[How do you really know if the obese patient has sleep apnea?].

Obesity is known to predispose to obstructive sleep apnea (OSA), a condition characterized by repeated episodes of apnea or hypopnea during sleep, due to the interruption of airflow through the nose and mouth. These episodes lead to the fragmentation of sleep and to decrease in oxyhaemoglobin saturation. Patients with massive obesity, with or without daytime hypersomnolence should be systematically screened for OSA, because many of them appear to be asymptomatic and unaware of their breathing abnormalities during sleep. Polysomnography (PSG) in an attended hospital laboratory setting is the gold standard for the diagnosis of OSA. However portable recording devices can be used for screening with good sensibility and specificity, and even for diagnosis when the apnea-hypopnea index is high. However the final diagnosis can only be carried out in a sleep laboratory using PSG by highly-qualified personnel, because of the limitations of the portable recording device. There is a strong association between OSA and the risk of traffic accidents. It has been established that OSA affects quality of life. There is also increasing evidence that OSA is an independent risk factor for cardio-vascular diseases. This has been successfully demonstrated for hypertension by prospective studies. But the evidence remains weak for myocardial infarction, stroke or mortality. Treating OSA with continuous positive airway pressure (CPAP) is the treatment of choice. CPAP improves quality of life, driving simulator performance, blood pressure and sleepiness, as demonstrated by randomised placebo controlled trials. The majority of obese OSA patients are currently not being offered diagnosis testing and treatment. It's a real challenge due to the epidemic increase of obesity prevalence. Portable recording devices could be available outside the sleep laboratory in nutrition department, where morbid obesity is treated. This emphasizes the need for a real collaboration between these departments and sleep experts.