GPT and obstructive sleep apnea syndrome: In a study conducted on 50 patients with OSAHS and 40 healthy controls [21], it was found that the level of ALT, TC, AST, BUN, and SCr were abnormally elevated in patients with mild to moderate and severe OSAHS compared to normal controls, while the elevation of AST and SCr was particularly severe in patients with severe OSAHS.