Polysomnographic Phenotypes of Obstructive Sleep Apnea in a Real-Life Cohort: A Pathophysiological Approach

Introduction: Obstructive sleep apnea (OSA) is heterogeneous and complex, but its severity is still based on the apnea–hypoapnea index (AHI). The present study explores using cluster analysis (CA), the additional information provided from routine polysomnography (PSG) to optimize OSA categorization. Methods: Cross-sectional study of OSA subjects diagnosed by PSG in a tertiary hospital sleep unit during 2016–2020. PSG, demographical, clinical variables, and comorbidities were recorded. Phenotypes were constructed from PSG variables using CA. Results are shown as median (interquartile range). Results: 981 subjects were studied: 41% females, age 56 years (45–66), overall AHI 23events/h (13–42) and body mass index (BMI) 30kg/m2 (27–34). Three PSG clusters were identified: Cluster 1: “Supine and obstructive apnea predominance” (433 patients, 44%). Cluster 2: “Central, REM and shorter-hypopnea predominance” (374 patients, 38%). Cluster 3: “Severe hypoxemic burden and higher wake after sleep onset” (174 patients, 18%). Based on classical OSA severity classification, subjects are distributed among the PSG clusters as severe OSA patients (AHI≥30events/h): 46% in cluster 1, 17% in cluster 2 and 36% in cluster 3; moderate OSA (15≤AHI<30events/h): 57% in cluster 1, 34% in cluster 2 and 9% in cluster 3; mild OSA (5≤AHI<15events/h): 28% in cluster 1, 68% in cluster 2 and 4% in cluster 3. Conclusions: The CA identifies three specific PSG phenotypes that do not completely agree with classical OSA severity classification. This emphasized that using a simplistic AHI approach, the OSA severity is assessed by an incorrect or incomplete analysis of the heterogeneity of the disorder. (AU)

Polysomnographic Phenotypes of Obstructive Sleep Apnea in a Real-Life Cohort: A Pathophysiological Approach.

INTRODUCTION: Obstructive sleep apnea (OSA) is heterogeneous and complex, but its severity is still based on the apnea-hypoapnea index (AHI). The present study explores using cluster analysis (CA), the additional information provided from routine polysomnography (PSG) to optimize OSA categorization. METHODS: Cross-sectional study of OSA subjects diagnosed by PSG in a tertiary hospital sleep unit during 2016-2020. PSG, demographical, clinical variables, and comorbidities were recorded. Phenotypes were constructed from PSG variables using CA. Results are shown as median (interquartile range). RESULTS: 981 subjects were studied: 41% females, age 56 years (45-66), overall AHI 23events/h (13-42) and body mass index (BMI) 30kg/m2 (27-34). Three PSG clusters were identified: Cluster 1: "Supine and obstructive apnea predominance" (433 patients, 44%). Cluster 2: "Central, REM and shorter-hypopnea predominance" (374 patients, 38%). Cluster 3: "Severe hypoxemic burden and higher wake after sleep onset" (174 patients, 18%). Based on classical OSA severity classification, subjects are distributed among the PSG clusters as severe OSA patients (AHI≥30events/h): 46% in cluster 1, 17% in cluster 2 and 36% in cluster 3; moderate OSA (15≤AHI<30events/h): 57% in cluster 1, 34% in cluster 2 and 9% in cluster 3; mild OSA (5≤AHI<15events/h): 28% in cluster 1, 68% in cluster 2 and 4% in cluster 3. CONCLUSIONS: The CA identifies three specific PSG phenotypes that do not completely agree with classical OSA severity classification. This emphasized that using a simplistic AHI approach, the OSA severity is assessed by an incorrect or incomplete analysis of the heterogeneity of the disorder.

Telemedicine home CPAP titration and follow-up in the COVID-19 scenario.

