3.1 | Literature search and characteristics of the included studies
This meta-analysis was organized according to the PRISMA statement.Figure 1 summarizes the results of the literature search and study selection. Our database search retrieved 4232 articles. After removing duplicated records, we excluded 1311. After reviewing the titles and abstracts, we excluded 2863. After a full-text review, we initially identified 19 potentially eligible studies. Subsequently, we excluded four studies for reasons reported in the PRISMA diagram.Supplementary Table 2 summarizes the main characteristics of these four studies excluded at the eligibility stage along with the exact reasons for exclusion. The search of the reference lists of the identified articles did not identify any additional relevant articles.
Table 1 summarizes the baseline characteristics of the eligible studies. All eligible studies were published between 2002 and 2020. A total of 15 studies with 6621 participants were included in the meta-analysis. Of these, one was conducted in America, 2 in Europe, and the remaining 12 in Asia. Sample sizes ranged from 52 to 1875. H. pylori infection was assessed using a rapid urease test in 8 studies, serum H. pylori antibody in 6 studies, and histological examination in 13 studies, suggesting that each individual study might have used more than one test for H. pylori infection at the same time. The RAC pattern was evaluated by standard endoscopy in 10 studies and by high-resolution magnified endoscopy in 7 studies, suggesting that each individual study might have used both standard endoscopy and high-resolution endoscopy at the same time. The prevalence of H. pylori among the included studies ranged between 15.3% and 76% (mean 46.1%).