100141 - Assessing the Safety, Effectiveness, and Impact of Community Pharmacy Penicillin Allergy Delabelling Service in Hong Kong: A Pilot Study

Mislabelled penicillin allergies represent a significant public health burden, leading to antimicrobial resistance and reduced health-related quality of life (HR-QoL). While hospital-based delabelling initiatives led by non-allergists have proven effective, the feasibility and impact of a community pharmacy-led model remain unexplored. This study evaluated a pilot penicillin allergy delabelling service in a community pharmacy, comparing its effectiveness and outcomes against established hospital-based pathways.

A retrospective observational cohort study was conducted across three sites: a university-affiliated community pharmacy (CP, HKUMed Community Pharmacy), a hospital pharmacy (HP, Queen Mary Hospital Pharmacist Clinic), and a hospital allergist clinic (Queen Mary Hospital Allergy Clinic). Adult patients with low-risk penicillin allergies were assessed and delabelled via direct oral provocation based on risk stratification per APAAACI guidelines. The primary outcome was the successful delabelling rate. Secondary outcomes included the change in HR-QoL, measured by the Drug Hypersensitivity Quality of Life Questionnaire (DrHy-Q), and process efficiency metrics.

Of 135 patients evaluated, 132 (97.8%) were successfully delabelled, with no significant difference in success rates between the CP (100%), HP (98%), and allergist (96%) groups (p=0.464). All pathways demonstrated significant within-group improvements in HR-QoL (p<0.001 for all). The CP group showed a significantly greater percentage improvement in DrHy-Q scores (86.0%) compared to the HP (60.0%) and allergist (41.0%) groups. The CP pathway eliminated wait times, with a median time to assessment of 0 days, compared to 80 days for HP and 401 days for the allergist (p<0.001).

Preliminary data shows that the community pharmacist-led penicillin allergy delabelling service is equally safe and effective as hospital-based pathways. Though a pilot program, early results indicate potential superior improvements in patient quality of life and reduction in waiting times, thereby addressing a critical healthcare access barrier. This model aims to show a highly scalable solution to hopefully tackle the pervasive problem of mislabelled penicillin allergy in the community.