Abstract P2-04-07: Insurance status as predictor of repeat mobile mammography utilization: 10 year analysis of a comprehensive cancer center
Authors: Riley EC , Roland LM , Barkley LE , Mandadi M , Pan J , Rai SN , Mizuguchi SG 
Published: August 2014

Abstract
Introduction: Mobile Mammography Units (MMU) have become a model of community outreach. The purpose of this study was to analyze the association between utilization of MMU and insurance status in the largest county in Kentucky. Methods: From January 2001- December 2010, our MMU performed 21,857 screening mammograms. Demographic data was retrospectively reviewed to identify insurance status and trends in utilization for each of these encounters. Insurance type was classified as Private Insurance, Public insurance/Medicaid, Public insurance/ Medicare and Uninsured. Insurance type was classified based on the patient's primary insurer. Utilization was defined as once or more than 2 times in a 10 year period. Descriptive statistics related to insurance status were produced and statistical comparisons were conducted between one-visit patients (11816 patients) and more than one-visit patients (10041 patients). P-values were calculated using Chi-square test for comparison between the two groups. Odds ratio and its 95% confidence interval were provided. All calculations were performed with SAS statistical software (SAS Institute Inc., Cary, NC). Results: Uninsured and Private insured accounted for the majority of encounters (43% and 36% respectively.) Medicaid accounted for the least at 5%. The majority of women utilized the MMU once in a 10 year period (54%.) Overall, Private insured patients were more likely than Uninsured to only utilize the van once in 10 year period. (OR 1.075 (1.012-1.142) p = &lt;.001.) Medicare patients were less likely than uninsured to utilize the van only once (OR 0.888 (0.821-0.959) p = &lt; .001.) Medicaid utilization was similar to that of uninsured (OR 1.123 (0.981-1.279.) Among the insured subgroup, Private insurance and Medicaid were more likely than Medicare to utilize the van only once in a 10 year period (OR 1.211 and 1.266 respectively).
Table 1: Insurance Type by Number of Screens (1 vs ≥2) Number of Screens VariablesTotal (N = 21857)1 (N = 11816) (%)≥ 2 (N = 10041) (%)p valueOdds Ratio (95% CI)Insurance &lt;.001 Private78814378 (55.6)3503 (44.4) 1.075 (1.012- 1.142)Medicaid1033585 (56.6)448 (43.4) 1.123 (0.987-1.279)Medicare35211788 (50.8)1733 (49.2) 0.888 (0.821-0.959)Uninsured94225065 (53.8)4357 (46.2) ReferenceInsured Subgroup &lt;.001 Private78814378 (55.6)3503 (44.4) 1.211 (1.119-1.312)Medicaid1033585 (56.6)448 (43.4) 1.266 (1.101-1.455)Medicare35211788 (50.8)1733 (49.2) Reference
Conclusion: To our knowledge this is the largest database of MMU reported in the literature. Unique to our MMU program is community outreach to both public health centers and corporate venues capturing varied insurance types. In this dataset, the majority of women, regardless of insurance type utilize the van only once in a 10 year period. Interestingly, an insured subgroup (Medicare) was the most likely to utilized the van more than once in a 10 year period. Further analysis is needed to understand how race and/or screening location impacts repeat utilization as it relates to insurance. The low number of Medicaid reaching the MMU (5%) is concerning given the partnership with Public Health Centers. Understanding utilization based on insurance has implications for funding and future patterns of outreach.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-04-07.