(B-115) Variations in antibiotic use in late premature and term newborns in neonatal care in Sweden 2012-2020

Background: Antibiotic overuse in neonates is a critical pharmacoepidemiological concern, contributing to antimicrobial resistance, neonatal microbiome disruption, and increased healthcare costs. Although Sweden reports low antibiotic use in late-preterm and term newborns, unwarranted regional and hospital-level variations in prescribing practices remain poorly characterized.

Objectives: This study aims to analyze population-level variations in early-life antibiotic exposure, incidence of culture-positive early-onset sepsis (EOS), and mortality in late-preterm and term newborns across Swedish regions (2012–2020).

Methods: A register-based cohort study included 1,025,515 newborns ≥34 weeks’ gestation using data from the Swedish Neonatal Quality Register. Antibiotic exposure (days 0–6), EOS incidence (days 0–2), and mortality were assessed across six healthcare regions including 37 neonatal units. Metrics included antibiotic days per 1,000 live births, durations of antibiotic therapy, EOS incidence, and mortality rates. Logistic regression was used to estimate the regional differences on antibiotic treatment in neonates with adjustments for factors related to infections.

Results: Out of 1 025 515 newborns, 19 286 (1.88%) newborns received antibiotics during the first week of life, with 2-fold regional variations (1.3%–3.0%). Among regions, antibiotic days per 1,000 live births ranged 70–176 by region; durations of antibiotic therapy (median) 4–7 days; EOS incidence per 1,000 live births 0.33–0.93; all-cause mortality per 1,000 live births 0.21–0.54. The logistic regression showed that the East region had the lowest treatment rate while the West had the highest. Benchmarking revealed high-performing region (antibiotic use 1.3%, EOS incidence 0.33/1,000) achieving low mortality without overtreatment, underscoring feasibility of optimized prescribing.

Conclusions: This analysis revealed wide variations in antibiotic treatment during the first week of life across different regions, despite all regions having a relatively low risk of EOS, EOS-associated mortality, and all-cause mortality. This identifies actionable disparities in neonatal antibiotic use, independent of infection risk or outcomes. The marked heterogeneity in treatment underscores systemic determinants of practice variation, including clinician thresholds for treatment initiation/discontinuation. These findings advocate for targeted, evidence-based policies to mitigate antimicrobial resistance risks and align neonatal care with best practices.