Skeletal Muscle Function in Relation to COPD Severity and Its Predictive Significance for Disease Progression.

Purpose: To compare skeletal muscle function levels in different COPD severities and explore their relationship with COPD severity and progression. Patients and Methods: The study included COPD patients from the First People's Hospital of Shuangliu District, Chengdu between May 2021 and May 2022, categorized into mild, moderate, severe and very severe groups based on FEV1%. Skeletal muscle function (quadriceps strength, respiratory muscle strength, 6MWD) was compared among these groups. Patients were followed up to assess disease progression, and logistic regression was used to analyze the predictive value of skeletal muscle function for COPD progression. Results: Among the 400 subjects, respiratory muscle strength, quadriceps strength, and 6MWD were all higher in the nonsmoking group than in the smoking group, with the mild group better than the moderate group, the moderate group better than the severe group, males stronger than females, the MMRC score ≤ 2 group better than the >2 group, and strength greater in the age ≤ 70 group than in the age >70 group. The mild group had a higher 6MWD than the moderate group, the moderate group was better than the severe group, non-smokers had a higher 6MWD than smokers, and the difference between males and females was greater with statistical significance. There are differences in quadriceps strength, respiratory strength, and 6MWD within the progression group. Logistic regression analysis showed that respiratory muscle strength, quadriceps strength, 6MWD, and COPD severity were risk factors for COPD progression (P < 0.05). Conclusion: COPD patients show skeletal muscle dysfunction that worsens with disease severity. Respiratory muscle strength, quadriceps strength, 6MWD, and COPD severity predict COPD prognosis.