Fatty liver greatly increases vulnerability to COVID-19 in obese people

Keith Alcorn
Published:
16 November 2020

Fatty liver disease combined with obesity places people at much higher risk of severe COVID-19, analysis of British people who tested positive for SARS-CoV-2 shows. Obesity alone did not increase the risk of being admitted to hospital with COVID-19 but obesity with high liver fat content doubled the risk of symptomatic illness and tripled the risk of being admitted to hospital with severe COVID-19 illness, Adriana Roca of Perspectum reported at the online AASLD Liver Meeting on Sunday.

Obesity and fatty liver disease are closely intertwined. Obesity is an established risk factor for severe COVID-19 but fatty liver disease’s role as an independent risk factor for COVID-19 illness is unclear. Studies have produced conflicting results.

Previous analysis of people who died of COVID-19 in hospital in the United Kingdom up to 25 April 2020 suggests that chronic liver disease has a similar impact to smoking or hypertension on the risk of COVID-19 death, raising the risk by approximately 60%.

Perspectum has carried out a study of liver disease status in UK Biobank study participants using Liver Multiscan (MRI scanning) to characterise liver damage. Liver scans are available for 41,791 participants in the UK Biobank, which comprises approximately 500,000 people participating in a prospective study of the relationship between genetic profile (genotype), physical and biochemical characteristics and disease incidence and prevalence.

Of the 41,791 people who underwent liver scans, 931 had been tested for SARS-CoV-2 and 106 had tested positive. Of these, 48 had been hospitalised with COVID-19. People admitted to hospital because of severe illness were significantly more likely to be male, had a higher body mass index and were more likely to have fatty liver disease (defined as liver fat content > 5%).

When the researchers further broke down the study participants by liver fat content above or below 10%, they found that liver fat content of 10% or above was the one of the strongest predictors of testing positive with COVID-19 symptoms (odds ratio 1.66 [95% CI 1- 2.77]) and of hospitalisation with severe COVID-19 (OR 2.17 [1.04-4.52]). Body mass index raised the risk of symptomatic illness or hospitalisation far less (OR 1.04 for symptomatic illness and 1.06 for hospitalisation).

Multivariate analysis showed that non-obese participants (body mass index > 30 kg/m2) were not at increased risk of symptomatic illness or hospitalisation if they had severe fatty liver disease (fat content > 10%) but obesity substantially increased the risk of hospitalisation in people with severe fatty liver disease. People who were obese and had liver fat > 10% had more than twice the risk of symptomatic illness (OR 2.31 [1.27-4.23]) and three times the risk of hospitalisation (OR 3.06 [1.34-7.01]) compared to obese people with normal liver fat.

Based on its analysis of liver disease in UK Biobank participants, Perspectum estimates that around 7.3 million people (11%) in the United Kingdom have both liver fat content of 10% or above and body mass index of 30 or above.

“This has huge implications both at the public health and socioeconomic levels,” said Adriana Roca. Treating fatty liver disease either through lifestyle interventions or upcoming therapeutic innovations should be considered, she said.

Perspectum is carrying out further research in the United Kingdom looking at the prevalence of organ impairment in people recovering from COVID-19, she said. The study is investigating the impact of body fat and organ fat on organ impairment in people recovering from COVID-19.

Reference

Roca-Fernandez A et al. Non-alcoholic fatty liver disease (NAFLD) associates with higher risk of developing symptomatic COVID19 infection- initial UK Biobank observations. AASLD Liver Meeting Digital Experience, abstract 104, 2020