Arterial Stiffness in Type I Diabetes Mellitus

Study Overview
=================
Brief Summary
-----------------
Using radial artery tonometry to study arterial stiffness, the plan is to study a cohort of 65 children with Type I diabetes mellitus. This prospective, crossover study will help determine if there is an acute increase in arterial stiffness in children with Type I diabetes mellitus who do not give extra insulin to cover a meal. This will give more support to show why it is so critical to bolus every time they eat and to bolus on time to decrease cardiovascular consequences of poorly controlled diabetes. The hypothesis is that giving insulin before a meal compared to not giving insulin before a meal will be associated with lower arterial stiffness in children with type I diabetes.

Detailed Description
-----------------
The subject will fast overnight (nothing to eat or drink for at least 8 hours). The subject will be asked to drink a mixed meal replacement drink (Boost) and will be randomized (like flipping a coin) to bolus insulin for the meal or to not bolus insulin using their standard insulin dose. Glucose will be monitored with a finger prick before they drink the meal replacement, 1 hour later and finally 2 hours after drinking the meal replacement. Stiffness of the blood vessel of the wrist will be determined using radial tonometry. Radial tonometry is safe and does not hurt. A pen like probe is placed on the blood vessel of the wrist. When the machine reads a good wave form the computer will calculate the stiffness of the blood vessel. This test will be done along with the glucose checks; before drinking the meal replacement drink, and 1 and 2 hours after drinking the meal replacement drink. During the next study visit, the subject will repeat the exact same study described above. However, this time they will receive the other insulin assignment they were assigned during the first study (either bolus or no bolus).

Official Title
-----------------
Acute Effect of a Mixed Meal With and Without Extra Insulin on Arterial Stiffness, a Prospective Randomized Study.

Conditions
-----------------
Arterial Stiffness in Youth With Type 1 Diabetes

Intervention / Treatment
-----------------
* Drug: Pre-meal bolus
* Drug: No meal bolus


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Type 1 diabetes based on clinical history Basal-bolus insulin regimen Duration of diabetes greater than 1 year Blood glucose 65-200 mg/dL fasting Exclusion Criteria: Use of metformin or any other hypoglycemic agents besides insulin Use of anti-hypertensives Caffeine or smoking within the past 24 hours

Ages Eligible for Study
-----------------
Minimum Age: 8 Years
Maximum Age: 21 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Pre-meal bolus then No meal bolus<br>A meal replacement drink (Boost) and bolus of rapid insulin will be given to this group. Glucose will be monitored with a finger prick before they drink the meal replacement, 1 hour later and finally 2 hours after drinking the meal replacement. Stiffness of the blood vessel of the wrist will be determined using radial tonometry and will be done at the same time as the glucose monitoring. Then 3 months later A meal replacement drink (Boost) will be given but the subject will not receive a meal bolus. Glucose will be monitored with a finger prick before they drink the meal replacement, 1 hour later and finally 2 hours after drinking the meal replacement. Stiffness of the blood vessel of the wrist will be determined using radial tonometry and will be done at the same time as the glucose monitoring | Drug: Pre-meal bolus<br>* Long acting insulin as scheduled per usual routine PLUS rapid/ short acting (bolus) prior to Boost<br>Drug: No meal bolus<br>* Long Acting insulin as scheduled per usual routine (given once daily)<br>|
| No meal bolus then Pre-meal bolus<br>A meal replacement drink (Boost) will be given but the subject will not receive a meal bolus. Glucose will be monitored with a finger prick before they drink the meal replacement, 1 hour later and finally 2 hours after drinking the meal replacement. Stiffness of the blood vessel of the wrist will be determined using radial tonometry and will be done at the same time as the glucose monitoring. Then 3 months later meal replacement drink (Boost) and bolus of rapid insulin will be given to this group. Glucose will be monitored with a finger prick before they drink the meal replacement, 1 hour later and finally 2 hours after drinking the meal replacement. Stiffness of the blood vessel of the wrist will be determined using radial tonometry and will be done at the same time as the glucose monitoring | Drug: Pre-meal bolus<br>* Long acting insulin as scheduled per usual routine PLUS rapid/ short acting (bolus) prior to Boost<br>Drug: No meal bolus<br>* Long Acting insulin as scheduled per usual routine (given once daily)<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determine the Difference Between Acute Effect of a Mixed Meal on Radial Artery Stiffness in Subjects With Type I Diabetes Mellitus Who do and Who do Not Take an Additional Bolus of Insulin. | Determine the difference between acute effect of a mixed meal on radial artery stiffness in subjects with type I diabetes mellitus who do and who do not take an additional bolus of insulin. Radial tonometry is used to calculate the augmentation index (AI). AI is expressed as a percentage of the pulse pressure and represents the difference between the first and second peaks of the central arterial waveform. The stiffer the artery the more positive elevation of the AI and the machine will indicate stiffness using a color indicator (green less stiff and red being stiff). AI is measured using the SphygmoCor VX version 7.01 (AtCor Medical, Syndey, Australia). AI will be corrected to a heart rate of 75 to eliminate differences related to heart rate variation. | From baseline to one hour then 2 hours | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
type I diabetes, healthy, children, adolescents, young adults