The Impact of an Integrated Antibiotic Allergy Testing Program on Antimicrobial Stewardship: A Multicentre Evaluation

Rationale:

Despite the high prevalence of patient-reported antibiotic allergy (so-called antibiotic allergy labels [AALs]) and their impact on antibiotic prescribing, incorporation of antibiotic allergy-testing (AAT) into antimicrobial stewardship (AMS) programs (AAT-AMS) is not widespread. We evaluated the impact of an AAT-AMS program on AAL prevalence, antibiotic usage and appropriateness of prescribing.

Methods:

A prospective multicentre cohort study was undertaken to evaluate the introduction of AAT-AMS at two large Australian hospitals during a 14-month period from May 2015. Baseline demographic, AAL history, age-adjusted Charlson co-morbidity index, infection history and antibiotic usage for 12-months prior to (pre-AAT-AMS) and 3-months following testing (post-AAT-AMS) were recorded for each participant. A patient was deemed to have been de-labelled if ≥ 1 AAL was removed.  Study outcomes included the proportion of patients who were “de-labelled” of their AAL, spectrum of antibiotic courses pre- and post-AAT-AMS, and antibiotic appropriateness (using standard definitions).

Results:

From the 118 AAT patients, 226 AALs were reported. AAT-AMS allowed AAL de-labelling in 98 (83%) patients - 56% (55/98) with all AALs removed. Post-AAT, prescribing of narrow spectrum penicillins more likely (adjusted OR [aOR] 2.81, 95% CI 1.45-5.42), as were narrow spectrum beta-lactams (aOR 3.52, 95% CI 1.98-6.33), and appropriate antibiotics (aOR 12.27, 95% CI 5.00-30.09); and less likely for restricted antibiotics (aOR 0.16, 95% CI 0.09-0.29), after adjusting for indication, Charlson comorbidity index, and care setting.

Conclusions:

An integrated AAT-AMS program was effective in appropriate de-labelling of AALs and significantly impacted antibiotic usage and appropriateness – suggesting AAT should become a routine component of AMS programs.