Insulin lispro protamine suspension in intensive insulin treatment: an Italian observational study

This observational study examined the effects of insulin lispro protamine suspension (ILPS) given as basal insulin in intensive insulin regimens in patients with type 1 and type 2 diabetes mellitus who attended a reference outpatient centre for the treatment of diabetes due to poor glycaemic control, frequent hypoglycaemia or intolerance to previous therapy.

The study population included 64 patients, 33 male and 31 female, mean age 59.6 years; 50 patients were receiving an insulin regimen, while 14 had previously been treated with oral antidiabetic drugs (OADs). The starting insulin dose for patients receiving OADs was 0.5-0.8 IU/kg which was titrated according to a standard algorithm. Patients also received an individualised programme for diet adjustment and physical activity. Fasting plasma glucose (FPG), glycosylated haemoglobin (HbA(1c)), hypoglycaemic events, lipid profile, body weight and blood pressure were measured at baseline and thereafter.

The mean duration of therapy was 229.3 days. Total insulin daily dosage did not change statistically in the observation period. FPG and HbA(1c) levels decreased significantly (p < 0.001) in this period, with no increase in hypoglycaemic episodes. Univariate analysis has shown that patients having higher HbA(1c) and FPG levels at baseline have higher improvement in HbA(1c) and FPG than those having better glycaemic control at baseline. Patients with concomitant pathologies at baseline had a significantly lower improvement in HbA(1c) and FPG, while females had a significantly higher improvement in HbA(1c). Frequency of hypoglycaemic episodes was significantly lower in those patients who had previously experienced hypoglycaemia, had previously used insulin therapy, had concomitant pathologies, had HbA(1c) above 6.5% at baseline and required higher total daily insulin doses. A significant improvement in total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride levels, together with a significant decrease in the cardiovascular risk index, were also observed, with no significant variation in body weight and blood pressure.

This study shows that the use of ILPS as basal insulin in intensive insulin therapy, improved glycaemic control with no significant increase in hypoglycaemic episodes in the 64 patients observed undergoing treatment at the Potenza outpatient clinic. Because of the nature of this study, these results have to be confirmed in further randomised, controlled clinical trials.