation (O2) on DKD were examined.

RESULTS

Two longitudinal and ten cross-sectional studies were included for our narrative synthesis, and seven studies for meta-analysis. Studies that performed multi-variable analysis demonstrated significant associations between OSA (assessed using either apnea-hypopnea index or ODI) and DKD in type 2 diabetes mellitus (T2DM). This was confirmed by meta-analysis (pooled OR 1.73, 95% CI: 1.13-2.64). There was some evidence to suggest that %TST < 90 may have an association with DKD. There was insufficient evidence to conclude on the relationship between minimum and mean oxygen saturation on DKD. There was no evidence available on the associations between OSA and other respiratory parameters in type 1 diabetes mellitus populations.

CONCLUSIONS

There is moderate evidence that OSA is associated with DKD in patients with T2DM. Large prospective studies with long-term follow up are needed to assess the possible bi-directional mechanisms between OSA and DKD.

Pulmonary function tests in type 1 diabetes adolescents with diabetic cardiovascular autonomic neuropathy

Chronic diabetic complications may afflict all organ tissues including cardiovascular and respiratory system. The aim of the study was to establish if the presence of cardiovascular autonomic neuropathy (CAN) was associated with impaired pulmonary function tests in adolescents with type 1 diabetes (T1D). 46 adolescents with T1D and 25 healthy subjects at the age 15-19years were enrolled to the study. Basic anthropometric data, diabetes onset and duration, plasma glucose and A1c were established. Pulmonary function tests were measured by spirometry and the presence of CAN was examined by heart rate variability. Adolescents with T1D had significantly lower pulmonary function test parameters - FVC (p<0.01), FEV1 (p<0.01), MMEF (p<0.05) and PEFR (p<0.05) compared to the control subjects. In diabetic group, patients with CAN (CAN+, n=19) had significantly lower FVC (p<0.05), FEV1 (p<0.05) and PEFR (p<0.05) compared to patients without CAN (CAN-, n=27). All spirometric parameters were significantly lower in CAN+ subjects compared to healthy controls; however, no significant difference was found in these parameters between CAN- subjects and healthy controls. Spirometric parameters (FVC, FEV1) significantly positively correlated with diabetes onset and body mass index; and negatively correlated with diabetes duration and resting heart rate. Our results indicate that CAN may be associated with reduced pulmonary functions in adolescents with T1D.

Effect of glycemic control on nocturnal arterial oxygen saturation: a case-control study in type 2 diabetic patients

BACKGROUND

There is growing evidence suggesting a deleterious effect of type 2 diabetes on lung function and sleep breathing. The aim of this case-control study was to evaluate whether or not an improvement in glycemic control could arrest or ameliorate nocturnal hypoxemia in type 2 diabetes.

METHODS

Thirty patients with type 2 diabetes with HbA1c ≥8% (cases) and 10 non-diabetic subjects were analyzed. Controls were closely matched to cases by age, gender, body mass index, and neck circumference. The nocturnal oxygen desaturation index (ODI) was calculated at baseline and 5 days after blood glucose improvement with pharmacological intervention. Four different oxygen desaturation thresholds (reductions in SaO2  ≥ 3%, 4%, 6%, and 8%) as indicators of hypoxemia severity (ODI-3%, ODI-4%, ODI-6%, ODI-8%) were used.

RESULTS

At baseline, patients with diabetes showed a higher number of ODI-3%, ODI-4%, and ODI-6% in comparison with controls. A significant reduction in ODI-3% (29.7 [4.8-107.9] events per hour at baseline versus 24.6 [3.1-97.7] e/h at discharge, P < 0.001), ODI-4% (21.7 [1.6-79.3] versus 14.7 [0.3- 79.4], P = 0.003), ODI-6% (9.3 [0.3-71.8] versus 4.0 [0.0-73.7], P = 0.001), and ODI-8% (4.1 [0.0-64.3] versus 1.1 [0.0-69.8], P = 0.033) was observed in patients with diabetes after 5 days of follow-up. However, no changes in ODI events were observed in non-diabetic patients after the same period. No significant changes in weight were observed in either group.

