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 HbA_1c 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 HbA_1c 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 HbA _1c (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 HbA_1c and less nocturnal glycemic variability and hypoglycemia.