GPT and COVID-19: Serum ALT (WMD: 7.19 [4.90, 9.48]; p < 0.001; I2 = 69%), AST (WMD: 9.02 [6.89, 11.15]; p < 0.001; I2 = 73%) and bilirubin levels (WMD: 1.78 [0.86, 2.70]; p < 0.001; I2 = 82%) were significantly higher in patients with severe COVID-19 when compared to patients with non-severe disease.