Investigators Review Gastrointestinal, Liver Connection to COVID-19

Ren Mao, MD

One of the biggest unknowns regarding the coronavirus disease 2019 (COVID-19) is how prevalent are gastrointestinal symptoms.

A team, led by Ren Mao, MD, Department of Gastroenterology, the First Affiliated Hospital of Sun Yat-sen University, reviewed studies published between January 1 and April 2020 that reported the epidemiological and clinical features of COVID-19 and the prevalence of gastrointestinal findings in infected patients.

The investigators examined various gastrointestinal symptoms including vomiting, nausea, diarrhea, loss of appetite, abdominal pain, and belching, as well as digestive system comorbidities including liver disease and gastrointestinal diseases.

The researchers pooled the raw data from studies to determine effect estimates.

In the analysis, the investigators examined 35 studies involving 6686 patients with COVID-19. Of these studies, 29 (n = 6064) reported gastrointestinal symptoms in COVID-19 patients at diagnosis, with a pooled prevalence of digestive system comorbidities of 4% (95% CI, 2—5; range 0–15; I² = 74%).

The pooled prevalence of digestive symptoms was 15% (10—21; range: 2–57; I²=96%) with nausea or vomiting, diarrhea, and loss of appetite being the three most common symptoms.

The pooled prevalence of abnormal liver functions from 12 studies (n = 1267) was 19% (9—32; range 1–53; I²=96%). In a subgroup analysis, the investigators found patients with severe COVID-19 infections had higher rates of gastrointestinal symptoms (OR, 1.60; 95% CI, 1.09-2.36; P = 0.0020; I² = 44%) compared to patients with less severe virus symptoms.

Patients with more severe COVID-19 symptoms also had higher rates of liver injuries (OR, 2.20; 95% CI, 1.60-3.02; P <0.00001; I²=36%) compared to patients with less severe virus infections.

The investigators also found patients in the Hubei province, where the initial outbreak started, were more likely to present with abnormal liver function (P <0.0001) compared to patients outside of Hubei.

Another discovery is that pediatric patients with COVID-19 had a similar prevalence of gastrointestinal symptoms to those of adult patients.

Also, 10% (95% CI, 4-19; range 3-23; I²=97%) of patients presented with gastrointestinal symptoms alone without the respiratory features commonly associated with COVID-19.

Patients who presented with gastrointestinal system involvement had delayed diagnosis (standardized mean difference 2.85; 95% CI, 0.22—5.48; P = 0.030; I² = 73%), while patients with gastrointestinal involvement had a higher prevalence of complication (OR, 2.51; 95% CI, 1.62—3.89; P <0.0001; I² = 0%).

“Our study showed that digestive symptoms and liver injury are not uncommon in patients with COVID-19,” the authors wrote. “Increased attention should be paid to the care of this unique group of patients.”

Since the beginning of the COVID-19 pandemic, the prevalence and prognosis of digestive system involvement for gastrointestinal symptoms and liver injuries is unknown.

Data shows that the gastrointestinal tract and liver might represent target organs of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the basis of the findings that angiotensin-converting enzyme 2 (ACE2), the major receptor of SARS-CoV-2, is expressed in the gastrointestinal tract as well as liver cells.

The study, “Manifestations and prognosis of gastrointestinal and liver involvement in patients with COVID-19: a systematic review and meta-analysis,” was published online in The Lancet Gastroenterology & Hepatology.