Cluster analysis reveals an exacerbator subtype among COPD patients = Cluster analysis reveals an exacerbator subtype among COPD patients

다국어 초록 (Multilingual Abstract)

Objectives: Acute exacerbation (AE) in patients with chronic obstructive pulmonary disease (COPD) is a poor prognostic factor and an important determinant of COPD therapy. We investigated the occurrence of AE according to COPD subtypes.
Methods: Among COPD patients in Korea COPD Subgroup Study cohort, 1,195 patients who had follow-up data for AE were included in our study. We selected seven variables for clustering analysis - age, body mass index, smoking status, past history of asthma, COPD assessment test (CAT) score, post-bronchodilator (BD) forced expiratory volume in 1 second (FEV1) % predicted, and diffusing capacity of carbon monoxide % predicted.
Results: K-means clustering identified four clusters: putative “asthma-COPD overlap (ACO)”, “mild COPD”, “moderate COPD”, and “severe COPD” subtypes. ACO group (n=196) showed the second-best post-BD FEV1 (75.5% vs. 80.9% [mild COPD, n=313] vs. 52.4% [moderate COPD, n=345] vs. 46.7% [severe COPD, n=341] predicted) and the lowest CAT score (12.2 vs. 13.7 vs. 15.6 vs 17.5) among four groups. Nonetheless, the ACO group had the greatest risk of the first AE compared to mild COPD group (hazard ratio [HR]: 1.766). The HRs of the moderate COPD group and the severe COPD group were 1.696 and 1.659, respectively. In addition, St. George’s Respiratory Questionnaire score (HR: 1.018) and gastroesophageal reflux disease were independent factors associated with the first AE (HR: 1.385).
Conclusions: Like our ACO group, there are subtypes to be susceptible to AE, and these subtypes need more aggressive treatment strategies to prevent AE.