Abstract
Background: Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by significant physical and psychological burdens. However, the influence of the disease's severity on psychological factors and functional outcomes remains unclear. This study aimed to investigate the impact of disease severity on psychological factors and functional outcomes in patients with moderate and severe COPD. Methods: This cross-sectional study included 98 patients with moderate (n = 44) or severe (n = 54) COPD. Anxiety and depression, guilt and shame, self-compassion, self-efficacy (PRAISE), and fear of negative evaluation were assessed. Functional capacity was evaluated with the six minute walk test (6MWT), and disease impact was assessed via the COPD assessment test (CAT). Lung function was measured through post-bronchodilator spirometry. Results: Compared with those with moderate COPD, those with severe COPD presented significantly greater levels of guilt (12 vs. 10; p < 0.01), anxiety (10 vs. 6.5; p < 0.01), and depression (7.5 vs. 6; p = 0.06). Self-compassion was significantly lower in the severe group (3.16 vs. 3.41; p < 0.01), whereas shame and fear of negative evaluation scores were similar between the groups. The functional capacity was significantly reduced in patients with severe COPD (217.04 ± 70.16 m vs. 286.46 ± 77.92 m; p < 0.01). Disease impact and dyspnea (CAT, mMRC) were worse in severe cases (p < 0.01). Conclusions: Patients with severe COPD presented significantly greater levels of guilt, anxiety, and depression, alongside lower self-compassion, worse functional outcomes, and poorer health-related quality of life, compared to those with moderate COPD.