Gastrointestinal manifestations of long COVID: A systematic review and meta-analysis

BACKGROUND: Prolonged symptoms after COVID-19 are an important concern due to the large numbers affected by the pandemic. OBJECTIVES: To ascertain the frequency of gastrointestinal (GI) manifestations as part of long GI COVID. DESIGN: A systematic review and meta-analysis of studies reporting GI manifestations in long COVID was performed. DATA SOURCES AND METHODS: Electronic databases (Medline, Scopus, Embase, Cochrane Central Register of Controlled Trials, and Web of Science) were searched till 21 December 2021 to identify studies reporting frequency of GI symptoms in long COVID. We included studies reporting overall GI manifestations or individual GI symptoms as part of long COVID. We excluded pediatric studies and those not providing relevant information. We calculated the pooled frequency of various symptoms in all patients with COVID-19 and also in those with long COVID using the inverse variance approach. All analysis was done using R version 4.1.1 using packages ‘meta’ and ‘metafor’. RESULTS: A total of 50 studies were included. The frequencies of GI symptoms were 0.12 [95% confidence interval (CI), 0.06–0.22, I(2) = 99%] and 0.22 (95% CI, 0.10–0.41, I(2) = 97%) in patients with COVID-19 and those with long COVID, respectively. The frequencies of abdominal pain, nausea/vomiting, loss of appetite, and loss of taste were 0.14 (95% CI, 0.04–0.38, I(2) = 96%), 0.06 (95% CI, 0.03–0.11, I(2) = 98%), 0.20 (95% CI, 0.08–0.43, I(2) = 98%), and 0.17 (95% CI, 0.10–0.27, I(2) = 95%), respectively, after COVID-19. The frequencies of diarrhea, dyspepsia, and irritable bowel syndrome were 0.10 (95% CI, 0.04–0.23, I(2) = 98%), 0.20 (95% CI, 0.06–0.50, I(2) = 97%), and 0.17 (95% CI, 0.06–0.37, I(2) = 96%), respectively. CONCLUSION: GI symptoms in patients were seen in 12% after COVID-19 and 22% as part of long COVID. Loss of appetite, dyspepsia, irritable bowel syndrome, loss of taste, and abdominal pain were the five most common GI symptoms of long COVID. Significant heterogeneity and small number of studies for some of the analyses are limitations of the systematic review.