Asthma COPD overlap: Impact of associated comorbidities

Asthma and chronic obstructive pulmonary disease (COPD) are common chronic pulmonary conditions worldwide which often coexist. Patients with asthma COPD overlap (ACO) may have worse outcomes than those with either disease alone, for example, more respiratory symptoms and frequent exacerbations, and worse lung function. Additionally, there is a growing interest in factors that affect the disease including comorbid conditions. Indeed, recent studies have demonstrated higher rates of comorbid conditions in the ACO population, but the mechanisms behind these observations remain unclear. The objective of this review is to describe current knowledge and clinical implications of the overlapping features of asthma and COPD, and discuss the prevalence and impact of comorbidities, such as osteoporosis, cardiovascular disease, gastroesophageal reflux disease, and depression, in this subgroup of patients.