Worldwide, COPD is a major cause of morbidity and mortality. The clinical and functional manifestations of COPD result from lung injury occurring through various mechanisms, including oxidative stress, inflammation, protease-antiprotease imbalance and apoptosis. Oxidative stress is central to the pathogenesis of COPD, since it can directly damage lung structures and exacerbate the other mechanisms involved. The cellular and molecular events involved in such lung injury are believed to occur long before the clinical and functional expression of COPD. Although the use of bronchodilators is currently the principal treatment for COPD, bronchodilators have little or no effect on disease progression. A better understanding of the pathogenesis of COPD, together with renewed efforts in basic and clinical research, will allow the diagnosis of COPD at a pre-clinical stage and provide more appropriate monitoring of disease activity, as well as leading to the development of novel therapeutic agents that will effectively prevent the progression of the disease.

Keywords: Pulmonary disease, chronic obstructive; Oxidative stress; Oxidants; Antioxidants; Inflammation.

Objective: To evaluate the association between degree of asthma control and health-related quality of life in patients with moderate or severe asthma. Methods: This was a descriptive observational study involving 59 outpatients with moderate or severe asthma under treatment at the Asthma Outpatient Clinic of the Federal University of Ceará Walter Cantídio University Hospital, in the city of Fortaleza, Brazil. The patients were evaluated regarding sociodemographic and clinical characteristics, as well as spirometric parameters. The asthma control status was assessed using the asthma control test (ACT), and quality of life was assessed using the Saint George's Respiratory Questionnaire (SGRQ). Results: The mean age of the patients was 55.0 ± 12.4 years, and 76.3% were female. The ACT score showed statistically significant negative correlations with all SGRQ scores: total (r = −0.72); symptoms (r = −0.78); activity (r = −0.67); and impact (r = −0.68). Multiple regression analysis showed that the most robust predictive variables for SGRQ total score were ACT score (coefficient = −3.18; 95% CI: −4.14 to −2.23) and duration of disease (coefficient = −0.29; 95% CI: −0.54 to −0.03). The ACT score also explained the linear variation of the SGRQ domains: symptoms (coefficient = −3.41; 95% CI: −4.45 to −2.37); activity (coefficient = −3.07; 95% CI: −4.57 to −1.57); and impact (coefficient = −2.68; 95% CI: −3.71 to −1.65). Conclusions: The degree of asthma control appears to have a significant impact on health-related quality of life.

Keywords: Asthma/prevention and control; Quality of life; Questionnaires.