Characteristics of Patients with Idiopathic Bronchiectasis in Comparison to Post-infectious Bronchiectasis in South Korea

BACKGROUND: Bronchiectasis has a complex and heterogeneous pathogenesis, with various etiologies, the majority being idiopathic. This study aimed to examine the characteristics of patients with idiopathic bronchiectasis in comparison to those with post-infectious bronchiectasis. METHODS: We analyzed data from patients with idiopathic and post-infectious bronchiectasis (including post-tuberculosis) from the Korean Multicenter Bronchiectasis Audit and Research Collaboration (KMBARC) registry, a prospective cohort study. RESULTS: Among the 866 patients enrolled in the study, 346 (40.0%) were classified as having idiopathic bronchiectasis, while 363 (41.9%) had post-infectious bronchiectasis. The idiopathic group demonstrated a shorter disease duration, a higher body mass index (BMI), a lower prevalence of chronic obstructive pulmonary disease (COPD), a higher prevalence of rhinosinusitis, a predominance of lower lobe distribution, less frequent use of regular respiratory treatments, better pulmonary function, and a statistically lower bronchiectasis severity index compared to the post-infectious group. A multivariable logistic regression analysis was conducted, considering factors such as gender, age, BMI, history of asthma, COPD, rhinosinusitis, rheumatoid arthritis, gastroesophageal reflux disease, and smoking status. A higher BMI (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.04 to 1.15) and a history of rhinosinusitis (OR, 3.10; 95% CI, 1.57 to 6.14) were associated with idiopathic bronchiectasis. In contrast, a history of COPD was linked to post-infectious bronchiectasis (OR, 0.57; 95% CI, 0.41 to 0.80). CONCLUSION: Patients with idiopathic bronchiectasis are characterized by a higher BMI and a history of rhinosinusitis compared to those with post-infectious bronchiectasis. These findings may provide exploratory insights into underlying systemic or non-pulmonary factors. Further research is necessary to clarify the clinical significance of these associations.