Influence of liver attenuation on the severity of course COVID-19: a retrospective cohort study

Introduction There is no unequivocal opinion concerning the influence of decreased liver attenuation on the COVID-19 severity, but its widespread occurrence among these patients has been shown. It is still debatable whether decreased liver attenuation is an independent risk factor for the severe course of CVID-19. Study objective To assess the prognostic value of liver attenuation on CT scan in patients with COVID-19. Material and methods A retrospective cohort study. Data of COVID-19 outpatients were analyzed. Inclusion criteria: two chest CT scans, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in blood, and polymerase chain reaction results to verify SARS-CoV-2. Subjects were categorized into four comparison groups depending on the severity of lung involvement. Liver attenuation was analyzed by automatic segmentation, where the values less than 40 HU were considered pathological. Results Data from 499 subjects were included. The groups differed in age and the level of liver attenuation on both CT scans. No correlation between ALT, AST and changes in liver attenuation was found. On follow-up CT, low liver attenuation was observed in males (odds ratio (OR) 2.79 (95% CI 1.42–5.47), p-value = 0.003) and in patients with a baseline reduced liver attenuation (OR 60.59 (95% CI 30.51–120.33), p-value < 0.001). Age over 60 years was associated with the development of lung lesions (OR 1.04 (95% CI 1.02–1.06) for extent of lung injury < 25%, OR 1.08 (95% CI 1.05–1.11) for 25–50%, OR 1.1 (95% CI 1.06–1.15) for 25– 50%, p-value < 0.001). Low liver attenuation on the baseline CT scan increased the odds of severe lung injury (OR 6.9 (95% CI 2.06–23.07), p-value = 0.002). Conclusion In COVID-19, patients with low liver attenuation are more likely to develop severe lung damage.