CONCLUSIONS

Glycemic control improvement significantly reduces the increased number of nocturnal oxygen desaturations that exist in type 2 diabetes. Although the mechanisms are not yet fully understood, the rapid effect without changes in body weight suggests a central mechanism involving respiratory center output.

Obstructive sleep apnoea in people with Type 1 diabetes: prevalence and association with micro- and macrovascular complications

AIMS

Few reports have assessed the relationship between Type 1 diabetes and sleep disorders. The purposes of our study were to determine the prevalence of obstructive sleep apnoea in Type 1 diabetes and to compare the clinical profile of people with Type 1 diabetes with or without obstructive sleep apnoea.

METHODS

In this cross sectional study of 67 consecutive people with Type 1 diabetes, we performed polysomnography as part of their yearly check-ups.

RESULTS

In our cohort, with a mean BMI of 25.8 ± 4.7 kg/m(2), the prevalence of obstructive sleep apnoea [apnoea-hypopnoea index (AHI) > 10/h] was 46%. Severe obstructive sleep apnoea (AHI ≥ 30/h) was present in 19% of the patients. We found no significant differences in age, sex, body mass index, HbA1c or Epworth sleepiness scale score between people with or without obstructive sleep apnoea. People with obstructive sleep apnoea had a longer course of diabetes mellitus (P < 0.01) and a higher prevalence of retinopathy (P < 0.01), neuropathy (P = 0.05), cardiovascular disease (P < 0.01) and hypertension (P < 0.01). The occurrence of macrovascular complications was independently associated with the presence of OSA [odds ratio (OR) 8.28; 95% confidence interval (CI), 1.56-43.97; P = 0.013] and the duration of diabetes (OR 1.08; 95% CI, 1.02-1.15; P = 0.01). Moreover, retinopathy was independently associated with OSA (OR 4.54; 95% CI, 1.09-18.82; P = 0.04) and the duration of diabetes (OR 1.09; 95% CI, 1.04-1.15; P = 0.001).

CONCLUSIONS

The prevalence of obstructive sleep apnoea was high in people with Type 1 diabetes. Obstructive sleep apnoea was independently associated with macrovascular complications and retinopathy. Obesity and excessive daytime sleepiness were uncommon in this population.

Sleep apnea-hypopnea syndrome and type 2 diabetes. A reciprocal relationship?

Epidemiological data suggest that sleep apnea-hypopnea syndrome (SAHS) is independently associated with the development of insulin resistance and glucose intolerance. Moreover, despite significant methodological limitations, some studies report a high prevalence of SAHS in patients with type 2 diabetes mellitus (DM2). A recent meta-analysis shows that moderate-severe SAHS is associated with an increased risk of DM2 (relative risk=1.63 [1.09 to 2.45]), compared to the absence of apneas and hypopneas. Common alterations in various pathogenic pathways add biological plausibility to this relationship. Intermittent hypoxia and sleep fragmentation, caused by successive apnea-hypopnea episodes, induce several intermediate disorders, such as activation of the sympathetic nervous system, oxidative stress, systemic inflammation, alterations in appetite-regulating hormones and activation of the hypothalamic-pituitary-adrenal axis which, in turn, favor the development of insulin resistance, its progression to glucose intolerance and, ultimately, to DM2. Concomitant SAHS seems to increase DM2 severity, since it worsens glycemic control and enhances the effects of atherosclerosis on the development of macrovascular complications. Furthermore, SAHS may be associated with the development of microvascular complications: retinopathy, nephropathy or diabetic neuropathy in particular. Data are still scant, but it seems that DM2 may also worsen SAHS progression, by increasing the collapsibility of the upper airway and the development of central apneas and hypopneas.

