Abstract A062: Glycemic control and risk of total and advanced prostate cancer in Veterans with diabetes: analysis of disparities by race/ethnicity
Authors: Marrone Michael T. , Bishu Kinfe G. , Axon Neal , Florez Hermes , Grubb Robert L. , Gebregziabher Mulugeta 
Published: September 2024

Introduction Access to quality healthcare is considered a key driver in the multifactorial process giving rise to racial inequities in two of the most common complex diseases in adult men in the US - prostate cancer and diabetes. Whether inequities in diabetes treatment and outcomes, and/or related metabolic and hormone signaling pathways contribute to racial differences in prostate cancer outcomes in an equal access setting is unknown. Our objective is to determine if associations between glycemic control assessed by routine clinically measured hemoglobin A1c (A1c), among men with diabetes and risk of total and advanced prostate are similar in Black and White men receiving care from the Veterans Health Administration (VHA). Methods We used clinical data from the VHA to construct a longitudinal cohort of male Veterans &gt;=45 years of age with diagnosed diabetes free of any cancer from 01/01/2010 to 12/31/2019. We classified men with total prostate cancer if the date of prostate cancer diagnosis preceded any other cancer diagnosis. Advanced prostate cancer was classified as prostate cancer diagnosis with Gleason score &gt;=8, or PSA &gt;=100 ng/mL, or metastasis, or death from prostate cancer. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CI) for time-updated annual mean A1c (&lt;7% [ref]; 7-8%; &gt;8%) and total and advanced prostate cancer risk adjusted for age; marital status; rurality, smoking; annual primary care visits; service-connected disability; comorbidities; statin use; and oral diabetes medication use for non-Hispanic Black (NHB) and non-Hispanic White (NHW) men separately. Results Among 736,964 Veterans with diabetes, we observed 31,330 prostate cancer events including 6,779 advanced prostate cancers. For NHW men, poor glycemic control (A1c &gt;8%) and moderate control (A1c 7-8%) were associated with a 19% (HR=0.81; 95%CI=0.78-0.84) and 8% lower risk (HR=0.92; 95%CI=0.89-95) of total prostate cancer incidence (p-trend&lt;0.001). Among NHB men, inverse associations were attenuated for poor (HR=0.90; 95% CI=0.86-0.95) and moderate (HR=1.01; 95% CI=0.96-1.06) glycemic control and total prostate cancer risk (p-trend &lt;0.001). For advanced prostate cancer, associations were inverse for poor (HR=0.90; 95% CI=0.83-0.97) and moderate glycemic control (HR=0.90; 95% CI=0.84-0.97) and advanced prostate cancer risk in NHW men, while non-statistically significant associations were observed in NHB men with poor HR=1.06; 95%CI=0.96-1.18) and moderate glycemic control (HR=1.04; 95%CI=0.94-1.16). Conclusion In the largest equal access healthcare system in the US, inverse associations for glycemic control and risk of total and advanced prostate cancer varied by race/ethnicity with stronger inverse associations observed in NHW men compared to NHB men. Whether the racial differences in diabetes treatment and care contribute to the observed disparities in total and advanced prostate cancer risk could inform precision public health efforts aimed at reducing inequities in both diabetes and prostate cancer outcomes.

Citation Format: Michael T. Marrone, Kinfe G. Bishu, Neal Axon, Hermes Florez, Robert L. Grubb, Mulugeta Gebregziabher. Glycemic control and risk of total and advanced prostate cancer in Veterans with diabetes: analysis of disparities by race/ethnicity [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A062.