Office Hours Versus Non–Office‐Hours Admissions to the Paediatric Intensive Care Unit: A Cohort Study on the Impact of Illness Severity on Length of Stay and Mortality

AIM: Paediatric intensive care unit (PICU) length of stay (LOS) significantly impacts healthcare resources and costs, yet the influence of admission timing remains uncertain. We compare PICU LOS in patients transferred from wards during office hours versus non-office hours and examine predictors of mortality and LOS among survivors. METHODS: This retrospective cohort study analysed data from children under 18 years admitted to the PICU from wards at King Chulalongkorn Memorial Hospital, Bangkok, Thailand (1 July 2018-30 June 2022). Patients from the emergency room, outpatient department, other hospitals or for post-procedural care were excluded. Variables included demographics, clinical features, laboratory parameters, severity scores (Paediatric Index of Mortality 3 [PIM-3] and Paediatric Logistic Organ Dysfunction 2 [PELOD-2]). RESULTS: Of 536 patients, 151 (28%) were admitted during office hours and 385 (72%) during non-office hours, with a median age of 1.8 years (IQR 0.7-7.4). Office-hours admissions had higher severity scores and a longer median LOS (5 days, IQR: 2-14 vs. 3.4 days, IQR: 1.6-7.1; p = 0.001). ICU mortality did not differ significantly (7.3% vs. 3.9%; p = 0.10). Multivariate analysis revealed that admission timing was not independently associated with outcomes; however, higher PELOD-2 independently predicted mortality (adjusted hazard ratio 3.51, 95% CI: 1.37-8.99; p = 0.009), and prolonged LOS among survivors (adjusted coefficient 0.45, 95% CI: 0.08-0.83; p = 0.018). CONCLUSIONS: Longer LOS among office-hour admissions is attributable to greater illness severity rather than admission timing, underscoring the need for early identification and management of high-risk patients. TRIAL REGISTRATION: The protocol was registered on 19 May 2023, in the Thai Clinical Trials Registry (TCTR), ID TCTR 20230519001.