Use of Mammography Services by Women Enrolled in Medicare--United States, 1991-1993

The incidence of invasive breast cancer among women age 65 years or older is twice that among those age 35 to 44 years, and the death rate from breast cancer is approximately three times higher among women 65 years old than among women 35 to 64 years of age. Although routine screening mammography among women age 50 years can reduce breast cancer mortality by 30% by detecting tumors at early, more treatable stages, older women are less likely to receive screening mammograms. The Health Care Financing Administration (HCFA) routinely examines trends in the use of health services by age, race, and sex to monitor access to medical care for Medicare beneficiaries. Using Medicare claims data, HCFA estimated rates of mammography use among women 65 years old during 1991 through 1993. This report presents the findings of that analysis.

Women enrolled in Medicare are eligible for diagnostic and screening mammograms under the Medicare Part B program, which enrolls approximately 96% of US residents 65 years old. Biennial screening mammography for women age 65 years has been a Medicare benefit since January 1, 1991; previously, only diagnostic mammograms were covered under Medicare Part B. Both screening and diagnostic mammography are reimbursed at 80% of allowed charges after an annual deductible of $100 for all Part B services.

For this analysis, Medicare claims data for services provided during 1991 through 1993 were used to calculate annual rates of mammography use for enrolled women age 65 years; age- and race-specific rates also were calculated. Race-specific rates are presented for blacks and whites only because identification of other racial groups is incomplete in the Medicare administrative data system. Because claims are not submitted for the Medicare population enrolled in managed-care plans (approximately 7% in 1993), rates are based on women enrolled in fee-for-service Medicare.

Three cohorts of women were established using the Medicare denominator files for 1991, 1992, and 1993. Each annual cohort consisted of approximately 16 million women who were continuously enrolled in fee-for-service Medicare parts A and B. Women excluded from this analysis were those less than 65 years old as of January 1 of the year, those enrolled in a health maintenance organization at any time during the year, and those who died during the year. Rates of mammography use represent the percentage of women in each cohort who had one or more mammograms (screening or diagnostic) during that year. Because providers do not uniformly apply the codes used to bill Medicare for mammograms, Medicare claims cannot reliably distinguish screening and diagnostic mammograms; therefore, both types of mammography are included in this analysis.

During 1991 through 1993, of each annual cohort of approximately 16 million women age 65 years who were continuously enrolled in fee-for-service Medicare, 3.8 to 4.0 million (approximately 25%) had one or more mammography claims. During this period, rates of mammography use varied inversely with age of the beneficiary (Figure 1); in all years, the rate for women aged 80 to 84 years old was less than half that for women 65 to 69 years old. For all age groups, black women were less likely than white women to have received mammograms, although this difference declined during each of the 3 years: in 1991, the black-to-white ratio of mammography rates was 0.64:1, compared with 0.71:1 in 1993.

Editorial Note from the CDC: The findings in this report are consistent with previous studies that indicate a low rate of mammography use among women 65 years old. In this analysis, black women and women 85 years old were least likely to have received mammograms under Medicare. A national health objective for the year 2,000 is to increase to 60% the percentage of women 50 years old who received a mammogram and clinical breast examination during the previous 2 years (objective 16.11). Among Medicare beneficiaries, the biennial rate of mammography use for 1992 to 1993 was 37% for women 65 years old.

In addition to the patient and physician attributes known to influence screening mammography use, three additional factors may explain the low rate of use among this elderly Medicare population. First, for women 75 years old, low rates of use maybe a consequence of variations in recommendations by professional associations to perform screening mammography for women in this age group. Second, for black women, low rates may reflect financial barriers (eg, the Part B deductible or copayments) and other obstacles in the delivery of health services to women of lower socioeconomic status. Finally, overall low use of mammography by Medicare beneficiaries also may reflect limited awareness of this health benefit: in 1992, approximately two-thirds of elderly women were unaware that mammography was a Medicare benefit.

In response to the low awareness and low use of the Medicare mammography benefit, HCFA has organized multimedia outreach efforts through its national and regional offices. Since May 1995, approximately 50 major organizations have participated in campaigns to publicize mammography as a Medicare benefit; participating organizations have included the CDC and other federal agencies, health-care provider associations, senior citizen groups, voluntary organizations, major corporations, and trade associations. These outreach efforts also are being promoted during National Breast Cancer Awareness Month in October. In addition to informational efforts aimed at elderly women enrolled in Medicare and their families, county-level and race-specific annual and biennial mammography rates were made available to local and national health organizations to assist in developing interventions to increase mammography use.