Oxidative Stress and Quolity of Life in Severe Copd in Stable Phase

Objective: Oxidative stress (OS) is a pathogenic mechanism present in Chronic Obstructive Pulmonary Disease (COPD), with a systemic effect and which can alter the quality of life of patients. The aim of this study is to study the relationship between OE and quality of life in patients with stable COPD. Patients and Methods Seventy-six subjects were studied, 54 with COPD and 22 controls. The amount of malondialdehyde (MDA) in serum (nmol/mL) and induced sputum (nmol/mg protein) were measured as markers of systemic and bronchial OE, respectively. In addition, quality of life was measured using the St. George's questionnaire, which is specific for COPD patients. Results: Patients with COPD presented higher serum MDA levels than controls (2.98±0.03 nmol/m L vs 1.2±0.03 nmol/mL, p<0.001 respectively). An inverse association was observed between FEV1%, MDA levels in sputum (r=-0.499, P=0.018) and serum (r=-0.29, P=0.029). Finally, controlling for degree of bronchial obstruction, a direct association was observed between serum MDA levels and Total Quality of Life domains (r= 0.48, P= 0.04), on impact (r= 0.57, P< 0.001) and on activity (r= 0.38, p= 0.028). Conclusions: Systemic oxidative stress is increased in stable phase COPD patients. In addition, increased bronchial obstruction increases both systemic and bronchial oxidative stress. Finally, regardless of the degree of bronchial obstruction, systemic oxidative stress decreases patients' quality of life.