Researchers at Massachusetts General Hospital, Boston, discovered Covid-positive patients had a “statistically significant” higher liver stiffness than the rest of the population.
Liver stiffness could indicate long-term liver injury such as inflammation or fibrosis, the buildup of scar tissue in the liver.
Healthier liver tissue diminishes over time causing the liver to stop functioning properly, and in severe cases progressive fibrosis can lead to liver cancer or failure.
Dr Firouzeh Heidari a Research Fellow at Massachusetts General Hospital, said their findings show damage caused by Covid persists for a long time.
She said: “Our study is part of emerging evidence that Covid-19 infection may lead to liver injury that lasts well after the acute illness.
“We don’t yet know if elevated liver stiffness observed after Covid-19 infection will lead to adverse patient outcomes.”
Researchers compared patients who had Covid with two control groups, and each received an ultrasound shear wave elastography.
Covid-positive patients had a high median liver stiffness of 7.68 kPa, compared to 5.99 kPa stiffness in those who didn’t have Covid.
Patients were organised into one of three groups, based on whether they received elastography and whether they tested positive for Covid.
The assessment undergone at Massachusetts General Hospital measures how stiff tissue is.
Covid participants received a positive PCR test at least 12 weeks before the exam.
There were 31 in the Covid group, and 50 in the control group who had the exam but had only tested negative on PCR tests during the pandemic.
Another 50 people, who had an elastography exam before the pandemic, formed the second control group.
Dr Heidari said: “We are currently investigating whether the severity of acute Covid-related symptoms is predictive of long-term liver injury severity.
“We hope to enrich our existing database with additional patient data and a broader scope of co-variates to better understand the post-acute effects of Covid-19 within the liver.”
The team believe the higher median stiffness among the pre-pandemic control group, versus the pandemic control group, was due to referral patterns changing during the pandemic, and because the pandemic control group were older.
The mean age of Covid-positive group was 53.1 years, 55.2 years for the pandemic control group, and the pre-pandemic cohort were on average 58.2. In total, 67 were women.
In the Covid-positive group, the elastography exams happened on average 44 weeks after a positive PCR result.
The research was presented at the annual meeting of the Radiological Society of North America.
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