The sensitivity of Medicare billing claims data for monitoring mammography use by elderly women.

Mammography use is monitored through Medicare billing claims; however, the sensitivity of this data source has not been previously described. This study included 10,852 Colorado women ages 65 and older with a mammogram in 1998 as registered by the Colorado Mammography Project who were Medicare fee-for-service (FFS) enrollees. These records were matched to Medicare billing data to assess the proportion of those mammograms submitted for payment to Medicare. The overall sensitivity of the FFS Medicare billing data for screening mammography was 85 percent. Medicare billing claims were less sensitive for younger women, African Americans, women with some college education, and women with supplementary private insurance. In Colorado, the Medicare FFS billing claims understates mammography usage by 15 percent. Care must be taken when comparing mammography use derived from Medicare billing claims, as the sensitivity of billing data can vary substantially by age, race, and socioeconomic status.