After WHO declared in March 2020 the infection caused by SARS-CoV-2 as a global pandemic, different studies have shown that the presence of gastrointestinal symptoms at the time of acute infection may or may not be combined with the presence of respiratory symptoms. However, reliable data on the long-term persistence of gastrointestinal symptoms as a consequence of COVID-19 infection were not yet available. Recently, an international study (GI-COVID19), led by the University Hospital of Bologna (Italy) and with the participation of Vall d'Hebron, has been completed, in which persistent gastrointestinal manifestations after hospitalization for SARS-CoV-2 infection and their evolution during the first year were evaluated. Their results have been published in the high-impact journal Gut.

To conduct the work, two groups of patients who required hospital admission during the period from May to October 2020 were compared. One group included 435 patients admitted for COVID-19 and the other group, considered as a control, included 188 patients hospitalized for other non-digestive medical causes other than COVID-19. The investigators followed up at one, six and twelve months after admission using questionnaires assessing the presence of gastrointestinal symptoms and symptoms of anxiety and depression.

The results show a significant increase in developing irritable bowel syndrome (3.2%) in those patients admitted for COVID-19 compared to controls (0.3%). "Previous history of allergies, the presence of dyspnea during acute SARS-CoV-2 infection and taking proton pump inhibitors (drugs to decrease acid production in the stomach) were found to increase the risk of developing irritable bowel syndrome in patients who suffered COVID-19", explains Dr. Beatriz Lobo, specialist of the Digestive System Service at Vall d'Hebron University Hospital and researcher of the Physiology and Pathophysiology of the Digestive Tract group at Vall d’Hebron Research Institute (VHIR). The authors think that this may be due to changes in the immune system and in the intestinal microbiota due to the viral infection. In fact, other studies have identified the presence of SARS-CoV-2 antigens in the gut of people who have had COVID-19 up to six months after infection, which may lead to immune system activation and inflammation that is related to the persistence of gastrointestinal symptoms.

Although the frequency of irritable bowel syndrome is low in patients with COVID-19, the researchers note that, given the high number of patients who have been infected with SARS-CoV-2 on a global scale, this may lead to an increase in cases having gastrointestinal dysfunction months later, as is being seen in specialty outpatient clinics.

"Unlike previous research, this brings the advantages of a controlled prospective study, with a high sample size of patients and follow-up for one year, ensuring the reliability of the results obtained", says Dr. Lobo. "More studies and investigation are needed to better understand the mechanisms underlying the development of digestive symptoms in these patients in order to develop prevention and treatment strategies", concludes Dr. Javier Santos, associate physician of the Digestive System Service at Vall d'Hebron University Hospital and principal investigator of the Physiology and Pathophysiology of the Digestive Tract group at VHIR and the CIBER of Liver and Digestive Diseases (CIBEREHD).

The GI-COVID-19 study has involved the collaboration of 36 centers from 14 countries around the world. The work has been led by Dr. G. Barbara from the University Hospital of Bologna with the participation of physicians, nursing staff and researchers from the Digestive System Service of the Vall d'Hebron University Hospital and from the Physiology and Pathophysiology of the Digestive Tract group of the VHIR (L. Aguilera, C. Barber, D. Guagnozzi, A. Henao, X. Serra, M. Puigcerver, J. Santos and Adoración Nieto), coordinated by Dr. Beatriz Lobo.