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CompletedNCT00469833Updated Jan 15, 2015Results posted

Insulin Secretion in Diabetes Before and After Glycemic Control

An interventional study of insulin glargine in Diabetes and Hyperglycemia, sponsored by US Department of Veterans Affairs. Completed at 1 site in United States. Open to participants aged 30 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2015-01-15.

Sponsored by US Department of Veterans Affairs · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
17
Allocation
Not applicable
Ages
30 Years to 65 Years
Sex
All
01

Study summary

The objective of this project is to understand defects in insulin secretion that contribute to abnormal glucose metabolism in patients with diabetes. In particular the effects of signals released from the intestine to stimulate insulin secretion will be tested. Patients with type 2 diabetes will have insulin secretion in response to glucose and intestinal factors before and after insulin treatment to lower their blood glucose. It is expected that the results of this work will provide valuable information for treating diabetic people.

Read the detailed description

The objective of this project is to understand defects in insulin secretion that contribute to abnormal glucose metabolism in patients with diabetes. Diabetes is a major problem for patients receiving care at VA medical centers among whom 20% are affected. Specifically, this project will seek to determine the mechanism(s) by which the incretin effect is impaired in diabetic patients. The incretin effect refers to the action of GI hormones and neural stimuli to increase insulin secretion after food intake, and accounts for approximately 50% of postprandial insulin secretion in nondiabetic humans. There are several studies indicating that this response is severely impaired in patients with type 2 diabetes. The mechanism(s) by which this occurs has not been explained. There is some evidence to suggest that secretion of the important incretins, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), may be impaired in diabetic individuals. There is also some data to suggest that the beta-cells in persons with diabetes are insensitive to the incretins. The problem with the current state of knowledge in this area is that previous work has involved small numbers of diabetic subjects, and did not directly test mechanisms by which the incretin effect is altered in diabetes.

In this project we will determine the role of hyperglycemia to impair the incretin effect. Type 2 diabetic subjects will have the incretin effect measured before and after intensified diabetes treatment. This study will test the effect of chronic hyperglycemia on incretin mediated insulin secretion. In all studies, the incretin effect will be measured before and after these interventions using studies with a within subjects design. A combined glucose clamp/meal tolerance test protocol will be used to quantify the incretin effect.

These studies will allow the role of incretin secretion, incretin action, and overall metabolic milieu, on postprandial insulin secretion to be defined. The results of these studies will add important new information for understanding abnormal beta-cell function in diabetes. By identifying the sites where the incretin effect is impaired this project will provide the basis for new approaches to treat diabetic patients. This is especially relevant with the recent availability of new medications that target the incretin pathways to lower blood glucose.

The blood samples will be drawn and processed in the GCRC. The samples will be frozen and stored in Building 15, Room 401. Samples will be shipped to the Genome Research Institute by staff trained in IATA shipping procedures.

02

Conditions studied

  • Diabetes
  • Hyperglycemia

Keywords

  • Diabetes
  • Glucose Tolerance
  • Incretin
  • Insulin
03

In context

Diabetes Mellitus

11,089 studies on the registry are indexed under Diabetes Mellitus; 1,319 are open to participants now.

This study's enrollment of 17 is below the median of 80 across 8,491 interventional studies indexed under Diabetes Mellitus.

Browse Diabetes Mellitus studies →

Lead sponsor

US Department of Veterans Affairs is the lead sponsor of 675 studies on the registry; none are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
30 Years to 65 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Aim 1:

    • (non-diabetics)

      • male/female 30-65 yrs old,
      • free of active medical disease,
      • no history of diabetes.
    • (diabetics)

      • HbA1c=6.5-8.5,
      • treated with metformin, a sulfonylurea, or combination,
      • Stable body wt with BMI 28-40.
  • Aim 2: Same as above
  • Aim 3: Diabetic with HgA1c 8.0-9.5

Exclusion criteria

Exclusion Criteria:

  • Aim 1: For both groups: no history of: pancreatitis, cardiac, gastrointestinal, renal or liver disease.
  • Aim 2: Same as above
  • Aim 3: Same as above, plus a diagnosis of incipient diabetic nephropathy severe nonproliferative, or proliferative retinopathy.
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
17 participants (actual)

Study arms

  • Experimental
    Arm 1

    Intervention: Insulin glargine treatment. The study is designed as a within subjects comparison of insulin secretion in type 2 diabetic patients before and after 2 months of insulin treatment to reduce blood glucose. Insulin secretion will be determined with a hyperglycemic clamp using 20% dextrose, and ingestion of an oral glucose solution (75 g).

