Clinical and Functional Lung Parameters Associated With Frequent Exacerbator Phenotype in Subjects With Severe COPD

BACKGROUND: COPD is currently recognized as a syndrome associated with a high prevalence of comorbidities and various phenotypes. Exacerbations are very important events in the clinical history of COPD because they drive the decline in lung function. In the present study, we aim to identify whether there are any clinical and functional specific features of frequent exacerbators in a population of patients with severe COPD.

METHODS: We conducted a cross-sectional, case control study. All subjects had Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 3 or 4 COPD (FEV₁ < 50% predicted). Frequent exacerbators (n = 183) reported ≥2 exacerbations or ≥1 determining hospitalization during the previous 12 months, and infrequent exacerbators (n = 162) reported <2 exacerbations over the last 12 months without hospitalization. Multivariate logistic regression was performed to determine the clinical and functional factors significantly associated with frequent exacerbator status.

RESULTS: Frequent exacerbators had a significantly lower inspiratory capacity percentage predicted. The Motley index (residual volume/total lung capacity percentage) was significantly increased in frequent exacerbators. Infrequent exacerbators had lower Modified Medical Research Council dyspnea scale and BODE index than frequent exacerbators. In the multivariate model, a reduced inspiratory capacity percentage predicted and an increase of residual volume/total lung capacity percentage, BODE index and Modified Medical Research Council dyspnea scale were associated with the frequent exacerbation phenotype.

CONCLUSIONS: Static hyperinflation and respiratory disability, measured by Motley index and Modified Medical Research Council dyspnea scale, respectively, in the same way as the multidimensional BODE index staging system, were independently associated with frequent exacerbation status in subjects with severe COPD.