Background and aim: While lispro insulin has been reported to lower postprandial blood glucose concentrations, less consistent effects have been shown for glycosylated hemoglobin (HbA1c) levels. Aim of this study was to determine whether pre-meal association of NPH, an intermediate-acting insulin, with lispro improves overall glycemic control in type 1 diabetic patients.
Methods and results: Eighty-five type 1 diabetic patients were studied in a multicenter randomized comparative (human regular vs lispro insulin) crossover (3-month) study in which NPH insulin was given as a dinner or bedtime injection and at breakfast and lunch if necessary. The number of injections was kept constant: 42% and 58% of patients injected insulin 3 and 4 times per day, respectively. Fasting and preprandial blood glucose levels were similar, while postprandial levels improved after lispro compared to human regular insulin (breakfast: 8.28 +/- 2.39 vs 9.28 +/- 2.72 mmol/l; lunch: 8.33 +/- 2.67 vs 9.06 +/- 2.67 mmol/l, dinner: 8.06 +/- 2.72 vs 9.28 +/- 2.44 mmol/l, ANOVA: p = 0.003). HbA1c also improved after lispro: 8.1 +/- 0.9 vs 8.3 +/- 0.8%, p < 0.05. The rate of hypoglycemia was similar. Patients showed better acceptance of lispro treatment (p < 0.001).
Conclusions: Lispro improves overall blood glucose control in type 1 diabetic patients without increasing the incidence of hypoglycemia. This can be achieved by an optimal combination of lispro insulin with NPH whenever the time intervals between meals are too long.