Obstructive sleep apnea increases hemoglobin A1c levels regardless of glucose tolerance status

The relationship between obstructive sleep apnea and haemoglobin A1c and the moderating role of glycaemic status in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

This study investigated the relationship between obstructive sleep apnea and haemoglobin A1c (HbA1c) among Hispanics/Latinos in the United States and assessed whether this relationship was moderated by glycaemic status. This was a cross-sectional analysis of the Hispanic Community Health Study/Study of Latinos cohort. The sample consisted of 13,394 participants with valid measures of obstructive sleep apnea, HbA1c, and study covariates. Obstructive sleep apnea was assessed with the apnea-hypopnea index and categorised as obstructive sleep apnea if the apnea-hypopnea index was ≥5 events/h. HbA1c measures were obtained through fasting blood samples. Fasting plasma glucose (FPG), 2-h post-load plasma glucose (2h-PG) and use of antihyperglycaemic medications were used to define glycaemic status (i.e., normoglycaemia [FPG < 5.6 mmol/L (< 100 mg/dL) and 2h-PG < 7.8 mmol/L (140 mg/dL)], prediabetes [FPG 5.6-6.9 mmol/L (100-125 mg/dL), and/or 2h-PG 7.8-11.0 mmol/L (140-199 mg/dL)], diabetes without treatment [FPG > 7.0 mmol/L (≥ 126 mg/dL) and/or 2h-PG ≥ 11.1 mmol/L (≥ 200 mg/dL)], and diabetes with treatment. Multivariable linear regression was used to calculate adjusted least square means. Overall, 25.9% of the sample had obstructive sleep apnea and 49.2% had normal glycaemic levels, 36.1% had prediabetes, 6.5% diabetes without receiving treatment, and 8.3% diabetes and undergoing treatment for it. Participants with obstructive sleep apnea had significantly higher adjusted mean HbA1c (adjusted mean [standard error] 5.85 [0.03)]) than those without (5.70 [0.02)]; p < 0.001). Models stratified by diabetes status showed that the association between obstructive sleep apnea (versus not) and higher HbA1c was only for participants with normal glycaemic status (adjusted mean [standard error] 5.27 [0.01] versus 5.30 [0.01]; p = 0.013) and prediabetes (5.59 [0.01] versus 5.66 [0.01]; p < 0.001). In conclusion, obstructive sleep apnea was associated with higher HbA1c in a diverse sample of Hispanic/Latino adults in the United States. This association was present only for participants with normal glycaemic status or with prediabetes. Studies are needed to further understand the clinical implications of the association between obstructive sleep apnea and HbA1c according to glycaemic status.

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

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

Sleep, cardiovascular risk factors, and kidney function: The Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVES

Examine the associations of sleep measures with kidney function changes over time among individuals from a community-based study.

METHODS

The sample includes 1657 participants (287 with chronic kidney disease [CKD]) in the Multi-Ethnic Study of Atherosclerosis Sleep Cohort (mean age: 57.7 years, male: 46.0%). We examined associations between a large set of sleep variables (polysomnography, actigraphy, and questionnaires) and cardiovascular disease risk factors and changes in estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio over approximately 5 years using high-dimensional regression. We investigated the modifying effect of sleep on the associations between cardiovascular disease risk factors and kidney function.

RESULTS

Sleep metrics predicted kidney function decline only among individuals with baseline CKD. Among this group, eGFR decline was associated with decreased stage N3 sleep (0.32 mL/min/1.73 m2/y per 10% decrease in N3, p < .001); increased actigraphy napping frequency (beta: -0.20 [-0.30, -0.07]); and actigraphy sleep midpoint trajectory in early morning (ref: midnight, beta: -0.84 [-1.19, -0.50]). Urinary albumin-to-creatinine ratio increase was associated with high wake bouts trajectory (ref: low, beta: 0.97 [0.28, 1.67]) and increased sleep-related hypoxemia (oxygen saturation %time<90 [≥5%], beta: 2.17 [1.26, 3.08]). Sleep metrics--N3 sleep, naps, and midpoint trajectory--significantly modified associations between hemoglobin A1C and eGFR decline.

CONCLUSIONS

Reduced deep sleep, daytime napping, increased wake bouts, delayed sleep rhythms, and overnight hypoxemia are associated with longitudinal kidney function decline, with effects most apparent in individuals with CKD. Deep sleep, napping, and sleep timing modified the association between hemoglobin A1C and kidney function.

Postprandial glucose and HbA1c are associated with severity of obstructive sleep apnoea in non-diabetic obese subjects

INTRODUCTION

Obstructive sleep apnoea (OSA) is an underdiagnosed condition frequently associated with glycaemic control impairment in patients with type 2 diabetes.

