Asthma-COPD Overlap Phenotypes and Smoking :Comparative features of asthma in smoking or non-smoking patients with an incomplete reversibility of airway obstruction

Abstract

ABSTRACTThe development of COPD features, such as an incomplete reversibility of airway obstruction (IRAO), in smoking or non-smoking asthmatic patients, a condition often named Asthma-COPD Overlap (ACO), has been recognized for decades. However, there is a need to know more about the sub-phenotypes of this condition according to smoking.This study aimed at comparing the clinical, physiological and inflammatory features of smoking and non-smoking asthmatic patients exhibiting IRAO.In this cross-sectional study, patients with an IRAO with (ACO, ≥20 pack-years) or without (NS-IRAO, <5 pack-years) significant smoking history completed questionnaires about asthma control (ACQ, score 0–6, 6 = better score) and quality of life (AQLQ, score 1–7, 1 = better score) and performed expiratory flows, lung volume and carbon monoxide diffusion capacity measurements. Blood sampling and induced sputum were obtained for systemic and lower airway inflammation assessment.A total of 115 asthmatic patients were included (75 ACO: age 61 ± 10 years, 60% women and 40 NS-IRAO: age 64 ± 9 years, 38% women). ACO patients had worse asthma control scores (1.8 ± 0.9 vs 1.4 ± 0.9, P = 0.02) and poorer asthma quality of life (5.3 ± 1.0 vs 5.9 ± 1.0, P = 0.003). In addition, ACO had higher residual volume (145 ± 45 vs 121 ± 29% predicted, P = 0.008) and a lower carbon monoxide diffusing capacity corrected for alveolar volume (90 ± 22 vs 108 ± 20% predicted, P = 0.0008). No significant differences were observed in systemic or lower airway inflammation.In conclusion, in smokers and non-smokers, the presence of IRAO in asthmatics is associated with different phenotypes that reflect the addition of smoking-induced changes to asthma physiopathology.