A Study of Heterogeneity of Chronic Obstructive Pulmonary Disease

Abstract

Objective: Chronic obstructive pulmonary disease (COPD) is responsible for significant morbidity and mortality worldwide. We evaluated the characteristics of stable COPD patients in the pulmonology clinics of southern Taiwan and also evaluated whether the exposure to biomass fuels and dusty jobs were related to respiratory symptoms, airflow limitation, and quality of life in the COPD patients. Methods: This cross-sectional observational study recruited 117 COPD patients from southern Taiwan. The patients underwent spirometry and were administered questionnaires about their exposure to cigarette smoking, biomass fuels, and dusty jobs in addition to respiratory symptoms and health related quality of life. Results: Of the patients, there appeared to be variations in the history of exposure to biomass fuels and dusty jobs and also in respiratory symptoms of cough, phlegm, wheeze, and dyspnea. These symptoms were more frequent in those COPD patients with a higher global initiative for chronic obstructive pulmonary disease (GOLD) stage (p ＜ 0.001 for all comparisons). The quality of life was poorer in those with a higher GOLD stage (44.3 vs. 35.6 vs. 27.3 vs. 14.5 of the St George’s Respiratory Questionnaire [SGRQ] total score, p ＜ 0.001). Dyspnea was more frequent in those COPD patients with a history of exposure to biomass fuels than without and those with a history of exposure to dusty jobs than without (p ＜ 0.05 for both comparisons). Airflow limitation was more severe in those COPD patients with a history of exposure to dusty jobs than without (43.6% predicted versus 50.7% of post-bronchodilator forced expiratory volume in 1 second [FEV1], P ＜ 0.05). Conclusions: In southern Taiwan, the characteristics of COPD patients vary and the history of exposure to biomass fuels or dusty jobs was related to frequency of dyspnea, while the history of exposure to dusty jobs was related to severe airflow limitation. The frequent symptoms and poor quality of life were related to higher GOLD stages.