Abstract C013: Racial difference in risk factors for monoclonal gammopathy of undetermined significance – The premalignant stage of multiple myeloma
Authors: Yu Yao-Chi , Wang Mei , Kumar Akhil , Vargo Kristin , Liu Lawrence , Thomas Theodore , Sanfilippo Kristen , Schoen Martin , Colditz Graham , Li Jr-Shin , Chang Su-Hsin 
Published: January 2023

Abstract
Background: Black race and obesity are known risk factors for type 2 diabetes mellitus (T2DM), multiple myeloma and its precursor condition – monoclonal gammopathy of undetermined significance (MGUS). Yet, little is known about what contributes to this racial difference, particularly in MGUS, and studies have inconsistently shown that T2DM may not be a risk factor for myeloma. We aimed to investigate the racial differences in risk factors for MGUS in patients with T2DM. Methods: Patients diagnosed with T2DM from 1999-2021 in the Veterans Health Administration were identified. We used a natural language processing-based algorithm to confirm MGUS diagnosis. Among them, patients of Black and White races with ≥2 BMI measurements were included. To preserve the prevalence of MGUS in the respective population, each Black patient with MGUS was matched to 27 Black patients without MGUS; and each White patient with MGUS was matched to 44 White patients without MGUS on BMI observation window. BMI observation window for each MGUS patient was defined as time from the 1st to the last BMI measurement before MGUS diagnosis. For the matched patients without MGUS, a similar length of observation window was selected along with ≥1 measurement beyond the window to ensure no loss to follow-up during the window. Each cohort was further split into the training (80%) and testing (20%) sets. Ad-hoc features for BMI in different statistics to summarize repeated measurements within the window were defined: average, variance (var), maximum (max), minimum (min), max BMI increase per month (max dBMI/m), max BMI decrease per month (min dBMI/m), and area under the dBMI curve. Ad-hoc features for other variables, HbA1c, creatinine, potassium, and glucose, were constructed in a similar fashion. To overcome the imbalanced MGUS cases (vs no MGUS), Synthetic Minority Over-Sampling Technique algorithm was used. To evaluate performance, we implemented 5-fold cross-validation using logistic regression and generated AUC score. Results: A total of 2,468 White and 3,981 Black T2DM MGUS patients were included. Logistic regression achieved an average AUC score of 0.76 (95% CI 0.72, 0.79) for Whites and 0.76 (95% CI 0.73, 0.78) for Blacks. In both races, the most significant risk factor for MGUS was max dBMI/m, followed by max BMI for Whites and var BMI for Blacks. Conversely, min glucose was the most significant factor inversely associated with the incidence of MGUS for both races. Conclusion: There is no significant difference in the most significant factors contributing to MGUS between the two races. In patients with T2DM, drastic change in body weight is the most significant risk factor for MGUS among others, while maintaining low glucose is the most protective factor for both races. Regardless of race, T2DM patients of high myeloma risk are encouraged to maintain a stable weight and low glucose level.
Citation Format: Yao-Chi Yu, Mei Wang, Akhil Kumar, Kristin Vargo, Lawrence Liu, Theodore Thomas, Kristen Sanfilippo, Martin Schoen, Graham Colditz, Jr-Shin Li, Su-Hsin Chang. Racial difference in risk factors for monoclonal gammopathy of undetermined significance – The premalignant stage of multiple myeloma [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C013.