Background. Soluble urokinase plasminogen activator receptor (suPAR) is an emerging biomarker in different clinical disorders but data in pediatric pneumonia is scarce. Our objective was to assess utility of suPAR in pediatric community-acquired and hospital-acquired pneumonia.

Methods. A prospective observational study including 120 hospitalized pneumonia patients and 55 healthy controls. Patients fell into two groups: community-acquired pneumonia (CAP) group (75 patients) and hospitalacquired pneumonia (HAP) group (45 patients). CAP severity scores were calculated, including Predisposition, Insult, Response, Organ dysfunction modified (PIROm) score and Pediatric Respiratory Severity (PRESS) Score. suPAR was measured to CAP patients on admission and to HAP patients on the day of pneumonia diagnosis. suPAR was also measured to controls.

Results. suPAR was higher among the whole patient cohort compared with controls (p < 0.001) and higher among CAP group compared with both controls (p < 0.001) and HAP group (p < 0.001). No significant difference was found between HAP and control groups. suPAR was higher among CAP patients with shock, PICU admission, mechanical ventilation, and death (p=0.013, 0.044, 0.019, 0.049 respectively). Among CAP patients, suPAR correlated with oxygen saturation, pulse rate, respiratory rate, PRESS, and PIROm. suPAR had area under Receiver Operating Characteristic Curve=0.68 for prediction of severe CAP. Among HAP group, suPAR was negatively correlated with oxygen saturation (rs=-0.31; p=0.048) and was higher among patients with shock (p=0.005) and among those with increased pediatric Sequential Organ Failure Assessment (pSOFA) score (p=0.034).

Conclusions. suPAR is promising for diagnosing pediatric CAP but not HAP. suPAR predicted illness severity in both CAP and HAP but performed better in the former.

Keywords: biomarkers, healthcare-associated pneumonia, pediatrics, pneumonia, urokinase plasminogen activator receptors, ventilatorassociated pneumonia