Obstructive sleep apnoea (OSA), a type of chronic intermittent hypoxia with increasing global prevalence, constitutes a multisystemic disorder often associated with cardiovascular and metabolic disorders.In total, 142 plasma samples were acquired: 50 from controls (CON), 45 from mild/moderate OSA (M-OSA) patients, and 47 from severe OSA (S-OSA) patients.Proteomic and metabolic signatures significantly differed among S-OSA, M-OSA, and CON samples.Omics analysis revealed the characteristics of OSA and uncovered potential mechanisms by which diabetes mellitus and cardiovascular disease risks are increased in OSA. These results might also provide new diagnostic biomarkers for OSA and the identification of severe cases.