Association of oxidative stress markers and C-reactive protein with multidimensional indexes in COPD.

To evaluate the oxidative stress and the C-reactive protein (CRP) in chronic obstructive pulmonary disease (COPD) patients and their correlation between the severity of the disease according to GOLD criteria and multidimensional indexes such as BODE index. A blood sample was collected for thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase, glutathione (GSH), homocysteine (HCY) and CRP analysis from 45 stable COPD patients. Lung function, body nutritional status, dyspnea and 6-min walk test (6MWT) were evaluated. Patients with GOLD stage IV presented a higher value for the TBARS than stage I patients (4.47 + 1.58 versus 2.27 + 1.04 nmol/mL, p < 0.05). CRP was higher for GOLD IV (2.46 + 3.68 mg/dL) than other stages (GOLD I: 0.39 + 0.25, GOLD II: 0.39 + 0.18 and GOLD III: 0.48 + 0.36 mg/dL, p < 0.05). Oxidative stress markers measured as TBARS presented a negative correlation between forced expiratory volume in the first second (FEV(1)) post bronchodilatador (% predicted; r = -0.39, p = 0.01) and positive correlations with Modified Medical Research Council Scale (MMRC) dyspnea index (r = 0.40, p = 0.01), multidimensional index (r = 0.49, p = 0.001) and BODE index (r = 0.51, p = 0.001).