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OBJECTIVE: To examine racial differences in breast cancer screening in an HMO that provides screening at no cost.
DESIGN: Retrospective cohort study of breast cancer screening among African-American and white women. Breast cancer screening information was extracted from computerized medical records.
SETTING: A large HMO in New England.
PATIENTS/PARTICIPANTS: White and African-American women (N = 2,072) enrolled for at least 10 years in the HMO.
MAIN RESULTS: Primary care clinicians documented recommending a screening mammogram significantly more often for African Americans than whites (70% vs 64%; P < .001). During the 10-year period, on average, white women obtained more mammograms (4.49 vs 3.93; P < .0001) and clinical breast examinations (5.35 vs 4.92; P < .01) than African-American women. However, a woman's race was no longer a statistically significant predictor of breast cancer screening after adjustment for differences in age, estimated household income, estrogen use, and body mass index (adjusted number of mammograms, 4.47 vs 4.25, P = .17; and adjusted number of clinical breast examinations, 5.35 vs 5.31, P = .87).
CONCLUSIONS: In this HMO, African-American and white women obtained breast cancer screening at similar rates. Comparisons with national data showed much higher screening rates in this HMO for both white and African-American women.
African-American women are more likely to have advanced breast cancer at the time of diagnosis, and they experience worse outcomes, stage for stage, than white women.1,2 Several explanations have been suggested for this disparity in survival, including differences in the access to or utilization of screening, differences in treatment, and possible biologic differences.3–15 In addition, some research has shown only marginal race differences in breast cancer survival rates after adjustment for such variables as missed appointments and stage at cancer diagnosis.16 National surveys have shown that African-American women obtain less breast cancer screening than white women.17 The degree to which financial and other barriers and lack of physician recommendations for screening contribute to racial differences in screening rates remains unclear.
Prepaid health plans offer settings in which financial barriers to preventive care and screening are minimized, and screening is encouraged among all members. Health maintenance organization enrollees are significantly more likely than fee-for-service patients to have received screening tests.18,19 However, in a search of medline, we could find no published study specifically examining breast cancer screening utilization by race in an HMO. We therefore examined whether racial differences existed in the utilization of breast cancer screening in a large HMO, and compared these utilization rates with those reported for the U.S. population at large.
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This study examined racial differences in breast cancer screening utilization in an HMO that encouraged breast cancer screening and included it as a covered benefit for all female members. African Americans were slightly less likely to comply with screening mammograms recommended by their physicians (76%) than whites (82%). The mean number of mammograms and clinical breast examinations over the 10 years was slightly lower for African Americans than for whites; these differences disappeared when adjusted for differences in age, estrogen use, estimated household income, and body mass index. The screening rates for both races in this HMO were markedly higher than those in published national samples. Over a 30-year lifetime period of breast cancer screening, our data suggest African-American members of this HMO would have an average of 1 fewer mammogram than white women. This difference is small and may have marginal, if any, clinical effects at an individual level.
The question remains why screening rates for African Americans would be lower at all in a health care setting that encourages and covers screening. Psychosocial variables, lack of knowledge about mammograms, specific health beliefs, cultural beliefs such as distrust of doctors and procedures, lack of transportation, and the need to obtain time off work to attend appointments may explain the racial difference in screening. The difference may also be due to differential recommendations by providers, as found by previous research in which physicians with minority patients were significantly less likely to recommend screening mammography compared with physicians with predominantly white patients.22 However, our data did not support this hypothesis. We searched for racial differences in mammogram recommendations following a clinical breast examination among women that had not had a screening mammogram in more than 1 year and found that clinicians documented recommending a screening mammogram significantly more often to African-American women (70%) than to white women (64%).
The screening rates in our study were much higher than those in several national published studies. Direct comparisons with national data are difficult, as most national samples use self-reported data, and our data are based on medical record documentation of actual breast cancer screening utilization. Two previous studies found that survey data overestimated mammogram utilization when compared with medical records,23,24 whereas another study reported no difference in accuracy between self-reported data and medical records.25 However, the surveys provide a general comparison between breast cancer screening in the U.S. population and that in this HMO. Our HMO estimates are conservative given that women in this HMO may have had a mammogram prior to 1983 that we did not capture.
The results of this study suggest that enrollment in an HMO that emphasizes preventive services may positively affect breast cancer screening utilization among both African-American and white women. Other factors, such as education or income levels of the HMO members, may also be responsible for the high utilization rates. Our sample consists of women who were enrolled in an HMO continuously for 10 years (1983–1993) in a part of the country where HMO enrollment has been consistently higher than in other parts of the country. Women with continuous medical care from a single source may be more likely to receive preventive services. Conversely, mammography utilization in the 1980s was generally lower than in the 1990s, so the effect we found may be conservative. We cannot determine how generalizable our results are to other clinical settings or other HMOs, some of which may not emphasize prevention to their members to the degree of the HMO under study.
With the data on racial minorities restricted to African-American women, the findings may not be generalizable to more ethnically diverse community settings. In addition, race was abstracted from charts based on clinician identification of the patient's race. The patients' own perceptions of their race would be a more accurate indicator for research purposes. Finally, we do not have mortality or morbidity outcome data for these women to determine whether or not the small racial differences in screening led to significantly different outcomes. As previously mentioned, recent research studies have cited a strong link between race and breast cancer morbidity and mortality. We also did not have available other indicators of socioeconomic status or of comorbidity, which would have enhanced the analysis.
Racial differences in breast cancer screening are a complex area of research. Two recent articles failed to find mammography screening a potential protective mechanism for breast cancer stage at diagnosis among African-American women.10,11 Jones and her colleagues found that a history of mammography screening was not an important explanatory variable in the association between race and cancer stage at diagnosis.11 Their patients were not HMO members, and African Americans received significantly less mammography screening, recent screening, and recommendations for follow-up by their physicians compared with whites. Hunter and colleagues, who found more advanced cancer stages at diagnosis in African Americans than in whites, also found that patients enrolled in an HMO presented with earlier-stage cancers, regardless of race.10
Our study suggests that African-American women enrolled in an HMO can obtain breast cancer screening at higher rates than the general population. In the HMO, we found screening rates for African-American women continued to be slightly lower than for white women, but the racial difference did not reach statistical significance in a multivariate model and is unlikely to have clinical significance. An HMO practice setting that removes financial barriers and encourages regular breast cancer screening for all patients, regardless of race, may result in increased rates of screening utilization.