# Serum inflammatory markers nt-probnp, hs-crp and il-6 predict disease severity and mortality in severe community-acquired pneumonia: A propensity score matching study

## TL;DR

This study shows that blood markers NT-proBNP, hs-CRP, and IL-6 help predict severity and death risk in severe pneumonia patients when combined with CT scans.

## Contribution

The study demonstrates that combining inflammatory biomarkers with CT scores improves SCAP diagnosis and mortality prediction.

## Key findings

- SCAP patients had significantly higher NT-proBNP, hs-CRP, and IL-6 levels compared to controls.
- A combined model of biomarkers and CT scores outperformed individual measures in predicting mortality (AUC 0.839).
- Elevated biomarker levels were identified as independent predictors of mortality in SCAP patients.

## Abstract

This study aimed to evaluate the involvementof serum inflammatory markers— N-terminal pro-brainnatriuretic peptide (NT-proBNP), hypersensitive-C reactiveprotein (hs-CRP), and interleukin-6 (IL-6) - in the pathological progression of severe community-acquired pneumonia (SCAP), examine their association with computedtomography (CT) scores, and assess their combined utilityfor diagnosis and outcome prediction.

We performed a propensity score-matched retrospective cohort study involving 164 SCAP patients(research group) and 164 age- and sex-matched healthycontrols (control group) enrolled between March 2024 andJanuary 2025. Serum NT-proBNP hs-CRP and IL-6 concentrations were quantified by enzyme-linked immunosorbent assay (ELISA), while chest computed tomography(CT) manifestations were evaluated using the AcuteExacerbation of Idiopathic Pulmonary Fibrosis (AE-IPF)scoring system. Comparative analyses of inflammatorymarkers and CT imaging findings were conducted, withsubsequent correlation studies, receiver operating characteristic (ROC) curve analysis, and multivariate regressionmodeling to determine their relationship with in-hospitalmortality.

Following propensity score matching, demographic characteristics were well-balanced between groups (standardized mean differences <0.1). SCAP patientsdemonstrated significantly elevated serum levels of NTproBNP hs-CRP and IL-6 (P< 0.01), along with higher CTscores than controls. Strong positive correlations wereobserved between inflammatory marker concentrationsand CT scores (P< 0.01). The combined model outperformed individual biomarkers or CT alone in diagnosingSCAP (AUC 0.934, 95%CI 0.910 -0.959; P< 0.001) andpredicting mortality (AUC 0.839, 95%CI 0.759-0.919;P< 0.001). Multivariate analysis identified the elevation ofthese biomarkers as independent predictors of mortality inSCAP patients (P< 0.01).

NT-proBNP hs-CRP and IL-6 play pivotal rolesin promoting SCAP progression by driving inflammatorycascades and pulmonary tissue injury. The integratedassessment of these biomarkers with CT scoring significantly improves disease monitoring and prognostic assessment accuracy, potentially guiding individualized antiinflammatory interventions in SCAP management.