Background: An international consensus aimed at standardizing the definition of bronchiectasis(BE) and COPD overlap has recently been published. The ROSE criteria (radiological bronchiectasis(R), obstruction: FEV1/FVC ratio <0.7 (O), symptoms (S) and exposure: >10 pack year smoking history (E) allows objective validation of clinical diagnosis of BE-COPD association.

Methods: Prospective registry across 28 countries of patients with CT confirmed bronchiectasis The ROSE criteria were used to objectively defined BE-COPD association and to identify possible under- or over- diagnosis.

Results: 16730 patients were included in the analysis. 3895/4336 patients with a diagnosis of COPD and 11249/12394 patients without a diagnosis of COPD had complete lung function and smoking data available for analysis. We observed marked overdiagnosis of COPD using the ROSE criteria. Only 3029 (77.8%) of patients with a diagnosis of COPD had airflow obstruction and 2951/3895 (68.1%) had a history of >10 pack years. Combining these two parameters the proportion with true COPD was 2157 (55.4%). Compared to patients without COPD, patients meeting ROSE criteria had increased risk of hospitalized exacerbations and oral antibiotic treated exacerbations during follow-up (IRR 1.69 95% CI 1.51-1.90 and 1.25 95%CI 1.15-1.35 respectively) but patients with a diagnosis of COPD who did not meet ROSE criteria also had increased risk of exacerbations.

Conclusions: The label of COPD is often applied to bronchiectasis patients without objective evidence of airflow obstruction and smoking history. Patients with a clinical label of COPD have poor outcomes irrespective of the presence of these criteria.