ABSTRACT
Introduction: During 3rd year of COVID-19 pandemic there is emerging published and experienced evidence that a significant number of COVID-19 survivors experience long term negative health impact. Post-COVID symptoms arise mostly from impaired function of respiratory tract although in many patients the dysfunction of gastrointestinal tract and liver (among others systems) may persist. Aims & Methods: This prospective single center study was performed from February through October 2021. Adult patients (>18 years) with both asymptomatic PCR confirmed acute SARS-CoV-2 infection and symptomatic (cough, fever or dyspnea) COVID-19 disease patients confirmed by antigen or PCR test were included in the study. Severity of the illness was evaluated according to the National Institute of Health (NIH) guidelines and these were used for distinguishing two main patient groups (with asymptomatic to mild and moderate to severe course of the disease). Patients with negative result of PCR test for SARS-CoV-2 were considered for the control group. Primary data collection was based on the short gastrointestinal symptom questionnaire developed at our department. A brief telephone survey within the patient and control group was performed five to eight months after the initial screening. Patients from the control group, who had been tested positive in the time between initial screening and telephone survey were excluded from the analysis.R ver. 4.0.5 was used for data explorations and analyses. Imbalanced RandomForest (RF) machine-learning algorithm was trained on the data to predict presence/absence of symptoms during acute phase in post-COVID phase. Result(s): 590 patients were included in the study. Of them, 337 patients responded to questions during the telephone survey after 7 months (205 SARS-CoV-2 positive patients, 132 SARS-CoV-2 negative controls). The general presence of gastrointestinal symptoms 208.2 days (153-230 days) after the initial acute SARS-CoV-2 infection was 19% for patients with moderate to serious course of the disease and 7.3% for patients with mild course compared to 3.0% in SARS-CoV-2 negative controls (p<0.001) (table). Persistent diarrhea and abdominal pain are the most prevalent post-COVID gastrointestinal symptoms. To identify possible predictor factors for post COVID gastrointestinal symptoms we performed machine-learning analysis with random forest algorithm with handpicked factors: acute symptoms (diarrhea, abdominal pain, heartburn, bloating, nausea), sex, age and antibiotics administration. Acute diarrhea and antibiotics administration seem to be the strongest predictors for gastrointestinal sequelae with Area under curve (AUC) 0.68. Conclusion(s): Presence of gastrointestinal sequelae 7 months after the initial SARS-CoV-2 infection is significantly higher in patients with moderate to severe course of the acute COVID-19 compared to asymptomatic patients or those with mild course of the disease. Most prevalent post-COVID gastrointestinal symptoms are diarrhea and abdominal pain. The strongest predictors for persistence of these symptoms are antibiotics administration and acute diarrhea during the initial infection.