AIM

To assess the relationship between glycometabolic parameters and OSA in obese non-diabetic subjects.

METHODS

Ninety consecutive subjects (mean age 44.9 ± 12 years, mean BMI 42.1 ± 9 kg/m²) underwent polysomnography and a 2-h oral glucose tolerance test (OGTT).

RESULTS

OSA was identified in 75% of subjects, with a higher prevalence of males compared to the group of subjects without OSA (62% vs 32%, p = 0.02). Patients with OSA had comparable BMI (42.8 kg/m² vs 39.4 kg/m²), a higher average HbA1c (5.8% vs 5.4%, p < 0.001), plasma glucose at 120 min during OGTT (2 h-PG; 123 mg/dl vs 97 mg/dl, p = 0.009) and diastolic blood pressure (81.1 mmHg vs 76.2 mmHg, p = 0.046) than obese subjects without OSA. HbA1c and 2 h-PG were found to be correlated with the apnoea-hypopnoea index (AHI; r = 0.35 and r = 0.42, respectively) and with percent of sleep time with oxyhaemoglobin saturation < 90% (ST90; r = 0.44 and r = 0.39, respectively). Further, in a linear regression model, ST90 and AHI were found to be the main determinants of 2 h-PG (β = 0.81, p < 0.01 and β = 0.75, p = 0.02, respectively) after controlling for age, sex, waist circumference, physical activity, and C-reactive protein. Similarly, ST90 and AHI persisted as independent determinants of HbA1c (β = 0.01, p = 0.01 and β = 0.01, p = 0.01, respectively).

CONCLUSION

Beyond the traditional clinical parameters, the presence of a normal-high value of 2 h-PG and HbA1c should raise suspicion of the presence of OSA in obese subjects.

Association between nocturnal hypoxemic burden and glucose metabolism

PURPOSE

To evaluate the association between a novel integrated event-based and hypoxemia-based parameter of polysomnography (PSG), hypoxemic load or HL100, and fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels.

METHODS

Adult patients, who underwent an in-lab PSG at the University of Iowa Hospitals and Clinics with FBG or HbA1c levels, were included. Event-based parameter and hypoxemia-based parameter data were derived. HL100, defined as the integrated area of desaturation between the 100% oxygen saturation and the measured saturation levels during sleep divided by the total sleep time, was calculated by Python software. Demographic data and glycemic parameters within 1 year prior to PSG (FBG and HbA1c) were retrieved from chart review. Spearman correlation analysis and stepwise backward regression analysis were performed to determine independent predictors of FBG and HbA1c levels.

RESULTS

Of the 467 patients who underwent an in-lab PSG, 218 had FBG levels, 84 had HbA1c levels, and 118 had both values. All event-based and hypoxemia-based parameters, including HL100, were significantly correlated to FBG and HbA1c levels. Stepwise backward regression analyses, adjusted for age, sex, body mass index, and diabetes status, revealed that log HL100 was significantly related to FBG (B = 23.9, p = 0.010), but none of log event-based or hypoxemia-based parameters were found to be significantly related HbA1c levels.

CONCLUSIONS

HL100 was shown to be an independent predictor of FBG in this cohort, implying that any degree of desaturation below 100% could adversely affect glucose metabolism. HL100 may be useful for interpretation of sleep studies, risk stratification, and patient management purposes in the future.

Slow-wave sleep and obstructive sleep apnea in patients with type 2 diabetes mellitus

PURPOSE

This study aimed to analyze sleep architecture and obstructive sleep apnea (OSA) in patients with type 2 diabetes and clarify the association between sleep characteristics and glycemic control.

METHODS

All participants underwent metabolism-related laboratory testing and a cross-sectional analysis of nocturnal polysomnography for sleep parameter analysis. Data were analyzed using the chi-squared test, a one-way analysis of variance, and Kruskal-Wallis test to compare the differences among three groups (type 2 diabetes, prediabetes, and control groups). The prevalence of OSA was evaluated using descriptive statistics and comparing the group divided into HbA1c quartiles. Univariate and multivariate linear regression analyses were used to determine factors associated with glycemic control.

RESULTS

Of 75 study participants (age 57.3 ± 4.1 years, 32 men), there were 25 participants each in the type 2 diabetes, prediabetes, and control groups. Participants with type 2 diabetes had significantly decreased slow-wave sleep duration (77.9 ± 30.0 min, p = 0.026) and shortened rapid eye movement sleep latency (median 75 min, p = 0.018) compared with those in the prediabetes and control groups. Forty-five participants (60%) had OSA (apnea-hypopnea index ≥ 5/h), 18 of whom were in the type 2 diabetes group. The prevalence of OSA in this group was 72%. The prevalence of moderate-to-severe OSA was significantly higher in the type 2 diabetes group than in the control group (p = 0.025) and in groups with HbA1c levels of > 6.7% than in groups with HbA1c levels of < 5.3% (p = 0.007). Multiple regression analysis showed that dyslipidemia (β = 0.179, p = 0.000) and slow-wave sleep duration (β =  - 0.113, p = 0.008) were independently associated with the HbA1c level.

