Emphysematous phenotype is an independent predictor for frequent exacerbation of COPD.

Abstract

SETTING: Frequent exacerbation is an important phenotype in chronic obstructive

pulmonary disease (COPD), while emphysema is associated with many comorbidities

and lung function decline. OBJECTIVE: To investigate unique features of frequent

exacerbators and test the hypothesis that emphysematous phenotype is associated

with frequent exacerbations of COPD. METHODS: A total of 380 COPD patients were

recruited from 16 hospitals in Korea from June 2005 to April 2012 for analysis.

We searched for independent predictors of frequent exacerbators in comparison

with non-exacerbators. RESULTS: As the severity of emphysema increased, forced

expiratory volume in 1 s (FEV(1)), and FEV(1)/FVC (forced volume capacity)

worsened; hyperinflationary features characterised by higher total lung capacity

(TLC) were observed (P < 0.05). Frequent exacerbators had lower body mass index

(BMI), higher St George's Respiratory Questionnaire (SGRQ) scores, higher

residual volume (RV)/TLC, more severe airflow limitation (lower FEV(1) and

FEV(1)/FVC), lower carbon monoxide diffusion capacity, lower serum protein levels

and a higher emphysema index than non-exacerbators (P < 0.05). In multivariate

analysis, frequent exacerbators were independently associated with a higher

emphysema index, lower serum protein levels and higher RV/TLC (P < 0.05).

CONCLUSION: Our data show that the severity of emphysema, severe static

hyperinflation and serum lower protein levels are independent predictors of

frequent exacerbations in COPD patients.