Baseline Dyspnea Associated With Risk for Severe Features of Bronchiectasis Phenotype in the US Bronchiectasis and Nontuberculous Mycobacterium Research Registry

Abstract Introduction Persistent dyspnea increases the risk of disability and impairs quality of life in older patients with bronchiectasis. The impact of dyspnea and fatigue on patients with bronchiectasis in long term follow-up has not been adequately established. We sought to determine if fatigue and higher-grade dyspnea are associated with worse clinical outcomes in 5-years of longitudinal follow-up. Methods We analyzed data collected from a prospective cohort of adult patients with bronchiectasis enrolled in the US Bronchiectasis and Nontuberculous Mycobacteria Research Registry. Patients with a modified Medical Research Council (mMRC) dyspnea score collected at baseline and during 3-5 years of follow-up were included and stratified as mMRC<2 versus mMRC ≥2. Kruskal-Wallis, independent sample t-tests and chi-square tests were used to test the differences in medians and means for continuous variables and associations between categorical variables, respectively, between the baseline mMRC groups and bronchiectasis severity index (BSI) components at follow-up. A multivariable logistic regression analysis was performed to determine the association between dyspnea and clinical outcomes (exacerbations and hospitalizations) at follow-up. Results 1185 adult patients with bronchiectasis met the inclusion criteria. The median age (interquartile range) was 76 (68 to 83) years. At baseline, patients with mMRC ≥2 had a higher proportion of co-existing diagnoses such as asthma, chronic obstructive pulmonary disease (COPD), otitis/rhinosinusitis, rheumatologic disease, and pneumonia compared to patients with mMRC <2 (all p<0.05, data not shown). Furthermore, patients with mMRC > 2 compared to patients with mMRC <2 had higher prevalence of fatigue, acute exacerbations and pulmonary related hospitalizations, and lower mean percentage predicted forced expiratory volume in one second (FEV1) at follow-up (all p< 0.05) (Table 1). Interestingly, body mass index was slightly higher among those with baseline mMRC ≥2 compared to mMRC <2 (p=0.02). Among those with mMRC ≥2 at both baseline and follow-up (n=67, 42%), the odds of having ≥1 exacerbation was 2.4 times higher (odds ratio [OR] 2.45, 95% confidence interval [CI] 1.45-4.1) and 2.8 times higher for ≥1 hospitalization (OR 2.8, 95% CI 1.45-5.2) during follow-up after adjusting for fatigue. Conclusion Elevated dyspnea was associated with a greater proportion of patients with bronchiectasis exhibiting acute exacerbations and pulmonary related hospitalizations and lower lung function during follow-up. Research is still needed to understand the causes (drivers) of dyspnea to implement better treatment strategies and reduce adverse outcomes in bronchiectasis patients.