Rationale: Two adipokines, leptin and adiponectin, regulate metabolic and inflammatory systems reciprocally. The role of adiponectin in chronic obstructive pulmonary disease (COPD) has been studied. However, there are few data evaluating the relationship of plasma leptin with COPD severity or progression.
Objectives: The objective of this study was to evaluate the relationship of leptin, adiponectin, and the leptin/adiponectin ratio with COPD severity and progression according to COPD phenotypes.
Methods: Plasma leptin and adiponectin levels were measured in 196 subjects with COPD selected from the Korean Obstructive Lung Disease cohort. Using a linear regression model and mixed linear regression, we determined the relationship of plasma leptin and adiponectin levels and the leptin/adiponectin ratio to COPD severity and progression over 3 years.
Measurements and main results: The concentration of adiponectin in plasma positively correlated with percent emphysema on initial computed tomography (CT) (adjusted P = 0.022), whereas plasma leptin concentrations and the leptin/adiponectin ratio exhibited a significant inverse correlation with initial FEV1 (adjusted P = 0.013 for leptin and adjusted P = 0.041 for leptin/adiponectin ratio). Increased plasma leptin and leptin/adiponectin ratio were significantly associated with change in percent emphysema over 3 years (adjusted P = 0.037 for leptin and adjusted P = 0.029 for leptin/adiponectin ratio), whereas none of the adipokines demonstrated an association with FEV1 decline over the 3-year period.
Conclusions: Plasma adiponectin and leptin vary according to COPD phenotypes. Plasma leptin and the leptin/adiponectin ratio, but not adiponectin, were significantly associated with changes in CT-assessed emphysema, suggesting a potential role as a biomarker in emphysema progression in patients with COPD.
Keywords: adiponectin; chronic obstructive pulmonary disease; emphysema; leptin.