Effect of 5-year continuous positive airway pressure treatment on the lipid profile of patients with obstructive sleep apnea: A pilot study

Continuous positive airway pressure (CPAP) provides a well-documented symptomatic relief for most patients with obstructive sleep apnea (OSA); however, its effect on dyslipidaemia remains contradictory. The aim of this longitudinal pilot study was to investigate the effect of long-term CPAP treatment on the lipid profile of patients with severe OSA. Fasting serum levels of total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C and HDL-C) and triglyceride (TG) were longitudinally measured in 33 OSA patients with an apnea-hypopnea index (AHI) of >= 30 events/hr, at the time of diagnosis (baseline) and at control visits following fixed-pressure CPAP treatment. Compared to baseline values, even as short as a 2-month CPAP therapy resulted in a significant decrease of both TC and LDL-C levels (TC, 5.62 +/- 0.22 vs. 5.18 +/- 0.21 mmol/L; LDL-C, 3.52 +/- 0.19 vs. 3.19 +/- 0.2 mmol/L; p < 0.05 for each). These lipid fractions exhibited similar improvements at 6 months and after 5 years of CPAP treatment (TC, 5.1 +/- 0.17 mmol/L; LDL-C, 2.86 +/- 0.16 mmol/L; p < 0.01 for each). The reduction in lipid levels was greater in younger patients and/or in those who had higher body mass index (BMI) (p < 0.05). There were no significant correlations between AHI and lipid levels (p > 0.05); BMI showed a weak negative association with HDL-C fraction (BMI, r = -0.263, p < 0.05). CPAP therapy had neither short- nor long-term effects on TG and HDL-C levels (p > 0.05). CPAP therapy has a rapid and long-lasting beneficial effect on the lipid profile of patients with severe OSA.