The Role of Smoking in Asthma and Chronic Obstructive Pulmonary Disease Overlap

Exposure to cigarette smoke has a key role in the development, adverse health outcomes, and impaired response to some therapies among individuals with features of asthma and chronic obstructive pulmonary disease overlap (ACO). To aid the identification of clinical subtypes, the description of ever smokers with features of asthma and COPD should include data on smoking status, cumulative smoking history, and the phenotype of asthma and smoking-related chronic airway disease. Pathogenic mechanisms in smoking-related ACO involve poorly understood, complex interactions between smoking-induced and asthma-induced airway inflammation, corticosteroid insensitivity, and tissue remodeling. Evidence for the clinical effectiveness of interventions for adults with smoking-related ACO is limited. Management currently involves the identification and targeting of treatable traits such as current smoking, type 2 high eosinophilic inflammation, symptomatic airflow obstruction, and extrapulmonary comorbidities.