Beneficial effects of insulin on glycemic control and beta-cell function in newly diagnosed type 2 diabetes with severe hyperglycemia after short-term intensive insulin therapy

Abstract

Objective: To evaluate whether treatment with insulin is advantageous compared with oral antidiabetes agents in newly diagnosed type 2 diabetes with severe hyperglycemia after short-term intensive insulin therapy.

Research design and methods: Newly diagnosed type 2 diabetic patients with severe hyperglycemia were hospitalized and treated with intensive insulin injections for 10-14 days. The oral glucose tolerance test (OGTT) was performed after intensive insulin treatment. After discharge, the patients were randomized to receive either insulin injections or oral antidiabetes drugs (OADs) for further management. The OGTT was repeated 6 months later, and beta-cell function and insulin sensitivity were evaluated again. These subjects were continually followed up for another 6 months to evaluate their long-term glycemic control.

Results: At the 6th month of the study, the A1C level was significantly lower in the insulin group than in the OAD group (6.33 +/- 0.70% vs. 7.50 +/- 1.50%; P = 0.002). During the follow-up visit, the A1C level was still better in the insulin group (6.78 +/- 1.21% vs. 7.84 +/- 1.74%; P = 0.009). All parameters regarding beta-cell function measured in the OGTT were improved significantly in both groups after 6 months of treatment. Compared with the OAD group, the homeostasis model assessment of beta-cell function index, insulin area under the curve, and insulinogenic index were better in the insulin group.

Conclusions: A 6-month course of insulin therapy, compared with OAD treatment, could more effectively achieve adequate glycemic control and significant improvement of beta-cell function in new-onset type 2 diabetic patients with severe hyperglycemia.

Trial registration: ClinicalTrials.gov NCT00506194.

Figure 1

Glycemic control in the insulin treatment group and OAD treatment group. A: FPG concentration (mean ± SE) in both groups in the study period; −2 weeks means prerandomization. •, insulin group; ○, OAD group. B: The A1C changes (mean ± SE) in both groups during the study period and follow-up visit. •, insulin group; ○, OAD group. C: The proportion with A1C <6.5 or 7.0% at 6 months and 1 year. *P < 0.05 between groups. ▪, insulin group; □, OAD group.

Figure 2

Mean ± SE for plasma glucose (A) and insulin (B) concentration during the OGTT at baseline and 6 months later in both groups. *P < 0.05 between groups; #P < 0.05 baseline vs. after treatment. •, OAD group, after treatment; ○, OAD group, at baseline; ▾, insulin group, after treatment; ▵, insulin group, at baseline.