The Impact of Antibiotic Initiation Timing in Children with Severe Community-Acquired Pneumonia: A Post-Hoc Analysis of an Observational Study

INTRODUCTION: The aim of this study was to examine the association between early antibiotic initiation and clinical outcomes in children admitted to the paediatric intensive care unit (PICU) with severe community-acquired pneumonia (CAP). METHODS: We conducted a post-hoc analysis of a multicentre observational study across nine Asian PICUs. Children with severe CAP were categorized into early (≤ 6 h) or late (> 6 h) antibiotic initiation groups (early and late antibiotic groups, respectively) relative to PICU admission. The primary outcome was PICU mortality; secondary outcomes were 28-day ventilation-free days (VFD) and intensive care unit-free days (IFD). Multivariable analyses adjusted for country as fixed effect, age, Paediatric Index of Mortality 3 (PIM 3) score and comorbidities, when feasible. RESULTS: Among the 544 paediatric patients included in the analysis, median age was 14.0 [interquartile range (IQR) 4.0-34.0] months and the PIM 3 score was 0.3 (IQR 0.0-6.8) %. Viral and bacterial pathogens were isolated in 206 (37.9%) and 145 (26.7%) patients, respectively. Almost all patients [537 (98.7%)] received antibiotics, with 475 (87.3%) and 62 (11.4%) patients in the early and late antibiotic groups, respectively. Late antibiotic initiation was associated with higher PICU mortality [adjusted odds ratio (aOR) 5.19, 95% confidence interval (CI) 1.94-13.88, P < 0.01], septic shock requiring inotropic support (aOR 3.25, 95% CI 1.45-7.28, P < 0.01) and multi-organ failure (aOR 4.60, 95% CI 2.11-10.04, P < 0.01). No significant associations were observed between late antibiotic initiation and VFD or IFD. CONCLUSION: In critically ill children with severe CAP, initiating antibiotics within 6 h of PICU admission was associated with improved outcomes. This 6-h window may serve as a practical benchmark for quality improvement initiatives.