Associations of Inflammatory Biomarkers with Disease Severity in Elderly Patients with Sepsis-Associated ARDS: A Cross-Sectional Study.

BACKGROUND

Sepsis-associated acute respiratory distress syndrome (ARDS) is associated with high mortality, particularly in elderly patients. Reliable biomarkers for early severity stratification remain limited.

OBJECTIVE

To evaluate the associations of four inflammatory biomarkers-endothelial cell-specific molecule-1 (ESM-1), soluble urokinase plasminogen activator receptor (suPAR), procalcitonin (PCT), and heparin-binding protein (HBP)-with disease severity in elderly patients with sepsis-associated ARDS.

METHODS

This cross-sectional study included 168 elderly patients (≥60 years) with sepsis-associated ARDS. Serum levels of ESM-1, suPAR, PCT, and HBP were measured at enrollment. Disease severity was assessed using the APACHE II, SOFA, and MLIS scores, and the PaO2/FiO2 ratio. Correlations were examined using Spearman's rank correlation coefficients. Multivariable logistic regression was performed to identify biomarkers independently associated with moderate-to-severe ARDS, and receiver operating characteristic (ROC) curves were generated to evaluate their discriminative ability.

RESULTS

All four biomarkers increased stepwise across the mild, moderate, and severe ARDS groups (all P < 0.001). ESM-1 showed the strongest correlation with ARDS severity (r = 0.557, P < 0.001) and the largest area under the ROC curve (AUC = 0.800, 95% CI: 0.728-0.872), followed by HBP (AUC = 0.773), PCT (AUC = 0.761), and suPAR (AUC = 0.704). After adjustment for age and sex, ESM-1 (OR = 3.302, 95% CI: 1.596-6.832, P = 0.001), PCT (OR = 1.409, 95% CI: 1.137-1.747, P = 0.002), and HBP (OR = 1.039, 95% CI: 1.017-1.061, P < 0.001) remained independently associated with moderate-to-severe ARDS.

CONCLUSION

ESM-1, PCT, and HBP are independently associated with disease severity in elderly patients with sepsis-associated ARDS. ESM-1 demonstrated discriminative ability comparable to conventional severity scores and may serve as an adjunctive marker for severity assessment at enrollment, pending prospective validation. Limitations include the single-center, cross-sectional design and the lack of external validation.