Associations of serum S100A9 with severity in obstructive sleep apnoea patients

Abstract

Abstract Objectives S100 calcium-binding protein A9 (S100A9) is secreted by activated neutrophils, monocytes, macrophages, platelets, and airway epithelial cells. S100A9 is implicated in many pulmonically inflammatory diseases. However, the role of S100A9 was unknown in obstructive sleep apnoea (OSA) patients. Methods All 173 patients diagnosed with OSA were enrolled. Fasting peripheral blood were collected. Demographic information and clinical characteristics were obtained from hospital records. The level of serum S100A9 was detected through enzyme linked immunosorbent assay (ELISA). Results Serum S100A9 was gradually elevated in parallel with the increased scores of AHI, STOP-BANG, and ESS, as well as apnea duration in OSA patients. Spearman correlation coefficient or Pearson rank correlation analyses indicated that serum S100A9 was strongly associated with many clinical characteristics in OSA patients. Multivariable linear regression found that serum S100A9 was positively correlated with AHI score, STOP-BANG score, ESS score, and apnea duration. Moreover, multivariable logistical regression revealed that the tertiles of serum S100A9 were positively related with the odd ratios (ORs) of AHI score, STOP-BANG score, and average heart rate in OSA patients. Serum S100A9 combination with severity scores elevated the predictive capacities for severe patients compared with single serum S100A9 or OSA severity scores. Conclusion There are significantly positive dose-response relationships between serum S100A9 with the severity scores, indicating that S100A9 is involved in the progression of OSA. Serum S100A9 may be regarded as a biomarker for severity in OSA patients.