Resp Res
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Comparative Study
Increased oxidative stress in asymptomatic current chronic smokers and GOLD stage 0 COPD.
Chronic obstructive pulmonary disease (COPD) is associated with increased oxidative and nitrosative stress. The aim of our study was to assess the importance of these factors in the airways of healthy smokers and symptomatic smokers without airway obstruction, i.e. individuals with GOLD stage 0 COPD. ⋯ Our results clearly indicate that several markers of oxidative/nitrosative stress are increased in current cigarette smokers compared to non-smokers and no major differences can be observed in these biomarkers between non-symptomatic smokers and subjects with GOLD stage 0 COPD.
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Randomized Controlled Trial
Health status measurement in COPD: the minimal clinically important difference of the clinical COPD questionnaire.
Patient-reported outcomes (PRO) questionnaires are being increasingly used in COPD clinical studies. The challenge facing investigators is to determine what change is significant, ie what is the minimal clinically important difference (MCID). This study aimed to identify the MCID for the clinical COPD questionnaire (CCQ) in terms of patient referencing, criterion referencing, and by the standard error of measurement (SEM). ⋯ This investigation, which is the first to determine the MCID of a PRO questionnaire via more than one approach, indicates that the MCID of the CCQ total score is 0.4.