    Drug: insulin glargine

Interventions

  • Diabetic subjects will be treated with insulin glargine once daily for 2 months. Subjects will monitor their blood glucose and have their insulin dose adjusted in steps of 4-6 units to achieve a goal of less than or equal to 120 mg/dl for fasting blood glucose.

    Also known as: Basal insulin, Long-acting insulin, Lantus

06

What researchers measure

Primary outcomes

  1. ISR in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

    Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first.

    Time frame: 180 minutes

  2. C-peptide Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

    Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first.

    Time frame: 180 minutes

  3. Insulin Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

    Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first.

    Time frame: 180 minutes

Secondary outcomes

  1. HbA1c Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

    Type 2 diabetic subjects had HbA1c measured before and after 2 months of basal insulin glargine treatment.

    Time frame: 2 months

07

Results

Posted Jan 15, 2015
Limitations and caveats
Two subjects could not complete the initial assessment due to poor IV access. All 15 subjects who completed the initial assessment and were started on insulin completed the study. There were no significant adverse events.

Participant flow

Recruited from VAMC from 2010-2012

Participant flow — Overall Study
MilestoneUncontrolled Type 2 Diabetic Subjects
Started17
Completed15
Not completed2
Withdrew: No iv access2

Outcome measures

PrimaryISR in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first.

Time frame:
180 minutes
Reported as:
Mean · pmol/min
ISR in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.
pmol/minOral GlucoseIV Glucose
Insulin secretion at baseline0.67 ± 0.070.75 ± 0.10
Insulin secretion at 8 weeks1.11 ± 0.220.76 ± 0.11
PrimaryC-peptide Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first.

Time frame:
180 minutes
Reported as:
Mean · nmol/L
C-peptide Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.
nmol/LOral GlucoseIV Glucose
C-peptide at baseline7.10 ± 0.925.63 ± 0.97
C-peptide at 8 weeks10.89 ± 2.206.02 ± 0.88
PrimaryInsulin Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

Subjects had glucose clamps for 270 minutes with serial sampling of blood for measurement of insulin and C-peptide. At 90 minutes into the clamp they consumed 75 g of oral glucose solution. Meal-stimulated insulin secretion was summarized as the mean plasma C-peptide from 90-270 minutes. This outcome measure was compared for each subject before treatment and after 2 months of insulin treatment to lower blood glucose. Subjects were started on 20 units of insulin glargine after their first visit and asked to measure their morning blood glucose daily. The dose of insulin was increased in increments of 4-6 units every 3 days targeting an average morning glucose level of less then 120 mg/dl. After 2 months of treatment the primary outcome was repeated with a second glucose clamp / oral glucose tolerance test, identical to the first.

Time frame:
180 minutes
Reported as:
Mean · pmol/L
Insulin Concentration in Response to a Glucose Clamp and Oral Glucose Ingestion Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.
pmol/LOral GlucoseIV Glucose
Insulin at baseline546.9 ± 162.6316.4 ± 59.0
Insulin at 8 weeks934.6 ± 282.2395.6 ± 106.3
SecondaryHbA1c Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.

Type 2 diabetic subjects had HbA1c measured before and after 2 months of basal insulin glargine treatment.

Time frame:
2 months
Reported as:
Mean · % glycosylated hemoglobin
HbA1c Before and After 2 Months of Insulin Treatment to Improve Average Glycemia.
% glycosylated hemoglobinUncontrolled Type 2 Diabetic Subjects
HbA1c at baseline8.6 ± 0.2
HbA1c at 8 weeks7.1 ± 0.2

Adverse events

Non-serious events are listed at a 1% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Arm 1—0/15 (0%)0/15 (0%)

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)Arm 1
<=18 years0
Between 18 and 65 years17
>=65 years0
Age, Continuous
Age, Continuous(years)Arm 1
Mean58.1 ± 6.6
Sex: Female, Male
Sex: Female, Male(Participants)Arm 1
Female1
Male16
Region of Enrollment
Region of Enrollment(participants)Arm 1
United States17
08

Study locations

1 site
  • VA Medical Center, Cincinnati
    Cincinnati, Ohio 45220, United States
09

References and documents

Publications

  • An Z, Prigeon RL, D'Alessio DA. Improved glycemic control enhances the incretin effect in patients with type 2 diabetes. J Clin Endocrinol Metab. 2013 Dec;98(12):4702-8. doi: 10.1210/jc.2013-1199. Epub 2013 Oct 3. PubMed 24092826 ↗
10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jan 15, 2015, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT00469833
Responsible party
Sponsor
First posted
May 7, 2007
Start date
Apr 2008
Primary completion
Dec 2011
Completion
Sep 2012
Results posted
Jan 15, 2015
Last update
Jan 15, 2015

Study contacts

David D'Alessio, MD
principal investigator · Cincinnati VA Medical Center

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

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