Effect of the fast-acting insulin analog lispro on the risk of nocturnal hypoglycemia during intensified insulin therapy. U.K. Lispro Study Group.

OBJECTIVE: To measure the effectiveness of insulin lispro, a fast-acting insulin analog, in reducing hypoglycemic episodes when used in a basal bolus regimen by patients with type 1 diabetes using intensive insulin therapy. RESEARCH DESIGN AND METHODS: In 11 diabetes outpatient clinics in the U.K., 165 subjects with type 1 diabetes were enrolled in a randomized crossover open-label study with a 2-month run-in period and then treated with a basal bolus regimen. Patients used human NPH insulin at night with either premeal insulin lispro for 4 months followed by human regular insulin for another 4 months or human regular insulin for 4 months followed by insulin lispro for another 4 months. The main outcome measures were the number of hypoglycemic episodes during both treatments and HbA1c level. RESULTS: A total of 135 patients were randomized, with 68 receiving insulin lispro and 67 receiving human regular insulin for the first 4 months. The data for the first 4 months of treatment only were compared as two independent groups because of a period effect and a treatment-period interaction. Glycemic control was equally tight during treatment with human regular insulin (HbA1c, 6.2 +/- 0.8%) and insulin lispro (6.0 +/- 0.9%). A total of 1,156 hypoglycemic episodes occurred during treatment with human regular insulin compared with 775 hypoglycemic episodes that occurred during treatment with insulin lispro (P = 0.04). This difference was chiefly because of a reduced number of nocturnal episodes (181 vs. 52, P = 0.001) in the insulin lispro group. CONCLUSIONS: The use of a fast-acting insulin analog, insulin lispro, as part of a basal bolus regimen reduces nocturnal hypoglycemia in patients with type 1 diabetes who maintain tight glycemic control during intensive insulin therapy.