Influence of proton pump inhibitor treatment on Helicobacter pylori stool antigen test

Background and study aims: The relationship between endoscopic atrophy classification (EAC) and histological gastric atrophy and intestinal metaplasia (IM) was examined before and after Helicobacter pylori (H. pylori) eradication in order to evaluate the usefulness of EAC for detecting the risk of gastric cancer following eradication. Patients and methods: A total of 230 patients (137 males, 93 females; mean age: 58.0 ± 11.8 y) with successful eradication were enrolled. EAC score was defined as follows: C0(none): 0, C1: 1, C2: 2, C3: 3, O1: 4, O2: 5, and O3(severe): 6. Histological atrophy and IM score (0 to 3) from the antrum and the corpus were evaluated with updated Sydney system for histological atrophy and IM. Results: The mean EAC scores were 3.46 before eradication and 3.20 after eradication (P = 0.026). The mean atrophy scores before and after eradication were 1.45 and 0.92 at the antrum (P < 0.001) and 0.50 and 0.07 at the corpus (P < 0.001), respectively. The mean IM scores before and after eradication were 0.55 and 0.47 at the antrum (P = 0.154), and 0.09 and 0.05 at the corpus (P = 0.096), respectively. The histological atrophy scores showed significant improvement after eradication, while IM showed no significant change. The Mantel-Haenszel test for trend indicated there was a significant correlation between EAC and histological atrophy and IM, except antral atrophy after eradication. Conclusions: EAC exhibited a significant correlation between histological atrophy and IM, and represents a noninvasive classification method. EAC may be beneficial in evaluating the risk of gastric cancer after H. pylori eradication.

The ¹³C-urea breath test (UBT) is widely used to examine the results of eradication therapy for Helicobacter pylori. We examined whether a stool antigen test can be used as efficiently as UBT. (i) Ninety-four patients infected with H. pylori underwent eradication therapy. Six or eight weeks after the completion of treatment, the results were evaluated by UBT and a stool antigen test (TPAg). In 77 out of 78 patients who had negative UBT results, the TPAg results were also negative. Among the 16 UBT-positive patients, 12 were also positive by TPAg. Agreement of UBT and TPAg was 94.7%. (ii) Twenty-two patients with peptic ulcers in the active stage also received eradication therapy followed by proton pump inhibitor (PPI) administration. TPAg and UBT were performed to examine the results of eradication therapy at the end of PPI administration and at least 7 days after its discontinuation. Of the 22 patients taking PPIs, TPAg evaluated the results of eradication therapy accurately in 21 patients. TPAg appears to be an accurate test for evaluating the results of H. pylori eradication therapy, and to be as efficient as ¹³C-UBT. Use of the stool antigen test should be considered as an alternative, particularly in patients who have to take PPIs in order to avoid the risk of peptic ulcers.