The direct medical costs of undiagnosed chronic obstructive pulmonary disease.

Objective: To estimate the costs of undiagnosed chronic obstructive pulmonary disease (COPD) by describing inpatient, outpatient, and pharmacy utilization in the years before and after the diagnosis.

Methods: A total of 6,864 patients who were enrolled in the Lovelace Health Plan for at least 12 months during the study period (January 1, 1999 through December 31, 2004) were identified. The first date that utilization was attributed to COPD was considered the first date of diagnosis. Each COPD case was matched to up to three age- and sex-matched controls. All utilization and direct medical costs during the study period were compiled monthly and compared based on the time before and after the initial diagnosis.

Results: Total costs were higher by an average of $1,182 per patient in the 2 years before the initial COPD diagnosis, and $2,489 in the 12 months just before the initial diagnosis, compared to matched controls. Most of the higher cost for undiagnosed COPD was attributable to hospitalizations. Inpatient costs did not increase after the diagnosis was made, but approximately one-third of admissions after the diagnosis were attributed to respiratory disease. Outpatient and pharmacy costs did not differ substantially between cases and matched controls until just a few months before the initial diagnosis, but remained 50% to 100% higher than for controls in the 2 years after diagnosis.

Conclusions: Undiagnosed COPD has a substantial impact on health-care costs and utilization in this integrated managed care system, particularly for hospitalizations.