CONCLUSION

Our results suggest that increasing slow-wave sleep is positively associated with glycemic control.

The impact of sleep disorders on microvascular complications in patients with type 2 diabetes (SLEEP T2D): the protocol of a cohort study and feasibility randomised control trial

BACKGROUND

Obstructive sleep apnoea (OSA) is very common in patients with type 2 diabetes (T2D). We and others have shown that OSA was associated with diabetes-related microvascular complications in patients with T2D in cross-sectional and longitudinal studies and that compliance with continuous positive airway pressure (CPAP) reduced the progression of microvascular complications. Hence, we hypothesised that adequate CPAP reduces the development of microvascular complication in patients with T2D.

METHODS

SLEEP T2D is a cohort study with embedded feasibility, open-label, parallel-arm, randomised control trial (RCT) over 2 years. The primary aim is the feasibility of conducting a definitive RCT assessing the impact of CPAP on chronic kidney disease and other microvascular complications in patients with T2D. The main parameters are to assess willingness of participants to be randomised, follow-up rates, CPAP adherence/compliance, to optimise the choice of outcome measures for a substantive trial, and to identify the parameters for sample size calculations. The secondary aims of the study are related to the impact of CPAP, sleep-related disorders, and sleep chronotype on a variety of diabetes-related end points. The study participants were recruited from the T2D services in multiple NHS trusts across England. The main exclusion criteria for the cohort study are as follows: T1D, eGFR < 15 mL/min/1.73 m², known OSA, active malignancy or chronic kidney disease from reasons other than diabetes, pregnancy, professional drivers, and a history of falling asleep whilst driving within last 2 years. The main exclusion criteria from the RCT were as follows: Apnoea-Hypopnoea Index < 10 and Epworth Sleepiness Score ≥ 11. Study participants were extensively phenotyped clinically and biochemically. The OSA diagnosis was based on multichannel portable device (ApneaLink Air^TM, Resmed).

DISCUSSION

The feasibility RCT will help us design the future RCT to assess the impact of CPAP on diabetes-related microvascular complications. The cohort study will generate preliminary data regarding the impact of sleep quality, duration, and chronotype on diabetes-related outcomes which could lead to further mechanistic and interventional studies.

TRIAL REGISTRATION

ISRCTN, ISRCTN12361838 . Registered 04 April 2018, Protocol version: v5.0 02.12.19.

Benefits of continuous positive airway pressure on glycaemic control and insulin resistance in patients with type 2 diabetes and obstructive sleep apnoea: A meta-analysis

AIM

To conduct a meta-analysis to determine the effects of continuous positive airway pressure (CPAP) treatment on glycaemic control and insulin resistance in patients with type 2 diabetes and obstructive sleep apnoea (OSA).

METHODS

A systematic search was made of the MEDLINE, SCOPUS, ISI Web of Science, Cochrane databases, and clinicaltrials.gov, without language restrictions. Randomized controlled trials on treatment of type 2 diabetes and OSA with CPAP, compared with sham CPAP or no CPAP, were reviewed. Studies were pooled to obtain standardized mean differences (SMDs), with 95% confidence intervals (CIs).

RESULTS

Seven trials (enrolling 691 participants) met the inclusion criteria. CPAP showed significant effects on glycated haemoglobin (HbA1c; SMD -0.32, 95% CI -0.60 to -0.03; P = 0.029), fasting glucose (SMD -0.39, 95% CI -0.76 to -0.02; P = 0.040), homeostatic model assessment of insulin resistance (HOMA-IR; SMD -1.05, 95% CI -1.91 to -0.19; P = 0.016), systolic blood pressure (SMD -1.18, 95% CI -2.29 to -0.07 mm Hg; P = 0.037), and diastolic blood pressure (SMD -1.29, 95% CI -2.48 to -0.09; P = 0.035).

CONCLUSIONS

Continuous positive airway pressure treatment significantly improved glycaemic control and insulin resistance, as shown by the decreased HbA1c levels, fasting glucose levels and HOMA-IR values in patients with type 2 diabetes and OSA.

Sleep questionnaires for the screening of obstructive sleep apnea in patients with type 2 diabetes mellitus compared with non-diabetic patients

BACKGROUND

Several tools have been used to screen for obstructive sleep apnea (OSA). Evaluation of the predictive performance of different questionnaires is essential in patients with type 2 diabetes mellitus (T2DM) because the prevalence of OSA in this population is high. The aim of this study was to evaluate different sleep questionnaires to identify T2DM patients with OSA, and to compare the predictive values of these questionnaires with a matched sample of non-diabetic patients.

