“…OHS is seen much more commonly in sleep disorders clinics, with estimated prevalence ranging from 9 to 20% of referred obese patients, and as high as 42% of referred patients with a BMI more than 35 kg/m 2 [7,8 && ]. Multiple recent epidemiologic studies confirm similar rates of OHS: 10-17% of referred patients in Europe [9], 12.3% of obese patients with OSA in Japan [7], 8.5% of all referred patients, and 21% of referred patients with BMI more than 40 kg/m 2 in Saudi Arabia [8 && ], and as high as 51% prevalence in a population of obese patients with chronic hypoxemia in Canada [10]. Rates are even higher in the in-patient setting, with reported prevalence of OHS in 30-60% of patients with a BMI more than 50 kg/m 2 [6,11 & ].…”