Consequences of reported β-lactam allergy on perioperative outcomes: a systematic review and meta-analysis of surgical site infection risk

Objective: To evaluate the impact of reported β-lactam allergy on the risk of surgical site infections (SSIs), given that most reported cases are unverified and may lead to suboptimal antibiotic prophylaxis. Design: Systematic review and meta-analysis. Methods: Four databases were systematically searched for studies reporting SSI rates in patients with and without β-lactam allergy. The primary outcome was SSI incidence; secondary outcomes included mortality, length of hospital stay (LOS) and adverse events. Subgroup analyses were conducted to explore potential sources of heterogeneity. Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a random-effects model. Risk of bias was assessed using the ROBINS-I tool. Results: Twenty-five retrospective observational studies comprising 460,284 patients were included. Reported β-lactam allergy was associated with a significantly increased risk of SSI (RR = 1.55, 95% CI = 1.24-1.94). This association remained consistent across sensitivity and subgroup analyses, particularly in studies relying on self-reported allergies. Patients receiving β-lactam antibiotics had a significantly lower SSI risk than that of patients receiving non-β-lactam alternatives (RR = 0.63, 95% CI = 0.42-0.94). No significant differences were found in LOS or hypersensitivity reaction rates. Mortality was not reported in any of the included studies. Conclusions: Reported β-lactam allergy is associated with an increased risk of SSI, highlighting the importance of accurate allergy assessment. Selective administration of β-lactam agents, such as cefazolin, may offer a safe and effective option for preoperative prophylaxis in patients without a history of severe hypersensitivity.