Comparison of Insulins Aspart and Lispro in Insulin Pumps

A Comparison of the Efficacy Beyond 48 Hours of Insulin Aspart (Novolog) and Lispro (Humalog) in Insulin Pumps

The purpose of the study is to compare the glycemic control between insulins aspart and lispro 48 to 100 hours after pump infusion line change in subjects with type 1 using diabetes using an insulin pump.

Continuous subcutaneous insulin infusion (Insulin pump therapy) is a well established tool for the management of type 1 diabetes. In clinical trials, insulin pump therapy has been shown to have increased efficacy over multiple daily injections. However, the overall glycemic control in patients using insulin pumps has been disappointing. The recommended duration of "needle use" in insulin pump treatment is 48 hours, based on anecdotal observations. One of the reasons for the suboptimal control may be that patients do not adhere to the advice of changing their pump infusion line every 48 hours. However, it is possible that the loss of glycemic control may be related to instability of insulin in the pump/line. In addition to premeal loss of control after 48 hours of line change, very little is known about post-prandial hyperglycemia leading to loss of efficacy of the insulin via an insulin pump bolus. The development of continuous glucose monitoring system (CGMS) and new tests for short term fluctuations in glucose control such as 1,5-anhydroglucitol make it easier to evaluate the impact of short term loss of control in patients using the insulin pump who delay changing their lines. The different variables will be compared between the two insulins using a paired t test. Glycemic control will be will be compared 24 to 100 hours after pump infusion line change using CGMS and daily serum 1,5-anhydroglucitol. Post prandial glycemic excursions in plasma glucose following a standardized breakfast 48, 72, and 96 hours after a pump infusion line change will be compared. The used pump infusion line will be collected from the patient and analyzed for insulin binding to the plastic, as well as other possible effects that may determine its role in loss of glycemic control. Comparison of some of the markers of coagulation, inflammation, protein glycation and oxidative stress 48, 72, and 96 hours after a pump infusion line change.

Type 1 diabetes mellitus, Glycemic control, Continuous subcutaneous insulin infusion, Continuous glucose monitoring system

Between insulin Aspart and insulin Lispro, the one that was not used as insulin 1 was then used as the second insulin for the second arm of the study.

Either one of these insulins were given to the patient as the second insulin (depending on which was given as the first one, the other insulin was insulin 2). Patients used this insulin in the same dose as they did prior to entering the study.

Patients were given either insulin Aspart or Lispro in test period 1. Then they were switched to the other insulin in test period 2.

Number of Participants With Glycemic Control (Glucose Levels Between 180-300 mg/dL) 24 to 100 Hours After Line Change

For each test period, we measured the duration of time that the same pump infusion line could be kept in place without losing glycemic control. Loss of glycemic control was defined as capillary blood glucose level >300 mg/dL.

Daily serum glycomark levels between day 3 and day 5 after the pump infusion line change. These levels were measured for both the test periods.

Free 15-F2t isoprostane was measured between days 3 and 5 after the keeping the same pump infusion line in place. It is a marker of oxidative stress due to hyperglycemia that was being compared between the two test periods.

Inclusion Criteria: Type 1 Diabetes treated with a pump for at least 3 months Exclusion Criteria: Pregnancy Plasma Creatinine > 1.2 mg/dl Inability to give informed consent HbA1c > 8% Known or suspected hypersensitivity to trial drugs or any of their components