Determinants of respiratory muscle strength in adult bronchiectasis

Abstract

<b>Background:</b> Respiratory muscle strength is widely used as an outcome measure in pulmonary rehabilitation programs. It is known that bronchiectasis affects respiratory muscle strength which has a crucial role in the growth of symptoms and functional limitation. Therefore, it is important to identify the determinants of respiratory muscle strength in patients with non-cystic fibrosis (non-CF) bronchiectasis. <b>Aim:</b> To identify the determinants of respiratory muscle strength in patients with non-CF bronchiectasis. <b>Methods:</b> Forty-one patients with non-CF bronchiectasis were recruited in this cross-sectional study. Demographic and spirometric values were recorded. Maximal inspiratory pressure [MIP] and maximal expiratory pressure [MIP] were evaluated using an electronic mouth pressure device. Fat-free mass, exercise capacity, quadriceps strength, and physical activity were assessed. <b>Results:</b> The mean age of patients was 58.8 y. MIP and MEP were correlated with fat-free mass (MIP: r=0.507, p=0.001; MEP: r=0.669, p&lt;0.001), ISWT distance (MIP: r=0.374, p=0.01; MEP: r=0.396, p=0.01), quadriceps strength (MIP: r =0.511, p=0.001; MEP: r =0.508, p=0.001) and total energy expenditure (MIP: r=0.392, p=0.01; MEP: r=0.476, p=0.002). The multiple regression analysis revealed that fat-free mass and quadriceps strength were independent predictors of MIP, accounted for 32% of the variance. Fat-free mass was independent predictors of MEP, accounted for 45.9% of the variance. <b>Conclusions:</b> Fat-free mass and quadriceps strength were found as determinants of respiratory muscle strength in patients. Respiratory muscle strength may be increased by improving fat-free mass and quadriceps strength in adult non-CF bronchiectasis.