The Widespread Use of Proton Pump Inhibitor (PPI) Medication Does Not Compromise the Accuracy of Serological Biomarker Test (GastroPanel ® Quick Test) in Point-of-care Diagnosis of Atrophic Gastritis Among Gastroscopy Referral Patients in India

Background/Aim: The diagnostic accuracy (DA) of the quick test version (GPQT) of the classical serological biomarker test (GastroPanel®; Biohit Oyj, Helsinki, Finland) was previously confirmed in gastroscopy referral patients in India. However, the potential impact of the widespread use of proton pump inhibitor (PPI) medication on GPQT results in this cohort needs more detailed survey. A matched case-control setting was used to estimate i) the impact of PPI use on the GPQT results, and ii) to disclose the significant predictors of the PPI user status. Patients and Methods: Of the original cohort of 266 gastroscopy-referral patients enrolled at the Department of Gastroenterology, Fortis Hospital (Mohali Chandigarh, India), age-matched case-control (1:3) pairs were built up, consisting of 68 PPI-non-users as cases and 198 PPI-users as controls. The GPQT results in the two study arms were compared using weighted kappa (κw) testing, and conditional logistic regression (CLR) models were used to estimate the co-variates of the PPI-user status. Results: The levels of the corpus- (PGI and PGII) (p<0.001) and the antrum (G-17b) (p=0.018) biomarkers were significantly different between the two groups. The agreement between GPQT and Updated Sydney System (USS)-classified gastric biopsies was significantly different (p<0.001) between cases and controls: κw=0.868, and κw=0.583, respectively. In CLR models, both the corpus (PGI, PGII)- and antrum (G-17b) biomarkers proved to be significant predictors of the PPI user status, higher levels being encountered among the PPI users. In ROC analysis, however, no difference in the DA of GPQT in detecting AGC2+ (moderate/severe atrophic corpus gastritis) was disclosed between cases and controls, AUC levels exceeding 0.950 in both study arms. Conclusion: Despite the fact that several of the GPQT biomarkers were significant co-variates of the PPI user status, the PPI-use did not compromise the DA of the GPQT in the detection of the most important diagnostic endpoint, AGC2+.