Epidemiology, multimorbidity patterns and outcomes of paediatric sepsis admissions in Ireland 2020-2025

Paediatric sepsis remains a leading cause of morbidity and mortality worldwide, yet national-level epidemiological data in Ireland are limited. Understanding patterns of disease, risk factors, and clinical outcomes is essential to support early recognition and management and optimise prevention strategies. A retrospective observational study was conducted using the Hospital In-Patient Enquiry database. All paediatric sepsis admissions in Ireland from January 2020 to December 2025 were included in the dataset. Episodes were classified as hospital-onset or community-onset according to whether the associated infection diagnosis was coded as hospital-acquired. Infection sources and comorbidities were identified using ICD coding and a validated paediatric comorbidity index. Multivariable logistic regression was used to examine factors associated with critical care admission and mortality among community-onset episodes. A total of 4,442 paediatric sepsis admissions were identified, of which 30.7% (n = 1,364) were hospital-onset and 69.3% (n = 3,078) were community-onset. Neonates (< 28 days) accounted for 76.2% of hospital-onset and 44.3% of community-onset episodes (p < 0.001). Hospital-onset sepsis was associated with significantly higher rates of critical care admission (84.0% vs 32.3%, p < 0.001) and mortality (7.6% vs 1.8%, p < 0.001) than community-onset sepsis. Among community-onset episodes, one or more underlying comorbidities were independently associated with critical care admission (adjusted OR 2.66, 95% CI 1.93-3.65 in neonates; adjusted OR 4.88, 95% CI 3.59-6.63 in non-neonates) and mortality (OR 7.18, 95% CI 4.05-12.72). However, a substantial proportion of critical care admissions and deaths also occurred in children without documented comorbidity.

Paediatric sepsis remains a substantial cause of critical illness in Ireland. Hospital-onset sepsis was associated with significantly greater illness severity and worse outcomes than community-onset sepsis. Although underlying comorbidity was strongly associated with adverse outcomes, severe illness also occurred in children without documented comorbidity, highlighting the importance of early recognition and timely escalation of care.

• Paediatric sepsis is a major cause of morbidity and mortality worldwide, but national epidemiological data from Ireland are limited.

• This first national Irish study (2020-2025) describes paediatric sepsis epidemiology and outcomes, showing that hospital-onset sepsis carries substantially higher mortality and critical care use, while neonates and children with comorbidities are at greatest risk. • Importantly, severe outcomes also occur in previously healthy children.