How often does COVID-19 cause liver disorders?

Keith Alcorn
Published:
21 July 2020
Image: Jarun Ontakrai/Shutterstock.com

Increases in liver enzymes are common in people with COVID-19 and occur more frequently in people with severe COVID-19, a meta-analysis of studies published in Hepatology International shows.

Most liver enzyme elevations were mild-to-moderate and did not result in severe liver injury, the review found. Only one case of liver failure was identified in the 128 studies reviewed.

Liver enzyme abnormalities were more likely to occur in people with chronic liver disease, the meta-analysis found.

Two coronaviruses with genetic similarities to SARS-CoV-2 (SARS-CoV and MERS-CoV) are known to cause liver damage so physicians were already alerted to the potential for liver injury when SARS-CoV-2 began to cause life-threatening illness in China in early 2020.

Since the first cases of COVID-19 were reported, over 300 studies have been published that report on liver function abnormalities in people with COVID-19. Researchers at Chandigarh University, India, carried out a systematic review of these studies, rejecting published studies which reported on less than five patients or where a diagnosis of COVID-19 was not confirmed by virological testing, leaving 128 studies.

The investigators calculated the pooled prevalence of liver function abnormalities reported in these studies:

  • Hypoalbuminemia – 61.2% (48.2-72.8)
  • GGT elevation – 27.9% (18.2-40.2)
  • Acute hepatic injury – 23.7% (16.3-33.1)
  • ALT elevation – 23.2% (19.9-27)
  • AST elevation – 23.4% (18.8-28.7)
  • Hyperbilirubinemia – 10.8% (95% CI 6.87-17.08)
  • ALP – 7.48% (3.9-13.8).

With the exceptions of ALT and AST, the relative risk of an abnormality was greater in people with severe COVID-19.

However, the review did not find a higher prevalence of underlying liver disease in severe COVID-19 cases. The investigators warn that the review cannot provide evidence on whether chronic liver disease places people at higher risk of severe COVID-19, especially because the designation 'chronic liver disease' embraces viral hepatitis, metabolic disorders, autoimmune disorders and other conditions.

When they compared the risk of liver abnormalities in people with hepatitis B to other people with chronic liver disease, the investigators found no increase in the risk of severe COVID-19 in people with hepatitis B. However, fatty liver disease was associated with a higher risk of severe COVID-19 in four out of five studies which reported on the association.

The investigators say it is impossible to tell whether liver abnormalities are caused by the virus, by the immune system’s response to the virus or by medications used to treat COVID-19, many of which cause liver enzyme elevations.

They also caution that most of the studies identified by the review reported on Chinese patients, so the findings may not capture important underlying differences between populations.

Reference

Kumar P et al. Coronavirus disease (COVID-19) and the liver: a comprehensive systematic review and meta-analysis. Hepatology International, 4 July 2020.

https://doi.org/10.1007/s12072-020-10071-9