The relationship between neutrophil to lymphocyte ratio, endothelial function, and severity in patients with obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is characterized by repetitive intermittent hypoxia and reoxygenation during sleep with elevated oxidative stress and promotes the development of atherosclerosis, as demonstrated by vascular dysfunction and chronic inflammation. An increased neutrophil to lymphocyte ratio (NLR) has been recognized to be a novel inflammatory biomarker for systemic inflammation. Objectives: We evaluated whether the NLR reflects the severity of OSA and if continuous positive airway pressure (CPAP) treatment ameliorates the endothelial function and NLR in patients with OSA. Methods: We enrolled 95 patients with suspected OSA and 29 patients who received CPAP therapy for 3 months. We evaluated the number of endothelial progenitor cells (EPCs) and NLR, the levels of nitric oxide (NOx) and asymmetric dimethylarginine (ADMA), and the endothelial function according to the flow-mediated dilatation (FMD) before and after CPAP treatment. Results: The levels of apnea-hypopnea index demonstrated an inverse relationship with the FMD and a positive relationship with the NLR. Moreover, NLR is an independent factor suggested for the presence of severe OSA. CPAP therapy increased the levels of EPC and NOx and decreased the level of ADMA. CPAP treatment also improved the FMD and decreased the NLR. Conclusions: NLR and endothelial dysfunction significantly correlates with the severity of OSA and FMD and other biochemical parameters improved and NLR decreased significantly after CPAP treatment. (C) 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.