METHODS

The study was a retrospective study of two patients groups (n = 350 with T2DM, n = 350 without T2DM) visiting a sleep clinic and matched by age, gender, body mass index, and the apnea-hypopnea index (AHI). Symptoms of OSA and Epworth Sleepiness Scale (ESS), STOP-Bang, Berlin questionnaire, and Athens insomnia scale (AIS) scores were compared, and sleep studies were performed.

RESULTS

Diabetic patients with OSA complained more frequently of nocturia (P = 0.025), morning headaches (P = 0.04), restless sleep (P = 0.002), and leg movements (P = 0.01) than non-diabetic patients with OSA. Most predictive values of the sleep questionnaires did not differ significantly between the two groups; however, the AIS was higher only in T2DM women (P = 0.01). In both groups, the Berlin and STOP-Bang questionnaires had the highest sensitivity. The ESS had the highest specificity in T2DM patients and the STOP and S-B questionnaires had the highest specificity in non-diabetics.

CONCLUSIONS

The predictive performance of the questionnaires was similar in both groups, especially in the case of moderate and severe OSA.

Characteristics of Obstructive Sleep Apnea Across the Spectrum of Glucose Tolerance in Obese Adolescents

BACKGROUND

It is not known if dysglycemia and sleep-disordered breathing are linked in adolescents, as in adults.

OBJECTIVE

To perform a pilot study evaluating measures of sleep-disordered breathing across the spectrum of glucose tolerance in obese adolescents. We hypothesized that dysglycemia would be associated with sleep-disordered breathing.

PARTICIPANTS/METHODS

This was a prospective, cross-sectional clinical pilot study that included 57 adolescents [body mass index (BMI) 38.9 ± 8.4 kg/m²] aged 12-18 years (14.5 ± 1.6) with normal glucose tolerance (NGT), or dysglycemia [impaired glucose tolerance (IGT) or type 2 diabetes (T2D)].

MEASURES

Anthropometrics, overnight polysomnogram, and oral glucose tolerance tests were performed. Participant characteristics and outcome measures were compared by glucose tolerance status. Correlational analyses were conducted to assess the associations between variables of interest.

RESULTS

Participants with dysglycemia (n = 21) were not different from those with NGT (n = 36) for BMI, waist circumference, body fat, or sleep characteristics. Nocturnal oxygen desaturation was associated with higher BMI (r = -0.334, p = 0.012). The apnea-hypopnea index (AHI) was not associated with physical and metabolic parameters. Although participants with dysglycemia tended to have higher AHIs (median 3.2, 2.2, and 1.6 events/h for T2D, IGT, and NGT, respectively), there was not a linear relationship between measures of glycemia and AHI.

CONCLUSION

Further study with a larger proportion of youth with prediabetes and T2D is necessary to determine whether evaluation for sleep-disordered breathing is uniformly warranted.

Distinct impacts of sleep-disordered breathing on glycemic variability in patients with and without diabetes mellitus

BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent in patients with diabetes mellitus (DM) and heart failure (HF) and contributes to poor cardiovascular outcomes. Enlarged glycemic variability (GV) is a risk factor of cardiac events independently of average blood glucose level, but the influence of SDB on GV is uncertain. In this study, we examined whether the impact of SDB on GV is modified by the presence of DM with or without HF.

METHODS AND RESULTS

Two hundred three patients (67.5±14.1 [SD] years old, 132 males) who were admitted to our institute for examination or treatment of DM and/or HF underwent continuous glucose monitoring and polysomnography. Both HbA1c (8.0±2.0 vs. 5.7±0.4%) and mean amplitude of glycemic excursion (MAGE, median: 95.5 vs. 63.5 mg/dl) were significantly higher in a DM group (n = 100) than in a non-DM group (n = 103), but apnea-hypopnea index (AHI: 29.0±22.7 vs. 29.3±21.5) was similar in the two groups. AHI was correlated with log MAGE in the non-DM group but not in the DM group, and multivariate regression analysis revealed that AHI was an independent variable for log MAGE in the non-DM group but not in the DM group. We then divided the non-DM patients into two subgroups according to BNP level (100 pg/ml). AHI was positively correlated with log MAGE (r = 0.74, p<0.001) in the non-DM low-BNP subgroup, but such a correlation was not found in the non-DM high-BNP subgroup. Continuous positive airway pressure (CPAP) reduced MAGE from 75.3 to 53.0 mg/dl in the non-DM group but did not reduce MAGE in the DM group.

