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The following is a summary of “Burden of β-lactam allergy labels in health care: a systematic review and meta-analysis,” published in the March 2025 issue of Lancet Infectious Diseases by Fu et al. 

The impact of unverified beta-lactam allergy labels on clinical outcomes is a significant but under-researched public health issue.  

Researchers conducted a retrospective study to evaluate existing evidence on clinical outcomes linked to β-lactam allergy labels (BALs) and assess the global impact.  

They searched PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), and Embase from January 1, 2000, to November 30, 2024. Observational and interventional studies were included, comparing clinical outcomes based on the presence or absence of a BAL as recorded in any clinical document, regardless of age or clinical setting. Outcomes analyzed included surgical site infections, infections or colonization by multidrug-resistant organisms (MDROs) or Clostridioides difficile, mortality, and hospital length of stay. Pooled estimates were obtained using random-effects models, with subgroup analyses based on region, country income level, BAL type, hospital setting, sample size, age group, and evidence quality. Publication bias was evaluated using Begg’s funnel plots and Egger’s regression test and the study was registered with PROSPERO (CRD42023484030).  

The results showed that 63 studies were included, with 60 (95%) from high-income countries. Studies were conducted in the Americas (41 [65%]), Europe (15 [24%]), and the Western Pacific region (7 [11%]), 7 studies were of moderate quality, and none were classified as low quality. No significant publication bias was found for most outcomes except for hospital length of stay (P =0.0062). The BALs were linked to higher rates of surgical site infections (OR 1.60, 95% CI 1.27–2.01; P <0.0001; I² =70.3%), infections or colonization with MDROs (OR 1.42, 95% CI 1.22–1.64; P <0.0001; I² =84.4%), and Clostridioides difficile infections (OR 1.26, 95% CI 1.16–1.37; P <0.0001; I² =56.4%), BALs were also linked to longer hospital stays (standardized mean difference 0.06 days, 95% CI 0.05–0.08; P <0.0001; I² =86.1%) and increased mortality at or after 180 days but showed no association with overall, in-hospital, or 30-day mortality.  

Investigators concluded that BALs were related with increased risks of adverse health outcomes, particularly infections, but not clinically significant prolonged hospital stays. 

Source: thelancet.com/journals/laninf/article/PIIS1473-3099(25)00019-2/abstract