Effects of umeclidinium bromide in the management of small airway disease: a pilot study

Umeclidinium bromide is a long-acting muscarinic antagonist that selectively inhibits muscarinic receptors, preventing bronchoconstriction and promoting sustained bronchodilation. This study aimed to assess the bronchodilatory efficacy of umeclidinium bromide, specifically in terms of its impact on airflow limitation, exertional dyspnea, and indices of lung hyperinflation. We analyzed 50 patients (21 males, 29 females) with a mean age of 67.3±9.59 years, all presenting with a preserved Tiffenau Index [forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC): 74.49±2.58%] but reduced forced mid-expiratory flow [forced mid-expiratory flow (FEF25-75): 37.85%±7.04%]. Patients exhibited an increased Motley Index ratio (135.24±9.78%), a mean FEV1 of 2.00±0.57 L, an FVC of 2.70±0.57 L, an airway resistance (Raw) of 225.52±56.66%, and a total lung capacity of 98.08±8.26%. Functional exercise capacity was evaluated using the 6-minute walking test (6MWT), with a mean distance of 308.48±31.91 m. Dyspnea severity was assessed using the modified Medical Research Council dyspnea scale (mMRC) (mean score: 1.80±0.73). Post-treatment assessments demonstrated a significant increase in FVC (p=0.04), FEF25-75 (p<0.001), and a significant decrease in total airway resistance (p<0.001), along with a marked reduction in the Motley Index ratio (p<0.001). Patients exhibited an increase in the distance covered during the 6MWT (p<0.001) and a reduction in dyspnea severity, as reflected by improvements in the mMRC scale (p<0.001). Umeclidinium bromide was effective in mitigating lung hyperinflation, improving exercise capacity, and reducing dyspnea.