Evaluation of the relationship between the parameters of peripheral skeletal and respiratory muscles in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a group of diseases with high levels of comorbidity. Pathological changes of peripheral skeletal and respiratory muscles in COPD patients, which are often underestimated, occupy a special place.

Aim. To study the relationship between functional and quantitative parameters of the peripheral (limb muscle) and respiratory muscles in COPD patients.

Materials and methods. 127 patients (98 men/29 women, mean age 67.6±8.2 years) were under observation without acute COPD. All COPD patients were classified according to GOLD (2019) into groups A, B, C, D. The algorithm of the European Working Group on Sarcopenia in Older People (EWGSOP2) was used to diagnose sarcopenia. The muscle mass was measured using dual energy X-ray absorptiometry (DXA) and the appendicular lean mass index (ASM) was estimated. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured by body plethysmograph MasterScreen Body. Quantitative assessment of thoracic muscle cross-sectional areas were performed using the CT scan using Vidar Dicom Viewer software.

Results. Sarcopenia was diagnosed in 43.3% of COPD patients. Respiratory muscle dysfunction was determined in 66.1% of patients with COPD, its probability increased in groups C and D in comparison with groups A and B [chance ratio 6.6 (95% confidence interval 2.9–15.0); p<0.0001]. Correlations between the functional parameters of sarcopenia and respiratory muscle strength as well as between the mass of peripheral skeletal muscles and respiratory muscle area have been established according to the data of computerized tomography (р<0.01). Sarcopenia as well as respiratory muscle dysfunction was observed more frequently in persons with severe and extremely severe airway obstruction and in patients with predominantly emphysematic COPD phenotype (p<0.01).

Conclusion. Sarcopenia is a frequent comorbidity in COPD and its development is connected with the severity of the course of the main disease. Correlation between parameters of peripheral (limb muscle) and respiratory muscles in patients with COPD has been determined.