Abstract
INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a progressive condition characterized by systemic inflammation, which leads to impaired respiratory function and a wide range of comorbidities. Mild cognitive impairment (MCI) has been identified as a precursor to dementia and is more prevalent in patients with COPD than in the general population. Pulmonary rehabilitation (PR) is recognized as the standard therapy for COPD in international guidelines; however, the frequency and long-term effects of PR remain insufficiently explored. We aimed to evaluate changes in MCI, physical function, physical activity, activities of daily living (ADL), mental health, and health-related quality of life (HRQOL) in male COPD patients with low-frequency outpatient PR once a month over a two-year period. METHODS: This retrospective, longitudinal study was conducted at a respiratory disease specialty hospital between April 2018 and September 2024. A total of 80 male patients with COPD were enrolled, of whom eight were excluded based on the exclusion criteria. Additionally, 51 patients who could not maintain PR for two years were also excluded, leaving 21 participants for the final analysis. Assessments included baseline characteristics, body composition, physical function, physical activity, cognitive function, frontal lobe function, HRQOL, ADL, and mental health. Outpatient PR sessions, conducted monthly in conjunction with physician consultations, included a 40-minute program consisting of exercise therapy, ADL guidance, and patient education. RESULTS: Significant reductions were observed in step counts (p = 0.048, d = 0.46) between baseline and two years. Significant reductions were observed in the ADL indices, specifically in the NRADL subdomains of movement speed (p = 0.007, d = -0.59), breath of shortness (p = 0.003, d = -0.64), oxygen flow (p = 0.035, d = -0.46), and the total score (p = 0.006, d = -0.46). No significant changes were observed in cognitive function, frontal lobe function, HRQOL, or psychological metrics. Reductions in the frequency of exacerbations and hospitalizations were observed in some patients, suggesting the stabilization of symptoms, particularly in specific Global Initiative for Chronic Obstructive Lung Disease (GOLD) categories and stages. DISCUSSION: While low-frequency PR over two years showed limited efficacy in maintaining physical activity levels and ADL, it contributed to symptom stabilization and a reduction in acute exacerbations. These findings suggest that monthly PR sessions are insufficient to achieve significant improvements in cognitive function or physical activity. High-frequency interventions may be required to optimize outcomes. Additionally, the challenges in maintaining long-term adherence to PR highlight the potential benefits of integrating home-based or telerehabilitation approaches into comprehensive intervention strategies.