Functional dyspepsia is distinguishable from Helicobacter pylori-associated dyspepsia. However, distinguishing H. pylori-associated dyspepsia from functional dyspepsia before H. pylori eradication is difficult. Therefore, in the present study, we aimed to investigate whether serum pepsinogen levels before H. pylori eradication are associated with the amelioration of dyspepsia after successful H. pylori eradication. Additionally, we examined the usefulness of serum pepsinogen levels and other factors in predicting dyspepsia outcomes. H. pylori eradication was effective in 14 patients (Responders) and ineffective in 19 patients (Non-responders). The pepsinogen I/II ratio in Responders (3.4 ± 1.2) and Non-responders (2.3 ± 1.0) differed significantly (p = 0.006). The optimal cut-off pepsinogen I/II value was 2.3. Multivariate logistic regression analysis showed that the adjusted odds ratio for Non-responders was 26.1 (95% confidence interval: 2.0–338.0, p = 0.012) for a pepsinogen I/II ratio ≤ 2.3 and 8.10 (95% confidence interval: 1.1–57.6, p = 0.037) for smoking habits. The pepsinogen I/II ratio and smoking habits were associated with the effects of H. pylori eradication on dyspeptic symptoms. Thus, the pepsinogen I/II ratio cut-off value can be used to identify patients likely to respond to H. pylori eradication after the resolution of dyspeptic symptoms.