The Relationship between Diabetic Neuropathy and Sleep Apnea Syndrome: A Meta-Analysis

Aims. High prevalence of sleep apnea syndrome (SAS) has been reported in patients with diabetes. However, whether diabetic neuropathy (DN) contributes to this high prevalence is controversial. Our aim of this study is to compare the prevalence of SAS between patients with and without DN. Methods. Systematic literature searches were conducted for cross-sectional studies that reported the number of patients with DN and SAS using MEDLINE (from 1966 to Nov 5, 2012) and EMBASE (from 1974 to Nov 5, 2012). Odds ratios (ORs) of SAS related to DN were pooled with the Mantel-Haenszel method. Results. Data were obtained from 5 eligible studies (including 6 data sets, 880 participants, and 429 cases). Overall, the pooled OR of SAS in patients with DN compared with that in non-DN patients was significant (OR (95% CI), −1.95 (1.03–3.70)). The pooled OR of SAS was 1.90 (0.97–3.71) in patients with type 2 diabetes. Excluding data on patients with type 1 diabetes, a higher OR was observed in younger patients (mean age <60 years) than in those ≥60 years among whom the OR remained significant (3.82; 95% CI, 2.24–6.51 and 1.17; 95% CI, 0.81–1.68). Conclusions. Current meta-analysis suggested the association of some elements of neuropathy with SAS in type 2 diabetes. Further investigations are needed to clarify whether the association is also true for patients with type 1 diabetes.

Impact of Obstructive Sleep Apnoea on Type 2 Diabetes and Vice Versa

Type 2 diabetes and obstructive sleep apnoea (OSA) are diseases with high prevalence and major public health impact. There is evidence that OSA is independently associated with alterations in glucose metabolism. Furthermore, OSA is a significant risk factor for the development of type 2 diabetes. Possible causes might be intermittent hypoxaemia and sleep fragmentation with increased oxidative stress and sympathetic activity, which are typical features of OSA. OSA might also be a reason for ineffective treatment of type 2 diabetes. There is further evidence that the treatment of OSA by continuous positive airway pressure (CPAP) therapy might improve glucose metabolism. On the other hand, there are also hints in the literature that type 2 diabetes might induce sleep apnoea, especially in patients with autonomic neuropathy, but that OSA also facilitates the development of neuropathy in terms of mutual interactions between OSA, type 2 diabetes and diabetic neuropathy. Based on the current scientific data, clinicians have to be aware of the relations between OSA and type 2 diabetes, both from the sleep medical and the diabetological point of view.

Obstructive sleep apnoea and type 2 diabetes mellitus: a bidirectional association

Obstructive sleep apnoea and type 2 diabetes are common medical disorders that have important clinical, epidemiological, and public health implications. Research done in the past two decades indicates that obstructive sleep apnoea, through the effects of intermittent hypoxaemia and sleep fragmentation, could contribute independently to the development of insulin resistance, glucose intolerance, and type 2 diabetes. Conversely, type 2 diabetes might increase predisposition to, or accelerate progression of, obstructive and central sleep apnoea, possibly through the development of peripheral neuropathy and abnormalities of ventilatory and upper airway neural control. Although more research is needed to clarify the mechanisms underlying the bidirectional association between the two disorders, their frequent coexistence should prompt all health-care professionals to embrace clinical practices that include screening of a patient presenting with one disorder for the other. Early identification of obstructive sleep apnoea in patients with metabolic dysfunction, including type 2 diabetes, and assessment for metabolic abnormalities in those with obstructive sleep apnoea could reduce cardiovascular disease risk and improve the quality of life of patients with these chronic diseases.

