Resting hyperinflation and emphysema on the clinical course of COPD.

The aim of this study is to clarify whether the combined evaluation of resting hyperinflation and emphysema confers any additional advantages in terms of predicting clinical outcomes in chronic obstructive pulmonary disease (COPD) patients. We included COPD patients from the Korean Obstructive Lung Disease (KOLD) cohort. Patients with a residual volume/total lung capacity (RV/TLC) over the upper limit of normal were defined as having resting hyperinflation, and those with an emphysema index >10% were defined as having emphysema. We investigated the impacts of resting hyperinflation and emphysema on exacerbations and mortality. A total of 310 COPD patients were analyzed over a mean of 61.1 months. After adjustment for covariates, resting hyperinflation was an independent predictor of earlier exacerbation (HR = 1.66, CI = 1.24-2.22), more frequent exacerbation (IRR = 1.35, CI = 1.01-1.81), and higher mortality (HR = 2.45, CI = 1.16-5.17) risk. Emphysema was also significantly associated with earlier exacerbation (HR = 1.64, CI = 1.15-2.35), and higher mortality (HR = 3.13, CI = 1.06-9.27) risk. Participants with both resting hyperinflation and emphysema had an additively higher risk of earlier exacerbations (HR = 1.71, 95% CI = 1.26-2.33) and mortality (HR = 3.75, 95% CI = 1.81-7.73) compared with those in other groups. In conclusion, resting hyperinflation and emphysema had additional worse impacts on exacerbations and mortality in COPD patients.