Self-reported beta-lactam allergy and the risk of surgical site infection: A retrospective cohort study

Abstract

Objective:To assess whether a self-reported β-lactam allergy is associated with an increased risk of surgical site infection (SSI) across a broad range of procedures and to determine whether this association is mediated by the receipt of an alternate antibiotic to cefazolin.Design:Retrospective cohort study.Participants:Surgical procedures sampled by an institutional National Surgical Quality Improvement Program database over an 18-month period (January 2017 to June 2018) from 7 surgical specialties.Setting:Tertiary-care academic hospital.Results:Of the 3,589 surgical procedures included in the study, 369 (10.3%) were performed in patients with a reported β-lactam allergy. Those with a reported β-lactam allergy were significantly less likely to receive cefazolin (38.8% vs 95.5%) or metronidazole (20.3% vs 26.1%) and were more likely to receive clindamycin (52.0% vs 0.2%), gentamicin (3.5% vs 0%), or vancomycin (2.2% vs 0.1%) than those without allergy. An SSI occurred in 154 of 3,220 procedures (4.8%) in patients without reported allergy and 27 of 369 (7.3%) with reported allergy. In the multivariable regression model, a reported β-lactam allergy was associated with a statistically significant increase in SSI risk (adjusted odds ratio [aOR], 1.61; 95% confidence interval [CI], 1.04–2.51; P = .03). This effect was completely mediated by receipt of an alternate antibiotic to cefazolin (indirect effect aOR, 1.68; 95% CI, 1.17–2.34; P = .005).Conclusions:Self-reported β-lactam allergy was associated with an increased SSI risk mediated through receipt of alternate antibiotic prophylaxis. Safely increasing use of cefazolin prophylaxis in patients with reported β-lactam allergy can potentially lower the risk of SSIs.

Investigating the impact of a β-lactam allergy label on preoperative antibiotic prophylaxis administration

“…We observed similar delays in vancomycin dosing in both groups, and we additionally identified the omission of gentamicin among patients with a BLA label as a contributor to inappropriate antibiotic prophylaxis. Notably, vancomycin use was high in our study and 40% of patients with no BLA label received vancomycin, compared to Blumenthal et al 6 (3%) and Lam et al 7 (0.1%). This difference can be attributed to the inclusion of different procedures and differences in institutional guidelines because we recommend vancomycin for knee replacement and CABG procedures.…”

“…Blumenthal et al 6 evaluated >8,000 patients who underwent 9,004 procedures and discovered a 50% increased odds of SSI among patients with a reported penicillin allergy, attributed to the receipt of second-line perioperative antibiotics. Lam et al 7 conducted a retrospective cohort study of >3,500 surgical procedures and found that a reported β-lactam allergy was also associated with a significant increase in SSI risk (adjusted odds ratio, 1.61; 95% confidence interval, 1.04-2.51; P = .03). 7 Our study outcomes are unique for several reasons.…”

“…Lam et al 7 conducted a retrospective cohort study of >3,500 surgical procedures and found that a reported β-lactam allergy was also associated with a significant increase in SSI risk (adjusted odds ratio, 1.61; 95% confidence interval, 1.04-2.51; P = .03). 7 Our study outcomes are unique for several reasons. First, our retrospective evaluation included matched patients to reduce potential differences in recommended antibiotic regimens and SSI risk.…”

“…Our findings were similar to previously published studies, including the increased likelihood of receiving vancomycin, gentamicin, and clindamycin among patients with a reported penicillin allergy, rather than cefazolin, cefoxitin, and ampicillin. 6,7 Furthermore, we were able to eliducate reasons for the use of these second-line agents among patients with BLA labels because antibiotic selection was often inappropriate based on the severity of the allergy.…”

“…Two retrospective cohort studies demonstrated an increased risk of SSI among surgery patients with a reported BLA. 6,7 This risk has been attributed to the receipt of second-line perioperative antibiotics. We sought to directly assess the appropriateness of preoperative antibiotic prophylaxis in patients with a BLA label compared those without a BLA label.…”