Long COVID patients are at a higher risk for digestive diseases, for up to one year, according to a study.

The study, published in the journal BMC Medicine, showed that people who suffered both severe and mild COVID-19 infections suffered from digestive diseases like gastrointestinal (GI) dysfunction, peptic ulcers, gastroesophageal reflux disease (GERD), gallbladder disease, nonalcoholic liver disease, and pancreatic disease.

“Our study provides insights into the association between COVID-19 and the long-term risk of digestive system disorders. Covid-19 patients are at a higher risk of developing digestive diseases,” said the researchers in the paper.

“The risks exhibited a stepwise escalation with the severity of COVID-19, were noted in cases of reinfection, and persisted even after 1-year follow-up.

This highlights the need to understand the varying risks of digestive outcomes in COVID-19 patients over time, particularly those who experienced reinfection, and develop appropriate follow-up strategies,” they added.

In the study, the team from Southern Medical University in China and the University of California Los Angeles, US, compared rates of digestive diseases among COVID survivors 30 or more days after infection (112,311), a contemporary comparison group (359,671), and a pre-COVID group (370,979) in the UK.

Participants were adults aged 37 to 73, and COVID-19 survivors were infected from January 2020 to October 2022. The contemporary group was made up of people who lived at the same time as recruitment of the COVID-19 group, and the historical group was made up of uninfected participants with data from January 2017 to October 2019.

Relative to the contemporary group, elevated risk in COVID-19 survivors was 38 per cent for GI dysfunction, 23 per cent for peptic ulcers, 41 per cent for GERD, 21 per cent for gallbladder disease, 35 per cent for severe liver disease, 27 per cent for nonalcoholic liver disease, and 36 per cent for pancreatic disease.

The risk of GERD rose stepwise with COVID-19 severity, and the risk of GERD and GI dysfunction persisted 1 year after diagnosis. Reinfected participants had a higher likelihood of having pancreatic disease.

This underscores the significance of ensuring that healthcare systems are equipped to provide appropriate care to this population of mild cases, as well as varying degrees of COVID severity.

In addition, the risks of GI dysfunction and GERD did not decrease after 1-year follow-up, revealing the long-term effect of COVID and the risks of digestive disorders.

The researchers explained that the reasons for the increased risks may be faecal-oral viral transmission, interactions between the SARS-CoV-2 spike protein and the expression of angiotensin-converting enzyme 2 (ACE2) receptors in the digestive tract, or virus-associated inflammation.

"This underscores the significance of ensuring that healthcare systems are equipped to provide appropriate care to this population of mild cases, as well as varying degrees of COVID-19 severity," they wrote.