Abstract
OBJECTIVE: Untreated chronic obstructive pulmonary disease (COPD) exacerbations are associated with short-term changes in lung function and decreased health-related quality of life (HRQoL). This study aims to examine the association between untreated exacerbations and long-term HRQoL, as well as differences in characteristics between treated and untreated exacerbations. METHODS: A secondary analysis was performed using data from a prospective observational cohort study of participants with COPD. Participants’ HRQoL was measured using the Chronic Respiratory Questionnaire (CRQ) at baseline and at 12 months. Exacerbations were ascertained with phone calls every 2 weeks, with detailed information regarding exacerbations obtained by research staff. Exacerbations were considered treated if participants took prednisone or antibiotics. Mixed models were used to analyze differences in treated and untreated exacerbation characteristics. Linear and logistic regression models were used to examine the association between the number of treated and untreated exacerbations and a change in CRQ at 12 months. RESULTS: Among 410 participants, 355 experienced 1097 exacerbations during the 12-month study period, of which 460 (42%) were treated. Treated exacerbations were more severe and lasted longer (25.5 versus 19.9 days, p<0.001) compared to untreated exacerbations. Each additional untreated exacerbation experienced was associated with a significant worsening of long-term HRQoL scores compared to those without exacerbations: CRQ dyspnea (adjusted b= -0.10; 95% confidence interval -0.18 to -0.03), CRQ fatigue (b= -0.07; -0.14 to -0.01), and CRQ emotional function (b= -0.08; -0.14 to -0.02). CONCLUSION: Untreated COPD exacerbations occurred frequently and were associated with worse long-term HRQoL, despite being shorter and less severe than treated exacerbations.