Relationship Between Plasma Neopterin and High Sensitivity C-Reactive Protein Levels and Circadian Rhythm of Blood Pressure in Hypertensive Patients with Obstructive Sleep Apnea Syndrome

Abstract

To investigate the relationship between plasma neopterin and high sensitivity C-reactive protein (hsCRP) levels and circadian rhythm of blood pressure in hypertensive patients with obstructive sleep apnea syndrome (OSAS). A total of 367 hospitalized hypertensive patients were recruited. They were divided into three groups according to polysomnography (PSG): hypertension alone (group A, n=212), hypertension with mild OSAS (group B, n=107) and hypertension with moderate to severe OSAS (group C, n=48). Plasma neopterin and hsCRP concentrations were measured on or after the day of PSG, and ambulatory blood pressure (ABPM) was monitored in the first week of admission. Plasma neopterin and hsCRP levels were significantly higher in group B and C compared to group A (P<0.05). Incidence of non-dippers was significantly lower in group A (44.5%) compared to group B (67.7%) and C (84.2%) (P<0.05). Nocturnal and diurnal blood pressures were negatively correlated with plasma neopterin and hsCRP. Multiple stepwise regression analysis showed that apnea hypopnea index (AHI), drop rate of systolic blood pressure, mean oxygen saturation (MSaO2), minimum oxygen saturation (SaO2 min) were the main factors for neopterin levels while AHI and MSaO2 were the major factors affecting hsCRP levels. Plasma neopterin and hsCRP levels are increased in hypertensive patients with OSAS and positively correlated with severity of OSAS.