Helicobacter pylori Eradication Rate Using Stool Antigen Test in Vietnamese Children: A Prospective Multicenter Study

Objectives: This study assessed the diagnostic value of a monoclonal immunoassay stool antigen test (HpSA) for Helicobacter pylori (H. pylori ) infection and the eradication outcomes. Methods: Children undergoing digestive endoscopy at 2 Children’s Hospitals in Ho Chi Minh City were recruited. Treatment was offered to H. pylori -infected children. Stool samples were collected on the same day as the endoscopy procedure and after 6 weeks post-treatment for HpSA. Diagnostic value and optimal cutoff of HpSA were assessed using biopsy-based tests as the gold standard. Eradication was defined as a negative HpSA post-treatment. Ethical approval was obtained, and informed consent was signed by the participants. Results: In total, 394 patients participated in the study. The most common symptoms were epigastric pain (74.6%) and vomiting (37.3%). H. pylori status was positive in 78% of patients (306/394), doubtful in 10.1%, and negative in 12.2%. HpSA was positive in 73.2% (142/194). Excluding doubtful infections, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of HpSA were 87.4%, 95.2%, 99.2%, 51.3%, and 88.4%, respectively. The optimal cutoff value of 0.148 provided similar accuracy to the recommended cutoff. The eradication rate was 56.1% in per-protocol analysis and 27.9% in intention-to-treat analysis. Treatment success was higher in boys, but lower among malnourished children and those infected with cagA+ strains. Conclusions: The HpSA is reliable for identifying H. pylori infection in epidemiological studies and assessing eradication outcomes. The low eradication rate highlights the need for an appropriate intervention strategy in Vietnamese children.