ABSTRACT
Background: SARS-CoV-2 infection (COVID-19 disease) can frequently affect the liver The most common manifestation is an asymptomatic, modest elevation of alanine aminotransferase and aspartate aminotransferase Initial histopathological reports of autopsies have described steatosis, mild lobular and portal activity, lymphocytic endotheliitis, and necrosis However, there is no consensus about the main histopathological findings in COVID-19. Aim: To characterize the pathological findings in liver injury due to SARS-CoV-2, from autopsies and biopsies of COVID-19 patients Methods: We conducted a systematic review with meta-analysis registered on PROSPERO (CRD42020192813), following PRISMA guidelines Eligible trials had to include patients of any age, diagnosed with COVID-19 based on a molecular diagnostic technique for SARS-CoV-2 We included liver histopathological reports from deceased COVID-19 patients who subsequently were studied with autopsy or liver biopsies Case reports and clinical series with less than 10 patients were excluded for meta-analysis Proportions were pooled using random-effects models We used Q statistic and I2 to quantify heterogeneity Level of evidence was evaluated using GRADE framework Results: We identified 18 studies from 7 countries;all were case reports and case series from autopsies All the patients were over 15 years old and 67 2% were males We performed a meta-analysis of 5 studies including 116 patients Pooled prevalence estimates of liver histopathological findings were hepatic steatosis 55.1% (95%CI: 46 2-63 8%), congestion of hepatic sinuses 34 7% (95%CI: 7 9-68 4%), vascular thrombosis 29 4% (95%CI: 0.4-87.2%), fibrosis 20.5% (95%CI: 0.6-57.9%), Kupffer cell proliferation or hyperplasia 13 5% (95%CI: 0 6-54 3%), portal inflammation 13.2% (95%CI: 0.1-48.8%), and lobular inflammation 11.6% (95% CI: 0.3-35.7%). We also identified the presence of venous outflow obstruction, phlebosclerosis of the portal vein, herniated portal vein, periportal abnormal vessels, hemophagocytosis, and necrosis Conclusion: In this systematic review and meta-analysis of autopsies from patients with COVID-19, we found a high prevalence of hepatic steatosis and the presence of vascular thrombosis as major histological liver features Other frequent histological features included portal and lobular inflammation and Kupffer cell hyperplasia Further studies are needed to establish the mechanism and implications of these findings.