β-cell function and long-term glycemic control in patients newly diagnosed with type 2 diabetes with moderate hyperglycemia after a 6-month course of basal insulin therapy

To evaluate whether treatment with insulin is advantageous compared with oral anti-diabetic drugs (OAD) for patients newly diagnosed with type 2 diabetes with moderate hyperglycemia. Patients newly diagnosed with type 2 diabetes with moderate hyperglycemia were recruited and randomized to receive insulin, metformin or sitagliptin treatment. The oral glucose tolerance test (OGTT) was performed before treatment and 6 months thereafter. The primary outcome was the glycohemoglobin (HbA1c) level change. For the secondary efficacy analysis, the β-cell function and insulin sensitivity were calculated from the OGTT, as was the proportion of subjects who reached the treatment target (HbA1c level < 7.0 % or < 6.5 %) at 6 months. We randomized 50 patients to the three groups and 32 patients who received the allocated treatment were analyzed. The change of HbA1c level in the insulin, metformin, and sitagliptin groups was − 2.06 ± 1.37 %, −0.43 ± 0.32 %, and − 1.62 ± 0.92 %, respectively. This change was smallest in the metformin group. There was no significant difference in the changes or final HbA1c levels between the insulin and sitagliptin groups. The treat-to-target (HbA1c level < 7.0 %) rates in the insulin, metformin and sitagliptin were 75 %, 50 % and 100 %, respectively. The treat-to-target rates were not significantly different among the three groups. The insulin secretion indices, including the Matsuda index and HOMA-IR, indicated that the groups did not differ after 6 months of therapy. A 6-month course of basal insulin therapy did not benefit patients newly diagnosed with diabetes with moderate hyperglycemia in terms of insulin sensitivity or insulin secretion.