The impact of penicillin allergy labels on antibiotic and health care use in primary care: a retrospective cohort study

Background: Suspected penicillin allergy (Pen-A) is often not verified by diagnostic testing. In third line penicillin allergy labels were associated with prescription of broad spectrum antibiotics, hospital stay duration and readmission. Objective: Assess the impact of Pen-A labels on antibiotic and health care use in primary care. Methods: A retrospective cohort study was conducted in primary care in the Utrecht area, the Netherlands. All patients registered with a penicillin allergy on 31 December 2013 were selected from the General Practitioner Network database. Each patient with a Pen-A label was matched for age, gender, follow-up period with three patients without Pen-A label. Risk (OR) of receiving a reserve and second choice antibiotic, number and type of antibiotics prescribed during follow-up and number of GP contacts were compared between the two cohorts. Results: Of 196,440 patients, 1254 patients (0.6%) with a Pen-A label were identified and matched with 3756 patients without Pen-A label. Pen-A labels resulted in higher risk of receiving ≥1 antibiotic prescription per year (OR 2.56, 95% CI 2.05-3.20), ≥1 s choice antibiotic prescription per year (OR 2.21 95% CI 1.11-4.40), and ≥4 GP contacts per year (OR 1.71 95% CI 1.46-2.00). The chance of receiving tetracyclins (OR 2.24, 95% CI 1.29-3.89), macrolides/lincosamides/streptogamins (OR 8.69, 95% CI 4.26-17.73) and quinolones (OR 2.59, 95% CI 1.22-5.48) was higher in Pen-A patients. Conclusions: In primary health care Pen-A labels are associated with increased antibiotic use, including second choice antibiotics, and more health care use.