Background: In a previous pilot study comparing insulin glulisine (GLU) with insulin aspart (ASP) administered by continuous subcutaneous insulin infusion (CSII), GLU-treated patients did show a trend toward fewer catheter occlusions compared with ASP-treated patients. Here we performed a randomized open-label, three-way crossover, controlled multicenter study comparing GLU with ASP and insulin lispro (LIS).
Methods: Subjects with type 1 diabetes were allocated to one of three treatment orders-GLU-ASP-LIS, ASP-LIS-GLU, or LIS-GLU-ASP-with each insulin used for 13 weeks. The study was designed to demonstrate the superiority of GLU over ASP and LIS on unexplained hyperglycemia and/or perceived infusion set occlusion. A prespecified P value of 0.025 was considered significant to correct for multiple testing.
Results: Percentages of subjects with at least one unexplained hyperglycemia and/or infusion set occlusion were not significantly different between GLU and ASP (68.4% [62.7-74.1%] vs. 62.1% [56.2-68.1%], P = 0.04) and GLU and LIS (68.4% [62.7-74.1%] vs. 61.3% [55.4-67.3%], P = 0.03). No differences were seen in hemoglobin A1c at end point, most points of the seven-point glucose curves, severe hypoglycemia, and symptomatic ketoacidosis. The overall rate of hypoglycemia with a plasma glucose level below 70 mg/dL per patient-year was significantly different between GLU and ASP (73.84 vs. 65.01, P = 0.008) and GLU and LIS (73.84 vs. 62.69, P < 0.001). Insulin doses remained unchanged during the trial.
Conclusions: GLU was not superior to ASP and LIS with no significant difference seen among GLU, ASP, and LIS in CSII use with respect to unexplained hyperglycemia and/or perceived catheter set occlusion. GLU was associated with a higher frequency of symptomatic hypoglycemia, possibly because of slight overdosing, as previous trials suggested lower insulin requirements when GLU is initiated in type 1 diabetes.
Trial registration: ClinicalTrials.gov NCT00607087.