Noninferiority effects on glycemic control and β-cell function improvement in newly diagnosed type 2 diabetes patients: basal insulin monotherapy versus continuous subcutaneous insulin infusion treatment

Abstract

Aims: In newly diagnosed type 2 diabetes mellitus (T2DM) patients, short-term insulin therapy might improve β-cell function and glycemic control. This study aimed to compare the effects of basal insulin monotherapy with continuous subcutaneous insulin infusion (CSII) treatment.

Methods: Fifty-nine cases of newly diagnosed T2DM patients with fasting plasma glucose of 9.0-16.7 mmol/L were recruited into this study. They were hospitalized and randomly assigned to a basal insulin monotherapy group (n=27) or a CSII group (n=32). Insulin dosage was titrated according to fasting capillary blood glucose levels, and treatment was stopped after 2 weeks. Intravenous glucose tolerance tests were performed, and blood glucose, insulin, C-peptide, and lipid profiles were measured before therapy and 2 days after therapy withdrawal.

Results: Both treatments reduced fasting and postprandial blood glucose levels (after treatment vs. baseline, both P<0.05). Fasting glycemic control target was achieved in 52 cases (88.14%) with 2 weeks of insulin treatment, and there were no significant differences between the glargine and CSII groups (P=0.059). The time to achieve fasting glycemic target in the CSII group was shorter than that in the glargine group (P<0.01). Plasma lipid profiles such as triglycerides and total cholesterol also decreased significantly after the intervention. Overall β-cell function improved significantly after insulin intervention (P<0.01). Variation did not differ between two groups, nor did the effects on insulin and C-peptide secretion (P>0.05).

Conclusions: The effect of basal insulin monotherapy was similar to that of CSII, and thus basal insulin monotherapy might be a reasonable alternative to CSII for initial insulin therapy in newly diagnosed T2DM patients.

FIG. 1.

Dynamic changes of capillary blood glucose with time in two insulin treatment schemes: (A) fasting blood glucose (FBG) and (B) 2-h postprandial blood glucose (PBG). FBG levels compared between the two groups were not significantly different (P>0.05); 2-h PBG levels compared between the two groups were significantly different (*P<0.05, **P<0.01). CSII, continuous subcutaneous insulin infusion.

FIG. 2.

Changes in (A) plasma fasting insulin and (B) C-peptide during intravenous glucose tolerance test before and after insulin treatment. Both groups' plasma fasting insulin and C-peptide levels were elevated after insulin treatment, compared with before (P<0.05), and there was no statistical difference between the two groups (P>0.05). CSII, continuous subcutaneous insulin infusion.

FIG. 3.

(A) Area under the curve for insulin (AUC_Ins), (B) area under the curve for C-peptide (AUC_Cpep), and (C) acute insulin response (AIR) in the two groups before and after insulin therapy. P<0.01 before versus after insulin therapy in each group, P>0.05 between the two groups both before and after insulin therapy.