Liver Injury in COVID-19 Infection: A Systematic Review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or novel coronavirus disease (COVID-19) pandemic is sweeping through the world. The overwhelming pathology seems to be in the upper and lower respiratory tract; however, the involvement of other organs, including the liver, has also been reported. Whether liver enzyme derangement is a common feature of COVID-19 is not known. For those patients who have concomitant liver enzyme derangement with COVID-19, the prevalence, extent, and rate of progression to liver failure is not known. In view of unclear evidence regarding this, we conducted a systematic review of the literature on liver injury in COVID-19 patients. The aim of this review was to ascertain whether liver enzyme derangement is a common feature in adult patients with confirmed COVID-19 infection, determine the relation of deranged liver enzymes with outcome or mortality in COVID-19, and determine if liver failure is a common feature of COVID-19. The PubMed and OVID Medline databases were searched systematically. Cross-sectional studies and case-control studies involving adult patients with confirmed COVID-19 and having data on liver enzymes were included. Independent extraction of the data was done by two independent authors.  A total of 23 articles were identified by the initial filtering search. Abstracts were reviewed and screened to shortlist studies. A full-text assessment of the shortlisted articles for eligibility criteria identified five articles. Manual searching via the LitCovid (National Library of Medicine tool) search hub produced a further two studies that were eligible. Many of the COVID-19 patients in the various studies had a varying degree of deranged liver enzymes. The degree of injury was mild in most cases; and it appears to correlate with the severity of COVID-19 infection. Severe liver injury causing significant liver damage, liver failure, or death is uncommon. The main limitations of the study were the heterogeneity of studies and incomplete data on the trajectory of liver tests during the disease course as well as the final outcomes of the patients in the studies.