Obstructive sleep apnea hypopnea syndrome

Obstructive sleep apnea hypopnea syndrome (OSAHS) is an important medical condition which is on the increase in the past 50 years. It causes significant morbidity and mortality in both developed and developing nations of the world. To review the relevant literature on obstructive sleep apnea. Literature review was carried out on the pathophysiology, clinical presentation, complications, diagnostic modalities, and treatment using computerized search. Additional information was obtained by cross referencing and using texts and journals in the medical libraries of Federal Medical Centre Owerri and University of Nigeria, Enugu. Most of the literature was from developed countries, with very few reports from Africa. Comprehensive management plan was lacking in many textbooks. OSAHS is an increasing medical and, more importantly, respiratory condition across the world. Early recognition and prompt appropriate intervention measures will reduce the mortality and improve the quality of life in patients with such conditions.

Type 2 diabetes and pre-diabetes are associated with obstructive sleep apnea in extremely obese subjects: a cross-sectional study

Background

Obstructive sleep apnea (OSA) is a common yet underdiagnosed condition. The aim of our study is to test whether prediabetes and type 2 diabetes are associated with obstructive sleep apnea (OSA) in extremely obese (BMI ≥ 40 kg/m²) subjects.

Methods

One hundred and thirty seven consecutive extremely obese patients (99 females) from a controlled clinical trial [MOBIL-study (Morbid Obesity treatment, Bariatric surgery versus Intensive Lifestyle intervention Study) (ClinicalTrials.gov number NCT00273104)] underwent somnography with Embletta^® and a 2-hour oral glucose tolerance test (OGTT). OSA was defined by an apnea-hypopnea index (AHI) ≥ 5 events/hour. Patients were categorized into three groups according to criteria from the American Diabetes Association: normal glucose tolerance, pre-diabetes and type 2 diabetes. Multiple logistic regression analysis was used to identify possible determinants of OSA.

Results

The patients had a mean (SD) age of 43 (11) years and a body mass index (BMI) of 46.9 (5.7) kg/m². Males had significantly higher AHI than females, 29 (25) vs 12 (17) events/hour, p < 0.001. OSA was observed in 81% of men and in 55% of women, p = 0.008. Twenty-nine percent of subjects had normal glucose tolerance, 42% had pre-diabetes and 29% had type 2 diabetes. Among the patients with normal glucose tolerance 33% had OSA, while 67% of the pre-diabetic patients and 78% of the type 2 diabetic patients had OSA, p < 0.001. After adjusting for age, gender, BMI, high sensitive CRP and HOMA-IR, both pre-diabetes and type 2 diabetes were still associated with OSA, odds ratios 3.18 (95% CI 1.00, 10.07), p = 0.049 and 4.17 (1.09, 15.88), p = 0.036, respectively. Mean serum leptin was significantly lower in the OSA than in the non-OSA group, while other measures of inflammation did not differ significantly between groups.

Conclusions

Type 2 diabetes and pre-diabetes are associated with OSA in extremely obese subjects.

Trial registration

MOBIL-study (Morbid Obesity treatment, Bariatric surgery versus Intensive Lifestyle intervention Study) (ClinicalTrials.gov number NCT00273104)

Autonomic imbalance: prophet of doom or scope for hope?

It has long been recognized that cardiac autonomic neuropathy increases morbidity and mortality in diabetes and may have greater predictive power than traditional risk factors for cardiovascular events. Significant morbidity and mortality can now be attributable to autonomic imbalance between the sympathetic and parasympathetic nervous system regulation of cardiovascular function. New and emerging syndromes include orthostatic tachycardia, orthostatic bradycardia and an inability to use heart rate as a guide to exercise intensity because of the resting tachycardia. Recent studies have shown that autonomic imbalance may be a predictor of risk of sudden death with intensification of glycaemic control. This review examines an association of autonomic dysregulation and the role of inflammatory cytokines and adipocytokines that promote cardiovascular risk. In addition, conditions of autonomic imbalance associated with cardiovascular risk are discussed. Potential treatment for restoration of autonomic balance is outlined.

