Hospitalization Outcomes of Patients with Asthma, COPD, and Asthma-COPD Overlap Syndrome

Chronic obstructive pulmonary disease (COPD) and asthma account for a significant health care burden within the United States. The asthma-COPD overlap (ACO) phenotype has been associated with increased exacerbation frequency and health care utilization compared to either disease alone. However, hospital-based outcomes of these diagnoses have not been described in the literature.

Hospitalization data were extracted from the Healthcare Cost and Utilization Project Nationwide Readmissions Database (HCUP-NRD 2012-2015). Using International Classification of Diseases, Ninth Revision, Clinical Modification codes, we classified patients as having asthma, COPD, or ACO. We used analytic sample weights to compute national estimates, and weighted regression analyses to evaluate hospitalization outcomes.

Of 2,522,013 patients reviewed, 1,732,946 (68.7%) had COPD, 668,867 (26.5%) had asthma, and 120,200 (4.8%) had ACO. Patients with ACO were younger than those with COPD (63 versus 69 years old, p< 0.05), with a higher rate of respiratory failure and an increased hospital length of stay. Index admission mortality was higher in patients with COPD (adjusted odds ratios [OR] [95%]: 2.10 [1.84; 2.40]) and asthma (adjusted OR [95%]: 1.59 [1.38; 1.83]) as compared to those with ACO. However, the all-cause readmission rate was higher in the COPD group (15.7%) but not in the asthma group (10.7%) as compared to the ACO group (11.5%).

While ACO was associated with higher rates of baseline comorbidities, increased length of stay, and higher health care cost during index admission, this did not translate into higher in-hospital mortality, complication rates, or risk for asthma-related readmission mortality when compared to asthma or COPD alone, highlighting the complexity of the ACO disease burden.