Costs of COPD by disease severity

Background: Chronic obstructive pulmonary disease (COPD) is one of the most common chronic and disabling diseases worldwide, and the societal costs are high. Aim: To estimate the societal costs of COPD in Sweden and to examine the relationship between disease severity and costs. Methods: The study sample was identified in earlier clinical examinations of general population cohorts within the OLIN (Obstructive Lung Disease in Northern Sweden) studies. The cohort consisted initially of 993 subjects fulfilling COPD spirometric criteria (GOLD). In 2009-2010, telephone interviews on resource utilization were made to a sample of 244 subjects, stratified by disease severity. Interviews were performed quarterly to minimize the risk of recall bias. A non-parametric Mann-Whitney U-test was used to test cost differences between groups; p-values adjusted by Bonferroni correction. Unit costs from 2010 were applied. Results: A highly significant relationship was found between disease severity and costs. The mean annual total cost per patient in relation to disease severity (GOLD) was: stage I €811; II €2,660; III €7,068; and IV €20,665. Indirect costs were higher than direct costs in all severity stages. For direct costs, main cost drivers were hospitalizations in stage III and IV, and drugs in stage I and II, respectively. The main cost driver in indirect costs was productivity loss due to early retirement, except in stage I where the driver was sick-leave. In comparison with a similar study performed in 1999 a numerical increase in mean annual total costs per patient was observed (ns). Conclusions: The results indicate that the societal costs of COPD in Sweden are substantial, and the costs increase considerably by disease severity.