Long‐term follow‐up of allergic bronchopulmonary aspergillosis treated with glucocorticoids: A study of 182 subjects

Abstract Background The long‐term outcomes of allergic bronchopulmonary aspergillosis (ABPA) are poorly characterised. Methods We retrospectively included treatment‐naïve subjects of acute stage ABPA‐complicating asthma from three randomised trials. All the subjects received oral prednisolone for 4 months and were monitored every 6 weeks for 6 months and then every 6 months. Our primary objective was to estimate the incidence rate and the frequency of subjects experiencing ABPA exacerbation. The key secondary objectives were to evaluate the factors predicting ABPA exacerbation and the changes in serum total IgE seen during treatment. Results We included 182 subjects. Eighty‐one (44.5%) patients experienced 120 exacerbations during 512 patient‐years of follow‐up. The incidence rate of ABPA exacerbations was 234/1000 patient‐years. Most (73/81, 90.1%) subjects experienced ABPA exacerbation within three years of stopping therapy. On multivariate logistic regression analysis, peripheral blood eosinophil count ≥1000 cells/μL (adjusted odds ratio [aOR] 2.43; 95% confidence interval (CI), 1.26–4.67), the extent of bronchiectasis (aOR 1.10; 95% CI, 1.03–1.18), age (aOR 0.97; 95% CI, 0.94–0.99), and female sex (aOR 2.16; 95% CI, 1.10–4.24) independently predicted ABPA exacerbation after adjusting for serum total IgE and high‐attenuation mucus. The best cut‐off for serum total IgE after 6 weeks for identifying treatment response and ABPA exacerbations was a 20% decline and a 50% increase, respectively. Conclusions ABPA exacerbations were common within 3 years of stopping treatment. Age, female sex, peripheral blood eosinophilia and the extent of bronchiectasis predicted ABPA exacerbations. The optimal serum total IgE cut‐off for defining ABPA response and exacerbations is a 20% decline and a 50% increase, respectively.