Influence of respiratory function parameters on the quality of life of COPD patients* Influência dos parâmetros funcionais respiratórios na qualidade de vida de pacientes com DPOC

Objective: To determine the quality of life of COPD patients by using the Medical Outcomes 36-item Short-Form Survey (SF-36) and the Saint George’s Respiratory Questionnaire (SGRQ), correlating the scores with respiratory function parameters. Methods: This was a cross-sectional study involving 42 COPD patients. We used the SGRQ (a specific questionnaire) and the SF-36 (a general questionnaire), together with their component summaries, in order to determine the quality of life of these patients. The functional profile was assessed by means of spirometry, arterial blood gas analysis and the six-minute walk test. Results: Of the 42 patients, 30 (71.4%) were male and 12 (28.6%) were female. The mean age of the patients was 65.4 ± 8.0 years. The mean physical component summary and mean mental component summary scores were 37.05 ± 11.19 and 45.61 ± 15.65, respectively. The physical component summary correlated significantly with FEV1 in L/s (r = 0.38; p = 0.012). There was a correlation between the SGRQ total score and FEV1 (r = −0.50; p < 0.01). The SGRQ activity domain showed negative correlations with all respiratory function parameters. The multiple regression analysis showed that only FEV1 correlated significantly with the SGRQ total score, as well as with the activity domain score (r= −0.32; p = 0.04 and r = −0.34; p = 0.03, respectively). Conclusions: In COPD patients, a decline in FEV1 is associated with poorer quality of life, as evaluated using the SGRQ.