Prognostic biomarkers help triage initial patients and inform targeted therapy selection. Here, we explored the role of progranulin (PGRN)—implicated in processes ranging from inflammation to neurodegeneration—in patients with community-acquired pneumonia (CAP).

A prospective observational cohort study was conducted during 2017. Patients who required invasive mechanical ventilation and/or had septic shock and were discharged from the hospital were cohort II. Those who died at the hospital were cohort III. Remaining patients discharged from the hospital were cohort I. The primary endpoint was that patients progressed to served as cohort II; the secondary endpoint was that patients progressed to served as cohort III. Serum PGRN levels were detected by ELISA.

A total of 280 patients constituted the study cohort. 194 (69.3%) were categorized into cohort I, 61 (21.8%) were categorized into cohort II, and 25 (8.9%) were categorized into cohort III. Serum PGRN levels were increased in CAP patients, independently of etiology. Adjusting for clinical parameters, the odds ratios (95%CI) of cohort III and combined cohort II–III were 34.968 (3.743–326.692) and 3.741 (1.496–9.351), respectively, comparing lowest-to-highest quartile PGRN levels. PGRN exhibited high accuracy in predicting 30-day mortality, with AUC 0.862. PGRN combined with CURB-65 or PSI significantly improved prediction performance. Cox proportional regression analysis showed PGRN was an independent predictor for 30-day mortality risk. Cox survival curves confirmed PGRN ≥89.51 ng/mL had a significantly higher mortality rate than PGRN <89.51 ng/mL.

Higher PGRN levels at admission were associated with higher odds of poor prognosis. PGRN can improve the prognostic power of CURB-65 or PSI, so PGRN could be apparently a prognostic biomarker for assisting triage of CAP patients.