The effect of insulin lispro on glycemic control in a large patient cohort.

BACKGROUND: The use of rapid-acting insulin analogs and regular insulin differs considerably in countries throughout the world. We therefore studied how glycemic control has been affected by using insulin lispro in clinical practice over 5 years in 14 hospitals in Sweden.

METHODS: We used a time period when most patients had not changed the basal insulin, but only the mealtime insulin. Accordingly the most recent years were not suitable since many patients had changed basal insulin from NPH to glargine or determir. We therefore analyzed the metabolic consequences on glycosylated hemoglobin (HbA1c) when changing from regular insulin to insulin lispro from 1997 and during the following 5 years. We studied 1,069 patients with diabetes taking NPH insulin as basal insulin and at least three daily injections of regular insulin, of whom 423 changed their mealtime insulin to insulin lispro and 646 controls who continued with regular insulin.

RESULTS: Patients changing to insulin lispro on average decreased by 0.19% units more in HbA1c than those remaining on regular insulin. The effect was most pronounced in patients with high HbA1c even after controlling for regression to the mean. A beneficial effect of insulin lispro was also indicated since patients had the same level of HbA1c during a long period of time with regular insulin but then dropped when changing to insulin lispro.

CONCLUSIONS: This study indicates that insulin lispro has had a beneficial and persisting effect on glycemic control when used in patients with diabetes on multiple daily injections of insulin in clinical practice.