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Clinical manifestations and diagnosis of obesity hypoventilation syndrome

Amanda Piper, PhD
Brendon Yee, MBChB, PhD
Section Editor
M Safwan Badr, MD
Deputy Editor
Geraldine Finlay, MD


Obesity Hypoventilation Syndrome (OHS) is defined as the presence of awake alveolar hypoventilation in an obese individual which cannot be attributed to other conditions associated with alveolar hypoventilation [1-3]. OHS is associated with increased cardiovascular morbidity and mortality. Consequently, early detection and treatment are crucial to minimize these adverse effects.

The clinical manifestations, diagnosis, and complications of OHS are reviewed here, while the pathogenesis and treatment are discussed separately. (See "Epidemiology and pathogenesis of obesity hypoventilation syndrome" and "Treatment and prognosis of the obesity hypoventilation syndrome" and "Noninvasive positive airway pressure therapy of the obesity hypoventilation syndrome".)


The major risk factor for OHS is obesity (body mass index [BMI] >30 kg/m2), in particular, severe obesity (BMI >50 kg/m2), where prevalence may be as high as 50 percent. However, not all patients with obesity develop OHS.

Risk factors in obese patients are poorly defined but may include [4-6]:

Significant increase in waist:hip ratio (ie, central obesity)

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Literature review current through: Nov 2017. | This topic last updated: Aug 18, 2017.
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