PROTON PUMP INHIBITORS HAVE A MORE PROFOUND EFFECT ON GASTRIC ACID SECRETION IN FEMALE AND OLDER GERD PATIENTS

Abstract

Purpose: Proton pump inhibitor (PPI) therapy is believed to be equally effective in all patients with upper GI symptoms. However, data is lacking on the degree of PPI efficacy in various subgroups including males, females, the young and old where acid secretion rates may differ (Gas-troenterology 1991; 101: 977-990). Therefore, our aim was to assess the influence of gender and age in PPI inhibition of basal and pentagas-trin (Pg)-stimulated gastric acid secretion (GAS) in symptomatic GERD patients. Methods: A total of 36 GAS studies were conducted in 15 male (22–69 y) and 10 female (35–67 y) HP-negative GERD patients on a daily AM dose of PPI therapy for 8–10 days. Basal and Pg (6 mcg/kg, s.c.)-stimulated GAS was measured during the trough period (22–24 h post-dose). Gastric acid was continuously aspirated via a nasogastric tube, aspirate volume recorded, [H+] measured by titration to pH 7.0, pH determined and GAS calculated. Results: In females, PPIs had a more significant effect on both basal and Pg-stimulated GAS compared to males (Table; median data; *+P <0.03). The same was true for inhibition of Pg-stimulated GAS in older (age >44 y) compared to younger (age <44 y) patients (Table). Differences in GAS were due to significant decreases in gastric [H] and volume secretion in female and older patients (Table). Interestingly, median intragastric pH under basal conditions was pH 2.0 or less during steady state conditions. Furthermore, median Pg-stimulated gastric volumes were over 100 ml/h in males and younger patients.Table: PPI-inhibition of GAS in GERD PatientsConclusions: In GERD patients on daily PPI therapy: 1. PPIs have a more profound effect on GAS in female and older subjects; and 2. Despite steady-state conditions, significant gastric acid secretion was noted. We speculate that these findings may explain the variability in PPI efficacy in GERD as is seen in clinical practice, and may have implications in nocturnal acid breakthrough.