Abstract PR16: All-cause and cause-specific mortality among Medicaid-insured women with preexisting type 2 diabetes diagnosed with breast cancer: A cancer registry-Medicaid linkage
Authors: Lawrence Wayne R. , Hosler Akiko S. , Kuliszewski Margaret Gates , Leinung Matthew C. , Zhang Wangjian , Boscoe Francis P. 
Published: December 2020

Abstract
Background: Previous studies have reported that women with type 2 diabetes mellitus (T2DM) diagnosed with breast cancer have greater overall morality compared to nondiabetic breast cancer patients, while limited knowledge exists on cause-specific mortality. Among the nonelderly U.S. population, Medicaid-insured individuals have higher breast cancer mortality and elevated risk of T2DM-related complications compared to other insurance types. However, the role of preexisting T2DM on mortality among Medicaid-insured women diagnosed with breast cancer remains unknown. We investigated the influence preexisting T2DM and antidiabetic drugs have on all-cause and cause-specific mortality among Medicaid-insured women diagnosed with breast cancer. Methods: Data for 9,221 women aged &lt;64 years who were diagnosed with breast cancer and reported to the New York State (NYS) Cancer Registry from 2004-2016 were linked with Medicaid claims data. Preexisting T2DM was determined by three diagnosis claims for T2DM with at least one claim prior to breast cancer diagnosis and a prescription claim for an antidiabetic drug within three months following breast cancer diagnosis. Estimated menopausal status was determined by age (premenopausal age &lt;50; postmenopausal age ≥50). Hazard ratios (HR) and 95% confidence intervals (95%CI) were calculated with Cox proportional hazards regression, adjusting for potential confounders. Results: Women with preexisting T2DM had greater all-cause (HR=1.42; 95%CI 1.22, 1.65), cancer-specific (HR=1.26; 95%CI 1.06, 1.50), and cardiovascular-specific (HR=2.45; 95%CI 1.54, 3.89) mortality hazard compared to nondiabetic women. In subgroup analyses, the association between T2DM and all-cause mortality was observed among non-Hispanic White (HR 1.80 95%CI 1.39, 2.32), postmenopausal (HR=1.49; 95%CI 1.24, 1.79) women, but not among other race/ethnicity groups or premenopausal women. Additionally, compared to women prescribed metformin, all-cause mortality hazard was elevated among women prescribed sulfonylurea (HR=1.44; 95%CI 1.07, 1.94) or insulin (HR=1.54; 95%CI 1.12, 2.11). Conclusion: Among Medicaid-insured women with breast cancer, those with preexisting T2DM have an increased mortality hazard, especially when prescribed sulfonylurea or insulin. Further research is warranted to determine the optimal course of treatment for women with preexisting T2DM diagnosed with breast cancer.
Citation Format: Wayne R. Lawrence, Akiko S. Hosler, Margaret Gates Kuliszewski, Matthew C. Leinung, Wangjian Zhang, Francis P. Boscoe. All-cause and cause-specific mortality among Medicaid-insured women with preexisting type 2 diabetes diagnosed with breast cancer: A cancer registry-Medicaid linkage [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PR16.