Characteristics and Prevalence of Asthma/Chronic Obstructive Pulmonary Disease Overlap in the United States

The asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) occurs in patients with fixed airway obstruction that defines COPD and with symptoms more typical of asthma. ACOS prevalence and the comorbidities associated with this syndrome have been inadequately characterized. Because this population is prone to more frequent exacerbations, we hypothesized that comorbidities associated with ACOS are higher than those with COPD, asthma, and control populations in the United States. We examined the self-reported demographics, smoking status, comorbidities, and hospitalization or emergency department (ED) visitation experience among study respondents older than 35 years of age (n = 90,851) in the Behavioral Risk Factor Surveillance System survey and compared participants with ACOS to COPD, asthma, and control groups. We used logistic regression to compare ACOS and COPD populations to model the impact of comorbid conditions and hospitalization/ED visits after adjusting for demographic factors and smoking status to generate odds ratios and confidence intervals. The U.S. prevalence of ACOS was 3.2%, COPD alone was 6.0%, and both increased with age. Respondents with ACOS were younger (64.0 ± 11.7 yr) than respondents with COPD (67.1 ± 11.8 yr) and older than respondents with asthma (59.0 ± 13.1 yr; P