The Impact of Exacerbation Frequency on Clinical and Economic Outcomes in Swedish COPD Patients: The ARCTIC Study

Purpose: The aim of this study was to assess the association between exacerbation frequency and clinical and economic outcomes in patients with COPD. Patients and Methods: Electronic medical record data linked to National Health Registries were collected from COPD patients at 52 Swedish primary care centers (2000-2014). The outcomes analyzed were exacerbation rate, mortality, COPD treatments, lung function and healthcare costs during the follow-up period. Based on the exacerbation rate two years before index date, the patients were initially classified into three groups, either 0, 1 or >= 2 exacerbations per year. After the index date, the classification into exacerbation groups was updated each year based on the exacerbation rate during the last year of follow-up. A sensitivity analysis was conducted excluding patients with asthma diagnosis from the analysis. Results: In total 18,586 COPD patients were analyzed. A majority of the patients (60-70%) who either have had no exacerbation or frequent exacerbations (>= 2/year) during the preindex period remained in their group (ie, with 0 or >= 2 annual exacerbations) during up to 11 years of follow-up. Compared with having no exacerbation, mortality was higher in patients having 1 (HR; 2.06 [1.93-2.201) and >= 2 (4.58 [4.33-4.841) exacerbations at any time during the follow-up. Lung function decline was more rapid in patients with frequent exacerbations and there was an almost linear relationship between exacerbations frequency and mortality. Total healthcare costs were higher in the frequent exacerbation group (>= 2/year) than in patients with no or one exacerbation annually (p<0.0001 for both). The results did not differ from the main analysis after exclusion of patients with a concurrent asthma diagnosis. Conclusion: In addition to faster lung function decline and increased mortality, frequent exacerbations in COPD patients imply a significant economic burden.