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Novel preventive approach to type 2 diabetes studied (PDF, 194 KB) »
Type 2 diabetes-a serious disease affecting 5 percent of adults worldwide and 14 percent in Kentucky-is increasing in epidemic proportions. It occurs when the body produces an insufficient amount of pancreatic insulin to turn blood sugar, or glucose, into energy.
Type 2 diabetes is increasing in epidemic proportions.
Type 2 diabetes is increasing in epidemic proportions.
Type 2 diabetes is more common among older adults and individuals who are overweight or obese, although in recent years it has been showing up more often in children. An extremely costly disease to manage, type 2 diabetes gives rise to a host of complications, including life-threatening organ failure and stroke.
Because it is difficult to control and prevent complications of type 2 diabetes, many studies have been conducted in recent years on prevention or delaying onset. Although not everyone with prediabetes symptoms goes on to develop full-blown diabetes, studies show that a large number will do so within 10 years if preventive steps aren’t taken. Doctors also believe that even though a person hasn’t yet been diagnosed as diabetic, having above-normal glucose levels puts them at increased risk for cardiovascular disease.
The largest diabetes prevention study to date is the DREAM Trial (Diabetes REduction Assessment with ramipril and rosiglitazone Medication). Conducted by researchers at McMaster University in Hamilton, Ontario, it included 5,269 people age 30 and up at 191 clinics in 21 countries. Participants had impaired fasting glucose, glucose intolerance or both and no signs of cardiovascular disease.
The purpose of the trial was to test the effectiveness of the diabetes drug rosiglitazone, marketed as Avandia by GlaxoSmithKline, and ramipril, a blood pressure drug sold as Altace by Sanofi-Aventis and King Pharmaceuticals, in reducing diabetes incidence. The report on the Avandia arm of the trial was published in The Lancet on Sept. 23, 2006; the Altace trial appeared Oct. 12, 2006, in the New England Journal of Medicine.
Between July 2001 and August 2003, participants in the DREAM trial were randomly assigned doses of Avandia at 8 milligrams daily and/or Altace at 15 mg. daily, or a placebo. Each patient was also counseled regularly on the importance of maintaining a healthy lifestyle and diet. According to the American Diabetes Association, there is a 58 percent reduction in the incidence of diabetes in people who make lifestyle changes including weight loss and exercise that control their blood glucose.
Among the participants who took Avandia, there was a 60 percent reduction in the risk of diabetes or death. Researchers concluded that the drug might have helped the body respond to its own insulin or aided in the body’s ability to produce insulin. Only 12 percent of the group taking Avandia developed diabetes, compared to 26 percent who got the placebo. It normalized glucose levels in 51 percent of those who took it, compared with 30 percent in the placebo group.
In contrast, there was no reduction in diabetes or death among subjects taking Altace, the blood-pressure medication. There was some evidence, however, that it could help normalize blood glucose levels. By the end of the study, 43 percent of those taking the drug had normal glucose levels, compared to 38 percent in the placebo group.
Avandia’s side effects posed two problems. The DREAM trial revealed a slight increase in the rate of heart failure among those taking the drug. Sixteen people out of 2,300 had nonfatal congestive heart failure due to fluid build-up. There was also more widespread weight gain in the hips.
But the study authors concluded the risk is worth the benefit. “Balancing both the benefits and risks suggests that for every 1,000 people treated with rosiglitazone for three years, about 144 cases of diabetes will be prevented, with an excess of four to five cases of congestive heart failure,” they wrote.
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I am a very strong advocate of lifestyle change as a means of preventing diabetes. I think at the root of the worldwide epidemic of obesity and diabetes is the fact that there’s very little need for physical activity in our culture and we have an abundance of processed, high-fat foods. As many as one in eight or nine adults in Kentucky now have diabetes. About 67 percent of Americans are overweight or obese, which puts them at risk for diabetes.
The DREAM study is very important because more than half the participants were able to achieve normal blood sugar levels by taking Avandia, and there was a significant decline in the progression of prediabetes to diabetes.
The main diagnostic criterion of diabetes is a fasting glucose level of 126 milligrams/deciliters or greater. That's when the risk for retinopathy, one of the complications of diabetes, starts. Normal fasting glucose is 65-99 mg./dl. In between, is a group of people with glucose levels of 100-126 mg./dl., which is impaired fasting glucose, or prediabetes.
“Once you become diabetic, your risk for cardiovascular disease and microvascular complications increases significantly.”
Prevention is, of course, the key here. Can we prevent the progression to diabetes in the very early stages when people have mild elevation of blood sugar? About 5 to 10 percent of the people in that range will convert to diabetes each year. Once you become diabetic, your risk for cardiovascular disease and microvascular complications increases significantly.
There have been several studies on the prevention of type 2 diabetes. A Finnish study and the Diabetes Prevention Program both found a 58 percent reduction in progression to diabetes with lifestyle changes among subjects with prediabetes. The participants were put through a very intensive program of dieting and counseling, with a lot of feedback and coaching. It may not be practical for the private practitioner to do this because you almost need a team approach.
Other studies have also looked at diabetes medications that lower glucose levels. In the TRIPOD Study, for example, participants who took troglitazone, a forerunner of Avandia, had about a 56 percent reduction in diabetes incidence.
Role of medication studies on the Pima Indians illustrate how lifestyle, obesity and environment predispose a person to diabetes. Among the Pimas of Northern Mexico, who eat a diet of natural foods and are very lean, there is only a 6 percent risk of diabetes. The Pimas of Arizona, who have adopted a more Westernized lifestyle, have a 40 percent risk of becoming diabetic. And the two groups are genetically identical.
The reality is, very few people can accomplish the lifestyle changes they need in order to lower their blood sugar levels. The Diabetes Prevention Program called for 45 minutes a day of exercise and seven to nine servings of fruits and vegetables a day to achieve a seven percent loss of excess weight.
There probably will be a role for medications in diabetes prevention, but we have to consider the cost and the potential side effects. A month’s supply of Avandia costs more than $120 and isn't yet covered by insurance for use in prediabetes. There are also risks-a modest weight gain, mostly in the hips and thighs, which is medically a minimal risk, and a very slight risk of heart failure as a result of increased fluid retention.
We don't know if there will be a sustained effect from taking Avandia, but evidence suggests it helps maintain or restore beta cell mass. The beta cells produce the body’s insulin. When you develop diabetes, you've already lost about 50 percent of your functioning beta cells. So if you can maintain or restore that mass with medication, how long do you need to take it? We don’t know yet.
Some people have type 2 diabetes for years without knowing it because symptoms may be mild or easily confused with signs of aging. It’s most commonly discovered during routine health examinations.
The American Diabetes Association recommends screening for:
Based on lessons learned from the Diabetes Prevention Program and the National Weight Control Registry, rigorously following these tips could lead to a significant reduction in weight and diabetes risk:
Dr. Reynolds is an endocrinologist with a special interest in diabetes and metabolism with UK HealthCare and an associate professor of medicine in the UK College of Medicine.
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