Clinical features and mechanism of liver injury in patients with mild or moderate coronavirus disease 2019

Abstract Background and Aim We aimed to identify clinical features that suggest that coronavirus disease 2019 (COVID‐19) should be a differential diagnosis in patients presenting with a chief complaint of fever and abnormal liver function. Methods We retrospectively studied the presence or absence of abnormal liver function in 216 patients diagnosed with mild–moderate severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection between February and September 2020. Results Abnormal liver function was observed in 51 patients with mild–moderate COVID‐19. The median peak aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were 57.5, 75.5, and 332.5 U/L, respectively. The median number of days from symptom onset to peak AST, ALT, and LDH were 8.5, 9, and 8.5, respectively. The median peak LDH/AST ratio was 9.0. Low lymphocyte‐to‐white blood cell ratio and elevated LDH were found to be independent contributing factors for intensive care unit (ICU) admission on a multivariate analysis. Conclusions AST‐predominant AST/ALT/LDH elevation peaking 8–9 days after symptom onset and not accompanied by elevated alkaline phosphatase or gamma‐glutamyl transferase may be a useful clinical feature for differentiating COVID‐19 from other diseases. Since the median LDH/AST ratio was 9.0, it seems that the abnormal liver function caused by SARS‐CoV‐2 is an indirect damage to liver cells due to elevated cytokine levels caused by liver‐infiltrating lymphocytes. SARS‐CoV‐2 infection should be considered in patients presenting with a chief complaint of fever and liver injury; those with a high lymphocyte‐to‐white blood cell ratio or and a high LDH/AST ratio may be admitted to the ICU.