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Obesity hypoventilation syndrome: does the current definition need revisiting?
  1. Nicholas Hart1,
  2. Swapna Mandal1,
  3. Ari Manuel2,
  4. Babak Mokhlesi3,
  5. Jean-Louis Pépin4,
  6. Amanda Piper5,
  7. John R Stradling6
  1. 1 Lane Fox Unit and Critical Care, St Thomas’ Hospital, London, UK
  2. 2 Oriel College, University of Oxford, Oxford, UK
  3. 3 Section of Pulmonary and Critical Care Medicine, University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
  4. 4University Grenoble Alpes, HP2 Laboratory, Grenoble, France; Inserm, U1042, Grenoble University Hospital, Sleep Laboratory and Physiology Department, Grenoble, France
  5. 5 Sleep Unit, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
  6. 6 Adult Respiratory Sleep Disorders, Oxford Centre for Respiratory Medicine, Oxford, UK
  1. Correspondence to Dr Ari Manuel, Oriel College, University of Oxford, Oriel Square, Oxford OX1 4EW, UK; ari.manuel{at}

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Obesity hypoventilation syndrome (OHS) has been conventionally (and to some extent arbitrarily) defined by the combination of obesity (body mass index (BMI) >30 kg/m2), daytime hypercapnia (arterial partial pressure of carbon dioxide (PaCO2) ≥45 mm Hg or 6 kPa) during wakefulness, and usually (but not always) the presence of ‘sleep disordered breathing’, such as obstructive sleep apnoea, rapid eye movement sleep hypoventilation or both.1 The survival curve for untreated OHS is significantly reduced compared with the non-obese,2 and so early identification and treatment for these patients is likely to be beneficial. Little is currently known about the true prevalence of OHS in ambulatory obese individuals, with estimates range from 0.3–0.4% of the general population,3 to around 30% of hospitalised patients with a BMI >35 kg/m …

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  • Contributors NH, SM, AM, BM, J-LP, AP and JRS all prepared, edited and reviewed the manuscript. JRS is the senior author for this submission.

  • Competing interests None.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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