Inspiratory muscle strength, diaphragmatic mobility, and body composition in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a systemic inflammatory disease that can cause repercussions on respiratory muscles and body composition. The aim of the current study was to evaluate inspiratory muscle strength, diaphragmatic mobility, and body composition in COPD subjects and to correlate these variables.

This was a cross-sectional study performed with 21 COPD patients. Inspiratory muscle strength (manovacuometry), pulmonary function test (forced vital capacity [FVC], forced expiratory volume in 1 s [FEV₁ ], and FEV₁ /FVC ratio), diaphragmatic mobility (ultrasonography), and body composition (bioelectrical impedance analysis) were examined.

COPD individuals in Stages II (28.9%), III (52%), and IV (19%) according to Global Initiative for Chronic Obstructive Disease were recruited, 61.9% of which were men. Inspiratory muscle weakness was found in 47.6% of subjects, who presented a lower fat-free mass percentage (p = 0.017) and smaller fat-free mass index (p = 0.001) and greater fat mass percentage (p = 0.029) and less diaphragmatic mobility (p = 0.007) compared with the nonrespiratory weakness group. Maximal inspiratory pressure exhibited a moderately positive relationship to the fat-free mass index (r = 0.767, p < 0.001) and a weak positive relationship to diaphragmatic mobility (r = 0.496, p = 0.022).

Our study showed a high prevalence of inspiratory muscle weakness based on the severity of airway obstruction and on the presence of muscular depletion. The evaluation of body composition detected important changes. It also demonstrated that not only muscular weakness was present in these patients but also this had repercussions on the mobility of the diaphragm muscle.