RESULTS: A total of 289 individuals were enrolled in the study. 219 subjects were found ODI>5/h (78 patients in mild OSA group, 66 in moderate and 74 in severe). A significant increasing trend among groups were observed in the indices of metabolic score and VAI (P=0.001, p=0.018, respectively). Additionally, a significant negative association with high-density lipoprotein-cholesterol (HDL-C) was observed (P=0.002). Both metabolic score and VAI were significantly correlated with waist circumference, body mass index, diastolic blood pressure, triglycerides, HDL-C, apnea-hypopnea index, ODI, mean nocturnal oxygen saturation and the percentage of sleep duration with SpO2<90% (all P<0.05). ROC curve showed a VAI of 1.739 had a sensitivity of 85.0% and a specificity of 70.3% in determining the occurrence of MetS in OSA patients. OSA patients with VAI≥1.739 tended to have significantly greater risk in incident MetS (odds ratio=13.957, p=0.000).