Fibroblast growth factor 21 predicts outcome in community-acquired pneumonia: secondary analysis of two randomised controlled trials

Acute systemic inflammatory conditions are accompanied by profound alterations of metabolism. However, the role of fibroblast growth factor 21 (FGF21), a recently identified central regulator of metabolism, is largely unknown in community-acquired pneumonia (CAP). This study aims to characterise the pattern of FGF21 in pneumonia and associations with disease severity and outcome.This is a secondary analysis of two independent multicentre randomised controlled trials in patients presenting to the emergency department with CAP. Primary and secondary efficacy parameters included 30-day mortality, length of hospital stay, time to clinical stability and duration of antibiotic treatment.A total of 509 patients were included in the analysis. FGF21 levels at admission strongly correlated with disease severity, as measured by the Pneumonia Severity Index. Increased levels of FGF21 were associated with prolonged time to clinical stability, antibiotic treatment and hospitalisation. FGF21 levels at admission were significantly higher in nonsurvivors than in survivors, yielding a 1.61-fold increased adjusted odds ratio of 30-day mortality (95% CI 1.21-2.14; p=0.001). Moreover, FGF21 was found to identify patients for 30-day mortality with superior discriminative power compared with routine diagnostic markers.Moderate-to-severe CAP patients with higher levels of FGF21 were at increased risk for clinical instability, prolonged hospitalisation and 30-day all-cause mortality.