Autonomic Dysfunction and Inflammation in Obstructive Sleep Apnea Syndrome

Objective: Obstructive sleep apnea syndrome (OSAS) increases the risk of cardiovascular disease. Autonomic dysfunction and inflammation are thought to play an important role in this increase. Heart rate variability (HRV) analysis provides noninvasive detection of autonomic dysfunction. The number and distribution of blood cells are also considered important markers of inflammation. In this study, HRV and hemogram parameters were examined in patients with OSAS, and the relationship between them was investigated. Materials and Methods: The data of all patients who had overnight polysomnography (PSG) recording and hemogram parameters between 2019 and 2021 were reviewed. HRV analysis was performed on all patients included in the study. Along with demographic and clinical characteristics, the relationship between PSG parameters, HRV, and hemogram parameters was statistically analyzed. The patients were divided into two groups as apnea hypopnea index (AHI) & GE;15/hr and AHI<15/hr, and the parameters were compared. Results: A total of 321 patients (210 men, 111 women) were included in this study. The mean age was 54.8 & PLUSMN;16.1 years. The white blood cells count, hemoglobin level, hematocrit level, and neutrophil count, which are considered as indicators of inflammation, were significantly higher in the AHI & GE;15/hr group (p=0.015; p=0.040; p=0.019 and p=0.012, respectively). Among the HRV parameters, the median low-frequency component power / high-frequency component power (LF/HF) ratio was 3.1 in patients with AHI>15/hr, while it was 2.1 in the AHI<15/hr group and was significantly higher in the moderate-severe OSAS group (p=0.012). A significant correlation was found between the LF/HF ratio and neutrophil count, leukocyte count, and neutrophil/lymphocyte ratio (r=0.201; p=0.005 and r=0.165; p=0.020 and r=0.189; p=0.008).Conclusion: In this study, the presence of increased inflammation and deterioration in sympathovagal balance in patients with OSAS has been demonstrated once again. The correlation of autonomic dysfunction with increased inflammation has been noted for the first time, suggesting that inflammation may play a primary role in sympathetic dysfunction, which is an important complication of OSAS.