Randomized controlled clinical trial of glargine versus ultralente insulin in the treatment of type 1 diabetes.

Objective: Multiple daily insulin injection programs are commonly accompanied by considerable glycemic variation and hypoglycemia. We conducted a randomized crossover design clinical trial to compare glargine with ultralente insulin as a basal insulin in type 1 diabetes.

Research Design And Methods: To determine whether the use of glargine insulin as a basal insulin would result in a comparable HbA1c and less glycemic variation and hypoglycemia than ultralente insulin, 22 individuals (aged 44 +/- 14 years [+/-SD], 55% men) with type 1 diabetes who were experienced with multiple daily insulin injections and had an HbA1c of <7.8% were randomized in a crossover design to receive either glargine or ultralente as the basal insulin for 4 months. Aspart insulin was used as the prandial insulin. Physicians providing insulin dose adjustment advice were masked to the type of basal insulin.

Results: Treatment with glargine resulted in lower mean HbA1c (6.82 +/- 0.13 vs. 7.02 +/- 0.13, difference: 0.2 +/- 0.08, P = 0.026), less nocturnal variability (plasma glucose 49.06 +/- 4.74 vs. 62.36 +/- 5.21 mg/dl, P = 0.04), and less hypoglycemia (24.5 +/- 2.99 vs. 31.3 +/- 4.04 events, P = 0.05), primarily due to less daytime hypoglycemia (P = 0.002). On the other hand, serious hypoglycemia and average glucose concentration measured with continuous subcutaneous glucose monitoring did not differ.

Conclusions: We conclude that while use of either ultralente or glargine as a basal insulin can result in excellent glycemic control, treatment with glargine is associated with slightly but significantly lower HbA1c and less nocturnal glycemic variability and hypoglycemia.