The Mass. General Diabetes Prevention Program (DPP)
Nancy Peters* (not her real name) doesn't want for herself or her children to have to endure what her mother went through. Living in the West Indies with her five young children, Peters' mother was unaware that she had diabetes until she had severe complications. "My earliest memories are of my mother administering insulin to herself with a needle, and as a child it frightened me," says Peters. "She was the strongest, most stoic and wonderful person, but diabetes weakened her over time, simply wore her down, and ultimately cut her life far too short at 58."
Unfortunately, her mother was not the only family member who suffered from diabetes. "I grew up with diabetes all around me," explains Peters, who moved to the United States from the West Indies in 1976 and now lives near Boston. Three of her aunts died of the disease, and two sisters now have diabetes. Because diabetes often strikes people with a strong family history of the disease, Peters says two years ago her physician told her that it was not a matter of "if" she would get diabetes, but "when."
When Peters learned that Mass. General, where she is both a patient and an employee, was taking the lead in a nationwide study to determine how to prevent or delay the onset of type 2 diabetes, she decided to fight back against what could be her destiny and join those striving to conquer this devastating disease. Peters was the first person accepted in the Mass. General Diabetes Prevention Program (DPP).
The MGH is one of 25 medical institutions across the country participating in the national DPP, a seven-year study sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases, a part of the National Institutes of Health (NIH). Moreover, David M. Nathan, MD, director of the Diabetes Research Center and Diabetes Clinic at the Mass. General, was chosen by the NIH and by his peers to be the national chairman of the study.
"The DPP is breaking entirely new ground in diabetes," says Nathan. "The DPP seeks to go back early in the progression of the disease, when it is only a metabolic abnormality, and attack it at the root instead of waiting until complications develop."
Type 2 diabetes, or non-insulin dependent diabetes mellitus, is rapidly becoming the most common chronic disease in the United States. Approximately 14 million people are affected — 6 to 7 million of them have not yet been diagnosed. If poorly controlled or untreated, diabetes can lead to blindness, kidney failure, nerve problems and amputations. Those with type 2 diabetes are at especially increased risk for cardiovascular disease and stroke.
"The complications of diabetes cause great suffering and expense," explains Nathan. "Health care costs related to diabetes total more than $100 billion each year. The discovery of effective methods for preventing the disease will provide enormous benefits to individuals and society as a whole."
The DPP seeks 4,000 volunteers older than 25 years of age from across the country, half of whom will represent minority groups. According to Nathan, diabetes is a disorder that particularly affects minorities. "As bad as it is for the overall population, it is even worse for African-Americans, Hispanic-Americans, American Indians, Asian-Americans and Pacific Islanders," he says. Because nearly one in five Americans is older than age 65 and the chance of developing type 2 diabetes increases with age, 20 percent of the volunteers in the study will be 65 or older. Nearly one in five Americans age 65 years or older has diabetes.
Diabetes occurs when either the pancreas does not make enough of the hormone insulin or the body does not use it properly. Without insulin the body cannot move sugar or glucose from the bloodstream into the cells. When blood sugar levels rise from normal levels, many health problems can result.
There are two forms of diabetes: type 1 and 2. About 10 percent of diabetics have type 1 or insulin-dependent diabetes, which usually develops in children and young adults. The pancreas produces very little or no insulin, so those with type 1 diabetes receive insulin injections every day.
The majority of diabetics, however, have type 2, which usually develops slowly and is more prevalent in those older than age 40. Although people with type 2 diabetes make some insulin, their bodies may not use it properly. Treatment focuses on bringing blood sugar to normal levels through diet, exercise and when necessary, medication.
The Mass. General is home to one of the oldest diabetes clinics in the country, established in 1920. Its researchers and scientists have pioneered many of the advances that have led to a better understanding and better treatment of diabetes. Mass. General also has participated in most of the major diabetes studies conducted in the United States during the past 30 years.
"By collaborating with the General Medicine Unit, we've been able to take our research findings from the laboratory bench to the patient bedside and even beyond by conducting long-term studies of the consequences of putting the latest scientific information into practice," says Nathan.
Outcomes studies can explore the impact clinical findings have on the day-to-day life of patients and society as a whole. Researchers study such questions as: How does intervention affect the work life of diabetes patients? Do doctors clearly understand diabetes care? How can patient care be made as cost effective as possible? Are new treatment recommendations being implemented? What is the impact on patients' everyday lies of following often complicated treatment regimens?
"Advances on several fronts now make the DPP possible," says Nathan. "First we have identified a condition called impaired glucose tolerance (IGT) that we know places a person at increased risk for eventually developing type 2 diabetes. Second, new classes of drugs are now available that not only lower blood sugar levels but also may help to prevent or delay onset of type 2 diabetes."
About 21 million Americans have IGT, or higher-than-normal blood sugar levels, and half of them will go on to develop type 2 diabetes. A simple blood test can determine the presence of IGT. Those at risk for the condition include overweight individuals, people with a family history of diabetes and women with a history of gestational diabetes (diabetes during pregnancy), as well as older people and members of the minority groups noted above.
After Peters heard about the study in an MGH publication, she went to a screening held for hospital staff. There she found she had IGT. Peters decided to continue with the screening process to see if she was an appropriate candidate for the study. "Even though my weight was within normal range for a person my age and height, with my strong family history of diabetes, I had a feeling I might fit the mold for the study," notes Peters. "After additional steps — including blood tests, lifestyle and nutrition questionnaires and a complete physical — I was accepted into the study and assigned to a group taking medication."
DPP volunteers are randomly assigned to one of four groups, each of which follows a different treatment plan including intensive lifestyle modification with a goal of reducing weight and increasing physical activity and pharmacologic intervention. The medicines being used include on drug currently used to treat type 2 diabetes and another being tested for its efficacy in treating type 2 diabetes. A control group also will take a placebo. All three groups taking medication also will receive information about diet and exercise. "These interventions were chosen because there is a high likelihood that one or even all of them will work," Nathan adds.
Peters and others in the DPP will be followed over a three- to six-year period, during which they will receive free medical checkups including tests for monitoring glucose levels, cardiovascular health, kidney function and exercise capability. "Now all I have to do is remember to take my pills and go for a checkup every three months," says Peters.
Peters feels that, although it requires some discipline and a commitment of time, she has an obligation to be part of the study. "The pioneering work that is being done at Mass. General gives me much hope for the future - for myself and for my daughters, who are also at risk. If I can do anything at all to fight back, to protect them and others, I will do it."