Introduction: Continuous positive airway pressure (CPAP) titration was dramatically affected by the coronavirus disease 2019 (COVID-19) pandemic due to increased biological risk. This study aimed to compare successful CPAP adaptation and compliance with home telemedicine CPAP titration with the usual method based on face-to-face visits. Methodology: A prospective cohort using telemedicine home CPAP titration and follow-up during the COVID-19 pandemic (TC) was compared with a retrospective cohort receiving face-to-face pre-pandemic home titration (RC). The TC included a subgroup with a smartphone application (TC-APP). Successful CPAP adaptation and compliance at 1 month of follow-up were the main endpoints, while patient satisfaction and costs were secondary endpoints. Results: 210 consecutive patients were evaluated (80 RC and 130 TC). 36 patients were in the TC-APP subgroup. CPAP titration was successful in 90% in RC versus 95% in TC and 100% in TC-APP. No compliance differences between groups were found at 1  month (4.79 h·night-1 RC, 4.33  h·night-1 TC and 4.59 h·night-1 TC-APP). Mean±sd patient satisfaction out of 10 was 7.69±2.05 in RC versus 9.02±0.64 in TC (p<0.001). 64% of the TC-APP subgroup reported that their telemedicine strategy influenced an increase in CPAP use (p=0.011). CPAP adaptation with follow-up had an estimated direct staff cost per patient of EUR 19.61±8.61 in TC with no smartphone application used versus EUR 23.79±9.94 in TC-APP (p=0.048). Conclusions: Telemedicine in CPAP titration and early follow-up is equivalent to the usual care in terms of successful adaptation and compliance, while achieving greater patient satisfaction.

Effect of Continuous Positive Airway Pressure on Lipid Profiles in Obstructive Sleep Apnea: A Meta-Analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with dyslipidemia. However, the effects of continuous positive airway pressure (CPAP) treatment on lipid profiles are unclear. METHODS: PubMed/Medline, Embase and Cochrane were searched up to July 2021. Randomized controlled trials (RCTs) of CPAP versus controls with ≥4 weeks treatment and reported pre- and post-intervention lipid profiles were included. Weighted mean difference (WMD) was used to assess the effect size. Meta-regression was used to explore the potential moderators of post-CPAP treatment changes in lipid profiles. RESULTS: A total of 14 RCTs with 1792 subjects were included. CPAP treatment was associated with a significant decrease in total cholesterol compared to controls (WMD = -0.098 mmol/L, 95% CI = -0.169 to -0.027, p = 0.007, I2 = 0.0%). No significant changes in triglyceride, high-density lipoprotein nor low-density lipoprotein were observed after CPAP treatment (all p > 0.2). Furthermore, meta-regression models showed that age, gender, body mass index, daytime sleepiness, OSA severity, follow-up study duration, CPAP compliance nor patients with cardiometabolic disease did not moderate the effects of CPAP treatment on lipid profiles (all p > 0.05). CONCLUSIONS: CPAP treatment decreases total cholesterol at a small magnitude but has no effect on other markers of dyslipidemia in OSA patients. Future studies of CPAP therapy should target combined treatment strategies with lifestyle modifications and/or anti-hyperlipidemic medications in the primary as well as secondary cardiovascular prevention models.

Documento internacional de consenso sobre apnea obstructiva del sueño / International Consensus Document on Obstructive Sleep Apnea

El objetivo principal de este documento internacional de consenso sobre apnea obstructiva del sueño es proporcionar unas directrices que permitan a los profesionales sanitarios tomar las mejores decisiones en la asistencia de los pacientes adultos con esta enfermedad según un resumen crítico de la literatura más actualizada. El grupo de trabajo de expertos se ha constituido principalmente por 17 sociedades científicas y 56 especialistas con amplia representación geográfica (con la participación de 4 sociedades internacionales), además de un metodólogo experto y un documentalista del Centro Cochrane Iberoamericano. El documento consta de un manuscrito principal, con las novedades más relevantes, y una serie de manuscritos online que recogen las búsquedas bibliográficas sistemáticas de cada uno de los apartados del documento internacional de consenso. Este documento no cubre la edad pediátrica ni el manejo del paciente en ventilación mecánica crónica no invasiva (que se publicarán en sendos documentos de consenso aparte). Palabras clave: Apnea obstructiva del sueño Diagnóstico Tratamiento

The main aim of this international consensus document on obstructive sleep apnea is to provide guidelines based on a critical analysis of the latest literature to help health professionals make the best decisions in the care of adult patients with this disease. The expert working group was formed primarily of 17 scientific societies and 56 specialists from a wide geographical area (including the participation of 4 international societies), an expert in methodology, and a documentalist from the Iberoamerican Cochrane Center. The document consists of a main section containing the most significant innovations and a series of online manuscripts that report the systematic literature searches performed for each section of the international consensus document. This document does not discuss pediatric patients or the management of patients receiving chronic non-invasive mechanical ventilation (these topics will be addressed in separate consensus documents). Keywords: Obstructive sleep apnea Diagnosis Treatment

International Consensus Document on Obstructive Sleep Apnea. / Documento internacional de consenso sobre apnea obstructiva del sueño.

