Exacerbation of chronic obstructive pulmonary diseases as a risk factor of the skeletal muscle dysfunction

Exacerbation of Chronic Obstructive Pulmonary Disease (COPD) contributes to increased systemic inflammation, oxidative stress, hypoxia, hypercapnia and other risk factors of the skeletal muscle dysfunction. This study aimed to determine whether the frequency of the COPD exacerbations promotes deterioration of the skeletal muscle dysfunction in patients with COPD and to figure out which characteristics of the muscles will reflect this changes. We examined 98 male COPD patients, mean age 60.4±11.2 years, GOLD groups B, C, D. To assess the degree of skeletal muscle dysfunction we used hand-grip strength, 6-minute walk test, bioelectrical impedance analysis. Quality of life was evaluated using St. George's respiratory questionnaire (SGRQ). Increase in the frequency of COPD exacerbations was associated with the decrease in the 6-minute walk test distance (r= -0.214, P = 0.034) and with the rise of sarcopenia according to the results of bioelectrical impedance analysis - lower fat-free mass index (r = -0.201, P = 0.047). Frequency of COPD exacerbations had a weak correlation with the degree of the activity limitation component of SGRQ (r = 0.436, P < 0.001). COPD exacerbation plays an important role in progression of the skeletal muscle dysfunction. It decreases endurance of the skeletal muscles, diminishing their size, which manifests itself in reduced exercise tolerance. Increase in the frequency of the COPD exacerbations also worsens all components of the life quality.