Serum GRB2 concentrations were significantly increased in T2DM combined with CAS, and serum GRB2 levels were linearly correlated with CIMT, suggesting that GRB2 may be involved in the occurrence and development of T2DM with CAS, which can be used as a predictor of whether T2DM is combined with CAS. Here, GRB2 is linked to type 2 diabetes mellitus.