The main aim of this international consensus document on obstructive sleep apnea is to provide guidelines based on a critical analysis of the latest literature to help health professionals make the best decisions in the care of adult patients with this disease. The expert working group was formed primarily of 17 scientific societies and 56 specialists from a wide geographical area (including the participation of 4 international societies), an expert in methodology, and a documentalist from the Iberoamerican Cochrane Center. The document consists of a main section containing the most significant innovations and a series of online manuscripts that report the systematic literature searches performed for each section of the international consensus document. This document does not discuss pediatric patients or the management of patients receiving chronic non-invasive mechanical ventilation (these topics will be addressed in separate consensus documents).

Idiopathic pulmonary fibrosis cluster analysis highlights diagnostic delay and cardiovascular comorbidity association with outcome.

INTRODUCTION: Idiopathic pulmonary fibrosis (IPF) prognosis is heterogeneous despite antifibrotic treatment. Cluster analysis has proven to be a useful tool in identifying interstitial lung disease phenotypes, which has yet to be performed in IPF. The aim of this study is to identify phenotypes of IPF with different prognoses and requirements. METHODS: Observational retrospective study including 136 IPF patients receiving antifibrotic treatment between 2012 and 2018. Six patients were excluded due to follow-up in other centres. Cluster analysis of 30 variables was performed using approximate singular value-based tensor decomposition method and comparative statistical analysis. RESULTS: The cluster analysis identified three different groups of patients according to disease behaviour and clinical features, including mortality, lung transplant and progression-free survival time after 3-year follow-up. Cluster 1 (n=60) was significantly associated (p=0.02) with higher mortality. Diagnostic delay was the most relevant characteristic of this cluster, as 48% of patients had ≥2 years from first respiratory symptoms to antifibrotic treatment initiation. Cluster 2 (n=22) had the longest progression-free survival time and was correlated to subclinical patients evaluated in the context of incidental findings or familial screening. Cluster 3 (n=48) showed the highest percentage of disease progression without cluster 1 mortality, with metabolic syndrome and cardiovascular comorbidities as the main characteristics. CONCLUSION: This cluster analysis of IPF patients suggests that diagnostic and treatment delay are the most significant factors associated with mortality, while IPF progression was more related to metabolic syndrome and cardiovascular comorbidities.

Telemedicine Strategy for CPAP Titration and Early Follow-up for Sleep Apnea During COVID-19 and Post-Pandemic Future / La estrategia de la telemedicina para la regulación de la CPAP y el seguimiento temprano de la apnea del sueño durante la pandemia de covid-19 y el futuro post-pandémico

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Role of Gastrointestinal Hormones as a Predictive Factor for Long-Term Diabetes Remission: Randomized Trial Comparing Metabolic Gastric Bypass, Sleeve Gastrectomy, and Greater Curvature Plication.

PURPOSE: Long-term studies comparing the mechanisms of different bariatric techniques for T2DM remission are scarce. We aimed to compare type 2 diabetes (T2DM) remission after a gastric bypass with a 200-cm biliopancreatic limb (mRYGB), sleeve gastrectomy (SG), and greater curvature plication (GCP), and to assess if the initial secretion of gastrointestinal hormones may predict metabolic outcomes at 5 years. MATERIAL AND METHODS: Forty-five patients with mean BMI of 39.4(1.9)kg/m2 and T2DM with HbA1c of 7.7(1.9)% were randomized to mRYGB, SG, or GCP. Anthropometric and biochemical parameters, fasting concentrations of PYY, ghrelin, glucagon, and AUC of GLP-1 after SMT were determined prior to and at months 1 and 12 after surgery. At 5-year follow-up, anthropometrical and biochemical parameters were determined. RESULTS: Total weight loss percentage (TWL%) at year 1 and GLP-1 AUC at months 1 and 12 were higher in the mRYGB than in the SG and GCP. TWL% remained greater at 5 years in mRYGB group - 27.32 (7.8) vs. SG - 18.00 (10.6) and GCP - 14.83 (7.8), p = 0.001. At 5 years, complete T2DM remission was observed in 46.7% after mRYGB vs. 20.0% after SG and 6.6% after GCP, p < 0.001. In the multivariate analysis, shorter T2DM duration (OR 0.186), p = 0.008, and the GLP-1 AUC at 1 month (OR 7.229), p = 0.023, were prognostic factors for complete T2DM remission at 5-year follow-up. CONCLUSIONS: Long-term T2DM remission is mostly achieved with hypoabsortive techniques such as mRYGB. Increased secretion of GLP-1 after surgery and shorter disease duration were the main predictors of T2DM remission at 5 years.

