Impact of geographic barriers on the utilization of mammograms by older rural women.

Objectives: To examine whether geographic proximity to mammography facilities influences mammogram utilization.

Design: Retrospective cohort analysis.

Setting: Rural state.

Participants: Female Kansas Medicare beneficiaries aged 65 to 79 (N=117,901).

Measurements: Using Medicare claims data, we measured county-level mammography rates for beneficiaries in Kansas. We calculated mammography rate differences for beneficiaries according to age, race, distance from permanent and mobile mammography sites, and county characteristics including county mammography service availability.

Results: Of 105 counties, 37% had only permanent mammography facilities, 22% had both permanent and mobile sites, 29% had only mobile facilities, and 11% had neither, representing 44%, 44%, 9%, and 3% of the 117,901 beneficiaries, respectively. Of the beneficiaries, 91% lived less than 20 miles from a permanent facility; of the remaining 9%, 67% lived less than 20 miles from a mobile site. In 30 counties with only mobile sites, 90% of the 10,439 beneficiaries residing in the counties had access to the sites fewer than 2 days per month. County-level mammography rates ranged from 37% to 72%. Mammography utilization was 57% in counties with permanent facilities only, 55% in counties with both permanent and mobile sites, 53% in counties with only mobile sites, and 53% in counties with neither (P=0.12). After adjusting for age, race, and county education level, the odds of receiving a mammogram was slightly lower for persons residing longer distances from a permanent facility (odds ratio=0.97 for each 5-mile increase in distance, 95% confidence interval=0.95-0.99).

Conclusion: The majority of Kansans live near a mammography facility. Although there is a large variation in county-level mammography rates across Kansas, this disparity is not well explained by proximity to mammography facilities.