Gastric Acid Suppression and Penicillin Allergy Label

Penicillin allergy status has an overall negative impact on patient health. Active de-labeling has been shown to improve healthcare outcomes. We assessed the risk of developing penicillin allergy among patients using proton pump inhibitors (PPI)s or histamine-2 receptor antagonists (HR2A)s as examples of potentially modifiable risk factors. We conducted a real-time retrospective cohort study using TriNetX Research Network in December 2020. An algorithm using a combination of ICD-10 codes and medications identified three cohorts of adult patients (³ 18 years-old): PPI group (had 5 annual visits with PPI documented), H2RA) group (had 5 annual visits with H2RA documented and control group (used neither PPIs nor H2RAs). The 5-year risk of acquiring an ICD-10 code of allergy status to penicillin was compared among the groups after a 1:1 propensity score matching for age, sex, race, atopic diseases, and HIV status. PPI users (N=67,338) had higher risk of acquiring penicillin allergy label (RR, 3.18; 95% CI, 2.94 to 3.45) relative to matched controls. H2RA users (N=5,487) had increased risk of acquiring penicillin allergy label (RR, 2.08; 95% CI, 1.55 to 2.77) relative to matched controls. The risk of developing penicillin allergy among PPI users was slightly higher than the H2RA users (RR, 1.63; 95% CI, 1.32 to 2). Similar results obtained when analysis was restricted to individuals who had exposure to a penicillin during the 5-year observation period. Gastric acid suppression by PPIs or H2RAs is associated with increased risk of acquiring penicillin allergy.