Interstitial changes in asthma-COPD overlap syndrome.

Introduction Asthma-COPD overlap syndrome(ACOS) is the widely recognized syndrome of asthma and COPD coexisting together. Cigarette smoking is a known risk factor for ACOS and is reported to be associated with interstitial lung diseases(ILDs). Subclinical ILDs have been frequently detected in smokers’ lungsby radiological and pathological examinations. This finding raises the possibility that unrecognized mild interstitial changes take place in lungs with ACOS. Objectives We sought to determine whether interstitial changes were present in the lungs of patients with ACOS and to characterize the clinical features of ACOS with interstitial changes. Methods Thirty patients with ACOS were enrolled in the study (26 men and 4 women, mean age 70.1 years). Interstitial changes in the lungs were estimated by high-resolution computed tomography(HRCT). Clinical findings and airway wall thickness on HRCT were assessed retrospectively and compared between ACOS patients with and without interstitial changes. Results Interstitial changes were found in seven patients (23.3%) with ACOS who had HRCT. The age and smoking amount were significantly higher in ACOS with interstitial changes than in ACOS without interstitial changes. ACOS with interstitial changes tended to have a higher rate of fungal sensitisation. Multivariate analysis showed pack-yearswere significantly related to the presence of interstitial changes. Airway walls assessed by HRCT were significantly thicker in ACOS with interstitial changes than in ACOS without interstitial changes. Conclusions The ACOS patients with interstitial changes were heavier smokers and had thicker airway walls on HRCT compared to the ACOS patients without interstitial changes.