Estimating racial/ethnic disparity in mammography rates: it all depends on how you ask the question

Background. Estimates of racial disparity in mammography appear to differ depending on the data source. This study examined the impact of different survey methodology on estimates of racial disparity in mammography. Methods. Responses from 3,090 women ≥40 years to two different questions from the 1996 Medical Expenditure Panel Survey (MEPS) were compared when a mammogram was last obtained versus what medical services, including mammography, were obtained over a 4-month interval, aggregated across 1 year. Results. There was no significant racial disparity in 1-year mammography prevalence based on the first question (white–black difference, 3.3%; 95% confidence interval [CI], −2.5, 9.2). In contrast, a significant disparity in 1-year mammography prevalence was found based on the medical services question (difference, 13.1%; 95% CI 8.6, 17.6). Disparity estimates by Hispanic ethnicity were similar for the two questions: white–Hispanic difference, 1.6%; 95% CI −4.3, 7.5, and white–Hispanic difference 5% (−0.2, 10.1). Adjustment for age, income, and insurance did not alter these findings. Conclusions. Estimates of racial, but not ethnic, disparities in mammography seem to depend on how the question is asked. These results caution against exclusive reliance on annual self-reports for monitoring disparities in preventive care.