Location decisions of mammography facilities: racial/ethnic disparities across zip-codes
- Presenter:
Chair: James Marton; Discussant: TBA Mon June 5, 2006 10:45-12:15 Room 235
Rationale: Among women age 40 and older, minority women have been found to have mammograms at a lower rate than white women. One potential cause may be that minority women live in neighborhoods with no mammography facilities in proximity to them, or because facilities in their neighborhoods are inadequately committed to patient service.
Study Objectives: To measure the effect of characteristics of a zip-code (and the surrounding area) on two sets of outcomes: (a) whether mammography facilities locate in the zip-code, and (b) commitment to patient service of mammography facilities in it. In particular, to measure if high percentage of minority population influences facility location decisions, above and beyond socio-economic factors.
Data: Data on demographic and socio-economic characteristics of zip-codes are obtained from the US Census. The list of mammography facilities and their zip-codes is obtained from the American College of Radiology (ACR) and Food and Drug Administration (FDA) databases of accredited mammography facilities. Patient-service commitment was measured using a pilot phone survey of 105 mammography facilities.
Methods:
The unit of analysis is the zip-code, referred to here as the target zip-code. Target zip-codes are categorized as high-white, high-black, high-Hispanic, and high-Asian based on the race and ethnicity of the largest sub-population in the zip-code. Quantitative outcomes of interest for the target zip-code are (i) presence of a mammography facility, (ii) the number of facilities per 100,000 women age 40 and older, and (iii) distance to nearest facility if the target zip-code has none. The explanatory variables are socio-economic characteristics of the target and surrounding zip-codes. Outcome (i) will be estimated using simple logistic regression and (ii) and (iii) with linear and log-linear regression.
In addition, we will use logistic regression to compare mammography facilities in high-minority and high-white zip-codes in terms qualitative factors, such as whether the facility accepts Medicaid and charity patients, language skills and minority composition of front office and technologist staff, types of outreach activities, etc.
Preliminary Results: We find no large differences in the minority composition of the population (31% vs. 30% minority respectively) between zip codes with and without mammography facilities. However, controlling for zip-code socio-economics and population density, high black and Hispanic zip-codes are much less likely to have a mammography facility in them than predominantly white zip-codes (for example, 10% increase in the black percentage of the population decreases the odds of a facility in the zip-code by 14%). There is no significant effect of percent of minority populations on the number of facilities per 100,000 women age 40 and older.
Facilities in high minority zip-codes seem to be more committed to patient service than those in high-white areas, for example, one-half of the facilities surveyed in high-Hispanic and three-fifths of those in high-black zip-codes use posters and flyers for outreach into the community to educate women about mammograms, whereas less than one-third of the facilities in the high-white zip-codes do.
Conclusion:
High-minority zip-codes are less likely to have mammography facilities, but facilities in high-minority zip-codes may be more committed to patient care than those in high-white zip-codes.
