Abstract P1-11-07: Multivariable analysis of repeat utilization of mobile mammography units: 10 year analysis of a comprehensive cancer center
Authors: Karedan Tezo , Riley Elizabeth , Roland Lane , Barkley Laura , Pan Jianmin , Rai Shesh , Mizuguchi Sarah 
Published: May 2015

Introduction: Mobile Mammography Units (MMU) are a model of outreach. This study analyzes the association of race, insurance and location to MMU utilization. Our group previously reported these variable as independent predictors of MMU repeat use. This study explores if race, age, insurance and location jointly can predict the utilization of MMU. Methods: From Jan 2001- Dec 2010, 48,324 screening mammograms were performed with 21,587 unique subjects. Demographic data was retrospectively reviewed to identify race/ethnicity, insurance and location for each encounter. Locations were grouped as Corporate (C), Partnership Clinic (PCl,) Partnership Community (PCo.) Insurance type was classified as Private Insurance (PI,) Medicaid (MCaid), Medicare (MCare) and Uninsured (UI.) Insurance type was classified based on the primary insurer. Utilization was defined as 1x or more than 2x in 10 yrs. Descriptive statistics related to different predictors were produced and statistical comparisons were conducted. P-values were calculated using Chi-square test for comparison between the two groups. Odds ratio and its 95% confidence interval were provided. Logistics regression analysis is used to jointly model the effect of independent factors on repeat unitization of MMU. Reference range for race, insurance and location were chosen based on prior work. Results were declared significant at significance level of 5%. Results: Univariable analysis of race, insurance status, location and age were predictive of repeat utilization of the MMU over a 10 yrs. (p= value &lt;.001, &lt;.001, &lt;.001 &lt;.002) respectively. All variables, race, insurance, location and age remained statistically significant for repeat use in multivariable analysis. Blacks (B) were more likely to repeat compared to Whites (W) and Hispanics (H). MCare patients remained most likely to repeat compared to PI, UI or MCaid patients in multivariable analysis. Location, PCl and Age 50-64 continued to predict for highest utilization rate within the respective cohorts. The estimated OR are shown in Table 1.

Table 1 Univariable Multivariable Reference pvalueOR (95% CI)pvalueOR (95% CI) Race&lt;.001 &lt;.001 BlackWhite&lt;.0010.880 (0.829-0.934)&lt;.0010.897 (0.843-0.955) Hispanic&lt;.0010.643 (0.555-0.745)&lt;.0010.701 (0.604-0.813) Insured&lt;.001 &lt;.001 MedicarePrivate&lt;.0010.834 (0.770-0.904)&lt;.0010.782 (0.700-0.874) Medicaid0.0030.804 (0.698-0.926)&lt;.0010.688 (0.587-0.806) Uninsured0.0060.828 (0.828-0.968)&lt;.0010.799 (0.718-0.890) Location&lt;.001 &lt;.001 P CLCorporate&lt;.0010.856 (0.805-0.911)0.0040.891 (0.822-0.964) PCo&lt;.0010.714 (0.666-0.766)&lt;.0010.732 (0.680-0.787) Age0.002 &lt;.001 50-6425-390.1500.849 (0.679-1.061)0.1500.848 (0.678-1.061) 40-49&lt;.0010.895 (0.844-0.949)&lt;.0010.901 (0.849-0.956) 65-890.0830.928 (0.654-1.010)&lt;.0010.809 (0.724-0.905) 

Conclusions: To our knowledge this is the reported largest database of MMU. Race, insurance status and location remained independent predictors of repeat utilization. Interestingly an insured subset (MCare) was more likely to repeat utilize the van regardless of race and location. This may reflect the average age of screening mammography however a better understanding of the uninsured subset may be important given the intended outreach of the MMU.

Citation Format: Tezo Karedan, Elizabeth Riley, Lane Roland, Laura Barkley, Jianmin Pan, Shesh Rai, Sarah Mizuguchi. Multivariable analysis of repeat utilization of mobile mammography units: 10 year analysis of a comprehensive cancer center [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-11-07.