NEW DIABETES DIAGNOSIS RECOMMENDATIONS
by Ed Bryant
On June 23, the American Diabetes Association sponsored a telephone news conference in which members of "the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus" presented their findings regarding the need to revise diabetes diagnosis and classification, and answered audience questions. Current estimates are that over 100 billion dollars a year (in direct and indirect costs), are poured into treating diabetes and its complications. This figure includes as much as 15% of managed care costs and 20% of the Medicare budget. The committee, which started addressing this problem in 1995, and finished this year, saw its report accepted for publication in the professional journal "Diabetes Care," Volume 20, No. 7, for July 1997.
First presenter was Dr. James Gavin, Senior Scientific Officer of Howard Hughes Medical Institute, past president of the American Diabetes Association, and the Chair of the Expert Committee. Other presenters were: Dr. Frank Vinicor, Director of the Office of Diabetes Translation, Centers for Disease Control and Prevention; Dr. Richard Eastman, Director of the Division of Diabetes, Endocrinology, and Metabolism, of the National Institute of Diabetes, Digestive, and Kidney Diseases; and Dr. George Alberti, Director of the Human Diabetes and Metabolic Research Center, part of the World Health Organization, Collaborating Center for Research and Development for Laboratory Techniques and Diabetes.
Dr. Gavin reminded listeners of the seriousness of diabetes, its impact on over 16 million Americans, and its explosive growth (The past 30 years have brought more than a tripling in the U.S. A.), and much of its cost has been for treatment of its long-term complications. These complications are driven largely by the high blood sugars of the disease, and we now know they can be prevented or delayed by early and aggressive treatment. Today we know more about diabetes than ever before. This heightened understanding has caused us to reevaluate the way diabetes is diagnosed and classified.
The current medical classifications and glucose test levels that would indicate an individual has the condition were last updated in 1979, and were based on then-current knowledge. In 1979 we didn't know about the autoimmune aspects of type I diabetes, we didn't know about genetic susceptibility, and we had far less understanding of the sub-types of diabetes. We have more than 16 years of new research to draw on. The Expert Committee's work represents an update of what we knew about diabetes back then. Conclusive data on population based research show serious complications of diabetes beginning earlier than previously thought, and at a lower level of blood sugar. With what we know now, it is time to revise, so as to take better advantage of the multiple opportunities for early intervention we now possess.
The single most important recommendation made by the committee is to move the "cut point" for a diagnosis of diabetes, downward from its current 140mg/dl fasting plasma glucose (FPG) to an FPG of 126. This 14-point drop, the researchers argue, will catch more of the estimated 8 million undiagnosed diabetics in the United States, perhaps up to 2 million, and catch them sooner than the current 7 to 10 years after onset. A "normal" (non-diabetic) fasting plasma glucose, they define as 110mg/dl or less.
The researchers addressed the problem of where to place individuals whose blood sugars are above the new "normal" cutoff of 110mg/dl FPG, but below the new diagnostic point of 126mg/dl FPG, an intermediate stage. The committee recommends two subdivisions of this new impaired glucose homeostasis category: Impaired Fasting Glucose (IFG), when the test results run between 110 and 126mg/dl, and Impaired Glucose Tolerance (IGT) when the Glucose Tolerance Test (OGTT) produces a reading of over 140 but less than 200mg/dl. This latter group is known to be at risk of microvascular complications, and for progression to full-blown type II diabetes.
The committee also looked at Gestational Diabetes (GDM), which only appears in pregnant women, and for which different diagnostic criteria must be used. As many women who experience GDM go on to type II diabetes, this classification is of great interest. The old recommendation for universal screening of all pregnant women has been replaced by an assessment of risk factors such as family history of diabetes, obesity, age at pregnancy (below 25 is considered low risk for GDM), and ethnicity.
An important committee recommendation was that the health care community should consider testing for diabetes in all adults age 45 and above, with repeat testing at three-year intervals. Individuals judged at high risk (obese, high blood pressure, family history of diabetes, or of Hispanic, Asian, or Native American or African ethnicity) should be tested more regularly, and at a younger age. The new "cut point" criteria, and recommended increase in testing activity would not increase the number of diabetics, but would lessen the number of those yet undiagnosed. Dr. Gavin pointed out, in response to a question, that there are many people whose blood sugars would fall into the "not normal" range, yet fall short of the "cut point" for full-blown diabetes. Such people need increased vigilance and counseling, as they are at risk.
The committee also recommends the universal adoption of the FPG as standard diagnostic test for diabetes. The OGTT (glucose tolerance test), a sensitive but expensive and time-consuming test, has been used for some diagnoses, but not others, with the results imperfectly mapping onto those produced by the FPG. Also the FPG is convenient, easy to administer, acceptable to patients, and very low in cost. (The HBA1C, or glycosylated hemoglobin test, while an excellent monitoring tool, is not recommended for diagnosis.)
Dr. Frank Vinicor, of the Centers for Disease Control, spoke on the public health impact of diabetes complications, and their preventability if diagnosed early. CDC approved of the new recommendations, he reported, and he anticipated their acceptance as government policy, both through his agency and other groups concerned with public health and epidemiology. Although the article and presentations were merely "committee recommendations," the Expert Committee's report has already been accepted (or is currently under review) by a number of agencies, including the American Academy of Physician's Assistants, the American Association of Clinical Endocrinologists, the American Association of Diabetes Educators, the American Diabetes Association, the American Dietetic Association, the Canadian Diabetes Association, the Centers for Disease Control, the Diabetes Treatment Centers of America, the Endocrine Society, Joslin Diabetes Centers, the Juvenile Diabetes Foundation International, the National Institute of Diabetes, Digestive, and Kidney Diseases, and the International Diabetes Center. Conference speakers said they expect their recommendations to become standard in the next few years.
A statement Dr. Gavin made struck me as the best possible explanation for the shift to new diagnostic criteria. In his own words:
We feel passionately that people need to take diabetes more seriously. Just because it doesn't hurt doesn't mean it isn't hurting you. It's a disease that is completely treatable, and we now know we can prevent or delay its complications, with early effective treatment. For adults in America, especially family members of people with diabetes and other high-risk individuals, these people should be more vigilant in getting checked for this disease on a regular basis, and should try to reduce their risk, by maintaining ideal weight, and seeking to control blood pressure and blood fat levels.
These new recommendations will not create new patients with diabetes, but will move more of them from the undiagnosed to the diagnosed category. Diagnoses, if these recommendations are followed, will be greatly simplified, less expensive, and we expect they will be made earlier, more often, and will allow us to eliminate those instances where we diagnose people late, often years after the onset of the disease, when they already have complications.
It is our hope and our expectation that these global recommendations will be embraced by the medical community for the benefit of all patients with diabetes.