GPT and COVID-19: Significant differences in ALT (WMD = 7.11 U/L; 95% CI, 5.47-8.75 U/L), aspartate aminotransferase (AST; WMD = 16.10 U/L; 95% CI, 14.00-18.20 U/L), and total bilirubin (WMD = 2.75 mmol/L; 95% CI, 2.11-3.40 mmol/L) were observed in patients with severe and non-severe COVID-19.