Mobile health application to support CPAP therapy in obstructive sleep apnoea: design, feasibility and perspectives.

BACKGROUND: Current continuous positive airway pressure (CPAP) devices can be monitored remotely; however, in-person visits are kept for clinical follow-up in order to promote CPAP use and resolve potential side-effects. Mobile health is a promising way to provide remote and easy clinical control for CPAP follow-up and support. We aimed to evaluate the feasibility and acceptance by obstructive sleep apnoea (OSA) patients and healthcare professionals of a newly designed mobile app (Appnea-Q) to promote clinical control through a self-monitoring tool for patients with CPAP supervised by sleep professionals. METHODS: Appnea-Q incorporates a simple follow-up questionnaire with automated responses, together with frequent problems and lifestyle recommendations sections. Feasibility, acceptance and usefulness were assessed. First, an internal validation was performed during outpatient CPAP follow-up visits with sleep professionals from various sleep units. Second, an external validation was performed in a subgroup of 15 patients at home. RESULTS: Most patients (n=75) considered the app useful and were willing to use it and recommend it (72-88%). Up to 64.87% agreed on its capacity to reduce hospital visits. Appnea-Q was rated as acceptable (79.37±19.29) by the system usability score. Sleep professionals (n=30) concurred on its usefulness for OSA patient follow-up, particularly during the first month of CPAP therapy. The external validation showed its feasibility among 11 out of 15 patients and their data were received accordingly on the professionals' web platform. CONCLUSIONS: According to our validation process, and the viewpoints of the patients and professionals, our new mobile app is a feasible and well-received tool for personal OSA management. Future clinical trials should substantiate its performance and cost-effectiveness in the clinical arena.

Effectiveness of an intensive weight-loss program for severe OSA in patients undergoing CPAP treatment: a randomized controlled trial.

STUDY OBJECTIVES: To determine whether an intensive weight-loss program (IWLP) is effective for reducing weight, the severity of obstructive sleep apnea (OSA), and metabolic variables in patients with obesity and severe OSA undergoing continuous positive airway pressure treatment. METHODS: Forty-two patients were randomized to the control (CG, n = 20) or the intervention group (IG, n = 22), who followed a 12-month IWLP. The primary outcome was a reduction in the apnea-hypopnea index (AHI) as measured at 3 and 12 months by full polysomnography. Metabolic variables, blood pressure, body fat composition by bioimpedance, carotid intima media thickness, and visceral fat by computed tomography were also assessed. RESULTS: Mean age was 49 (6.7) years, body mass index 35 (2.7) kg/m², and AHI 69 (20) events/h. Weight reduction was higher for the IG than the CG at 3 and 12 months, -10.5 versus -2.3 kg (P < .001), and -8.2 versus -0.1 kg (P < .001), respectively, as was loss of visceral fat at 12 months. AHI decreased more in the IG at 3 months (-23.72 versus -9 events/h) but the difference was not significant at 12 months, though 28% of patients from the IG had an AHI < 30 events/h compared to none in the CG (P = .046). At 12 months, the IG showed a reduction in C-reactive protein (P = .013), glycated hemoglobin (P = .031) and an increase in high density lipoprotein cholesterol (P = .027). CONCLUSIONS: An IWLP in patients with obesity and severe OSA is effective for reducing weight and OSA severity. It also results in an improvement in lipid profiles, glycemic control, and inflammatory markers. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Title: Effectiveness of an Intensive Weight Loss Program for Obstructive Sleep Apnea Syndrome (OSAS) Treatment; Identifier: NCT02832414; URL: https://clinicaltrials.gov/ct2/show/record/NCT02832414.

Anthropometrical phenotypes are important when explaining obstructive sleep apnea in female bariatric cohorts.

