A prospective study to optimize insulin treatment by switching to insulin glargine in type 2 diabetic patients previously uncontrolled on premixed insulin: the optimization study

Objective: To evaluate the efficacy, safety and treatment satisfaction of insulin glargine plus oral antidiabetic drugs (OADs) in Chinese individuals with Type 2 diabetes inadequately controlled with premixed insulin plus OADs. Methods: In this open-label, single-arm, 16-week, phase IV study, 313 subjects with Type 2 diabetes inadequately controlled with premixed insulin plus OADs were switched to insulin glargine plus OADs. Changes in glycaemic control, incidence of hypoglycaemia and treatment satisfaction using the Diabetes Treatment Satisfaction Questionnaire (DTSQ) were evaluated. Results: Switching to insulin glargine was associated with significant reductions in levels of glycosylated haemoglobin (HbA(1c); 8.4 +/- 0.6 to 7.9 +/- 1.0%; p<0.001) and fasting plasma glucose (FPG; 9.50 +/- 2.10 to 6.58 +/- 2.07 mmol/L; p<0.001). A total of 32.9% of subjects experienced hypoglycaemia, including two cases of severe hypoglycaemia. Treatment satisfaction was improved with insulin glargine (DTSQ 8-item scores, all p<0.001). Logistic regression analysis showed a significant association between baseline HbA(1c), disease duration, endpoint FPG and HbA(1c)<57%. Conclusion: This single-arm study suggested that switching to insulin glargine plus OADs significantly improved glycaemic control, with a low incidence of hypoglycaemia, in patients with Type 2 diabetes uncontrolled on premixed insulin plus OADs. Switching to insulin glargine was also associated with better patient treatment satisfaction compared with previous treatment. The main limitations to this study are the open-label design and the lack of a control arm.