Comparison of exenatide with biphasic insulin aspart 30 on glucose variability in type 2 diabetes: study protocol for a randomized controlled trial

BACKGROUND: Apart from the mean level of glycemic control, the extent of glucose excursions is another important issue to consider in type 2 diabetes mellitus (T2DM) management. Studies have showed that fluctuations of glucose seem to have more deleterious effects than sustained hyperglycemia in the development of diabetic complications as acute glucose swings activate the oxidative stress. However, until now, no randomized controlled trials have been conducted with the primary aim to evaluate glycemic fluctuation in the comparison between twice-daily exenatide and other treatment paradigms (for example, biphasic insulin aspart 30). METHODS/DESIGN: This multicenter, open-label, randomized, parallel trial includes a 1-week screening period and a 16-week treatment period. After the screening period, 150 patients with confirmed type 2 diabetes who are treated with stable, maximum-tolerated doses of metformin will be randomly assigned to one of two groups for antihyperglycemic therapies: exenatide and biphasic insulin aspart 30. The treatment with exenatide will be initiated at a low dose of 5 μg twice a day for 4 weeks and then titrated up to a standard dose of 10 ug twice a day until the completion of the study. The adjustment of insulin dose is instructed to achieve an optimal balance between glycemic control and the risk of hypoglycemia as dictated by clinical practice. The primary outcome is the absolute change of mean amplitude of glycemic excursion from baseline to week 16, which is calculated based on a real-time continuous glucose monitoring system (CGMS). DISCUSSION: This is the first randomized controlled trial using a CGMS to evaluate glycemic fluctuation between twice-daily exenatide and insulin aspart 30, which will provide beneficial evidence of exenatide usage in patients with T2DM. TRIAL REGISTRATION NUMBER: NCT02449603. Date of registration: 11 May 2015.