Central obesity is the main risk factor for obstructive sleep apnea (OSA). Whether there exists a central-obesity anthropometric that better explains apnea-hypopnea index (AHI) variability in the general population and in sleep cohorts is unknown, and this is even less explored among increasing grades of obesity. The objective of the study is to investigate whether there is an anthropometric that better explains AHI variability in a sample of morbidly obese women awaiting bariatric surgery (BS). A prospective multicentre cross-sectional study was conducted in consecutive women before BS. Demographic and anthropometric characteristics included age, body mass index (BMI), neck circumference (NC), waist circumference (WC), hip circumference (HC) and waist-to-hip ratio (WHR). OSA was diagnosed by polysomnography. The capacity of anthropometrics to explain AHI variance was investigated using regression linear models. A total of 115 women were evaluated: age, 44 ± 10 years; BMI, 46 ± 5 kg/m2 ; AHI, 35 ± 26 events/hr. AHI was associated with all anthropometrics except weight, height and HC. The best univariate predictor was WHR, which accounted for 15% of AHI variance. The simplest model (age + BMI) accounted for 9%, which increased to 20% when applying more complex measurements (age + BMI + NC + WC + HC). The explanatory capacity did not change significantly when applying a simpler model (age + WHR + NC, 19%). In this female morbidly obese cohort, anthropometrics explained one-fifth of AHI variability. WHR is the best univariate parameter and models including waist and neck data provide more information than BMI when explaining AHI variability. Thus, even in young women with extreme obesity, OSA seems to be linked to a specific central-obesity phenotype rather than to a whole-obesity pattern.

Food addiction and preoperative weight loss achievement in patients seeking bariatric surgery.

INTRODUCTION: Evidence suggests that food addiction (FA) is prevalent among individuals with obesity seeking bariatric surgery (BS), but there is no evidence about whether FA is a predictor of weight loss (WL). We aimed to analyse the prevalence of FA in patients with obesity seeking BS and to examine whether FA could predict WL following dietary intervention before surgery. METHOD: The study included 110 patients with obesity who underwent a dietetic intervention. Assessment included endocrinological variables, a semistructured interview to rule out mental disorders, and Yale Food Addiction Scale version 2.0 (YFAS 2.0). RESULTS: In our sample, the prevalence of FA was 26.4%. Those who met YFAS 2.0 criteria showed less WL after dietetic intervention and regain weight during dietary intervention. CONCLUSIONS: FA appears to be prevalent in obesity. Our findings confirmed a lower WL throughout dietary intervention before surgery in patients who fulfilled baseline criteria for FA. Future interventions should include multidisciplinary intervention to maximize WL before and after BS.

Weight Loss Trajectories in Bariatric Surgery Patients and Psychopathological Correlates.

This study aimed to explore the empirical trajectories of body mass index (BMI) 1 year following bariatric surgery (BS) and to identify the risk factors for each trajectory. The study included 115 patients with severe obesity who underwent BS. Assessment included metabolic variables, psychopathological and personality measures. Growth mixture modelling identified four separated trajectories for the percentage of total weight loss course shape (namely, T1 'good-fast', T2 'good', T3 'low' and T4 'low-slow'). After adjusting for BS subtype and metabolic baseline state, T1 and T2 registered less eating and general psychopathology. T1 was characterized by the lowest scores in novelty seeking and self-transcendence, whereas T4 was defined by the highest scores in novelty seeking and the lowest scores in persistence. Our findings suggest that psychological state prior to BS is predictive of BMI trajectories during the 12 months following BS. These results could be useful in developing more efficient interventions for these patients. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Conventional Polysomnography Is Not Necessary for the Management of Most Patients with Suspected Obstructive Sleep Apnea. Noninferiority, Randomized Controlled Trial.

