Prospective, multi-centre, head-to-head comparison between allergists vs non-allergists in low-risk penicillin allergy delabelling: effectiveness, safety and quality of life (HK-DADI2).

BACKGROUND: Penicillin "allergy" labels are prevalent but frequently misdiagnosed. Mislabelled allergies are associated with adverse outcomes and increased antimicrobial resistance. With an urgent need to delabel the overwhelming number of mislabelled allergies, non-allergist evaluations have been advocated for low-risk individuals. Despite growing interest in non-allergist-led initiatives; evidence on their effectiveness, safety, and impact by direct comparisons are lacking.

OBJECTIVE: We assessed the comparative outcomes of penicillin allergy evaluations conducted by allergists vs. non-allergists.

METHODS: A prospective, multi-centre, pragmatic study was conducted at four tertiary hospitals (one allergist- vs. three non-allergist-led) for low-risk penicillin allergy patients in Hong Kong - the Hong Kong Drug Allergy Delabelling Initiative 2 (HK-DADI2).

RESULTS: Among 228 low-risk patients who underwent testing (32.9% by allergists, 67.1% by non-allergists), only 14 (6.1%) had positive penicillin allergy testing. Delabelling rates (94.1% vs. 93.3%, p=0.777), positive skin tests (2.6% vs. 2.7%, p=1.000) and drug provocation tests (3.3% vs. 2.7%, p=1.000) were similar between allergists and non-allergists. There were no systemic reactions in either cohort. All patients had significant improvements in health-related quality-of-life (DrHy-Q scores -5.00 vs. -8.33, p=0.072). Non-allergist evaluations had shorter waiting times (0.57 vs. 15.7 months, p<0.001), while allergists required fewer consultations with higher rate of completing evaluations within a single-visit (OR=0.04, p<0.001).

CONCLUSION: With training and support, non-allergists can independently evaluate low-risk penicillin allergies. Compared to allergists, evaluation of low-risk penicillin allergy by non-allergists can be comparably effective, safe, and impactful on quality-of-life. More multi-disciplinary partnerships to empower non-allergists to conduct allergy evaluations, should be encouraged.