Serum leptin and multi-detector computed tomography (MDCT)-measured bone attenuation among low BMI male patients with moderate-severity chronic obstructive pulmonary disease in exacerbation and stable states

Abstract

Introduction Several studies have shown high prevalence of osteoporosis and weight loss in patients with chronic obstructive pulmonary disease (COPD). Leptin regulates bone metabolism, body weight, and pulmonary artery pressure. The association of bone density and serum leptin with BODE score in moderate COPD patients is still unclear. Aim of the study The aim of the study was to explore the association of serum leptin with average bone attenuation assessed by routine chest MDCT, and their correlation with clinical and echocardiographic parameters. Patients and methods The study included 54 male patients with low BMI and moderate COPD severity. Patients were divided into two groups: those with COPD exacerbations (24 patients; group I) and those with stable COPD (30 patients, group II). Twenty male volunteers of matched age and BMI were included as controls (group III). Calculation of BMI and BODE score was done. Spirometry and echocardiography were performed in all participants. Average bone attenuation of the thoracic spine was estimated by MDCT. Serum leptin was estimated. Results Group I and group II had significantly lower bone attenuation and higher BODE index, pulmonary artery systolic pressure (PASP), and right ventricle diameter (RVD) as compared with healthy controls (P < 0.001). Serum leptin level and leptin/BMI ratio were significantly increased in group I than in other groups (P < 0.001). Group II had significantly lower serum leptin than did controls. Serum leptin correlated positively with age, BMI, COPD severity, and bone attenuation and showed significant negative correlation with BODE score and serum calcium in group II. Meanwhile; it showed significant positive correlation with BMI and PASP in group I. In the stable COPD group, PASP, RVD, BMI, and bone attenuation were independent predictors of serum leptin, whereas BODE score, FEV 1 , FEV 1 /FVC, PASP, RVD, BMI, and serum leptin were independent predictors of bone attenuation. Conclusion COPD patients with moderate severity and low BMI had increased circulating leptin and low calcium level during exacerbation. Serum leptin level correlated with bone attenuation in stable but not in exacerbation states.