International Clinical Trial to Evaluate Benefits of Two Commonly Prescribed Drugs
The University of Maryland Joslin Diabetes Center is taking part in a large-scale international clinical study to determine whether two commonly prescribed medications for diabetes and high blood pressure can help prevent Type 2 diabetes in people at risk to develop the disease. Researchers will also look at whether the drugs can slow the progression of cardiovascular disease.
The six-year study -- the largest diabetes prevention trial ever conducted, according to its sponsor, the drug manufacturer Novartis -- targets people who have impaired glucose tolerance (IGT), a prediabetic condition in which their blood sugar levels are too high after eating. One in seven people over age 40 in industrialized nations have IGT, which puts them at high risk to develop both Type 2 diabetes and cardiovascular problems.
The University of Maryland Joslin Diabetes Center, which is part of the University of Maryland Medical Center, is one of about 750 medical centers in 30 countries to participate in the trial.
"This study has the potential to be enormously important for millions of people," says Nanette Steinle, M.D., an endocrinologist at the University of Maryland Joslin Diabetes Center and an assistant professor of medicine at the University of Maryland School of Medicine.
"With the baby-boomers entering their late 50s, a growing number of people are at increased risk of developing diabetes. If this study is successful, it will provide important insights into slowing or avoiding this destructive disease," Dr. Steinle says.
People with Type 2 diabetes, the most common form of diabetes, don't produce enough insulin or use it properly, hampering their ability to convert sugar into energy. They need to control their blood sugar levels with diet and exercise and by taking medication and sometimes taking insulin.
To qualify for the study, candidates must be at least 50 years old and be at risk for developing diabetes. They must also have cardiovascular disease or a risk factor, such as cigarette smoking or high blood pressure, which would make them more likely to develop heart disease.
The participants will receive nateglinide, an oral antidiabetic drug, or valsartan, a high blood pressure medicine, or both drugs or neither of them. Those who don't get the medications will be given placebos. The patients will be selected at random, and neither they nor the doctors will know which medications they are getting.
Nateglinide, which is also known by the brand name Starlix, helps to treat Type 2 diabetes because it produces a burst of insulin that prevents blood glucose levels from spiking after meals. Valsartan, also called Diovan, reduces high blood pressure by causing blood vessels to dilate, but it might also help the body use insulin more effectively.
The study has been dubbed the Navigator study, which stands for Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research. About 7,500 people around the world are expected to take part in the trial.
Michelle Sheldon-Rubio, R.N., CDE, the clinical trial coordinator of the study at the University of Maryland Joslin Diabetes Center, says the center hopes to enroll at least 13 patients.
Sheldon-Rubio says that in addition to receiving free medication, participants will also be taught how to eat healthier, exercise more and to lose weight -- which could also prevent them from developing Type 2 diabetes or cardiovascular problems. Participants will keep diaries to document their eating and exercise habits, so that researchers can take those factors into account when evaluating the effect of the medications, she says.
Those who take part in the study will receive regular checkups and be closely monitored by the staff at the University of Maryland Joslin Diabetes Center. Patients will be followed for three years to see if they develop Type 2 diabetes and for another three years to track their cardiovascular health. Novartis expects the study to be completed in 2007.
The incidence of diabetes worldwide has risen dramatically, with the number of people diagnosed with the disease expected to double within the next 25 years, to 270 million. About 16 million in the United States have diabetes, more than 348,000 of them in Maryland. More than 90 percent have Type 2 diabetes. Obesity and an increasingly sedentary lifestyle are believed to have played a major role in the increase.
For more information about the clinical trial at Joslin Diabetes Center, contact Michelle Sheldon-Rubio, R.N., CDE, at 410-328-6584.
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