Acute Effect of CPAP on Weight in Patients With Obstructive Sleep Apnea

Study Overview
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Brief Summary
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The effect of CPAP on weight and fluid homeostasis will be assessed. Obstructive sleep apnea treatment-naive subjects will randomized to CPAP and control groups. Weight change, and changes in overnight urinary volume, intra and extracelullar volume, plasmatic B-type natriuretic peptide (BNP) and antidiuretic hormone (ADH) and urinary osmolality will be compared between groups.

Detailed Description
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There is a bidirectional relationship between Obstructive Sleep Apnea (OSA) and obesity. Although obesity can lead to OSA, patients with OSA are more likely to gain weight. The mechanisms that lead to weight gain during the treatment of OSA are not known. Some evidence supports the hypothesis that fluid accumulation could be a possible explanation for weight gain after treatment for OSA. The hypothesis is that one night of CPAP treatment promotes increased body weight and reduced diuresis in patients with OSA. Participants will be submitted to 2 consecutive nights of polysomnography (PSG). A baseline PSG will be performed during the first study visit. During the second study night, participants will be randomized into two groups, CPAP and control (repeat baseline PSG). Overnight urinary volume will be determined. Intra and extracellular water volume will be assessed using electrical bioimpedance before bedtime and just after the subject wakes up. Plasmatic BNP and ADH and urinary osmolality will also be determined during each morning following PSG.

Official Title
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Acute Effect of Continuous Positive Airway Pressure (CPAP) on Weight in Patients With Previously Untreated Obstructive Sleep Apnea

Conditions
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Obstructive Sleep Apnea

Intervention / Treatment
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* Device: Continuous Positive Airway Pressure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with a diagnosis of Obstructive Apnea Sleep Over 18 years of age No previous treatment with Continuous Positive Airway Pressure Exclusion Criteria: Congestive heart failure Renal insufficiency Hepatic failure Urinary incontinency Diuretic therapy

Ages Eligible for Study
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Minimum Age: 18 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: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br>During the first and second study nights, subjects will undergo baseline polysomnography. | |
| Experimental: Continuous Positive Airway Pressure<br>Baseline polysomnography will be perfomed during the first study night and CPAP titration polysomnography will be performed during the second study night. | Device: Continuous Positive Airway Pressure<br>* Continuous Positive Airway Pressure will be used during the second night of polysomnography .<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Weight change | Weight change with just one night of CPAP treatment. | After 6 hours of Continuous Positive Airway Pressure treatment | 
| Diuresis change | diuresis change with just one night of CPAP treatment. | After 6 hours of Continuous Positive Airway Pressure treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Urinary osmolarity | Urine will be collected | After 10 hours of the nocturnal polysomnography | 
| Atrial natriuretic peptide and antidiuretic hormone | Blood samples will be collected | After 10 hours of the nocturnal polysomnography | 
| Intra and extracellular fluid volume | Intra and extracellular fluid volume accumulation will be assessed by bioelectrical impedance | Before the beginning and after 10 hours of the nocturnal polysomnography. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obstructive Sleep Apnea, Continuous Positive Airway Pressure, Weight Gain