Impact of obstructive sleep apnea on functional performance and muscle quality of patients with COPD

This study investigated the association between nocturnal oxygen desaturation, muscle quality, and functional performance in individuals with Chronic Obstructive Pulmonary Disease (COPD), with and without coexisting Obstructive Sleep Apnea (OSAS). Forty-four participants (COPD: n = 22; COPD-OSAS: n = 22) underwent a standardized three-day evaluation protocol comprising: (1) clinical assessment, body composition analysis, and pulmonary function testing; (2) cardiac function evaluation and home sleep monitoring; and (3) handgrip strength (HGS) and six-minute walk test (6MWT). Muscle quality was operationalized as the ratio between appendicular skeletal muscle mass and isometric strength. Sleep parameters, including the apnea-hypopnea index (AHI) and oxygen desaturation index (ODI), were obtained via home polysomnography. Patients with COPD-OSAS showed significantly reduced 6MWT distance and HGS values compared with those with isolated COPD (p < 0.05). Indices of sleep-disordered breathing exhibited significant inverse associations with functional performance and muscle quality. In multivariable regression, sex, AHI, and ODI were identified as independent predictors of muscle quality, with ODI representing the strongest contributor after adjustment. These findings indicate that individuals with COPD-OSAS present greater impairments in muscle quality and physical performance, and that hypoxic burden is closely related to these outcomes. Further studies with larger cohorts and longitudinal designs are needed to elucidate underlying mechanisms and to determine the long-term clinical implications of these associations.