This study is an extension of the randomized clinical trial titled “Short and Long-Term Effects of a DPP-4 Inhibitor Versus Bedtime NPH Insulin as Add-On Therapy in Patients with Type 2 Diabetes” (11) where 35 adult outpatients with T2D (aged 57 ± 7 years, 57.1% female) inadequately controlled with metformin plus glyburide, were randomized to receive either sitagliptin (100 mg once daily; SITA group) or bedtime NPH insulin (final dose of 11.0 ± 6.7 IU; NPH group). This evidence concerns the gene INS and type 2 diabetes mellitus.