The Importance of Systemic Immune-Inflammation Index in Obstructive Sleep Apnea Syndrome

This study aims to explore the importance of systemic immune-inflammation index (SII) in patients diagnosed with obstructive sleep apnea (OSA). In this study planned as a retrospective cohort, the files of the patients who presented with sleep apnea/snoring complaint between 10.01.2017 and 10.01.2021 and underwent polysomnography (PSG) and complete blood count analyses were reviewed. PSG findings (age, sex, body mass index (BMI), apnea–hypopnea index (AHI), mean oxygen saturation) were compared with SII in 194 patients meeting study eligibility criteria. Patients included in this study were divided into 4 groups by AHI value. Statistical difference was detected between the groups in terms of age, sex, body mass index (BMI), and mean oxygen saturation (p < 0.05). There is an approximately 30% positive statistically significant correlation between the severity of OSA and SII (p < 0.001). As for the mean SII values of the AHI groups, it was observed that the more severe AHI is, the higher the mean SII value is. The correlation between SII and the severity of OSA was found to be more significant than the correlation with neutrophil–lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR). There is a significant correlation between SII and the severity of OSA. This correlation is stronger compared to NLR and PLR. SII can be used to demonstrate the chronic systemic inflammation observed in OSA patients, and can be utilized as a simple and inexpensive biomarker as it can be easily calculated from the parameters present in routine blood analyses.