Presence and sequence of bronchiectasis onset impact on the clinical characteristics in asthmatic patients

BACKGROUND: Asthmatic patients with comorbid bronchiectasis (ACB) show significantly severe condition with various inflammatory phenotypes; bronchiectasis is a heterogeneous disease caused by asthma and other multiple etiological factors. We aimed to investigate the inflammatory characteristics and their clinical significance in asthmatic patients according to the presence and onset time of bronchiectasis. METHODS: This prospective cohort study recruited outpatients with stable asthma. All the enrolled patients were divided into the non-bronchiectasis group and the ACB group, and the ACB group was separated into the bronchiectasis-prior group and the asthma-prior group. Demographic and clinical data were collected, and peripheral blood and induced sputum eosinophil counts, sputum pathogens, the fraction of exhaled nitric oxide (FeNO), lung function, and chest high-resolution computed tomography were examined. RESULTS: A total of 602 patients (mean age: 55.36±14.58 years) were included, of which 255 (42.4%) were males. Bronchiectasis was present in 268 (44.5%) patients, with 171 (28.41%) in the asthma-prior group and 97 (16.11%) in the bronchiectasis-prior group. For the asthma-prior group, the presence of bronchiectasis was positively correlated with age, presence of nasal polyps, severe asthma, ≥1 pneumonia in the last 12 months, ≥1 severe exacerbation of asthma in the last 12 months (SEA), peripheral blood eosinophil counts, and sputum eosinophil ratio; the extent and severity of bronchiectasis were positively correlated with ≥1 SEA and FeNO levels; and the bronchiectasis severity index (BSI) scores were positively correlated with ≥1 SEA and immunoglobulin E levels. For the bronchiectasis-prior group, bronchiectasis was positively correlated with previous pulmonary tuberculosis or pneumonia in childhood and ≥1 pneumonia in the last 12 months and negatively correlated with forced expiratory volume in one second (FEV(1)) % and the FeNO level. The extent and severity of bronchiectasis were positively correlated with ≥1 pneumonia in the last 12 months and negatively correlated with FEV(1)%. The BSI scores were positively correlated with the duration of bronchiectasis. CONCLUSIONS: The sequence of bronchiectasis onset may indicate distinct inflammatory characteristics and may be helpful in targeted therapy for patients with asthma.