Inhaled Anticholinergics in Bronchiectasis: Prescribing Practices, Exacerbations, and Culture Data from the US Bronchiectasis and Nontuberculous Mycobacterium Research Registry

Abstract Introduction Inhaled anticholinergics (iAC) are commonly prescribed for patients with obstructive lung diseases, including asthma, COPD, and bronchiectasis. Herein we describe the prevalence of iAC prescriptions in patients with bronchiectasis (pwBE), and describe the association with sputum characteristics, exacerbation frequency and bacterial pathogen isolation at one year follow-up. Methods Patients enrolled in the US Bronchiectasis and Nontuberculous Mycobacteria (NTM) Research Registry (BRR) with available data on iAC use, sputum characteristics, exacerbations and bacterial culture results at baseline and follow-up were eligible. Patients with cystic fibrosis were excluded. Demographics, co-existing conditions, clinical characteristics, sputum volume, and exacerbations and culture positivity at follow-up were described for patients with and without iAC treatment (Table 1). Kruskal-Wallis, independent sample t-tests, and chi-square tests were used to assess differences in medians, means, and frequencies, respectively, between the two groups. Multivariable logistic regression analyses were used to determine the odds of bacterial culture positivity at follow-up among those prescribed anticholinergics at baseline after adjusting for baseline demographic and clinical characteristics. Results: 3421 pwBE met the inclusion criteria. 582 (17.0%) were treated with iAC. Overall, the median age (inter quartile range) was 70 (62.0 to 76.0) years, 79.6% female. At baseline, patients prescribed iAC were more likely to be current or former smokers, carry a diagnosis of asthma or COPD, have a lower FEV1, a higher BMI, and more likely to have had an exacerbation in the two years prior to enrollment (Table 1). Those prescribed iAC were more likely to have had at least one positive respiratory culture for Pseudomonas aeruginosa and had higher volumes of sputum expectoration. PwBE prescribed iAC were more likely to have experienced one or more exacerbations (49.2% vs. 39.5%, p=0.006) and have one or more sputum culture positive for pathogenic bacteria at annual follow-up (58.8% vs. 41.8%, p<0.001). After adjusting for all baseline covariates, the odds of at least one positive bacterial culture at follow-up was 1.5 times higher among those prescribed iAC at baseline compared to those who weren't (OR =1.46, 95% CI: 1.02-2.10, data not shown). Conclusion Overall, prescription prevalence of iAC in pwBE at baseline was 17.0%, and associated with higher daily sputum volume, positive bacterial cultures, exacerbation frequency, and a diagnosis of asthma or COPD. Isolation of an airway pathogen at follow-up was associated with use of iAC. Table 1. Baseline and Follow-up characteristics of pwNCFB prescribed or not prescribed inhaled anticholinergics.