Influence of nCPAP on Metabolic Consequences Associated With OSAS

Study Overview
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Brief Summary
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Context: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular morbidity. Recurrent episodes of occlusion of upper airways during sleep result in hormonal changes that may predispose to high cardiovascular risk.These risks can rapidly be reduced by effective nasal continuous positive airway pressure (nCPAP) therapy Objective: To evaluate hypothalamic pituitary adrenal axis, insulin resistance, blood pressure values and adipokines in severe obese patients with and without OSAS and to determine if continuous positive airway pressure therapy (nCPAP) influenced responses.

Detailed Description
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Background: There is evidence that obstructive sleep apnea syndrome (OSAS) increases the risk of cardiovascular events. Sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA) axis activation may be the mechanism of this relationship. We evaluate HPA axis and metabolic consequences in obese patients with and without OSAS and we determine if continuous positive airway pressure therapy (nCPAP) influenced responses. Methods: Plasma inflammatory cytokines, insulin resistance index, 24-hour ambulatory blood pressure monitoring and overnight cortisol suppression test with 0.25 mg of dexamethasone were performed in 22 severe obese patients with OSAS and 23 obese controls. Ten patients with severe apnea were re-evaluated three months after nCPAP therapy. Results: Body mass index, abdominal circumference, blood pressure levels and insulin resistance indexes of OSAS patients and obese controls were very similar. In OSAS patients, adiponectin (p<0.05) and salivary cortisol suppression pos DEX (p<0.05) were lower, while heart rate (p<0.05) and TNF-alpha levels (p<0.05) were higher compared with obese controls. After nCPAP therapy, patients showed a reduction in heart rate (p=0.036) and a higher cortisol suppression after dexamethasone (p=0.001) and there were no differences in insulin resistance (HOMA p=0.139), arterial blood pressure (p=0.183) and adipokines compared with baseline. Cortisol suppression was positively correlated with the improvement of apnea hypopnea index while on nCPAP therapy (r= 0.799, p=0.010). Conclusions: Patients with OSAS present nocturnal hypercortisolism, hyperactivity of sympathetic central nervous system, a higher degree of inflammation and hypoadiponectinemia independent of the body mass index. Furthermore, hyperactivity of HPA axis and sympathetic nervous system are recovered by nCPAP.

Official Title
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Improvement in Hypothalamic-Pituitary-Adrenal Axis Function After Continuous Positive Airway Pressure Therapy in Obstructive Sleep Apnea Syndrome

Conditions
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Obstructive Sleep Apnea Syndrome, Obesity

Intervention / Treatment
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* Procedure: nasal continuous positive airway pressure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged from 18 to 65 years Body mass index between 35-60 who were submitted to polysomnography Exclusion Criteria: History of smoking Sleep apnea treatment Cardiovascular disease Malignancies tumor Thyroid disorders Depression Subjects with known diabetes mellitus on medications Chronic renal or hepatic failure On hormonal replacement therapy, as well as use of medication that could potentially affect steroid hormone or cytokines secretion (alcohol, psychotropics, steroids, sympathomimetics, beta-blockers).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: A<br>10 patients with severe OSAS (Apnea Hypopnea Index of more than 30 events per hour of sleep) were treated with nCPAP for three months and all mentioned measurements above were repeated. | Procedure: nasal continuous positive airway pressure<br>* After an average interval of three months, 10 patients with severe OSAS (AHI of more than 30 events per hour of sleep) treated with a mean nCPAP pressure of 11.2 ± 0.7 cm of H2O were reassessed and all mentioned measurements above were repeated<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To explore the interactive mechanisms of HPA axis, sympathetic nervous system activation, inflammatory cytokines, insulin resistance and hypertension in patients with and without sleep apnea, excluding the interference of the degree of fat accumulation. |  | one day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To evaluate low-dose dexamethasone-induced cortisol suppression and circadian rhythm of cortisol secretion in severe obese patients with sleep apnea in response to treatment with continuous positive airway pressure. |  | three months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sleep apnea,, adiponectin ,, HPA axis