LAUSR

BACKGROUND Matrix metalloproteinase 3 (MMP3) is known as an inflammatory factor; however, the effectiveness of MMP3 for diagnosis of pneumonia and predicting outcomes is unclear. We evaluated the diagnostic and prognostic value of serum MMP3 in patients with pneumonia. METHODS One hundred and eighty-five patients with pneumonia and 52 healthy controls were enrolled. Serum MMP3, neutrophil gelatinase-associated lipocalin (NGAL), interleukin 6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) concentrations were measured at admission. The patients were followed up for 90 days. RESULTS Compared with healthy controls, the concentrations of MMP3, NGAL, and IL-6 at admission were significantly higher in patients with pneumonia (p < 0.05). The median concentrations of MMP3, NGAL, and IL-6 were significantly higher in the patients with severe pneumonia than the group of non-severe pneumonia (p < 0.05). Compared with PCT (AUC = 0.778), CRP (AUC = 0.719), and IL-6 (AUC = 0.726), MMP3 (AUC = 0.846) and NGAL (AUC = 0.826) had significantly higher AUC values for distinguishing the severity of pneumonia. The ROC of the combination of MMP3, neutrophil to lymphocyte ratio (NLR), and D-dimer showed the best performance of predicting pneumonia severity, which gave an AUC of 0.956. The AUC of MMP3 (0.950) for predicting mortality was highest, followed by NLR (AUC = 0.945), D-dimer (AUC = 0.938), and NGAL (AUC = 0.913). Multivariable logistic regression analysis showed MMP3, D-dimer, and NLR were the independent predictors of hospital mortality in patients with pneumonia. Patients with MMP3 concentration > 124.3 ng/mL had a significantly higher risk of mortality (p < 0.05). CONCLUSIONS MMP3 is a valuable biomarker in assessment of the severity and prediction of mortality in patients with pneumonia.