INS and diabetes mellitus: Diabetic subjects were divided into 4 subgroups: those receiving monotherapy with metformin (n = 34); those receiving combination therapy without metformin [instead receiving sulfonylurea (SU), and thiazolidinedione (TZD) with or without insulin] (n = 28); those receiving combination therapy with metformin (metformin, SU, and TZD with or without insulin) (n = 241); and non-treated diabetes (n = 8).