Q&A: Obesity, fatty liver play role in increased risk for COVID-19
Data from the UK BioBank demonstrated patients with obesity and fatty liver had an increased risk for symptomatic COVID-19 infection, according to a release from Perspectum.
However, patients with obesity, but normal liver fat had no increased risk.
Healio Gastroenterology spoke with Matt Kelly, PhD, chief innovation officer at Perspectum, about results from the study that comprised over 40,000 participants from the UK BioBank. Investigators used MRI scanning with Perspectum’s LiverMultiScan to determine if patients had fatty liver disease. They combined these results with those from COVID-19 testing to determine risk factors correlated with severe COVID-19 infection.
Healio: What was the purpose and design of the study?
Kelly: The purpose was to understand how key measures of liver health may impact COVID-19 and the likelihood of infection, or the severity of the infection once they become infected. Like a lot of organizations, at the start of the pandemic, we looked at what we could do to contribute to the efforts to combat COVID-19. The UK BioBank is a 500,000-patient study in the United Kingdom where they are collecting detailed phenotypical and genotypical information from volunteers and following up with healthcare records. Over 42,000 people in the UK BioBank have LiverMultiScan data. When they released COVID-19 test data for these people, we were in a unique position to look at various characteristics including those from the LiverMultiScan and determine how they correlate to the likelihood of having a positive test.
Healio: What were the results?
Kelly: If you had a lot of fat in your liver, above 10%, then you were about two times more likely to have symptomatic COVID. Initially only those symptomatic and hospitalized were tested for COVID-19, that allowed us to determine from the data that if patients had a positive test then they would have been quite severe to require hospitalization. Now, testing is far more widespread, lot more people were tested with only mild symptoms. We were able to see a link between positive test results and symptomatic or severe COVID-19. We looked at a sub-analysis of obesity and liver fat to see if they are correlated; a lot of people who are obese do not have liver fat above 10%. We found that people who are obese and had liver fat above 10% were at increased risk. In that sub-analysis, the risk went up nearly three-fold. When you compare people, who are obese and have liver fat below 5%, they are not at increased risk and although it was not significant it was pointing to a slightly protective effect. So, you were less likely to have a positive test if you were obese but had a low or healthy liver fat.
Healio: What is the conclusion?
Kelly: The link between liver fat and the severity of the COVID-19 is important information for resource planning because we know there are certain populations right now that are shielded or known to be at increased risk for the disease. Fatty liver puts you in a high-risk category and is something that should be considered. You can’t determine someone’s body fat based on a person’s size. Just because someone may be obese, there is only about a 30% chance that they are in the high-risk category.
Healio: What is the take-home message of the study?
Kelly: As more data become available from the UK BioBank, we will have more concrete information. Fatty liver disease appears to play a role in the severity of COVID-19 infection. Greater liver fat correlated with more severe disease and that is independent of obesity. Something about the mechanism in fatty liver disease increases their susceptibility to COVID-19. We hope the results, as we get more data, have the potential to inform health policies around this at-risk population.
Healio: What is the next step in research?
Kelly: The UK BioBank is still releasing more test data for their patients. We are getting a higher proportion of test data as more people are being tested in the population. We will also be adding richer data regarding hospital admissions. As these data become available, we will be able to look more at the detail and the role of other conditions such as hypertension or diabetes.
We can assess genetic risk factors as well. We are expanding on the study on the UK BioBank, with people we know have been hospitalized for COVID-19. They are getting very detailed scanning after the infection, so we can see if there is evidence of damage that has happened as a result of the infection. We are looking at the risk and pre-risk and the impact of COVID-19 on organ health and function after an infection and how well they recover. This will give us a comprehensive assessment of the interplay between multi-organ disease, liver disease and COVID-19.
These data are preliminary, so it is not a complete study that has been peer-reviewed yet. They are exciting results that are aligned with other data that we are seeing coming from Asia — from China in particular — a French study in patients with diabetes and a U.K. study with the open safety organization that is looking at deaths links to COVID-19. All those studies identified liver disease as a risk factor. A lot of patients do not realize they have increased liver fat because it is generally pre-symptomatic.