RESUMO
BACKGROUND: Given that airway obstruction in asthma is not always fully reversible, reduced bronchodilator reversibility (BDR) may be a special asthma phenotype. OBJECTIVE: To explore the characteristics of BDRhigh/low phenotypes (defined using two BDR criteria) and their associations with asthma exacerbations (AEs). METHODS: After baseline assessments, all patients were classified into BDRhigh or BDRlow phenotypes. This study consisted of 2 parts. Part I was a 12-month prospective observational cohort study designed to identify the clinical characteristics and associations with future AEs in BDRhigh/low phenotypes (n = 456). Part II, designed as a post hoc analysis of the data obtained in Part I, was conducted to assess the association between BDRhigh/low phenotypes and treatment responsiveness (n = 360). RESULTS: Subjects with BDRlow phenotypes had better baseline asthma symptom control and was negatively associated with eosinophilic asthma and type 2 (T2) high asthma. During the 12-month follow-up, those with BDRlow phenotypes had a higher risk of severe AEs (SAEs) (guideline-based criterion: RRadj = 2.24, 95% CI = [1.25, 3.68]; Ward's criterion: RRadj = 2.46, 95% CI = [1.40, 4.00]) and moderate-to-severe AEs (MSAEs) (guideline-based criterion: RRadj = 1.83, 95% CI = [1.22, 2.56]; Ward's criterion: RRadj = 1.94, 95% CI = [1.32, 2.68]) in the following year according to logistic regression models. Similar findings were obtained with negative binominal regression models. BDRlow phenotype was a risk factor for an insensitive response to anti-asthma treatment (guideline-based criterion: ORadj = 1.96, 95% CI = [1.05, 3.65]; Ward's criterion: ORadj = 2.01, 95% CI = [1.12, 3.58]). CONCLUSION: We identified that BDRlow phenotype was associated with non-T2 high asthma and future AEs. These findings have clinically relevant implications for asthma management.
