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

Abstract

The 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.

<p>Longitudinal comparison of outcomes in patients with smoking-related asthma-COPD overlap and in non-smoking asthmatics with incomplete reversibility of airway obstruction</p>

“…From the initial cohort of 75 patients with ACO and 40 patients with NS-IRAO who were the subject of the cross-sectional study,3 71 patients with ACO and all patients with NS-IRAO completed this 12-month follow-up study. The main characteristics are available in Table S1 of the online supplement while detailed phenotypic assessment of these patients have been published elsewhere 3…”

“…Two groups of asthmatic subjects with an IRAO were recruited from the asthma outpatient clinic of the Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval (IUCPQ-UL), a tertiary care center in Quebec city: 1) one composed of current smokers or ex-smokers (≥20 pack-years history of cigarette smoking), ACO and 2) one involving never-smokers or ex-smokers with a non-significant smoking history of less than five pack-years who had quitted smoking more than 12 months before study inclusion, NS-IRAO. Inclusion criteria and baseline evaluation have been reported previously 3. Briefly, we included patients aged 40 years and over, with a previous diagnosis of asthma based on the Canadian Thoracic Society criteria,4 who required inhaled corticosteroids with or without additional asthma medication, and who showed IRAO, as defined by persistence of a post-bronchodilator FEV 1 /FVC ratio <0.7 in addition to a FEV 1 less than 80% of predicted value on at least two occasions while on a treatment considered as optimal by a respirologist 4.…”

“…When patients demonstrate features of both asthma and COPD, they are often considered to have asthma-COPD overlap (ACO) 1,2. We previously showed that patients with ACO, defined as asthmatic patients with an IRAO and a significant smoking history, had a different phenotype compared to non-smoking asthmatic patients with IRAO 3…”

“…The clinical course of patients with smoking-related ACO remains, however, to be compared to that of non-smokers with IRAO (NS-IRAO), and these observations may have important implications for the clinical management of these patients. The present analysis is a 12-month longitudinal follow-up of patients with ACO or NS-IRAO who were the subject of an extensive cross-sectional phenotypic characterization 3. The present investigation was intended to specifically focus on the clinical outcomes of these two groups of asthmatics with emphasis on the frequency of exacerbations and symptom control.…”

Asthma-COPD Overlap (ACO) PRO-CON Debate. ACO: Call Me by My Name

“…non fully reversible airflow obstruction, reduction of diffusion capacity and emphysema on computed tomography scans. These individuals could be considered as having both asthma and COPD or an overlap (ACO) [14][15][16].…”