CONCLUSION

Severity of SDB was associated with higher GV, but DM as well as HF diminished the contribution of SDB to GV. Treatment with CPAP was effective for reduction of GV only in patients without DM.

Features of continuous glycemic profile and glycemic variability in patients with obstructive sleep apnea syndrome

AIMS

To investigate glycemic variability (GV) in Obstructive Sleep Apnea Syndrome (OSAS) patients by monitoring continuous blood glucose profile.

METHODS

OSAS group (n=86) and normal control group (n=40) were included. Continuous blood glucose was monitored. The relationship of GV, insulin resistance index (IRI) and the respiratory disturbance index (AHI) were analyzed.

RESULTS

The daily average blood glucose level was significantly higher in the OSAS patients than in the control group (6.31±0.61vs. 4.94±0.78; P<0.01). The postprandial glycemic peaks in the OSAS patients were significantly higher and prolonged. The indicators of GV were all significantly higher in the OSAS patients, including blood glucose fluctuation coefficient (BGFC, 1.93±0.71vs. 1.21±0.38, P<0.05), mean amplitude of glycemic excursions (MAGE, 4.18±0.65vs. 2.18±0.48; P<0.05) and night mean amplitude of glycemic excursions (NMAGE, 2.00±0.53vs. 1.11±0.43; P<0.05). Pearson correlation analysis showed that among the OSAS patients, the severity of OSAS (AHI) was positively correlated with the IRI (r=0.310); and the GV indicators (MAGE and NMAGE) were positively correlated with IRI and AHI (r=0.318 and 0.349, respectively) (P<0.01 or 0.001).

CONCLUSIONS

Continuous glycemic spectrum and GV provide comprehensive glycemic profiles and may reveal important aspects of glucose metabolism abnormality beyond regular examinations, and are therefore of particular significance for glycemic management in OSAS patients.

Effects of a lifestyle intervention on REM sleep-related OSA severity in obese individuals with type 2 diabetes

The aim of this study was to determine if an intensive lifestyle intervention (ILI) reduces the severity of obstructive sleep apnea (OSA) in rapid-eye movement (REM) sleep, and to determine if longitudinal changes in glycaemic control are related to changes in OSA severity during REM sleep over a 4-year follow-up. This was a randomized controlled trial including 264 overweight/obese adults with type 2 diabetes (T2D) and OSA. Participants were randomized to an ILI targeted to weight loss or a diabetes support and education (DSE) control group. Measures included anthropometry, apnea-hypopnea index (AHI) during REM sleep (REM-AHI) and non-REM sleep (NREM-AHI) and glycated haemoglobin (HbA1c) at baseline and year 1, year 2 and year 4 follow-ups. Mean baseline values of REM-AHI were significantly higher than NREM-AHI in both groups. Both REM-AHI and NREM-AHI were reduced significantly more in ILI versus DSE, but these differences were attenuated slightly after adjustment for weight changes. Repeated-measure mixed-model analyses including data to year 4 demonstrated that changes in HbA1c were related significantly to changes in weight, but not to changes in REM-AHI and NREM-AHI. Compared to control, the ILI reduced REM-AHI and NREM-AHI during the 4-year follow-up. Weight, as opposed to REM-AHI and NREM-AHI, was related to changes in HbA1c. The findings imply that weight loss from a lifestyle intervention is more important than reductions in AHI for improving glycaemic control in T2D patients with OSA.

Association of subclinical inflammation, glycated hemoglobin and risk for obstructive sleep apnea syndrome

Objective

To investigate the inter-relation between high sensitivity C-reactive protein and glycated hemoglobin in prediction of risk of obstructive sleep apnea.

Methods

We included all individuals participating in a check-up program at the Preventive Medicine Center of Hospital Israelita Albert Einstein in 2014. The Berlin questionnaire for risk of obstructive sleep apnea was used, and the high sensitivity C-reactive protein and glycated hemoglobin levels were evaluated.

Results

The sample included 7,115 participants (age 43.4±9.6 years, 24.4% women). The Berlin questionnaire showed changes in 434 (6.1%) individuals. This finding was associated with high sensitivity C-reactive protein and glycated hemoglobin levels (p<0.001). However, only the association between the Berlin questionnaire result and glycated hemoglobin remained significant in the adjusted multivariate analysis, for the traditional risk factors and for an additional model, including high-density lipoprotein cholesterol and triglycerides.

Conclusion

The glycated hemoglobin, even below the threshold for diagnosis of diabetes, is independently associated with obstructive sleep apnea syndrome, even after adjustment for obesity and C-reactive protein. These findings suggest a possible pathophysiological link between changes in insulin resistance and obstructive sleep apnea syndrome, independently from obesity or low-grade inflammation.

