Cardiovascular Disease (CVD) Risk and Prevention in Early Glucose Intolerance

Not Applicable

Completed

Conditions: Impaired Glucose Tolerance
Prediabetic State

Interventions: Drug: Aspirin
Drug: Olmesartan
Drug: Placebo
Drug: Alpha lipoic acid

Registration Number: NCT00122447

Lead Sponsor: Emory University

Brief Summary: The purpose of this study is to determine whether cardiovascular disease (CVD) risk markers, β-cell function, and insulin sensitivity can be improved by targeting mechanisms of both diabetes and CVD - using an antioxidant, an angiotensin II receptor blocker (ARB), or an anti-inflammatory agent - in patients with impaired glucose tolerance (IGT) in a randomized, controlled trial.

Detailed Description: Diabetes is a common, major health problem in the United States, and it significantly increases the risk of developing heart disease, which is the leading cause of death. Research studies have shown that the risk of heart disease is increased, even in the "pre-diabetes" or impaired glucose tolerance (IGT) stage, before the onset of true diabetes. While many studies have shown that aggressive management of diabetes lowers the risk of heart disease, at the present time, it is not known how best to treat patients with impaired glucose tolerance (pre-diabetes) to prevent the development of heart disease. It is also not known where in the range of blood sugar levels risk begins to increase. The purpose of this study is to determine:

* whether medications, which target pathways involved in the development of heart disease, can decrease the risk of heart disease in individuals with impaired glucose tolerance; and

* whether a "high" blood sugar level measured one hour after drinking a standard high-sugar drink is associated with an increased risk of heart disease even in individuals who have no evidence of diabetes or pre-diabetes.

The purpose of Aim 1 of this study is to determine whether medications, which target pathways involved in the development of heart disease, can decrease the risk of heart disease in individuals with impaired glucose tolerance. One hundred-twenty volunteers with impaired glucose tolerance and 30 volunteers with normal glucose tolerance (normal blood sugars after ingesting a standard high-sugar drink) will be recruited from the "Screening for Impaired Glucose Tolerance" (SIGT) study. The 30 volunteers with normal glucose tolerance will not take any study medication, but will undergo medical testing to determine their risk of heart disease at the beginning of the study, after which their participation in the study will be complete. The 120 volunteers with impaired glucose tolerance will be randomly assigned to one of four medications to be taken over a one-year period:

* alpha lipoic acid (an antioxidant, dietary supplement);

* olmesartan (a drug used to treat high blood pressure);

* aspirin (an anti-inflammatory drug); and

* placebo (an inactive, "dummy" pill).

Subjects with impaired glucose tolerance will undergo medical testing to determine their risk of heart disease at the beginning of the study (before beginning study medications), after 3 months of intervention, and again at the end of the study (12 months after enrollment). Test results will be compared between the subjects taking each of the active medications and those taking placebo, to determine if the medications lead to a significant reduction in the risk for the development of heart disease. The medical tests used in this study are currently used in medical practice, and include blood and urine specimens, ultrasound testing of the artery at the arm, and an insulin sensitivity test (test of how effectively the body uses sugar). All visits and tests will be conducted in the General Clinical Research Centers of Emory University Hospital and Grady Memorial Hospital.

The purpose of Aim 2 of this study is to determine whether a "high" blood sugar level measured one hour after drinking a standard high-sugar drink (1-hour blood sugar level) is associated with an increased risk of heart disease even in individuals who have no evidence of diabetes or pre-diabetes. Seventy-five volunteers with normal glucose tolerance (normal blood sugars after ingesting a standard high-sugar drink) will be recruited from the SIGT study, as well as 15 subjects with impaired glucose tolerance and 15 with diabetes. The subjects with normal glucose tolerance will be grouped into those with "low", "middle", and "high" 1-hour blood sugar levels. All subjects will undergo medical testing (as in Aim 1 above) to determine their risk of heart disease. Test results of subjects with "low", "middle", and "high" 1-hour blood sugar levels will be compared against one another, as well as against those of subjects with IGT and diabetes. If subjects with normal glucose tolerance but "high" 1-hour blood sugar levels are found to have increased risk for heart disease compared to those with "low" 1-hour blood sugar levels, then the 1-hour blood sugar levels may provide important information regarding an increased risk of heart disease even in individuals with normal glucose tolerance but "high" 1-hour blood sugar levels - a population which otherwise would not be identified with the current standard tests used for the diagnosis of diabetes and pre-diabetes.

Over 40 million Americans have pre-diabetes (impaired glucose tolerance), which is associated with an increased risk of the development of both diabetes and heart disease. Findings from these studies will provide important insights into the pathways that lead to the development of heart disease related to pre-diabetes, prevention of heart disease in the pre-diabetic population, and identification of individuals at high risk for heart disease earlier in their natural history - even before the onset of pre-diabetes.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 84

Inclusion Criteria

Impaired glucose tolerance

Exclusion Criteria

Diagnosis of diabetes
Taking an ACE inhibitor (ACE-I), angiotensin II receptor blocker (ARB), or aspirin
Have systolic blood pressure >140 mm Hg
Have a chronic inflammatory disorder (i.e. rheumatoid arthritis, inflammatory bowel disease, sinusitis)
Vascular disease (cardiac, peripheral, cerebral)
Renal insufficiency or hepatic abnormalities
Gastrointestinal bleeding (defined as gastric or duodenal ulcer, hematemesis, and/or blood in the stool) or significant other upper gastrointestinal problems (i.e. gastritis) within the previous 6 months
Anemia or a history of bleeding disorder
Have a history of ARB or aspirin allergy
Have the syndrome of asthma, rhinitis, and nasal polyps
Have other medical problems which would preclude taking potential study medications for 12 months
Are pregnant or have a positive pregnancy test
Are breast feeding
Are unable or unwilling to tolerate having one catheter in each arm for 4 hours
Have health status such that the envisioned blood sampling would confer a physiologic risk
Have other physical, social, or behavioral problems which would decrease the likelihood that they would remain in the study for 12 months
Do not appear capable of giving informed consent

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Anti-inflammatory agent	Aspirin	Aspirin (ASA)
Angiotensin receptor blocker (ARB)	Olmesartan	Olmesartan (ARB)
Placebo	Placebo	Aspirin placebo once a day Olmesartan placebo once a day Alpha lipoic acid placebo twice a day
Antioxidant	Alpha lipoic acid	Alpha lipoic acid (ALA)

Primary Outcome Measures

Name	Time	Method
AIM 1: Change in Flow Mediated Dilation (FMD) (%)	12 months of intervention	Surrogate measure of endothelial function defined as the percent change in dilation of the brachial artery after cuff compression of arm compared to before cuff compression

Secondary Outcome Measures