Circulating Adipokines as Diagnostic and Prognostic Markers in Idiopathic Pulmonary Fibrosis

Dysregulation of lipid metabolism has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). We aimed to evaluated the predictive value of adipokines in IPF diagnosis and prognosis.

Clinical data of patients with IPF (n = 100) and healthy controls (n = 64) were retrospectively analysed. Plasma adipokine levels including leptin and adiponectin were measured using enzyme-linked immunosorbent assay.

The mean age of patients with IPF was 68.4 years and 83.0% were male; they were older than controls. The plasma leptin levels were higher in patients with IPF than those in controls and were independently associated with IPF presence (odds ratio: 1.007, 95% confidence interval [CI]: 1.003-1.011; P < 0.001) after adjusting age. Patients with high adiponectin levels (≥ 2700 ng/mL) had poorer survival than those without (median survival time: 25.0 vs. 62.0 months; P = 0.019). High adiponectin levels (≥ 2700 ng/mL) demonstrated an increased risk of mortality (hazard ratio [HR]: 2.304, 95% CI 1.041-5.102; P = 0.040) after adjusting the body mass index, forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide (DLCO), and treatment. Additionally, high adiponectin group demonstrated higher risk of acute exacerbation (AE) than low adiponectin group in the Kaplan-Meier analysis (log rank, P = 0.021). High adiponectin levels were also significantly associated with AE in the unadjusted Cox analysis (HR: 4.748; 95% CI 1.100-20.507; P = 0.037), but this association was not significant after adjusted for FVC and DLCO (HR: 3.821; 95% CI 0.872-16.742; P = 0.075).

Plasma adipokines are useful biomarkers for IPF diagnosis and prognosis.