Double-site rapid urease test versus histopathology for the diagnosis of Helicobacter pylori among patients with dyspepsia on proton pump inhibitors-A diagnostic accuracy study.

Abstract

Background and aims: In real-world settings, many patients cannot or do not stop proton pump inhibitors (PPIs) due to symptoms, but guidelines do not address H. pylori testing in PPI users. We compared the rapid urease test (RUT) and histopathology (HPE) when H. pylori testing and endoscopy are indicated for patients with a recent history of PPI use.

Methods: A prospective study of 164 patients who used PPIs within two weeks of endoscopy was conducted. Gastric antrum and body biopsies were used for double-site RUT and polymerase chain reaction (PCR) analyses. The updated Sydney protocol was followed for HPE. Patients with at least two out of three positive tests were considered infected with H. pylori. Fifty patients, who underwent only PCR for H. pylori diagnosis after stopping PPIs for two weeks, were enrolled as controls to assess the effect on detection rates. Additionally, an analysis utilizing PCR as the gold standard was conducted.

Results: In patients on PPIs, there was no significant difference in detection rates (positivity rate) between HPE and RUT (31.7% vs. 27.4%, p = 0.3771 [McNemar]). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of double-site RUT were 89.13%, 96.61%, 91.11%, 95.80% and 94.51%, respectively, whereas HPE was 82.61%, 88.14%, 73.08%, 92.86% and 86.59%. PCR had a much greater detection rate and there was no significant difference in detection rate by the PCR method in patients on and off PPI for at least two weeks prior to testing for H. pylori (48% vs. 44%, p = 0.58). The sensitivity of double-site RUT and HPE was still comparable, albeit low, when only PCR was considered the gold standard (43.75% vs. 40%, respectively). Atrophic gastritis and intestinal metaplasia are found in approximately 9% and 5% of gastric body biopsies and 9% and 2.5% of gastric antrum biopsies, respectively.

Conclusion: PPI use does not affect PCR-based testing for H. pylori. If PCR-based testing is unavailable, double-site RUT offers a cost-effective alternative for H. pylori testing in PPI users at the point of care, particularly in resource-limited settings, in comparison to HPE. The choice between biopsy using validated protocols or double RUT is also contingent upon the underlying risk factors for gastric cancer.