Prevalence and clinical characteristics of obesity hypoventilation syndrome among individuals reporting sleep-related breathing symptoms in northern Greece

Introduction Evidence suggests that obesity hypoventilation syndrome (OHS) is underrecognized and undertreated. Aim of this study was to evaluate the prevalence and clinical characteristics of OHS among patients reporting sleep-related breathing disorders in northern Greece. Materials and methods Individuals (n=276) who consecutively underwent an attended night polysomnography, for possible obstructive sleep apnea syndrome, were recruited. OHS was defined as a combination of obesity (body mass index 30 >= kg/m(2)), daytime hypercapnia (PaCO(2)>= 45 mmHg), and sleep-disordered breathing, without any other known cause of hypoventilation. Anthropometric and sleep characteristics, daytime sleepiness, spirometry, and arterial blood gases' analysis in awake, were compared between OHS and non-OHS patients. Results OHS was identified in 38 of the 276 subjects (13.8%). Among study population, OHS patients were older, more obese, and more somnolent. They did not differ significantly in terms of pulmonary function in awake, whereas they differed, as expected, in arterial blood gases values in awake (PaO(2), PaCO(2)). Furthermore, OHS patients displayed lower average and minimum SpO(2) during sleep and spent more time in SpO(2) < 90% than non-OHS patients. The most common comorbidities were arterial hypertension, diabetes mellitus, and congestive heart failure. Conclusions In our study population, OHS was accounted for a significant percentage of the patients with reported breathing disorders in sleep. As obesity has become an international epidemic, it is crucial that physicians have the ability to recognize and treat obesity-associated diseases.