Racial Differences in the Association of Glucagon-like Peptide 1 Agonist Use and the Progression of Monoclonal Gammopathy of Undetermined Significance to Multiple Myeloma in US Veterans with Diabetes Mellitus

Background: Glucagon-like peptide 1 (GLP-1) agonists are antidiabetic medications that exert cardiac and renal benefits in addition to their well-established antihyperglycemic effects. A prior analysis has shown that GLP-1 agonist use is associated with a 65% reduction in the risk of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM) in US Veterans with diabetes mellitus (DM). However, it is unknown whether there are racial differences to this effect of GLP-1 agonists. We aimed to assess the racial differences in the association between GLP-1 agonist use and the progression risk in diabetic patients with MGUS.

Methods: Patients diagnosed with MGUS in the Veterans Health Administration (VHA) database from 10/1/99-12/31/21 were identified using ICD codes. A natural language processing algorithm was used to confirm MGUS diagnosis and progression to smoldering MM or MM. Patients diagnosed with MGUS before DM and those who experienced progression within 1 year of MGUS diagnosis or within 2 years of DM diagnosis were excluded. For each race, we performed 1:2 matching for patients with and without GLP-1 agonist use based on follow-up time. The outcome was progression to smoldering MM or MM. Cumulative incidence functions stratified by GLP-1 agonist use (ever vs. never use) were plotted and a Gray's test was performed to detect the difference between the functions. The association between time-varying GLP-1 agonist use and MGUS progression was estimated using a multivariable Fine-Gray subdistribution hazard model with death as a competing event.

Results: Our NLP algorithm confirmed 20,832 patients with DM and MGUS. After applying our inclusion and exclusion criteria, we had 9,294 white patients and 4,981 black patients, of which 909 and 403, respectively, were GLP-1 agonist users. After matching, our analytic cohort included 2,718 white patients (33.3% with GLP-1 agonist use) and 1,191 black patients (33.3% with GLP-1 agonist use). GLP-1 agonist use was associated with a dramatically significant reduction in progression rate in white patients (aHR 0.25; 95% CI 0.09-0.68), while the association was not shown in black patients (aHR 1.01; 95% CI 0.36-2.90).

Conclusion: For patients with MGUS and DM, GLP-1 agonist use is associated with a 75% reduction in progression risk in white patients and no significant reduction in black patients. This highlights a racial disparity in the potential role of GLP-1 agonist for chemoprevention in the management of MGUS.