Objetivo

Investigar a inter-relação entre proteína C-reativa de alta sensibilidade e hemoglobina glicada na predição do risco de apneia obstrutiva do sono.

Métodos

Foram incluídos todos os indivíduos participantes do programa de check-up do Centro de Medicina Preventiva Hospital Israelita Albert Einstein em 2014. Foi aplicado o questionário de Berlin sobre risco de apneia do sono, e avaliadas as dosagens de hemoglobina glicada e proteína C-reativa de alta sensibilidade.

Resultados

Foram incluídos 7.115 participantes (idade 43,4±9,6 anos, 24,4% mulheres). A prevalência de alteração no questionário de Berlin foi de 434 (6,1%). A alteração do questionário de Berlin associou-se positivamente aos resultados da proteína C-reativa de alta sensibilidade e da hemoglobina glicada (p<0,001). No entanto, apenas a associação entre o resultado do questionário de Berlin e a hemoglobina glicada permaneceu significativa na análise multivariada ajustada tanto para fatores de risco tradicionais quanto para um modelo adicional, que incluiu também lipoproteína de alta densidade-colesterol (HDL-c) e triglicérides.

Conclusão

A hemoglobina glicada, mesmo em valores abaixo do critério diagnóstico para diabetes mellitus, está associada de forma independente ao risco para síndrome da apneia obstrutiva do sono, mesmo após ajuste para obesidade e proteína C-reativa. Estes achados sugerem possível ligação fisiopatológica entre alterações na resistência insulínica e a síndrome da apneia obstrutiva do sono, que independe da obesidade ou inflamação de baixo grau.

Effect of Continuous Positive Airway Pressure on Glycemic Control in Patients with Obstructive Sleep Apnea and Type 2 Diabetes. A Randomized Clinical Trial

RATIONALE

Obstructive sleep apnea (OSA) is a risk factor for type 2 diabetes that adversely impacts glycemic control. However, there is little evidence about the effect of continuous positive airway pressure (CPAP) on glycemic control in patients with diabetes.

OBJECTIVES

To assess the effect of CPAP on glycated hemoglobin (HbA1c) levels in patients with suboptimally controlled type 2 diabetes and OSA, and to identify its determinants.

METHODS

In a 6-month, open-label, parallel, and randomized clinical trial, 50 patients with OSA and type 2 diabetes and two HbA1c levels equal to or exceeding 6.5% were randomized to CPAP (n = 26) or no CPAP (control; n = 24), while their usual medication for diabetes remained unchanged.

MEASUREMENTS AND MAIN RESULTS

HbA1c levels, Homeostasis Model Assessment and Qualitative Insulin Sensitivity Check Index scores, systemic biomarkers, and health-related quality of life were measured at 3 and 6 months. After 6 months, the CPAP group achieved a greater decrease in HbA1c levels compared with the control group. Insulin resistance and sensitivity measurements (in noninsulin users) and serum levels of IL-1β, IL-6, and adiponectin also improved in the CPAP group compared with the control group after 6 months. In patients treated with CPAP, mean nocturnal oxygen saturation and baseline IL-1β were independently related to the 6-month change in HbA1c levels (r(2) = 0.510, P = 0.002).

CONCLUSIONS

Among patients with suboptimally controlled type 2 diabetes and OSA, CPAP treatment for 6 months resulted in improved glycemic control and insulin resistance compared with results for a control group. Clinical trial registered with www.clinicaltrials.gov (NCT01801150).

HbA1c levels are associated with severity of hypoxemia and not with apnea hypopnea index in patients with type 2 diabetes: Results from a cross-sectional study

BACKGROUND

The aim of the present study was to evaluate the effect of untreated sleep apnea syndrome (SAS) on glycemic control, evaluated by HbA1c, in patients with type 2 diabetes (T2D).

METHODS

The study sample consisted of 100 consecutive adult (≥18 years) patients with T2D without a prior diagnosis of sleep apnea recruited from an outpatient diabetes clinic. All patients underwent an in-hospital cardiorespiratory study using a three-channel portable sleep diagnostic tool; 64 were found to have sleep apnea, 36 were not. Information on medical history, body weight, height, sleep apnea symptoms, Epworth Sleepiness Scale scores, and HbA1c and fasting plasma glucose levels were recorded.

RESULTS

After adjusting for factors known to affect HbA1c (gender, age, diabetes duration, diabetes treatment, body mass index [BMI], and waist circumference), HbA1c was higher in patients with than without SAS (8.4 % vs 7.6 %, respectively; P = 0.04). A positive correlation was found between the presence of sleep apnea and HbA1c (r = 0.24; P = 0.02). After adjusting for confounding factors (including BMI), only mean and lowest O₂ saturation during sleep were significantly associated with HbA1c (β = -0.23 [P = 0.03] and β = -0.24 [P = 0.007], respectively). After further adjusting for waist circumference, only lowest O₂ saturation during recording remained independently associated with HbA1c (β = -0.21; P = 0.05).

