Racial and ethnic differences in use of mammography between Medicare Advantage and traditional Medicare.

BACKGROUND Breast cancer is a leading cause of mortality for women in all racial/ethnic groups. We compared use of mammography by race/ethnicity in Medicare health maintenance organizations (HMOs), preferred provider organizations (PPOs), and traditional Medicare. METHODS We matched 495 836 women in HMOs and 81 480 women in PPOs who were aged 65 to 69 years during 2009 to women enrolled in traditional Medicare by race/ethnicity, Medicaid eligibility status, and geographic area. We identified mammography use from the Healthcare Effectiveness Data and Information Set for Medicare HMOs and PPOs and from claims data for traditional Medicare with the same specifications. We then compared racial/ethnic differences in rates of mammography in HMOs and PPOs to matched populations in traditional Medicare and estimated differences with z tests. All statistical tests were two-sided. RESULTS Relative to matched white women, mammography rates were statistically significantly higher for black, Hispanic, and Asian/Pacific Islander women in HMOs (6.1, 5.4, and 0.9 percentage points, respectively; all P ≤ .003) and statistically significantly lower for all three groups in traditional Medicare (3.3, 7.4, and 7.7 percentage points, respectively; all P < .001). Similar improvements in mammography rates also were observed in PPOs among all minority groups relative to traditional Medicare. CONCLUSIONS Higher rates of mammography in HMOs and PPOs were associated with a reversal of racial and ethnic differences observed in traditional Medicare. These differences may be related to lower patient cost-sharing and better systems to promote preventive services in managed care plans, as well as unmeasured characteristics or beliefs of minority women who enroll in these health plans relative to those in traditional Medicare.