Decreased high-density lipoprotein cholesterol is associated with severe community-acquired pneumonia in children: a single-center retrospective cohort study

Abstract Background Community-acquired pneumonia (CAP) is a leading infectious cause of death among children. Recent evidence suggests that blood lipid levels are correlated with disease severity in sepsis and other inflammatory conditions; however, evidence on the association between lipid levels and severe CAP in children remains limited. This study aimed to evaluate the association between blood lipid levels and severe CAP in children and the discriminative ability of lipid parameters for severe CAP. Methods In this single-center retrospective cohort study, we included 1588 hospitalized children with CAP between September 2023 and September 2024. The children were divided into a severe pneumonia group ( n = 400) and a nonsevere pneumonia group ( n = 1188) according to disease severity. Clinical characteristics and serum lipid levels measured within 24 hours of admission were compared between the two groups. Receiver operating characteristic (ROC) analyses and multivariable logistic regression adjusted for age, sex, and body mass index (BMI) were used to evaluate the discriminative ability of each lipid parameter for severe pneumonia. A combined model including high-density lipoprotein cholesterol (HDL-C), procalcitonin, C-reactive protein, and neutrophil count was further evaluated. . Results Children with severe CAP had lower total cholesterol, HDL-C, low-density lipoprotein cholesterol, and apolipoprotein A1 levels than those with non-severe CAP (all P < 0.05). Among the lipid parameters, HDL-C showed the best discriminative performance for severe pneumonia, with an area under the ROC curve (AUC) of 0.705 (95% CI: 0.674 − 0.735, P < 0.001). In multivariable analysis, higher HDL-C was independently associated with lower odds of severe CAP (OR = 0.086, 95% CI:0.052–0.142), whereas higher procalcitonin, C-reactive protein, and neutrophil count were associated with higher odds. Adding HDL-C to the inflammatory marker-based model improved the AUC from 0.696 to 0.757. Conclusions Children with severe CAP exhibit an abnormal lipid profile characterized by decreased TC, HDL-C, LDL-C, and ApoA1. HDL-C was independently associated with severe CAP and improved discrimination when combined with PCT, CRP, and the neutrophil count.