Relationship between Helicobacter pylori positivity based on stool antigen testing and AST levels: pediatric outpatient clinic data

Aims: This study aimed to evaluate the association between stool Helicobacter pylori (H. pylori) antigen positivity and biochemical and hematological blood parameters in patients presenting to a pediatric outpatient clinic with dyspeptic complaints. Methods: Data from patients who underwent stool H. pylori antigen testing (n=870) were retrospectively reviewed. Concurrent measurements of ferritin, vitamin B12, ALT (alanine aminotransferase), AST (aspartate aminotransferase), and complete blood count were recorded. Randomly selected patients were divided into two groups: H. pylori antigen-positive (n=25) and H. pylori antigen-negative (control group) (n=75). Results: AST levels were higher in the H. pylori antigen-positive group than in the antigen-negative group (p=0.019). In regression analyses adjusted for age and sex, H. pylori positivity was significantly associated with AST (p=0.023), AST/ULN (p=0.033), and AST>ULN (p=0.049). When ALT and log(CRP+1) were added as covariates (sensitivity analysis), only the association with AST remained significant (p=0.037). No significant between-group differences were observed for ALT or for the other evaluated parameters. Conclusion: In this study, AST levels were significantly higher in children with stool H. pylori antigen positivity compared with antigen-negative controls. To our knowledge, this is the first study in our country to examine the association between SAT-confirmed H. pylori positivity and AST levels among children with dyspeptic complaints. When AST levels are elevated in children presenting with dyspeptic symptoms, stool H. pylori antigen positivity may be considered as one of the possible accompanying factors. Given the single-center retrospective design and the limited number of antigen-positive cases (n=25), these findings should be interpreted as associative and hypothesis-generating rather than causal.