Three-Month Continuous Positive Airway Pressure (CPAP) Treatment Decreases Total and LDL-Cholesterol Levels but Does Not Affect Serum Homocysteine and Leptin Levels in Patients with Obstructive Sleep Apnoea Syndrome (OSAS) without Co-Existent Ischaemic Heart Disease (IHD) ^†

Introduction: Continuous positive airway pressure (CPAP) treatment reduces cardiovascular morbidity and mortality in patients with obstructive sleep apnoea syndrome (OSAS). Homocysteine and leptin may play a role in the development of ischaemic heart disease (IHD) in these patients. The aim of the study was to assess the effects of 3-month CPAP treatment on the risk factors of IHD in patients with OSAS without co-existing IHD (OSAS without IHD) and on OSAS with co-existing IHD (OSAS with IHD). Material and methods: CPAP treatment was commenced in 42 patients with OSAS without IHD and in 23 patients with OSAS with IHD. Baseline and end-of-treatment levels of homocysteine, leptin, C-reactive protein (CRP), fibrinogen, lipids parameters and visceral obesity related parameters were determined. Results: No significant changes in the levels of homocysteine, leptin, fibrinogen or CRP in either of the study groups were observed at the end of the treatment. No changes in lipid parameters or the degree of obesity were observed in the OSAS with IHD group. A significant reduction in total and LDL-cholesterol levels were observed in the OSAS without IHD group (202.5 ± 38.5 mg/dl v. 186.7 ± 33.5 mg/dl, p = 0.001 and 127.3 ± 32.9 mg/dl v. 116.4 ± 26.9 mg/dl, p = 0.02, respectively). There were no significant changes in body mass index (30.4 ± 3.8 kg/m² v. 30.6 ± 3.6 kg/m², p = 0.5) or the amount of visceral fat, as measured by waist circumference (108.5 ± 8.0 cm v. 107.0 ± 7.5 cm, p = 0.09) and waist-to-hip ratio (1.03 ± 0.04 v. 1.01 ± 0.03, p = 0.07). Conclusions: Three-month CPAP treatment did not affect the levels of homocysteine or leptin in patients with OSAS, although there was a significant reduction in lipid parameters in patients with OSAS without co-existent IHD, which confirms the beneficial effect of this method of treatment on the risk factors of IHD.