Differences in physical function, self-efficacy, and health-related quality of life by disease severity in community-dwelling patients with chronic obstructive pulmonary disease

Abstract

Purpose: This study investigated the differences in physical function, self-efficacy (SE), and health-related quality of life (HRQoL) categorized by disease severity in community-dwelling patients with chronic obstructive pulmonary disease (COPD). Methods: This cross-sectional study included 182 patients with COPD selected from the pulmonology outpatient department of a tertiary hospital. Disease severity was measured using forced expiratory volume in 1 second (FEV1). Physical function, SE, and HRQoL were measured with the six-minute walking distance, pulmonary rehabilitation self-efficacy (PRAISE), and St. George's Respiratory Questionnaire (SGRQ). Disease duration, FEV1, and 12-month history of exacerbations were obtained from medical records. Patients were categorized by Global Initiative for Chronic Obstructive Lung Disease (GOLD) category. Data were analyzed using the two-sample t-test, χ2 test, and one-way ANOVA. Results: Most of the participants were male and nonsmokers. The disease duration was 10.76 ± 10.03 years, the mean FEV1% was 62.13 ± 22.80, and 70.3% of the participants were in GOLD category 2 (moderate) or milder. Half of the participants reported modified Medical Research Council scores ≥ 2. Patients in GOLD categories 1 and 3 (mild and severe) exhibited significantly higher PRAISE scores than those in the other groups (F = 8.23, p < .001). The total SGRQ scores were highest in GOLD 4 (very severe), indicating the lowest HRQoL. Significant differences were identified among GOLD 1, GOLD 2 and 3, and GOLD 4 (F = 9.92, p < .001). Conclusion: We identified potentially useful variables to comprehensively assess disease severity and tailor management strategies, including airflow limitation, and to determine the consequences of COPD from patients’ perspectives.