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

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

Methods: Hospitalization data was extracted from the Healthcare Cost and Utilization Project Nationwide Readmissions Database (HCUP-NRD 2012-2015). Using ICD-9-CM 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.

Results: 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 vs. 69 years old, p< 0.05), with a higher rate of respiratory failure and increased hospital length-of-stay (LOS). Index admission mortality was higher in patients with COPD (adjusted 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, 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%).

Conclusion: While ACO was associated with higher rates of baseline comorbidities, increased length of stay and higher healthcare 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.