Postoperative complication risks associated with penicillin allergy in tissue expander-based breast reconstruction: A propensity score-matched retrospective cohort study.

BACKGROUND

Reported penicillin allergy often leads to avoidance of first-line β-lactam prophylaxis in favor of less effective alternatives, potentially increasing surgical site infection (SSI) risk. Tissue expander (TE)-based breast reconstruction, despite being a clean procedure, has infection rates of up to 30%. This study evaluates whether reported penicillin allergy is associated with increased postoperative infection risk in this population.

METHODS

The TriNetX database was queried to identify patients who underwent TE-based breast reconstruction. Patients were stratified into two cohorts: those with a documented history of penicillin allergy and those without. Propensity score matching was applied to balance infection-related risk factors. The primary outcome was implant infection, while secondary outcomes were SSI, wound dehiscence, emergency department visits, antibiotic uses, and TE removals. Outcomes were assessed at 30, 60, and 90 days postoperatively.

RESULTS

After matching, 1868 patients were included in each cohort. At 90 days following surgery, patients with a history of penicillin allergy had significantly increased risks of implant infection (risk ratio [RR] 1.41, p=0.003), SSI (RR 1.54, p=0.042), antibiotic uses (RR 1.38, p<0.001), emergency department visits (RR1.75, p<0.001), and TE removals (RR 1.20, p=0.044), compared to matched controls. Elevated risks were also partly observed at 30 and 60 days postoperatively.

CONCLUSION

In this large retrospective study of TE-based breast reconstruction, a reported history of penicillin allergy was associated with significantly higher risks of implant infection and related postoperative complications compared with patients without such a history.