DALES, Drug Allergy Labels in Elective Surgical patients: a prospective, multicentre cross-sectional study of prevalence, nature and anaesthetists' approach to management.

BACKGROUND: We sought to define the prevalence and nature of patient-reported drug allergies, determine their impact on prescribing, and explore drug allergy knowledge and attitudes amongst anaesthetists. METHODS: We performed a prospective cross-sectional study in 213 UK hospitals in 2018. Elective surgical patients were interviewed, with a detailed allergy history taken in those self-reporting drug allergy. Anaesthetists completed a questionnaire concerning perioperative drug allergy. RESULTS: Of 21 219 patients included, 6214 (29.3 %) (95% confidence interval [CI]: 28.7-29.9) reported drug allergy. Antibiotics, NSAIDs, and opioids were the most frequently implicated agents. Of a total of 8755 reactions, 2462 (28.1%) (95% CI: 29.2-31.1) were categorised as high risk for representing genuine allergy after risk stratification. A history suggestive of chronic spontaneous urticaria significantly increased the risk of reporting drug allergy (odds ratio 2.68; 95% CI: 2.4-3; P<0.01). Of 4756 anaesthetists completing the questionnaire, 1473 (31%) (95% CI: 29.7-32.3) routinely discuss perioperative allergy risk with patients. Prescribing habits in the presence of drug allergy labels differ depending on the implicated agent. Most anaesthetists (4678/4697; 99.6%) (95% CI: 99.4-99.8) prescribe opioids when reactions are consistent with side-effects, although 2269/4697 (48%) (95% CI: 46.9-49.7) would avoid the specific opioid reported. CONCLUSIONS: Almost 30% of UK elective surgical patients report a history of drug allergies, but the majority of reported reactions are likely to be non-allergic reactions. Allergy labels can impact on perioperative prescribing through avoidance of important drugs and use of less effective alternatives. We highlight important knowledge gaps about drug allergy amongst anaesthetists, and the need for improved education around allergy.

DALES, Drug Allergy Labels in Elective Surgical patients: a prospective multicentre cross-sectional study of incidence, risks, and attitudes in penicillin de-labelling strategies.

BACKGROUND: Penicillin allergy is associated with a range of poor health outcomes. Allergy testing can be made simpler by using a direct drug provocation test in patients at low risk of genuine allergy. This approach could allow population-level 'de-labelling'. We sought to determine the incidence and nature of penicillin allergy labels in UK surgical patients and define patient and anaesthetist attitudes towards penicillin allergy testing. METHODS: A prospective cross-sectional questionnaire study was performed in 213 UK hospitals. 'Penicillin allergic' patients were interviewed and risk-stratified. Knowledge and attitudes around penicillin allergy were defined in patients and anaesthetists. RESULTS: Of 21 219 patients, 12% (n=2626) self-reported penicillin allergy; 27% reported low-risk histories potentially suitable for a direct drug provocation test; an additional 40% reported symptoms potentially suitable for a direct drug provocation test after more detailed assessment. Of 4798 anaesthetists, 40% claimed to administer penicillin routinely when they judged the label low risk. Only 47% of anaesthetists would be happy to administer penicillin to a patient previously de-labelled by an allergy specialist using a direct drug provocation test; perceived lack of support was the most common reason for not doing so. CONCLUSIONS: At least 27% of patients with a penicillin allergy label may be suitable for a direct drug provocation test. Anaesthetists demonstrated potentially unsafe prescribing in patients with penicillin allergy labels. More than half of anaesthetists lack confidence in the results of a direct drug provocation tests undertaken by a specialist. Our findings highlight significant barriers to the effective implementation of widespread de-labelling in surgical patients.