A Randomized Trial of Step-up Treatment with Premixed Insulin Lispro-50/50 vs. Aspart-70/30 in Patients with Type 2 Diabetes Mellitus

INTRODUCTION When insulin treatment is started in patients with type 2 diabetes mellitus (T2DM), there are many regimens that control serum glucose levels to a normal range. Basal-bolus insulin therapy is one of the most effective treatments for improving glycemic control to prevent the progression of diabetic microvascular complications. This study was conducted to determine whether step-up insulin treatment with premixed insulin aspart-30/70 (BIAsp 30) or lispro-50/50 (Mix50) in Japanese patients with type 2 diabetes mellitus could achieve better glycemic control. METHODS In this open label study, 72 insulin-naïve patients with poorly controlled T2DM (HbA1c ≥8.4%), who had been taking oral antidiabetic drugs for at least 12 months, were randomized to receive BIAsp 30 or Mix50 therapy. Patients started treatment of a pre-dinner injection of each type of insulin (Step 1). At 16 ± 2 weeks, a pre-breakfast injection of each type of insulin was added if HbA1c exceeded 7.4% (step 2). If patients had still not achieved HbA1c <7.4% after an additional 16 ± 2 weeks, a pre-lunch insulin injection was added (step 3). Hypoglycemic episodes were also recorded. RESULTS The cumulative percentages of subjects who achieved HbA1c <7.4% were 36.1% (13/36) for both Mix50 and BIAsp 30 in step 1, 62.9% (23/36) for BIAsp 30 and 52.8% (19/36) for Mix50 in step 2, and 66.7% (24/36) in BIAsp 30 and 72.2% (26/36) in Mix50 in step 3. The achievement rates of HbA1c <7.4% were not statistically different between the two groups. A total of ten hypoglycemic episodes occurred in this study. However, there were no severe hypoglycemic episodes. All cases recovered by taking glucose and drinking juice. CONCLUSION Mix50 step-up treatment has a clinical effect in achieving good glycemic control equal to that of BIAsp 30 treatment.