Background
Knowledge of the effects of undernourishment on the severity of respiratory impairment, systemic inflammation and oxidative stress during acute exacerbations of COPD (AECOPD) is limited. In patients with AECOPD, we assessed the relationships between BMI, lung function, and markers of systemic inflammation and oxidative stress.
Material and Method
We measured pulmonary function, serum C-reactive protein (CRP), tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, malondialdehyde (MDA), erythrocytic glutathione-peroxidase (GPx), superoxiddismutase (SOD), and catalase (CAT) in 113 patients admitted to the hospital due to an AECOPD (80 males, age 66.2+/-11.0 years, FEV1 41.5+/-13.7% predicted).
Results
From the low (<21 kg/m2) towards the normal (21-24.9 kg/m2), high (25-29.9 kg/m2) and obese (>30 kg/m2) BMI groups, FEV1, FEV1-to-forced vital capacity (FVC) ratio, inspiratory capacity (IC), and the IC-to-total lung capacity (IC/TLC) ratio increased (p<0.01; p<0.001; p=0.039; p=0.002, respectively), while residual volume (RV), TLC and RV/TLC ratio were reduced (p<0.001; p<0.001; p=0.018, respectively). Patients with low BMI had significantly lower FEV1, FEV1/FVC, IC and IC/TLC, and higher RV and TLC values compared to the high and obese BMI groups. From the low towards the normal, high and obese BMI, reductions in serum CRP, and a trend towards increases in erythrocytic GPx were observed (p=0.023; p=0.056, respectively). No differences were seen in circulating TNF-alpha, IL-6 or IL-8, MDA or erythrocytic CAT and SOD between the groups.
Conclusions
In patients with acute exacerbations of COPD, low BMI is associated with higher degree of bronchial obstruction and pulmonary hyperinflation, in association with higher circulating CRP levels.

Keywords: Nutritional Status - physiology, Inflammation - physiopathology, Pulmonary Disease, Chronic Obstructive - physiopathology, Body Mass Index, Cohort Studies, Respiratory Function Tests