Associations between computed tomography features and obstructive lung diseases: The NOVELTY-CT substudy

Obstructive lung diseases, such as asthma and COPD, are characterized by chronic or variable airflow limitations and similar symptoms, hindering differential diagnosis. We therefore sought to investigate the clustering of clinical features, based on multiple computed tomography (CT) findings, in patients with physician-assigned diagnoses of asthma and/or COPD.

We used data for Japanese patients enrolled in the NOVELTY study, and a subset of patients with CT scans available within 1 year prior to the baseline visit (NOVELTY-CT substudy). We applied hierarchical cluster analysis (Ward's method with the Gower distance) for four CT features: emphysema, mucus plugs, increased bronchial wall thickness, and fibrosis.

Data were collected for 228 patients, of whom 121 (53.1%), 46 (20.2%), and 61 (26.8%) were diagnosed with asthma, asthma + COPD, and COPD, respectively. Cluster analysis using data from 184 patients yielded four clusters: (C1) pauci-specific findings (74 patients); (C2) predominant-emphysema with bronchial features (9 patients); (C3) emphysema with mucus plugs (95 patients); and (C4) emphysema with fibrosis (6 patients). Baseline characteristics varied across the clusters, particularly the physician's diagnosis, age, respiratory function, disease severity, and patient-reported outcomes for symptom burden and quality of life/well-being.

Patients with obstructive lung diseases were classified into four different clusters using CT findings. The classification was achieved by using objective CT features, which may support more tailored management.