INS and type 2 diabetes mellitus: Patients with T2DM were categorized into one of the three groups: (1) patients on treatment with oral hypoglycemic agent(s) only, (2) patients on combination treatment with oral hypoglycemic agent(s) and insulin, and (3) patients diagnosed with or suspected to have T2DM with no current or past experience with T2DM drug treatment (treatment naïve).