In this nationwide cohort study of more than 80 000 older adults with T2D and CVD, we found that those in the highest quartile of OOP costs were 13% and 20% less likely to initiate a GLP-1 RA or SGLT2 inhibitor, respectively, when compared with those in the lowest quartile of OOP costs. This evidence concerns the gene SLC5A2 and type 2 diabetes mellitus.