A total of 57 studies were ultimately selected for complete data extraction; 56 from our search and 1 additional manuscript (under review) was included to provide more data on a US cohort20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76 (see Supplementary Figure 1 for Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram). Of the 57 selected studies, 47 reported on unique patients based on hospital name (with no duplication of cohorts from the same hospital). An additional 10 studies were identified with potentially overlapping cohorts based on hospital name, but these were included if they provided unique information about a specific symptom (eg, diarrhea at initial presentation when the larger cohort did not clearly state that it was at initial presentation). Based on our comprehensive selection process, we believe that the included 47 studies reported data on 10,890 unique COVID-19 patients. The majority of studies (70%) in our analysis were from China; these were selected from 118 reports published or prepublished from China (Supplementary Figure 2). The studies included mainly adults, although a few studies included a small proportion of pediatric patients. Two studies reported on outpatients only, whereas the remaining 55 studies reported on hospitalized patients or a combination of outpatients and hospitalized patients. Based on our inclusion strategy: 55 studies (96%) provided information on any GI symptom and 32 studies (56%) reported any data on liver abnormalities. Fewer studies, 21 (37%), provided information on underlying GI conditions. Table 2 provides a summary of the pooled prevalence estimates.
Table 2 Summary of the Pooled Prevalence Estimates of Gastrointestinal/Liver Manifestations
GI and liver manifestations All studies Studies from China Studies from countries other than China
% (95% CI) Patients/ studies, n % (95% CI) Patients/ studies, n % (95% CI) Patients/ studies, n
Diarrhea in all patientsa 7.7 (7.2 to 8.2) 43/10,676 5.8 (5.3 to 6.4) 32/8612 18.3 (16.6 to 20.1) 11/2064
Nausea/vomiting in all patientsa 7.8 (7.1 to 8.5) 26/5955 5.2 (4.4 to 5.9) 19/4054 14.9 (13.3 to –16.6) 7/1901
Abdominal pain in all patientsa 3.6 (3.0 to 4.3) 15/4031 2.7 (2.0 to 3.4) 10/2447 5.3 (4.2 to 6.6) 5/1584
Patients with elevated AST 15.0 (13.6 to 16.5) 16/2514 14.9 (13.5 to 16.4) 14/2398 20.0 (12.8 to 28.1) 2/116
Patients with elevated ALT 15.0 (13.6 to 16.4) 17/2711 14.9 (13.5 to 16.3) 15/2595 19.0 (12.0 to 27.1) 2/116
Patients with elevated total bilirubin 16.7 (15.0 to 18.5) 10/1841 16.7 (15.0 to 18.5) 10/1841 — —
a Regardless of hospitalization and timing of symptoms.