Obstructive sleep apnea and type 2 diabetes

Type 2 diabetes and obstructive sleep apnea (OSA) are diseases with high prevalence and major public health impact. There is evidence that regular snoring and OSA are independently associated with alterations in glucose metabolism. Thus, OSA might be a risk factor for the development of type 2 diabetes. Possible causes might be intermittent hypoxia and sleep fragmentation, which are typical features of OSA. OSA might also be a reason of ineffective treatment of type 2 diabetes. There is further evidence that the treatment of OSA by continuous positive airway pressure (CPAP) therapy might correct metabolic abnormalities in glucose metabolism. It is assumed that this depends on therapy compliance to CPAP. On the other hand, there are also hints in the literature that type 2 diabetes per se might induce sleep apnea, especially in patients with autonomic neuropathy. Pathophysiological considerations open up new insights into that problem. Based on the current scientific data, clinicians have to be aware of the relations between the two diseases, both from the sleep medical and the diabetological point of view. The paper summarizes the most important issues concerning the different associations of OSA and type 2 diabetes.

Vascular dysfunction in obstructive sleep apnea and type 2 diabetes mellitus

Despite the high prevalence of obstructive sleep apnea (OSA) in type 2 diabetes mellitus (DM), the attributable vascular risk from each condition is unknown. We hypothesize that OSA may have a similar effect on vascular function as type 2 diabetes does. Healthy normal-weight subjects, healthy obese subjects, subjects with type 2 diabetes, and obese subjects with OSA were enrolled. Vascular function was assessed with brachial artery ultrasound for flow-mediated dilatation (FMD) and in skin microcirculation by laser Doppler flowmetry. One hundred fifty-three subjects were studied: healthy normal-weight controls (NCs) (n = 14), healthy obese controls (OCs) (n = 33), subjects with DM (n = 68), and obese subjects with OSA (n = 38). The DM group did not undergo sleep study and thus may have had subclinical OSA. The OSA and type 2 diabetes groups had impaired FMD as compared to both the normal-weight and OC groups (5.8 ± 3.8%, 5.4 ± 1.6% vs. 9.1 ± 2.5%, 8.3 ± 5.1%, respectively, P < 0.001, post hoc Fischer test). When referenced to the NC group, a multiple linear regression model adjusting for covariates found that baseline brachial artery diameter (β = -3.75, P < 0.001), OSA (β = -2.45, P = 0.02) and type 2 diabetes status (β = -2.31, P = 0.02), negatively predicted % FMD. OSA status did not seem to affect nitroglycerin-induced vasodilation (endothelium-independent) of the brachial artery or vascular function in the skin microcirculation. OSA impairs endothelial function in the brachial artery to a similar degree as type 2 diabetes does. OSA, however, does not appear to affect brachial endothelium-independent vasodilation or skin microcirculatory function. Treatment of OSA in patients with concomitant type 2 diabetes, therefore, may be a potential therapeutic option to improve macro-, but not microvascular outcomes.

Prevalence of sleep apnoea in diabetic patients

BACKGROUND

Diabetes and obstructive sleep apnoea (OSA) syndrome share a high prevalence in industrialized nations. The presence of OSA seems to promote the development of diabetes mellitus (DM) and vice versa.

MATERIALS AND METHODS

In order to assess the prevalence of sleep disordered breathing, we studied 498 patients with DM type 2 and 58 patients with DM type 1 from 15 centres, using a screening device determining airflow and pulse oximetry. Age of the patients was 59.9 ± 13.1 years, mean body mass index was 31.9 ± 6.9 kg/m(2) . Duration of diagnosis of DM was 9.3 ± 7.3 years.

RESULTS

Among the patients, 37.4% had an apnoea-hypopnoea index (AHI) ≥15/h suggestive of OSA. The prevalence of an AHI ≥ 15/h among the patients with DM type 1 was 10.3%. One hundred ninety-three (35.2%) patients suffered from neuropathy. We found a higher prevalence for neuropathy, nephropathy, hypertension, cardiovascular disease and heart failure in the group with an AHI ≥ 15/h.

