Factors associated with in-hospital mortality and treatment withdrawal in mechanically ventilated children with severe pneumonia: a retrospective cohort study.

Background: Severe pneumonia requiring mechanical ventilation (MV) remains associated with substantial mortality and treatment failure in pediatric intensive care units (PICUs). Although several prognostic scoring systems have been developed for critically ill children, readily available laboratory biomarkers that may facilitate early prognostic assessment in mechanically ventilated children with severe pneumonia have not been well established. Therefore, this retrospective cohort study aimed to identify laboratory factors associated with in-hospital mortality and treatment withdrawal in mechanically ventilated children with severe pneumonia. Methods: This retrospective cohort study included children diagnosed with severe pneumonia who required MV and were admitted to the Pediatric Intensive Care Unit (PICU) of People's Hospital of Qiannan Buyei and Miao Autonomous Prefecture between June 2022 and June 2025. Laboratory biomarkers obtained within 24 hours of PICU admission were analyzed. Poor outcomes were defined as in-hospital mortality or treatment withdrawal because of critical illness, with survival status confirmed by follow-up after discharge. Multivariable logistic regression was performed to identify factors independently associated with poor outcomes. Receiver operating characteristic (ROC) analysis was conducted as an exploratory assessment of the discriminative performance of the identified prognostic factors. Results: A total of 185 eligible children were included, among whom 15 experienced poor outcomes. Multivariable logistic regression demonstrated that absolute neutrophil count (ANC), platelet count (PLT), and alanine aminotransferase (ALT) were independently associated with poor outcomes. Exploratory ROC analysis showed that the combination of these laboratory markers demonstrated better discriminative performance than any individual marker. Given the limited number of outcome events, these findings should be interpreted as exploratory and require validation in larger prospective studies. Conclusions: In this retrospective cohort study, elevated ANC and ALT levels together with reduced PLT levels were independently associated with poor outcomes in mechanically ventilated children with severe pneumonia. These routinely available laboratory biomarkers may provide complementary prognostic information during early clinical assessment. However, because of the retrospective single-center design and the limited number of poor outcome events, the present findings should be regarded as exploratory and require prospective validation in larger multicenter cohorts before clinical implementation.