Impact of a Pharmacist-Conducted Preoperative Beta-Lactam Allergy Assessment on Perioperative Cefazolin Prescribing

Background: Cefazolin is guideline recommended for perioperative prophylaxis in orthopedic surgery. Despite its unique R1 side chain, cefazolin is often avoided in patients with beta-lactam allergy with concern for cross reactivity. Objectives: The primary outcome was the percentage of patients who received cefazolin perioperatively. Secondary outcomes included the percentage of patients with a beta-lactam allergy clarified following the telephone interview and clinical outcomes including acute kidney injury, surgical site infection, Clostridioides difficile infection, and re-admission at 30 and 90 days. Methods: This single-center, quasi-experimental study evaluated a pilot program in which a pharmacist phoned patients > 18 years of age with a scheduled orthopedic surgery and a documented beta-lactam allergy to assess their allergy preoperatively. Recommendations to use cefazolin were based on an algorithm. Patients were divided into pre- and post-intervention cohorts. Results: A total of 832 patients were screened for inclusion with 135 and 66 patients included in the pre- and post-intervention cohorts. No significant difference was identified in the primary outcome. In the post-intervention cohort, 62% had a beta-lactam reaction updated in the electronic medical record. Those with a beta-lactam allergy delabeled or made less severe were numerically more likely to receive cefazolin than those with an unchanged reaction or a reaction made more severe (95.2% vs 68% vs 65%). There were no differences in clinical outcomes between groups. Conclusion: A pharmacist-conducted preoperative beta-lactam allergy interview in adult patients undergoing elective orthopedic surgery improved beta-lactam allergy documentation but, did not result in increased utilization of cefazolin.