Metabolic disturbances in patients with obstructive sleep apnoea syndrome

The metabolic disturbances in patients with obstructive sleep apnoea syndrome (OSAS) include insulin resistance and elevated levels of pro-inflammatory cytokines and vascular adhesion molecules, as well as an elevation of hormones derived from the adipose tissue as leptin. These phenomena might, in part, be an explanation for the excess morbidity and mortality of OSAS patients concerning cardiovascular disease. Several of these factors have been described as being independently associated with OSAS and not only related to its comorbidities, including obesity. A promising approach to studying the metabolic phenomena in these OSAS patients would be to monitor patients before and during the course of continuous positive airway pressure therapy, as nocturnal sleep disturbances are treatable and may revert the impact of OSAS on the metabolic phenomena; however, patients do frequently (and unfortunately) maintain their body weight. Although not confirmed by all investigations, a tendency towards an improvement in some of the above-mentioned metabolic parameters has been reported in several studies in obstructive sleep apnoea syndrome patients and may be reflected by the decreased occurrence of new cardiovascular events, the reduction of systolic blood pressure and the improvement of left ventricular systolic function.