The purpose of this investigator-initiated trial is to compare the effect of a daily injection of insulin degludec vs. basal insulin delivery via Continuous Subcutaneous Insulin Infusion (CSII), both in combination with bolus insulin delivery via the patient's usual insulin pump with insulin aspart, on glycemic variability, overall blood glucose control and incidence of hypoglycemia, all assessed by continuous glucose monitor (CGM), as well as patient satisfaction, in patients with type 1 diabetes currently using CSII.
The primary objective of this trial is to determine whether insulin degludec will provide an equally stable and consistent basal glycemic profile with lower glycemic variability as determined by Continuous Glucose Monitoring compared to insulin aspart delivered by Continuous Subcutaneous Insulin Infusion in patients with type 1 diabetes experienced in use of insulin pump therapy. Specifically, this study will determine if the percent time in the target glycemic range (70 to 180 mg/dl) by Continuous Glucose Monitoring is superior using insulin degludec than continuously infused insulin aspart, and if degludec is associated with lower glucose variability as assessed by the standard deviation (SD) of the mean daily glucose by Continuous Glucose Monitoring. Particular attention will be given to the nocturnal glucose profile (from midnight to 6 am) which most closely reflects basal insulin action as it is typically the time of day least affected by bolus insulin, food intake or exercise. Quality of life questionnaires regarding treatment preference will be used to capture patient preference for method of basal insulin delivery. RESEARCH DESIGN AND METHODS Study hypothesis: It is anticipated, based on the low glycemic variability of insulin degludec shown in glucose clamp studies and seen in clinical practice, that insulin degludec will provide more stable 24 hour basal insulin action than insulin aspart by Continuous Subcutaneous Insulin Infusion (CSII) in patients with type 1 diabetes. Primary endpoint: Percent time in euglycemia (BG 70 to 180 mg/dl) by Continuous Glucose Monitoring (CGM) during the final 14 days of each treatment period during steady state (with basal insulin delivery as either one daily injection of insulin degludec or as insulin aspart via CSII). Study type: This will be a randomized, cross-over, open label, single-center study consisting of a 20 week period on each of two basal insulin delivery methods, both in combination with insulin aspart with boluses taken by insulin pump. Each 20 week period will consist of a 4 week insulin optimization period for titration of basal and bolus insulin doses, followed by a 16 week maintenance period. The final 2 weeks of the maintenance period during each treatment arm will be used for endpoint data collection. The treatment sequence will occur in random order. The study population will include patients with type 1 diabetes with good baseline glycemic control who are experienced in the use of both CSII and CGM; the cross-over design allows each subject to serve as his or her own control.
A population of well controlled patients with type 1 diabetes who are experienced in the use of both Continuous Subcutaneous Insulin Infusion (CSII) and Continuous Glucose Monitor (CGM) was chosen in order to assess the effect of the change in glycemic profile using two different methods of basal insulin delivery. Allowing the subjects to use their insulin pumps for bolus insulin delivery, as they are accustomed, will minimize the chances of skipping meal boluses and correction doses. Replacing basal insulin delivery by CSII with a single daily injection of degludec will add minimal, if any, treatment burden which will be offset by potential therapeutic benefits. These benefits include the potential for reduced glycemic variability and the elimination of the risk of hyperglycemia and DKA with basal insulin interruption which can occur with infusion set occlusion or disgorging inherent to Continuous Subcutaneous Insulin Infusion.
Mountain Diabetes and Endocrine Center
Asheville, North Carolina, United States
Percent time in euglycemia (BG 70 to 180 mg/dl) by CGM
Percent time in euglycemia (BG 70 to 180 mg/dl) by CGM during the final 14 days of each treatment period during steady state (with basal insulin delivery as either one daily injection of insulin degludec or as insulin aspart via CSII)
Time frame: 46 weeks
Standard Deviation (SD) of blood glucose by CGM for two week period
SD of interstitial fluid glucose by CGM for 2 week period during each basal insulin delivery method. (Note: because the Dexcom Platinum G5 CGM is currently only FDA approved for 7 days of use, two contiguous CGM periods using 2 sensors, each for 7 days, will be performed to capture 2 weeks of continuous CGM data.) Dexcom G6 is approved by FDA for 10 days of use so 2 sensors will be used during the CGM periods.
Time frame: 46 weeks
SD of blood glucose by CGM during the nocturnal period
SD of blood glucose by CGM during the nocturnal period (midnight to 6 am) during each basal insulin delivery method
Time frame: 46 weeks
Percent time in hypoglycemia by CGM
Percent time in hypoglycemia by CGM, captured at 2 levels of hypoglycemia: BG \< 54 mg/dl (level 2) and BG 55-69 mg/dl (level 1), for each basal insulin treatment.
Time frame: 46 weeks
Percent time in normoglycemia
Percent time in normoglycemia (BG 70 to 140 mg/dl) by CGM during each basal treatment period.
Time frame: 46 weeks
Time to recovery from level 2 hypoglycemia
Time to recovery from level 2 hypoglycemia (BG \>70 with resolution of symptoms) on each treatment. If a second event (BG \< 70 mg/dl) occurs within 60 minutes of a previous hypoglycemic event, this will be considered part of the same hypoglycemic episode.
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
59
Time frame: 46 weeks
Patient satisfaction
Patient satisfaction by TRIM-D questionnaires with each basal insulin treatment.
Time frame: 46 weeks
Patient satisfaction
Patient satisfaction by TRIM-DD questionnaires with each basal insulin treatment.
Time frame: 46 weeks
HbA1c
HbA1c after 20 weeks of each basal insulin treatment.
Time frame: 46 weeks
Total daily insulin dosage
Total daily insulin dose, total basal insulin dose, and total bolus insulin dose on each treatment.
Time frame: 46 weeks