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

The incidence of invasive breast cancer among women age 65 yearsor older is twice that among those age 35 to 44 years, and thedeath rate from breast cancer is approximately three times higheramong women 65 years old than among women 35 to 64 years of age.Although routine screening mammography among women age 50 yearscan reduce breast cancer mortality by 30% by detecting tumorsat early, more treatable stages, older women are less likely toreceive screening mammograms. The Health Care Financing Administration(HCFA) routinely examines trends in the use of health servicesby age, race, and sex to monitor access to medical care for Medicarebeneficiaries. Using Medicare claims data, HCFA estimated ratesof mammography use among women 65 years old during 1991 through1993. This report presents the findings of that analysis.

Women enrolled in Medicare are eligible for diagnostic and screeningmammograms under the Medicare Part B program, which enrolls approximately96% of US residents 65 years old. Biennial screening mammographyfor women age 65 years has been a Medicare benefit since January1, 1991; previously, only diagnostic mammograms were covered underMedicare Part B. Both screening and diagnostic mammography arereimbursed at 80% of allowed charges after an annual deductibleof $100 for all Part B services.

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

Three cohorts of women were established using the Medicare denominatorfiles for 1991, 1992, and 1993. Each annual cohort consisted ofapproximately 16 million women who were continuously enrolledin fee-for-service Medicare parts A and B. Women excluded fromthis analysis were those less than 65 years old as of January1 of the year, those enrolled in a health maintenance organizationat any time during the year, and those who died during the year.Rates of mammography use represent the percentage of women ineach cohort who had one or more mammograms (screening or diagnostic)during that year. Because providers do not uniformly apply thecodes used to bill Medicare for mammograms, Medicare claims cannotreliably distinguish screening and diagnostic mammograms; therefore,both types of mammography are included in this analysis.

During 1991 through 1993, of each annual cohort of approximately16 million women age 65 years who were continuously enrolled infee-for-service Medicare, 3.8 to 4.0 million (approximately 25%)had one or more mammography claims. During this period, ratesof mammography use varied inversely with age of the beneficiary(Figure 1); in all years, the rate for women aged 80 to 84 yearsold was less than half that for women 65 to 69 years old. Forall age groups, black women were less likely than white womento have received mammograms, although this difference declinedduring each of the 3 years: in 1991, the black-to-white ratioof mammography rates was 0.64:1, compared with 0.71:1 in 1993.

Editorial Note from the CDC: The findings in this reportare consistent with previous studies that indicate a low rateof mammography use among women 65 years old. In this analysis,black women and women 85 years old were least likely to have receivedmammograms under Medicare. A national health objective for theyear 2,000 is to increase to 60% the percentage of women 50 yearsold who received a mammogram and clinical breast examination duringthe 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 influencescreening mammography use, three additional factors may explainthe low rate of use among this elderly Medicare population. First,for women 75 years old, low rates of use maybe a consequence ofvariations in recommendations by professional associations toperform 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 thedelivery of health services to women of lower socioeconomic status.Finally, overall low use of mammography by Medicare beneficiariesalso may reflect limited awareness of this health benefit: in1992, approximately two-thirds of elderly women were unaware thatmammography was a Medicare benefit.

In response to the low awareness and low use of the Medicare mammographybenefit, HCFA has organized multimedia outreach efforts throughits national and regional offices. Since May 1995, approximately50 major organizations have participated in campaigns to publicizemammography as a Medicare benefit; participating organizationshave included the CDC and other federal agencies, health-careprovider associations, senior citizen groups, voluntary organizations,major corporations, and trade associations. These outreach effortsalso are being promoted during National Breast Cancer AwarenessMonth in October. In addition to informational efforts aimed atelderly women enrolled in Medicare and their families, county-leveland race-specific annual and biennial mammography rates were madeavailable to local and national health organizations to assistin developing interventions to increase mammography use.