Hyaluronic Acid is Associated with Severity and Prognosis in Patients with Community-Acquired Pneumonia

Hyaluronic acid (HA) is a novel inflammatory biomarker with a prognostic value for several infectious diseases. This study investigated the association of HA with severity and prognosis in hospitalized patients with community-acquired pneumonia (CAP).

We analyzed the differences of HA levels in different groups. Logistic regression analysis was performed to identify independent risk factors for severe CAP (SCAP). The predictive value of HA for SCAP was assessed using receiver operating characteristic (ROC) curves. Kaplan-Meier survival analysis was used to compare 30-day mortality between the high and low HA groups.

Compared to healthy controls (49.2 ± 15.3 ng/mL), patients with CAP exhibited significantly elevated levels of HA (P < 0.001). In CAP patients, increased HA levels were more pronounced in those with SCAP (SCAP vs non-SCAP:135.6 ± 51 ng/mL vs 100.7 ± 47.8 ng/mL, P < 0.001). Compared to survivors (109.9 ± 48.7 ng/mL), HA levels in non-survivors were significantly higher (180.9 ± 67.8 ng/mL) (P < 0.001). HA was an independent predictor of SCAP [odds ratio (OR): 1.013, 95% confidence interval (CI): 1.003-1.022, P = 0.011] with high diagnostic accuracy [areas under the curve (AUC): 0.709, 95% CI: 0.622-0.797, P = 0.001]. Additionally, HA was independently associated with death risk in patients with CAP (OR: 1.022, 95% CI: 1.005-1.039, P = 0.010). Kaplan-Meier survival curves indicated that CAP patients in the high HA group exhibit a higher 30-day mortality rate compared to those in the low HA group (8.6% vs 1.5%, P = 0.008). Post hoc analysis indicated that our study possessed 98.857% statistical power.

In conclusion, High HA levels are associated with severity and mortality in patients with CAP, and HA could serve as a novel serum biomarker to predict the risk of CAP progression.