Chronic obstructive pulmonary diseases (COPD) is one of the leading cause of death and is increasing in incidence. The forced expiratory volume in one second (FEV1) is usually used to grade the clinical severity of COPD. However, assessment of functional capacity is also important to understand clinical state of patients. The aim of this study was thus to retrospectively examine what factors reflects clinical stability in patients with COPD.
Twenty-six patients with COPD volunteered and completed the test sequence, which included pulmonary function tests, 6-minute walk distance (6-MWD), complete blood count, blood chemistry, blood pressure, and body mass index. The patients were divided into two groups, stable and unstable group, according to the presence of acute exacerbation history during last one year. After dividing, we retrospectively validated factors that reflect clinical stability of patients.
At presentation, Mean age of 26 patients was 65.3 ± 9.0 years (mean ± SD). Sixteen patients were included in stable group and 10 patients in unstable group. FEV1 was 63.3 ± 20.6% for stable group and 46.9 ± 9.4 for unstable group (p=0.02). Mean 6-MWD was 461.9 ± 88.3 meter and 298.0 ± 72.1 meter respectively (p<0.01). The number of patients in each stage based on Global Initiative of Obstructive Lung Diseases (GOLD) showed significant difference between two groups (p=0.03) and number of patients who walked more than 400 meter was 13 out of 16 for stable group and no one for unstable group (p<0.001). 6-MWD and stage of COPD showed significant correlation (p<0.01).
6-MWD, a simple test to evaluate clinical status, showed significant correlation with GOLD stage of COPD. Multidimensional approach should be done to evaluate clinical stability.
For the evaluation of severity of COPD, not only the degree of airflow limitation but also functional status such as 6-MWD should be included.
Jee-Hong Yoo, None.