RATIONALE: Home respiratory polygraphy may be a simpler alternative to in-laboratory polysomnography for the management of more symptomatic patients with obstructive sleep apnea, but its effectiveness has not been evaluated across a broad clinical spectrum. OBJECTIVES: To compare the long-term effectiveness (6 mo) of home respiratory polygraphy and polysomnography management protocols in patients with intermediate-to-high sleep apnea suspicion (most patients requiring a sleep study). METHODS: A multicentric, noninferiority, randomized controlled trial with two open parallel arms and a cost-effectiveness analysis was performed in 12 tertiary hospitals in Spain. Sequentially screened patients with sleep apnea suspicion were randomized to respiratory polygraphy or polysomnography protocols. Moreover, both arms received standardized therapeutic decision-making, continuous positive airway pressure (CPAP) treatment or a healthy habit assessment, auto-CPAP titration (for CPAP indication), health-related quality-of-life questionnaires, 24-hour blood pressure monitoring, and polysomnography at the end of follow-up. The main outcome was the Epworth Sleepiness Scale measurement. The noninferiority criterion was -2 points on the Epworth scale. MEASUREMENTS AND MAIN RESULTS: In total, 430 patients were randomized. The respiratory polygraphy protocol was noninferior to the polysomnography protocol based on the Epworth scale. Quality of life, blood pressure, and polysomnography were similar between protocols. Respiratory polygraphy was the most cost-effective protocol, with a lower per-patient cost of 416.7€. CONCLUSIONS: Home respiratory polygraphy management is similarly effective to polysomnography, with a substantially lower cost. Therefore, polysomnography is not necessary for most patients with suspected sleep apnea. This finding could change established clinical practice, with a clear economic benefit. Clinical trial registered with www.clinicaltrials.gov (NCT 01752556).

A randomized controlled trial: branched-chain amino acid levels and glucose metabolism in patients with obesity and sleep apnea.

There is evidence that changes in branched-chain amino acid (BCAA) levels may correlate with the efficacy of therapeutic interventions for affecting improvement in metabolic control. The objective of this study was to evaluate whether serum concentrations of BCAAs (leucine, isoleucine, valine) could mediate in insulin sensitivity and glucose tolerance after continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). A prospective randomized controlled trial of OSA patients with morbid obesity was conducted. Eighty patients were randomized into two groups: 38 received conservative treatment and 42 received CPAP treatment for 12 weeks. Plasma levels of BCAA, glucose tolerance and insulin resistance were evaluated at baseline and after treatment. After treatment, significant decreases of leucine levels were observed in both groups when compared with baseline levels (P < 0.005). With respect to patients with normal glucose tolerance (NGT), patients with impaired glucose tolerance (IGT) had higher baseline levels of isoleucine (78 ± 16 versus 70 ± 13 µmol L-1 , P = 0.014) and valine (286 ± 36 versus 268 ± 41 µmol L-1 , P = 0.049), respectively. Changes in levels of leucine and isoleucine after treatment were related negatively to changes in fasting plasma glucose and glycosylated haemoglobin values only in the conservative group (P < 0.05). In summary, we found that the treatment with CPAP for 12 weeks caused similar changes in circulating BCAAs concentrations to conservative treatment and a differential metabolic response of CPAP and conservative treatment was observed between the relationship of BCAAs and glucose homeostasis. Additional studies are needed to determine the interplay between branched-chain amino acids and glucose metabolism in patients with sleep apnea.

A Randomized Controlled Trial of Continuous Positive Airway Pressure on Glucose Tolerance in Obese Patients with Obstructive Sleep Apnea.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is associated with an increased prevalence of metabolic syndrome (MetS), even in patients with morbid obesity. Our goal was to address whether continuous positive airway pressure (CPAP) treatment improved glucose metabolism in this population. METHODS: A prospective randomized controlled trial was performed in severe OSA patients with morbid obesity without diabetes in two university referral hospitals. Patients received conservative (CT) versus CPAP treatment for 12 weeks. MetS components, homeostasis model assessment of insulin resistance (HOMA-IR) and oral glucose tolerance were assessed at baseline and after treatment. RESULTS: A total of 80 patients completed the study (42 CPAP and 38 CT patients). After 12 w of CPAP treatment, weight loss was similar in both groups and physical activity, prevalence of MetS, and HOMA-IR did not change in either group. In the CPAP group impaired glucose tolerance (IGT) reversed in nine patients and IGT developed in none, whereas IGT reversed in five patients and IGT developed in five patients in the CT group (P = 0.039 in the Fisher test). Changes in 2-h plasma glucose after glucose load were greater in the CPAP group than in the CT group (CPAP: -0.5 ± 1.5 versus CT: 0.33 ± 1.9, P = 0.007). CONCLUSIONS: The improvement of glucose tolerance in morbidly obese patients with severe obstructive sleep apnea, without changes in homeostasis model assessment of insulin resistance, supports an improvement in peripheral insulin resistance after continuous positive airway pressure treatment. CLINICAL TRIALS REGISTRATION: NCT 01029561.