Background and Objective: The aim of this study is to systematically analyze and summarize the implications of COVID-19 on the digestive system by quantitatively evaluating the prevalence of gastrointestinal symptoms such as nausea, vomiting, abdominal pain, constipation, diarrhea, anorexia. reported in COVID-19 cases. We simultaneously investigated other variables to determine the association of such symptoms in COVID-19 patients which can potentially influence the disease prognosis and outcome. This systematic review presents an updated literature on the issue as it requires more scientific discussion in order to better inform the medical community and authorities so that appropriate measures can be taken to control the virus outbreak.

Methods: MEDLINE database was searched to identify relevant articles. Data was analyzed and synthesized from the 16 eligible studies which exclusively reported GI symptoms in COVID-19 patients along with the disease prognosis. A meta-analysis of studies having adequate information regarding the prevalence of specific GI symptoms in association with other relevant independent variables was performed.

Results: From the search strategy, we identified 16 articles which fit our eligibility criteria comprising of 10 cross-sectional studies, 2 cohort study, 1 RCT and 3 observational studies. From these pooled studies, 6 articles exclusively talked about COVID-19 patients in which GI symptoms were reported and adequately discussed. In a total of 3646 patients, GI symptoms were documented in (16.2%-10.1%) patients. The most prevalent GI symptom was diarrhea (47%) but the most common clinical manifestation reported was fever (77.4%). Among the adult patients, hypertension (11.6%) was the most frequently reported comorbidity. Presence of viral RNA in stool sample was noted in 16.7% patients with GI symptom. In patients who complained of having GI symptoms, an abnormal liver function was largely observed, with an elevated ALT level in (10.9%) and an elevated AST in (8.8%) of the patients. Evidence of vertical transmission (14.2%) was reported in one study which highlights the extent and mode of viral transmission. It was observed that a great majority of the patients in the 6 studies reporting specifically on patients with GI symptoms were on antiviral therapy (68.6%) as the standard disease management protocol but the eventual disease outcome as in this case died (8.4%), discharged (45.6%) was not linked to just one therapeutic factor but other indicators of disease severity such as positive chest CT findings (87.82%) have led to a poor disease prognosis which was noted in (28.9%) severe patients with GI symptoms compared to (71.1% %) non-severe COVID-19 patients with GI symptom.

Conclusion: Presence of GI symptoms in COVID-19 patients has shown to have a positive association with the poor disease prognosis likely as a result of direct viral toxicity. It is important for the physicians to recognize digestive symptoms as an important characteristic in COVID-19 patients. Hence, precise and targeted documentation of GI symptoms and viral stool sample investigations should be performed in order to understand the rapidly evolving disease symptomology.