The influence of bronchial asthma as a comorbidity of COPD on the COPD assessment test (CAT)

Introduction: Bronchial asthma (BA) represents features similar to Chronic Obstructive Pulmonary Disease (COPD). Despite, in intervention study, distinction from one another is required which may lead to a study population dissociated from that we face in clinical practice. The concept that these two disease actually coexist in one airway has become widely accepted. The aim of this study is to see if BA as a comorbidity of COPD has affected the COPD assessment test (CAT). Methods: Records of Total 75 COPD patients who entered the University of Tokyo Hospital from 2012 onwards were analyzed. Results: Out of 20 patients who were diagnosed as having BA alongside with COPD (COPD/BA+) by their respective attending physicians, 16 had inhaled corticosteroid (ICS) when CAT was performed. Ratio of patients who met the criteria of CAT≥10 was 0.60 for both COPD patients without BA (COPD/BA-) and COPD/BA+, 12.7 ± 0.89 (mean ± SEM) and 12.3 ± 1.6, respectively. The ratio was 0.56 (11.9 ± 1.87) for COPD/BA+ with ICS (ICS+) and 0.75 (13.8 ± 3.3) for COPD/BA+ without ICS (ICS-). Whilst, in COPD/BA- patients, it was 0.80 (14.7 ± 1.95) for ICS+ and 0.52 (12.2 ± 1.28) for ICS-. ΔCAT (CAT maximum−CAT minimum) was evaluated for 35 patients whose CAT was followed up for over 6 months. In COPD/BA-, ΔCAT was 7.5 ± 1.91 and 5.93 ± 1.27, for ICS+ and ICS- respectively. In COPD/BA+, it was 5.57 ± 0.48 and 9.33 ± 3.67 for ICS+ and ICS- respectively. Conclusion: Our preliminary data seems to suggest that CAT of COPD/BA+ is more susceptible to ICS compared to COPD/BA-. We will further process this cohort analysis in desire to have a better understanding of COPD patients associated with BA.