CONCLUSIONS

The prevalence of sleep disordered breathing is increased in patients with DM. Most of these patients had no typical clinical symptoms of OSA and would have been undiagnosed without diagnostic assessment of OSA.

[Links between diabetes mellitus and sleep disorders: focusing on obstructive sleep apnea]

During the past decades obesity and diabetes have become increasingly common in modern, industrialized societies. At the same time sleep disorders, chronic sleep loss and sleep deprivation have also become more and more prevalent. There may be a positive feed back circle between the two disorders: sleep problems may affect endocrine function and metabolic conditions, while metabolic abnormalities potentially interfere with sleep regulation. Sleep-disordered breathing, obstructive sleep apnea in particular, has the strongest association with glucose metabolism. Prevalence and severity of obstructive sleep apnea are higher among diabetic individuals compared to non-diabetic subjects. Central obesity is an important risk factor both in diabetes and sleep apnea, and recent evidence supports the direct association between them. Diabetic neuropathy and metabolic syndrome parameters correlate with the presence and severity of obstructive sleep apnea. Intermittent hypoxia may cause insulin resistance, consequently increasing the risk of diabetes and further impairing glycemic control. Specialists in both diabetology and sleep medicine need to work together to prevent the negative interactions between these two groups of disorders and to also preserve patients' quality of life and to improve outcomes.

Impact of untreated obstructive sleep apnea on glucose control in type 2 diabetes

RATIONALE

Obstructive sleep apnea (OSA), a treatable sleep disorder that is associated with alterations in glucose metabolism in individuals without diabetes, is a highly prevalent comorbidity of type 2 diabetes. However, it is not known whether the severity of OSA is a predictor of glycemic control in patients with diabetes.

OBJECTIVES

To determine the impact of OSA on hemoglobin A1c (HbA1c), the major clinical indicator of glycemic control, in patients with type 2 diabetes.

METHODS

We performed polysomnography studies and measured HbA1c in 60 consecutive patients with diabetes recruited from outpatient clinics between February 2007 and August 2009.

MEASUREMENTS AND MAIN RESULTS

A total of 77% of patients with diabetes had OSA (apnea-hypopnea index [AHI] > or =5). Increasing OSA severity was associated with poorer glucose control, after controlling for age, sex, race, body mass index, number of diabetes medications, level of exercise, years of diabetes and total sleep time. Compared with patients without OSA, the adjusted mean HbA1c was increased by 1.49% (P = 0.0028) in patients with mild OSA, 1.93% (P = 0.0033) in patients with moderate OSA, and 3.69% (P < 0.0001) in patients with severe OSA (P < 0.0001 for linear trend). Measures of OSA severity, including total AHI (P = 0.004), rapid eye movement AHI (P = 0.005), and the oxygen desaturation index during total and rapid eye movement sleep (P = 0.005 and P = 0.008, respectively) were positively correlated with increasing HbA1c levels.

CONCLUSIONS

In patients with type 2 diabetes, increasing severity of OSA is associated with poorer glucose control, independent of adiposity and other confounders, with effect sizes comparable to those of widely used hypoglycemic drugs.

[The role of family physicians in the recognition and screening of obstructive sleep apnea]

Obstructive sleep apnea is the most frequent sleep disorder. The prevalence of sleep apnea in the general population is 2-4% and the main characteristic of the disease is the intermittent cessation or substantial reduction of airflow during sleep, caused by complete, or near complete upper airway obstruction. Decreased airflow is followed by oxygen desaturation and intermittent arousals. The clinical presentation of the disorder is complex. Loud snoring with breathing pauses and daytime sleepiness should raise the suspicion of sleep apnea, but we have to consider this disease if the patient has therapy resistant hypertension, heart failure, arrhythmias, stroke, depression or memory problems. Family physicians have an important role in recognizing sleep apnea. High risk patients can easily be identified by the main symptoms and using the Berlin sleep apnea questionnaire. These patients should be referred to a sleep laboratory for polysomnographic assessment and, if necessary, for further treatment.