We enrolled 1,114 subjects from within South Korea and investigated the clinical characteristics of these South Korean COPD patients, their COPD exacerbation rate and the risk factors associated with COPD exacerbations. A total of 1,357 COPD exacerbations occurred in the study period.
When patients were grouped based on GOLD spirometry classifications, the exacerbation rate increased with disease severity, as has been demonstrated in Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study (15).
Patients were divided into groups based on the frequency of exacerbation during the retrospective study, and among the subjects who had not experienced any exacerbations during the retrospective period, 18.6% were found to have had one or more COPD exacerbations in the prospective observation period. In contrast, among the subjects who had two exacerbations in the retrospective analysis, 61.6% of subjects were found to have experienced one or more exacerbations in the prospective period. This data verifies that subjects who had a higher case of COPD exacerbation in the past have an increased probability of experiencing exacerbations.
In the multivariate logistic regression analysis, the association of exacerbation status was 5.67 times higher among subjects who had two or more exacerbations than among subjects who had less than two exacerbations. On the whole, this result corroborates the ECLIPSE study, which concluded that the single best predictor of exacerbations is a history of exacerbations (15).
The exacerbation rate was 18.09 times greater among patients who had experienced pneumonia in the retrospective analysis than among those who did not have pneumonia. This indicated that among COPD patients, history of pneumonia is an important predictor of the risk of COPD exacerbation. In the UK National COPD Resources and Outcomes Project of 2008, COPD exacerbations were associated with worse outcomes among patients with a history of pneumonia. In patient mortality was 11% and 7% and 90-day mortality was 17% and 13% for pneumonia and non-pneumonia patients, respectively (P