Plasma Leptin Is Elevated in Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Background. The natural history of idiopathic pulmonary fibrosis (IPF) is very complex and unpredictable. Some patients will experience acute exacerbation (AE) and fatal outcomes. Methods. The study included 30 AE-IPF patients, 32 stable IPF (S-IPF) patients, and 12 healthy controls. We measured the plasma concentrations of leptin and KL-6. Simple correlation was used to assess associations between leptin and other variables. Plasma leptin levels were compared between AE-IPF and S-IPF subjects, decedents, and survivors. Kaplan-Meier curves were used to display survival and Cox proportional hazards regression was used to examine risk factors for survival. Results. In subjects with AE-IPF, plasma leptin was significantly greater than in subjects with S-IPF (p = 0.0003) or healthy controls (p < 0.0001). Plasma leptin was correlated with BMI, KL-6, LDH, CRP, and PaO(2)/FiO(2) (p = 0.007; p = 0.005; p = 0.003; p = 0.033; and p = 0.032, resp.). Plasma leptin was significantly greater in 33 decedents than in the 23 survivors (p = 0.007). Multivariate Cox regression analysis showed leptin (>13.79 ng/mL) was an independent predictor of survival (p = 0.004). Conclusions. Leptin could be a promising plasma biomarker of AE-IPF occurrence and predictor of survival in IPF patients.