Medicare Coverage, Supplemental Insurance, and the Use of Mammography in Older Women

BACKGROUND. On January 1, 1991, the Medicare program began offering reimbursement for screening mammography every two years. This study examined the use of mammography in women covered by Medicare during the first two years that the screening benefit was offered. METHODS. Medicare bills for 1991 and 1992 from a nationally representative sample of 4110 women 65 years of age or older were examined to determine the degree of compliance with recognized guidelines for screening mammography and the extent to which the use of mammography was associated with having supplemental insurance, which shields patients from the out-of-pocket costs associated with using Medicare benefits. RESULTS. A total of 36.9 percent of older U.S. women had mammography during the first two years of the Medicare benefit for screening mammography. Only 14.4 percent of the women lacking supplemental insurance had mammography, as compared with 44.7 percent of those with employer-sponsored supplemental insurance, 40.1 percent of those with self-purchased supplemental insurance, and 23.9 percent of those with Medicaid supplemental insurance. These differences persisted in the stratified and multivariate analyses. As compared with women lacking supplemental insurance, women with employment-based supplemental insurance were more likely to undergo mammography (adjusted odds ratio, 3.03; 95 percent confidence interval, 2.17 to 4.23), as were women with self-purchased supplemental insurance (adjusted odds ratio, 2.97; 95 percent confidence interval, 2.13 to 4.15) and women with Medicaid supplemental insurance (adjusted odds ratio, 1.99; 95 percent confidence interval, 1.30 to 3.07). CONCLUSIONS. The use of mammography was substantially below recommended levels during the first two years of Medicare coverage for screening mammography. Women lacking supplemental health insurance were at particularly high risk of failing to undergo mammography. Requiring copayments for preventive services is an obstacle to the effective mass screening of older women for breast cancer.