Chronic proton pump inhibition therapy in the diagnostic accuracy of serum pepsinogen I and gastrin concentrations to identify pernicious anaemia.

Background: Chronic use of proton pump inhibitors (PPIs) leads to increases in gastrin and pepsinogen-I serum concentrations.
Aim: To asses if chronic treatment with PPIs has an effect on serum gastrin and pepsinogen-I concentrations for the diagnosis of pernicious anaemia (PA).
Materials and Methods: Serum gastrin and pepsinogen-I were measured in 38 patients with PA and 74 without PA (controls); 17/38 PA patients and 36/74 controls were treated with PPIs. Receiver Operating Curves (ROC) were used to compare diagnostic accuracy of gastrin and pepsinogen-I for PA in patients under chronic treatment with PPIs and in untreated patients.
Results: PPI treatment increased pepsinogen-I in patients and in controls, while gastrin increased only in controls. In untreated patients, a pepsinogen-I <8.3ng/mL had 95.2% sensitivity and 100% specificity, whereas a gastrin >115pg/mL had 100% sensitivity and 92.11% specificity for PA diagnosis. In PPI-treated patients, a pepsinogen I<24.1ng/mL had a lower sensitivity (82.4%) but retained 100% specificity, however the best cut-off point for gastrin, 610pg/mL, had a very low sensitivity (58%).
Conclusions: PPI chronic treatment decreased the diagnostic accuracy for the studied biomarkers, particularly of gastrin. In PPI-treated patients, serum pepsinogen-I concentrations >24.1ng/mL allowed rejecting a PA diagnosis with 100% specificity.
(Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)