Prevalence of Obesity Hypoventilation Syndrome

Study Overview
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Brief Summary
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Rationale of the BIO-OHS study (Prevalence of Obesity Hypoventilation Syndrome): The overall prevalence of Obesity Hypoventilation Syndrome (OHS) has never been directly assessed in the general population. Actually, this prevalence has been assessed in patients referred to sleep clinics with a potential diagnosis of sleep-disordered breathing or in patients already diagnosed with sleep apnea. The purpose of this study is to determine the prevalence of Obesity Hypoventilation syndrome in obese patients referred to clinical laboratories for regular follow-up medical analysis.

Detailed Description
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No additional description

Official Title
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Prevalence of Obesity Hypoventilation Syndrome in Subjects With Obesity Referred to Clinical (Medical Analysis) Laboratories for Regular Follow-up

Conditions
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Obesity Hypoventilation Syndrome

Intervention / Treatment
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* Procedure: Blood test analysis in the clinical labs
* Procedure: Pneumologist consult to establish the diagnosis of OHS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years old ans more BMI over 30 kg/M2 Stable state (respiratory, metabolic and cardio-vascular) for the last 2 months Addressed to a clinical labs for a blood check-up whatever the prescription Exclusion Criteria: No social security Non cooperative patient, as judged by the investigator

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: [HCO3-] >= 27 mmol/L (Group 1)<br>All obese patients with plasmatic[HCO3-] >= 27 mmol/L will be addressed to a pneumologist. The pneumology investigations will establish(or not) the diagnosis of OHS | Procedure: Blood test analysis in the clinical labs<br>* for specific measurement of plasmatic bicarbonate<br>Procedure: Pneumologist consult to establish the diagnosis of OHS<br>* complete respiratory check-up: Arterial blood gases analysis, spirometry, anthropometry, polygraphy or polysomnography. Medical history, previous treatments.<br>|
| Other: [HCO3-]< 27mmol/L+pneumologist (Group 2)<br>Among obese patients with serum [HCO3-]< 27 mmol/L, 300 randomized patients will be addressed to a pneumologist. The pneumology investigations will refute(or not)the diagnosis of OHS. | Procedure: Blood test analysis in the clinical labs<br>* for specific measurement of plasmatic bicarbonate<br>Procedure: Pneumologist consult to establish the diagnosis of OHS<br>* complete respiratory check-up: Arterial blood gases analysis, spirometry, anthropometry, polygraphy or polysomnography. Medical history, previous treatments.<br>|
| Other: [HCO3-]< 27 mmol/L (Group 3)<br>Obese patients with a [HCO3-]<27 mmol/L randomized to group 3 will receive usual medical follow-up (end of study) | Procedure: Blood test analysis in the clinical labs<br>* for specific measurement of plasmatic bicarbonate<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of Obesity Hypoventilation Syndrome (OHS) in obese subjects referred to clinical laboratories for regular blood test analysis. | OHS prevalence, validated by arterial blood gases analysis, will be assessed by the percentage of patients with OHS among all patients included in the study | From date of inclusion until the end of the study currently planned (up to 2 years) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity and specificity of plasmatic [HCO3-] to detect OHS | A ROC curve will determine if the threshold of 27 mmol/L has the best diagnostic value. Decision trees will show if the diagnostic value of plasmatic [HCO3-]could be optimized by a combination with other clinical parameters. | From date of inclusion to the end of the study currently planned (2 years) | 
| Prevalence of metabolic and cardiovascular comorbidities in patients with OHS | Prevalence will be estimated by the percentage and the confidence interval. Prevalences of metabolic and cardiovascular comorbidities among patients with OHS and without OHS will be compared by a KHI-2 test or Fisher Exact depends on the theorical number. | From date of inclusion to the end of the study currently planned (2 years) | 
| To determine which medical specialties referred patients with OHS to clinical labs | estimated by percentage | From date of inclusion to the end of the study currently planned (2 years) | 
| Incidence of serious health events at 1 and 2-year follow-up | Cardiovascular, metabolic and respiratory events (measured by percentages in OHS group and non-OHS group) will be compared by logistic regressions. | From time of OHS diagnostic to 1 and 2-year follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity Hypoventilation Syndrome, Prevalence, Bicarbonate