Gastrointestinal symptoms common in COVID-19 patients, Stanford Medicine study reports

In one of the earliest studies of U.S. patients with the coronavirus, researchers found one-third of patients reported symptoms such as loss of appetite, nausea and diarrhea.

- By Tracie White

A new study found that in addition to upper respiratory symptoms, a significant number of people sick with COVID-19 suffer from loss of appetite, nausea, vomiting and diarrhea.

Fever, cough and shortness of breath are the classic symptoms of COVID-19, but there may be gastrointestinal symptoms, such as nausea and diarrhea, that are getting missed, according to a new Stanford Medicine study.

Researchers found that, in addition to upper respiratory symptoms, a significant number of those sick with the new virus also suffered from loss of appetite, nausea, vomiting and diarrhea. 

The study, one of the earliest on U.S. patients with the coronavirus, was published online April 10 in Gastroenterology. Gastroenterology fellows George Cholankeril, MD, and Alexander Podboy, MD, share lead authorship. Aijaz Ahmed, MD, professor of gastroenterology and hepatology, is the senior author.

“COVID-19 is probably not just respiratory symptoms like a cough,” Podboy said. “A third of the patients we studied had gastrointestinal symptoms. It’s possible we may be missing a significant portion of patients sick with the coronavirus due to our current testing strategies focusing on respiratory symptoms alone.”

Unique situation

As the coronavirus pandemic hit the San Francisco Bay Area in early March, hospitals began canceling elective surgeries and postponing nonemergency patient visits to make room for a surge of coronavirus patients. With their clinics closed and other projects on hold, a group of gastroenterology fellows had time to work together on a project, Podboy said. 

“George recognized early on that since Stanford was among the first hospitals to get COVID-19 patients in the U.S., that any type of early experience would be important,” he said. “We were in a unique position to look into this subject of gastrointestinal symptoms among coronavirus patients at Stanford.”

The researchers were aware of a growing body of research out of China and Singapore that showed a prevalence of GI symptoms in COVID-19 patients, but could find no data on the topic from patients in the United States. They decided to conduct their own study by examining the charts of the earliest group of patients treated for the virus at Stanford Health Care.

Study results

Researchers analyzed data collected from 116 patients who tested positive for the coronavirus at Stanford Health Care from March 4-24. The majority were treated and released from a hospital emergency room or a clinic. A total of 33 were hospitalized, eight of those in an intensive care unit. The median age of the patients was 50, and 53% of them were men. Only one death was reported within the group.

Study co-authors Alexander Podboy, Vasiliki Aivaliotis and George Cholankeril.
Courtesy of Vasiliki Aivaliotis

Gastrointestinal symptoms were reported by 31.9% of the patients. The majority of that group described the symptoms as mild. Twenty-two percent said they experienced loss of appetite, 22% had nausea and vomiting, and 12% had diarrhea, the study said.

“We also noticed that 40% of patients had elevated levels of an abnormal liver enzyme, and that those with high levels required more hospitalization,” Cholankeril said.

Testing recommended

The researchers suggest that while this data is early and from only a single institution, the results do raise the possibility that people exposed to the coronavirus who are experiencing gastrointestinal symptoms — not just those with respiratory symptoms — should also be tested.

“In our current cohort of patients, all patients had respiratory symptoms prior to the development of gastrointestinal symptoms,” Podboy said. “No patients had gastrointestinal symptoms prior to the development of respiratory symptoms or as their only manifestation of COVID-19.”

 He added, “However, that may be a product of who we were testing. Currently, testing is only offered for patients that meet specific criteria — criteria that often require the presence of pulmonary symptoms.” 

The researchers plan to study the role of GI symptoms in COVID-19 and their implication on disease severity and hospitalization outcomes, Cholankeril said. They also plan to continue working as a team.

“We had six fellows working together and we were able to go through these charts pretty quickly,” Cholankeril said. “It was a terrific collaboration between colleagues to be able to join forces to study this new disease. We think that by looking at patients here at Stanford, it can help improve our understanding of this emerging disease.”

Other Stanford co-authors are gastroenterology fellows Vasiliki Aivaliotis, MD, Branden Tarlow, MD, PhD, Edward Pham, MD, PhD, and Sean Spencer, MD, PhD; research scholar Donghee Kim, MD, PhD; and Ann Hsing, PhD, professor of medicine at the Stanford Prevention and Research Center.

The study was supported by the National Institutes of Health (grant T32DK007056).

About Stanford Medicine

Stanford Medicine is an integrated academic health system comprising the Stanford School of Medicine and adult and pediatric health care delivery systems. Together, they harness the full potential of biomedicine through collaborative research, education and clinical care for patients. For more information, please visit

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