Cost differences for COPD with and without physician-diagnosis.

Previous studies have presented divergent estimates of the cost of illness of COPD due to differences in methodology. The objective of this study was to examine differences between register-based estimates versus population-based estimates on the burden of COPD. This study therefore examined differences in costs of COPD among physician-diagnosed and un-diagnosed subjects. During a one-year period, four telephone interviews were made with 212 randomly selected subjects with COPD derived from the Obstructive Lung Disease in Northern Sweden (OLIN) studies. Health care resource utilization and productivity losses were measured, and the costs were also transformed with the estimated COPD prevalence in Sweden. Average annual costs were SEK 18,252 (USD 2,207, EUR 2,072), and SEK 9,327 (USD 1,128, EUR 1,059) for subjects with and without a physician-diagnosis, respectively. Although lower per individual, the costs of undiagnosed subjects accounted for approximately 40% of the total costs in Sweden, since the majority of subjects with COPD in Sweden lack a physician-diagnosed disease. In conclusion, we found that the costs due to COPD differed considerably between those with and without physician-diagnosed disease. This study indicates that register-based studies result in underestimated costs of COPD.