Bronchiectasis and increased mortality in patients with corticosteroid-dependent severe asthma: a nationwide population study

Background: Long-term corticosteroid (CS) use is associated with increased mortality in patients with asthma, and comorbid bronchiectasis is also associated with frequent asthma exacerbation and increased healthcare use. However, there is limited information on whether bronchiectasis further increases mortality in patients with CS-dependent asthma. This study examined the impact of bronchiectasis on mortality in patients with CS-dependent asthma. Methods: A retrospective cohort of patients with CS-dependent asthma > 18 years old was established using records from the Korean National Health Insurance Service database from 2005 to 2015. Patients with CS-dependent asthma with and without bronchiectasis were matched by age, sex, type of insurance, and Charlson comorbidity index. We evaluated the hazard ratio (HR) for all-cause mortality in patients with bronchiectasis compared with those without bronchiectasis. Results: The study cohort included 754 patients with CS-dependent asthma with bronchiectasis and 3016 patients with CS-dependent asthma without bronchiectasis. Patients with CS-dependent asthma with bronchiectasis had a higher all-cause mortality than those without bronchiectasis (8429/100,000versus6962/100,000 person-years, p < 0.001). The adjusted HR for mortality in patients with CS-dependent asthma with bronchiectasis relative to those without bronchiectasis was 1.33 (95% confidence interval, 1.18-1.50), and the association was primarily significant for respiratory diseases (subdistribution HR = 1.65, 95% confidence interval, 1.42-1.92). Conclusions: Bronchiectasis further increases all-cause mortality in patients with CS-dependent asthma, a trend that was especially associated with respiratory diseases including chronic obstructive pulmonary disease. Strategies to improve treatment outcomes in patients with CS-dependent asthma with bronchiectasis are urgently needed to improve long-term survival. The reviews of this paper are available via the supplemental material section.