Factors associated with exacerbation in mild- to-moderate COPD patients

INTRODUCTION COPD exacerbation negatively impacts the patient's quality of life and lung function, increases mortality, and increases socioeconomic costs. In a real-world setting, the majority of patients with COPD have mild-to-moderate airflow limitation. Therefore, it is important to evaluate COPD exacerbation in patients with mild-to-moderate airflow limitation, although most studies have focused on the patients with moderate or severe COPD. The objective of this study was to evaluate factors associated with COPD exacerbation in patients with mild-to-moderate airflow limitation. METHODS Patients registered in the Korean COPD Subtype Study cohort were recruited from 37 tertiary referral hospitals in Korea. We obtained their clinical data including demographic characteristics, past medical history, and comorbidities from medical records. Patients were required to visit the hospital to document their COPD status using self-administered questionnaires every 6 months. RESULTS A total of 570 patients with mild-to-moderate airflow limitation were enrolled. During the first year of follow-up, 30.5% patients experienced acute exacerbation, with exacerbations being more common in patients with poor lung function. Assessed factors associated with COPD exacerbation included COPD assessment test scores, modified Medical Research Council dyspnea assessment test scores, St George's Respiratory Questionnaire for COPD scores, a previous history of exacerbation, and histories of pneumonia and allergic rhinitis. Logistic regression tests revealed St George's Respiratory Questionnaire for COPD scores (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.00-1.04; P=0.034), a previous history of exacerbation (OR, 3.12; 95% CI, 1.35-7.23; P=0.008), and a history of pneumonia (OR, 1.85; 95% CI, 1.06-3.25; P=0.032) as risk factors for COPD exacerbation. CONCLUSION Our results suggest that COPD exacerbation in patients with mild-to-moderate airflow limitation is associated with the patient's quality of life, previous history of exacerbation, and history of pneumonia.