Cost of breast-related care in the year following false positive screening mammograms.

OBJECTIVE: We sought to estimate the direct cost, from the perspective of the health insurer or purchaser, of breast-care services in the year following a false positive screening mammogram compared with a true negative examination.
DESIGN: We identified 21,125 women aged 40 to 80 years enrolled in an integrated healthcare delivery system in Washington State, who participated in screening mammography between January 1, 1998 and July 30, 2002. Pathology and cancer registry data were used to identify breast cancer diagnoses in the year following the screening mammogram. A positive examination was defined as a Breast Imaging Reporting and Data System assessment of 0, 4, or 5. Women with a positive screening mammogram but no breast cancer diagnosed within 1 year were classified as false positives. We used diagnostic and procedure codes in automated health plan data to identify services received in the year following the screening mammogram. Medicare reimbursement rates were applied to all services. We used ordinary least-squares linear regression to estimate the difference in costs following a false positive versus true negative screening mammogram.
RESULTS: False positive results occurred in 9.9% of women; most false positives (87.3%) were followed by breast imaging only. The mean cost of breast-care following a false positive mammogram was $527. This was $503 (95% confidence interval, $490-$515) more than the cost of breast-care services for true negative women.
CONCLUSIONS: The direct costs for breast-related procedures following false positive screening mammograms may contribute substantially to US healthcare spending.