SARS-CoV-2 was detected in GI tracts of patients with COVID-19 but not associated with inflammation, and GI symptoms were associated with lower mortality among COVID-19 patients, according to a recent two-part study.
The study, published by Gastroenterology on March 4, compared human intestinal biopsy tissues from 19 COVID-19 patients with those from 10 uninfected controls. Electron microscopy was used on samples from 16 infected patients and detected SARS-CoV-2 in the small intestinal epithelial cells in 14 of them. High-dimensional analyses of GI tissues revealed low levels of inflammation, including in key genes, and reduced frequencies of proinflammatory dendritic cells in patients with COVID-19 compared to controls. “Given the observed downregulation of key inflammatory genes, we hypothesized that intestinal involvement in COVID-19 is associated with a milder disease course,” the study authors wrote.
To examine this hypothesis, the researchers looked at cohorts of hospitalized COVID-19 patients in the U.S. and Europe. In a discovery cohort, 299 patients (47%) reported GI symptoms. Diarrhea was the most common (39%), followed by nausea (25%) and vomiting (13%). Adjusted analyses showed that patients presenting with GI symptoms had less severe disease than patients without (P<0.001). Mortality was significantly lower in patients with GI symptoms than in those without (15.7% vs. 31.0%; P<0.0001). These associations were true for each individual GI symptom, as well as in a validation cohort.
“In two distinct and large cohorts of COVID-19 patients, we observed a significant reduction in mortality in patients presenting with GI symptoms compared to those without GI symptoms, even after adjusting for multiple confounders including age and comorbidities,” the authors wrote. “Notably this finding is different from early reports suggesting increased severity with GI symptoms, likely attributable to the inclusion of abnormal liver function tests which are associated with poor outcomes.” They recommended that the potential role of the GI tract in attenuating inflammation from SARS-CoV-2 be further examined in future studies.