Date of Award


Degree Name

Master of Science (MS)



Second Advisor


Third Advisor



Chronic Obstructive Pulmonary Disease (COPD) is a debilitating and degenerative lung disease characterized by progressive airway obstruction and alveolar destruction. When asthma and COPD co-occur and interact, with asthma having been diagnosed first, the resulting respiratory disease is called Asthma-COPD Overlap Syndrome (ACOS). Current research suggests that persons with ACOS may have more severe respiratory disease and lifestyle limitations than those with either disease alone. The purpose of the current study was to determine if and how disease progression differs in patients with ACOS versus COPD only, using data collected during the COPDGene cohort study. Demographic characteristics and disease outcome measures were compared at baseline and five-year follow-up for patients with ACOS versus COPD only. Changes in these metrics were compared using multiple linear regression and multinomial logistic regression models controlling for BMI, pack-years of smoking, gender, race, age, and current smoking status. The prevalence of ACOS in the current study population was 8.5%. Overall, subjects with ACOS were younger, had less pack-years of smoking, were more likely to be female, and were more likely to be of non-white race compared with subjects with COPD only. Subjects with ACOS had lower quality of life scores, larger bronchodilator responses and forced vital capacities, less emphysema, and were more likely to experience severe COPD exacerbations at both study visits. However, changes in disease outcomes over a five-year period were very similar between the two groups, with the exception of frequent exacerbation status and bronchodilator response (BDR) status. Subjects with ACOS were less likely to experience frequent COPD exacerbations, and also less likely to display a bronchodilator response after the follow-up period, compared with subjects with COPD alone. The reduction of frequent COPD exacerbations in patients with ACOS suggests that treatment strategies currently used to treat asthma may have a positive effect on COPD, while the reduction in the frequency of BDRs in these patients suggests that understanding the inflammatory response in ACOS and preventing the associated airway remodeling may be important topics for future research