CONCLUSIONS

The presence of sleep apnea is associated with poorer glycemic control in patients with T2D. In patients with sleep apnea and T2D, greater levels of oxygen desaturation are associated with poorer glycemic control.

Blood biomarkers of endocrine, immune, inflammatory, and metabolic systems in obstructive sleep apnea

OBJECTIVE/BACKGROUND

Obstructive sleep apnea (OSA) is a common disorder, affecting over 100 million adults. Untreated OSA leads to serious health consequences and perturbations in endocrine, immune, inflammatory, and metabolic systems. Study objectives are to evaluate the association between OSA and biomarkers, and to test the hypothesis that a combination of markers may be useful in screening for OSA.

PATIENTS/METHODS

A multicenter trial was conducted enrolling symptomatic male patients with suspected OSA. All subjects underwent in-laboratory overnight polysomnography. A non-symptomatic control group was also obtained. Eleven biomarkers were tested: HbA1c, CRP, EPO, IL-6, uric acid, cortisol, hGH, prolactin, testosterone, DHEA (Beckman Coulter UniCel DxC 600i Synchron® Access® Clinical Systems), IGF-1.

RESULTS

73 male subjects were enrolled; 26 had moderate/severe OSA. ROC curve analysis showed HbA1c, CRP, EPO, IL-6, and Uric Acid (AUCs: 0.76, 0.73, 0.65, 0.65, 0.61) were superior to the Epworth Sleepiness Scale (AUC: 0.52). Concurrent elevation of HbA1c and CRP provide even greater predictive power. A combination of elevated HbA1c, CRP, and EPO provided 0.08 increase in AUC (0.84 [0.75 - 0.94]) over individual markers (p<0.05), with high sensitivity (85%), and specificity (79%) for moderate/severe OSA.

CONCLUSIONS

OSA induces characteristic endocrine, immune, inflammatory, and metabolic disturbances that can be detected with blood biomarkers. These biomarkers are superior to standard screening questionnaires. Various clusters of these biomarkers have an even greater association with OSA and thus may represent physiologic signatures of the disorder that may have value in initial screening for OSA as well as for follow-up of therapy response.

Biomarkers to improve diagnosis and monitoring of obstructive sleep apnea syndrome: current status and future perspectives

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent episodes of upper airway collapse associated with oxygen desaturation and sleep disruption. It is proposed that these periodic changes lead to molecular variations that can be detected by assessing serum biomarkers. Studies have identified inflammatory, oxidative, and metabolic perturbations attributable to sleep-disordered breathing. Given that OSAS is associated with increased cardiovascular and cerebrovascular morbidity, the ideal biomarker should enable timely recognition with the possibility of intervention. There is accumulating data on the utility of serum biomarkers for the evaluation of disease severity, prognosis, and response to treatment. However, current knowledge is limited by data collection techniques, disease complexity, and potential confounding factors. The current paper reviews the literature on the use of serum biomarkers in OSAS. It is concluded that the ideal serum biomarker still needs to be discovered, while caution is needed in the interpretation of hitherto available results.

Sleep-disordered breathing, type 2 diabetes and the metabolic syndrome

Sleep-disordered breathing (SDB) encompasses a spectrum of conditions that can lead to altered sleep homeostasis. In particular, obstructive sleep apnoea (OSA) is the most common form of SDB and is associated with adverse cardiometabolic manifestations including hypertension, metabolic syndrome and type 2 diabetes, ultimately increasing the risk of cardiovascular disease. The pathophysiological basis of these associations may relate to repeated intermittent hypoxia and fragmented sleep episodes that characterize OSA which drive further mechanisms with adverse metabolic and cardiovascular consequences. The associations of OSA with type 2 diabetes and the metabolic syndrome have been described in studies ranging from epidemiological and observational studies to controlled trials investigating the effects of OSA therapy with continuous positive airway pressure (CPAP). In recent years, there have been rising prevalence rates of diabetes and obesity worldwide. Given the established links between SDB (in particular OSA) with both conditions, understanding the potential influence of OSA on the components of the metabolic syndrome and diabetes and the underlying mechanisms by which such interactions may contribute to metabolic dysregulation are important in order to effectively and holistically manage patients with SDB, type 2 diabetes or the metabolic syndrome. In this article, we review the literature describing the associations, the possible underlying pathophysiological mechanisms linking these conditions and the effects of interventions including CPAP treatment and weight loss.

