title: Prevalence of obesity hypoventilation syndrome in ambulatory obese patients attending pathology laboratories.
abstract: The prevalence of obesity hypoventilation syndrome (OHS) in the unselected obese is unknown. Our objectives were: (i) to determine the prevalence of OHS in ambulatory obese patients not previously referred to a pulmonologist for suspicion of sleep breathing disorders and (ii) to assess whether venous bicarbonate concentration [HCO3-v] can be used to detect OHS.
  
  
  
  In this prospective multicentric study, we measured [HCO3-v] in consenting obese patients attending pathology analysis laboratories. Patients with [HCO3-v] ≥ 27 mmol/L were referred to a pulmonologist for comprehensive sleep and respiratory evaluations. Those with [HCO3-v] < 27 mmol/L were randomized to either referral to a pulmonologist or ended the study.
  
  
  
  For the 1004 screened patients, the [HCO3-v] was ≥27 mmol/L in 24.6% and <27 mmol/L in 45.9%. A total of 29.5% who had previously consulted a pulmonologist were excluded. A population of 241 obese patients underwent sleep and respiratory assessments. The prevalence of OHS in this population was 1.10 (95% CI = 0.51; 2.27). In multivariate analysis, PaCO2, forced expiratory volume in 1 s (FEV1), apnoea-hypopnoea index (AHI), BMI, use of ≥3 anti-hypertensive drugs, anti-diabetics, proton pump inhibitors and/or paracetamol were related to raised [HCO3-v].
  
  
  
  The prevalence of OHS in our obese population was lower than previous estimations based on hospitalized patients or clinical cohorts with sleep breathing disorders. Apart from hypercapnia, increased [HCO3-v] may also reflect multimorbidity and polypharmacy, which should be taken into account when using [HCO3-v] to screen for OHS.
authors.affiliation: HP2 Laboratory, INSERM U1042, Grenoble Alpes University, Grenoble, France.|AGIR à dom. Association, Meylan, France.|EFCR Laboratory, Thorax and Vessels Division, Grenoble Alpes University Hospital, Grenoble, France.
authors.forename: Jean-Christian
authors.identifier: 0000-0003-4140-6210
authors.initials: JC
authors.lastname: Borel
authors.affiliation: ORIADE-NOVIALE Laboratory, Vizille, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Guerber
authors.affiliation: HP2 Laboratory, INSERM U1042, Grenoble Alpes University, Grenoble, France.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Jullian-Desayes
authors.affiliation: HP2 Laboratory, INSERM U1042, Grenoble Alpes University, Grenoble, France.|EFCR Laboratory, Thorax and Vessels Division, Grenoble Alpes University Hospital, Grenoble, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Joyeux-Faure
authors.affiliation: AGIR à dom. Association, Meylan, France.|EFCR Laboratory, Thorax and Vessels Division, Grenoble Alpes University Hospital, Grenoble, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Arnol
authors.affiliation: AGIR à dom. Association, Meylan, France.
authors.forename: Nellie
authors.initials: N
authors.lastname: Taleux
authors.affiliation: HP2 Laboratory, INSERM U1042, Grenoble Alpes University, Grenoble, France.|EFCR Laboratory, Thorax and Vessels Division, Grenoble Alpes University Hospital, Grenoble, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Tamisier
authors.affiliation: HP2 Laboratory, INSERM U1042, Grenoble Alpes University, Grenoble, France.|EFCR Laboratory, Thorax and Vessels Division, Grenoble Alpes University Hospital, Grenoble, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pépin
mesh_terms: D000328:Adult; D001639:Bicarbonates / Q000097:blood; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D010845:Obesity Hypoventilation Syndrome / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D011446:Prospective Studies; D012129:Respiratory Function Tests
chemical_list: D001639:Bicarbonates
keywords: bicarbonate; hypercapnic respiratory failure; obesity; obesity hypoventilation syndrome; sleep apnoea