Association of β-lactam allergy labels with antibiotic use patterns, clinical outcomes and economic burden in China: a retrospective observational study

β-lactam allergy labels (BALs) influence antibiotic prescribing decisions, prompting clinicians to opt for alternative antibiotics over β-lactams. However, evidence from China remains limited. We conducted a multicenter retrospective cohort study using data from 7 hospitals in China between January 1 and June 30, 2021. Hospitalized patients who received systemic antibacterial therapy were included. The primary outcome was the pattern of antibiotic use. Secondary outcomes included hospital length of stay (LOS), in-hospital mortality and total hospitalization costs. Propensity score matching (PSM) was performed within each hospital to balance covariates between patients with and without a documented BAL. Hospital-specific associations were estimated using logistic or linear regression models and subsequently pooled through meta-analysis. Among 152,326 patients, 8,633 (5.7%) had a BAL. After PSM, 8,476 patients with and 32,767 without a BAL were analyzed. BALs were associated with lower use of β-lactam antibiotics (odds ratio [OR] 0.27, 95% confidence interval [CI] 0.20–0.37) and higher use of alternatives (OR 3.62, 95% CI 2.91–4.50). BALs were also associated with increased use of World Health Organization Access (OR 1.66, 95% CI 1.13–2.45) and Reserve (OR 1.66, 95% CI 1.19–2.32) antibiotics. No significant associations were observed with LOS or mortality, but BALs were associated with reduced hospitalization costs (MD -281.40 US dollars [USD], 95% CI -444.51 to -118.28 USD). BALs were significantly associated with antibiotic prescribing patterns and lower hospitalization costs, but not with LOS or in-hospital mortality. Further research is warranted to explore these associations in specific populations.