Hypoxemia and glycemic control in type 2 diabetes mellitus with extreme obesity

CONTEXT

Obstructive sleep apnea (OSA) has been shown to be associated with type 2 diabetes mellitus (DM). Studies on healthy individuals found that OSA is associated with lower insulin sensitivity. We hypothesized that nocturnal hypoxemia from OSA is associated with poorer glycemia in severely obese DM individuals.

DESIGN AND SETTING

This was a retrospective observational study of 122 non-DM, 126 non-insulin-treated DM, and 35 insulin-treated DM patients. Data were collected on demographic characteristics, body mass index, and comorbidities. An overnight sleep study was performed in all patients, and OSA was defined as an apnea-hypopnea index of ≥5 events/h.

RESULTS

There were more males (P = .003) and a lower proportion of white Europeans (P = .010) among DM patients. The prevalence of OSA was 80.1% in DM and 63.1% in non-DM individuals (P = .001). DM individuals also had lower oxygen saturation (O2) (P = .0106), greater percentage of time spent under 90% oxygen saturation (%TST<90%) (P = .0067), and higher apnea-hypopnea index (P = .0085). Regression analysis showed that %TST<90% and minimum O2 saturations were associated with worse hemoglobin A1c results among DM individuals. Every 10% reduction in minimum O2 was associated with a 0.3% increase in HbA1c, whereas a 10% increase in %TST<90% was associated with a 0.2% increase in hemoglobin A1c after adjusting for a range of potential confounders.

CONCLUSION

The high OSA prevalence in DM individuals and a positive relationship between nocturnal hypoxemia and glycemia supports the need to assess correction of hypoxemia as a management strategy for glycemic control.

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.

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.

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.

Cardiovascular autonomic neuropathy contributes to sleep apnea in young and lean type 1 diabetes mellitus patients

Knowledge about association between sleep apnea and cardiovascular autonomic neuropathy (CAN) in type 1 diabetes mellitus (T1DM) might give some insight into the pathogenesis of this condition in these patients. In obese patients, excessive central adiposity, including a large neck circumference, can contribute to obstructive sleep apnea (OSA). Its presence in non-obese patients, however, indicates that it could be correlated with autonomic neuropathy. The aim of this study was to compare the prevalence of OSA in young and lean T1DM patients with and without CAN. We studied 20 adult, non-obese, T1DM patients who were divided into two groups according to the results of the cardiovascular autonomic reflex tests (CARTs). These two groups (9 with CAN and 11 without CAN) were compared to a control group of 22 healthy individuals, who were matched by age and BMI. A polysomnography was performed and sleep was analyzed. The CAN+ group had a significantly higher prevalence of sleep apnea compared to the other groups (67% CAN+; 23% CAN-; 4.5% controls: CAN+ vs. Control; p = 0.006 and CAN+ vs. CAN-; p = 0.02). The CAN- group had higher sleep efficiency compared to the CAN+ group, demonstrating impaired sleep architecture in diabetics with this chronic complication. In conclusion, OSA may be related to the presence of CAN in young and lean T1DM patients. It could contribute to worse the prognosis and reducing the quality of life of these patients without specific treatment of these conditions.

Affective brain areas and sleep-disordered breathing

The neural damage accompanying the hypoxia, reduced perfusion, and other consequences of sleep-disordered breathing, found in obstructive sleep apnea, heart failure, and congenital central hypoventilation syndrome (CCHS), appears in areas that serve multiple functions, including emotional drives to breathe, and involve systems that serve affective, cardiovascular, and breathing roles. The damage, assessed with structural magnetic resonance imaging (MRI) procedures, shows tissue loss or water content and diffusion changes indicative of injury, and impaired axonal integrity between structures; damage is preferentially unilateral. Functional MRI responses in affected areas also are time- or amplitude-distorted to ventilatory or autonomic challenges. Among the structures injured are the insular, cingulate, and ventral medial prefrontal cortices, as well as cerebellar deep nuclei and cortex, anterior hypothalamus, caudal raphé, ventrolateral medulla, portions of the basal ganglia and, in CCHS, the locus coeruleus. Caudal raphé and locus coeruleus injury have the potential to modify serotonergic and adrenergic modulation of upper airway and arousal characteristics, as well as affective drive to breathe. Since both axons and gray matter show injury, the consequences to function, especially to autonomic, cognitive, and mood regulation, are major. Several of the affected rostral sites mediate aspects of dyspnea, especially in CCHS, while others participate in initiation of inspiration after central breathing pauses, and the medullary injury can impair baroreflex and breathing control. The ancillary injury associated with sleep-disordered breathing to central structures can elicit multiple other distortions in cardiovascular, cognitive, and emotional functions in addition to effects on breathing regulation.

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.

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.