Data Synthesis
Data were summarized narratively and presented in tabular format. A meta-analysis was done with the meta package in the R program (Vienna, Austria). A forest plot was used to visualize the proportion of gastrointestinal manifestations in each study and the overall pooled prevalence estimates. The fixed effect model will be used to derive the pooled prevalence estimates, assuming that all effect estimates in each study estimate the same underlying effect and avoiding giving greater weighting to studies with smaller sample sizes. The heterogeneity was measured using the I2. Subgroup analyses were done to compare studies based on the study location (African vs. non-African studies) and age groups (Adult only, Mixed, Pediatrics only). Test for subgroup differences was performed, and a p-value for interaction of <0.1 indicates a statistically significant difference between subgroups. The publication bias was qualitatively assessed by visualizing the studies with a funnel plot and quantitatively using an Egger’s test. A p-value of less than 0.05 suggests the presence of publication bias.