OBJECTIVES : Estimates on the economic impact of chronic obstructive pulmonary disease (COPD) for third-party payers and society based on real world data are lacking. Therefore, the aim of this study was to estimate the economic impact of COPD severity and its comorbidities on direct and indirect health care costs.

METHODS : Data from 39,307 patients in GOLD grade 1 (mild) to 4 (very severe) enrolled in the German Disease Management Program COPD from a large regional statutory health insurance fund were included. We used generalized linear models to analyze the association of COPD severity and the comorbidities diabetes, stroke, myocardial infarction (MI) and arthritis with direct and indirect costs, while adjusting for sex, age, income, smoking status, and body mass index (BMI).

RESULTS : More severe COPD was significantly associated with higher health care costs. Compared to GOLD grade 1 direct costs increased by a factor of 1.13 (1.10-1.16) in grade 2, by 1.46 (1.41-1.51) in grade 3, and by 2.18 (2.06-2.32) in grade 4. Similarly with disease progression indirect costs increase by a factor of 1.08 (0 .99-1.18) in grade 2, by 1.36 (1.21-1.52) in grade 3, and by 1.74 (1.45-2.09) in grade 4.

Furthermore, comorbidities had significant additional effects. Direct costs were increased by a factor of 1.32 (1.29-1.36) for diabetes, 1.30 (1.27-1.34) for stroke, 1.51 (1.46-1.57) for MI, 1.38 (1.35-1.42) for cancer, and 1.19 (1.15-1.23) for arthritis. Slightly lower increases could be found in indirect costs for diabetes by 1.22 (1.11-1.35), stroke by 1.25 (1.13-11.39), MI by 1.16 (1.01-1.34), cancer by 1.27 (1.16-1.39), and arthritis by 1.22 (1.07-1.39).

CONCLUSIONS : The findings indicate that more severe COPD grades are associated with substantial additional direct and indirect costs, with comorbidities significantly further increasing costs. In consequence, effective and intervention that slows down disease progression could reduce the follow-up cost of COPD.