Mild liver enzyme increases seen in COVID-19 patients in China

Last Updated: 2020-07-01

By Marilynn Larkin

NEW YORK (Reuters Health) - Close to 30% of COVID-19 patients presented with mildly elevated liver enzymes in a retrospective study in China.

Enzyme levels did not rise significantly during hospitalization and no patients experienced liver failure, however.

Dr. Yi-Da Yang of Zhejiang University in Hangzhou and colleagues studied 788 patients hospitalized with COVID-19 in the Zhejiang Province from January 17 to February 12, 2020. Liver enzyme level elevation at admission was defined as alanine aminotransferase (ALT) level >35 U/L for men and >25 U/L for women. Patients with normal ALT levels were controls.

As reported in the American Journal of Gastroenterology, ALT was elevated in 222 patients (28%) - including five patients (2.3%) who were taking medications that can induce liver failure. The median age of those with elevated ALT on admission was 47; 40.5% were women; 9.9% were smokers; and median BMI was 24 kg/m2. Chronic liver disease was present in 6.8% of patients with high ALT and in 2.8% of controls.

Overall, being male, overweight, and smoking increased the risk of liver enzyme elevation. For those with elevated liver enzymes, the median time from illness onset to hospital admission was three days.

Those with liver enzyme elevations had less pharyngalgia and more diarrhea than controls; 16 (7.2%) developed acute respiratory distress syndrome and four (1.8%) were mechanically ventilated and admitted to the ICU.

Complications and treatments were generally comparable in patients with and without high liver enzymes.

The authors state, "With early medical intervention, liver enzyme level elevation did not worsen the outcomes of patients with COVID-19."

The authors did not respond to requests for a comment, but three U.S. gastroenterologists commented in emails to Reuters Health.

Dr. Kenneth Sherman, Director/Chief, Division of Digestive Diseases at the University of Cincinnati College of Medicine, said, "The mechanism(s) of SARS-CoV-2 (liver) injury are unknown. The injury could result from direct infection of the virus into the liver cells, viral products that cause liver cells to die, or to the broad immune response (cytokine storm) seen in those with COVID. It may also be due to medications used to treat those with COVID."

"Data from other sources suggests that those with pre-existing liver disease are most susceptible to subsequent infection with SARS-CoV-2," he added.

Dr. Will Bulsiewicz, a gastroenterologist at East Cooper Medical Center and Roper Mt. Pleasant Hospital in South Carolina, commented, "The most important takeaway from this study, from my perspective, is that the liver function abnormalities were extremely mild and did not progress. Therefore, although it is possible that SARS-CoV-2 can affect the liver, we now have evidence that it is highly unlikely to cause liver failure."

"It's interesting to consider that patients with liver function abnormalities were more likely to be male, obese and smokers -- all characteristics that would increase ACE2 receptor levels," he noted. "This might suggest that the virus, which is known to invade through the ACE2 receptor, is in fact directly responsible for these liver function abnormalities."

It's also possible that the mild liver function abnormalities "are simply a manifestation of a systemic inflammatory response, or may even be related to other risk factors, such as medication use," he added. "In the future, we will need a study that includes liver biopsy information to help identify the presence or absence of SARS-CoV-2 in the liver tissue."

Dr. Patrick T. Koo of St. Jude Medical Center in Fullerton, California, agreed that "liver enzyme elevations are a known manifestation of COVID-19 but the severity of liver injury appears to be mild in the vast majority of cases."

That said, he noted, "Given how heterogenous the U.S. population is compared to China, it may be possible that the U.S. experience may be different. Further research still needs to be performed."

SOURCE: https://bit.ly/2BWGmBE American Journal of Gastroenterology, online June 1, 2020.