A comparison of twice-daily biphasic insulin aspart 70/30 and once-daily insulin glargine in persons with type 2 diabetes mellitus inadequately controlled on basal insulin and oral therapy: a randomized, open-label study.

Objective: To compare efficacy and safety of biphasic insulin aspart 70/30 (BIAsp 30) with insulin (glargine) in type 2 diabetic patients who were not maintaining glycemic control on basal insulin and oral antidiabetic drugs.

Methods: In a 24-week, open-label, parallel-group trial, type 2 diabetic patients who were not maintaining glycemic control on basal insulin (glargine or neutral protamine Hagedorn) + oral antidiabetic drugs were randomly assigned to twice-daily BIAsp 30 + metformin or once-daily glargine + metformin + secretagogues (secretagogues were discontinued in the BIAsp 30 arm).

Results: One hundred thirty-seven patients were randomly assigned to the BIAsp 30 group and 143 patients were randomly assigned to the glargine group. Of 280 patients randomized, 229 (81.8%) completed the study. End-of-trial hemoglobin A1c reductions were -1.3% (BIAsp 30) vs -1.2% (glargine) (treatment difference: 95% confidence interval, -0.06 [-0.32 to 0.20]; P = .657). Of patients taking BIAsp 30, 27.3% reached a hemoglobin A1c level <7.0% compared with 22.0% of patients taking glargine (treatment difference: P = .388). Glucose increment averaged over 3 meals was lower in the BIAsp 30 arm (treatment difference: -17.8 mg/dL, P = .001). Fasting plasma glucose reductions from baseline were -13.8 mg/dL (BIAsp 30) vs -42.5 mg/dL (glargine) (P = .0002). Final minor hypoglycemia rate, insulin dose, and weight change were higher in the BIAsp 30 arm (6.5 vs 3.4 events/patient per year, P<.05; 1.19 vs 0.63 U/kg; and 3.1 vs 1.4 kg, P = .0004, respectively).

Conclusions: Despite not receiving secretagogues, patients taking BIAsp 30 + metformin achieved similar hemoglobin A1c levels and lower postprandial plasma glucose compared with those receiving glargine + metformin + secretagogues. The large improvement in the glargine group suggests the patients were not true basal failures at randomization. While switching to BIAsp 30 improves glycemic control in this patient population, remaining on basal insulin and optimizing the dose may be equally effective in the short term.