question: BACKGROUND AND AIMS: SARS-CoV-2 is mainly a respiratory virus that has relevant systemic effects. We assessed the impact of the baseline liver function (AST, ALT, and bilirubin) on COVID-19-related outcomes, including on mortality, intensive care unit admission, and non-fatal severe complications. METHODS: After a systematic review of the relevant studies, odds ratio, mean difference, sensitivity, specificity, and positive and negative likelihood ratios, were calculated for the prediction of relevant COVID-19 outcomes by performing a meta-analysis using fixed and random effects models. A Fagan nomogram was used to assess the clinical utility. Heterogeneity was explored by sensitivity analysis and univariable meta-regression. RESULTS: Twenty-six studies were included (22 studies and 5271 patients for AST, 20 studies and 5440 subjects for ALT, and 9 studies and 3542 patients for bilirubin). The outcomes of the studies were: survival (n=8), intensive care unit admission (n=4), and non-fatal severe complications (n=16). AST>ULN (OR 3.10 (95%CI 2.61-3.68)), ALT>ULN (OR 2.15 (95%CI 1.43-3.23)), and bilirubin >ULN (OR 2.78 (95%CI 1.88-4.13)) were associated with an increased prevalence of severe complications, with 78%, 77% and 94% of specificity, respectively. The mean difference between mild and severe COVID-19 was 10.7 U/L (95%CI 5.8-15.6) for AST, 8 U/L (95%CI 1.0-15) for ALT, and 0.3 mg/dL (95%CI 0.16-0.45) for bilirubin. CONCLUSIONS: Patients showing liver injury had significantly higher risks of developing severe COVID-19 compared to those with normal liver function tests at admission. We should include the assessment of AST, ALT, and total bilirubin routinely in patients affected by SARS-CoV-2 in order to anticipate those at risk of developing COVID-19-related outcomes.