New Definitions for the Types of Diabetes |
TYPE 1 |
Characterized by beta cell destruction,
usually leading to absolute insulin deficiency. It has two forms:
Immune-Mediated Diabetes Mellitus:
Results from a cellular mediated
autoimmune
destruction of the
beta cells
of the pancreas.
Idiopathic Diabetes Mellitus:
Refers to forms of the disease that have no known etiologies.
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TYPE 2 |
Diseases of
insulin resistance
that usually have
relative (rather than absolute) insulin
deficiency.
Can range from predominant insulin
resistance with relative insulin
deficiency to
predominant insulin deficiency
with some
insulin resistance.
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Impaired Glucose Homeostasis |
A metabolic stage intermediate
between normal glucose homeostasis and diabetes.
A risk factor for diabetes and cardiovascular disease.
Impaired Fasting Glucose
Fasting plasma glucose higher than normal, and less than diagnostic.
Impaired Glucose Tolerance
Plasma glucose higher than normal, and less than diagnostic, following administration of
a glucose load
of 75 grams.
|
|
Glucose intolerance in pregnancy.
The definitions are unchanged from before.
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Other Specific Types |
Diabetes caused by other identifiable etiologies.
- Genetic defects of beta cell function (e.g.,
MODY
1, 2, 3)
- Genetic defects in insulin action
- Diseases of the exocrine pancreas (e.g., cancer of the pancreas,
cystic fibrosis,
pancreatitis)
- Endocrinopathies (e.g.,
Cushing's)
- Drug or chemical induced (e.g., steroids)
- Infection (e.g., rubella, Coxsackie, CMV)
- Uncommon forms of
immune-related diabetes
- Other genetic syndromes
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On Monday morning, June 23, 1997, at the
ADA meeting in Boston, this revised classification system, and revised diagnostic criteria
(below) were announced.
The new guidelines were a joint activity of committees from the American Diabetes Association and from the World Health Organization;
the two separate
committees ended up in agreement on the changes (with one exception, screening criteria for gestational diabetes).
This proposal for a new classification of diabetes has been in development for several years.
As indicated
above,
the definitions of the terms Type 1
and Type 2 have been revised (and the terms IDDM and NIDDM are dropped);
new cutoff values for blood sugar normality have been defined (see the table
below).
Criteria for children and for the elderly are the same as
for other age groups.
Press stories from
The New York Times,
CNN and the
Associated Press
are appended at the end of this webpage.
The official report of these guidelines, and an accompanying editorial, have been published in
the July, 1997 issue of Diabetes Care, and are available at the American
Diabetes Association website.
The article is entitled
Report
of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus.
(See reference, at end of this article).
Diagnosing Diabetes
From the Boston Beacon (the daily newsletter of the ADA 57th Annual Meeting), Tuesday, June 24, 1997, page 6
(mmol/L / mg/dl)
|
|
Stage
|
Fasting Plasma Glucose Test
(FPG)
(Preferred) *
|
Casual Plasma Glucose Test |
Oral Glucose Tolerance Test (OGTT) |
| Diabetes |
FPG greater than or equal to
7.0
/
126 ** |
Casual Plasma Glucose
greater than or equal to
11.1
/
200
plus symptoms ***
|
Two-hour plasma glucose (2hPG)
greater than or equal to
11.1
/
200 ****
|
| Impaired Glucose Homeostasis
|
Impaired Fasting Glucose (IFG) =
FPG
greater than or equal to
6.1
/
110
and less than
7.0 / 126
|
|
Impaired Glucose Tolerance (IGT)
= 2hPG
greater than or equal to
7.8
/
140
and less than
11.1 / 200
|
|
Normal |
FPG
less than
6.1 / 110
|
|
2hPG less than
7.8
/
140
|
|
Notes:
* The FPG is the preferred test for diagnosis, although any of the three is acceptable.
In the absence of unequivocal hyperglycemia with acute metabolic decompensation, one of these three tests should be used on a different
day to confirm the diagnosis.
** Fasting is defined as no caloric intake for at least eight hours.
*** Casual is defined as any time of day without regard to time since last meal;
symptoms are the classic ones of polyuria,
polydipsia, and unexplained weight loss.
**** OGTT should be performed using a 75 gram glucose load. The OGTT is not recommended for routine clinical use.
Press Stories
Diabetes screening guidelines
strengthened
All adults should be tested by age
45
From CNN
June 23, 1997
11:55 p.m. EDT
From Medical Correspondent Rhonda
Rowland
ATLANTA (CNN) -- Of the estimated 16 million people in the United States
with diabetes, about half of them don't know they have it.
In an effort to improve that situation, new recommendations have been
issued calling for changes in the way diabetes is detected and diagnosed.
The guidelines were developed by an international panel of experts and
have been endorsed by the National Institutes of Health.
For the first time, all adults are being urged to undergo a blood test for
diabetes by age 45 and have additional tests every three years thereafter.
Previously, only people who doctors suspected might have diabetes were
screened.
"Potentially, there are 1 to 2 million people in the population who could be
diagnosed using this criteria," said Dr. Richard Eastman of the NIH. "We
think that many will be diagnosed, since it's a relatively easy test to perform
on routine blood work done in a doctor's office."
There's another change being recommended in the arena of diabetes
screening. Previously, a blood sugar reading of 140 or more would result in
a diagnosis of diabetes. The new threshold is 126.
"The problem with the former cutoff of 140 is that by the time people were
diagnosed with diabetes, about 20 percent already had complications,"
Eastman says. "We know that the risk goes up sharply for those
complications when the blood sugar gets to be about 126."
Preventing complications is the impetus behind the new recommendations.
Early diagnosis of diabetes is the key to preventing eye, heart, kidney and
nerve damage that can be caused by an untreated diabetic condition.
"It's really a pity when the first time we see someone who's diagnosed as
diabetic is when they're having their heart attack or when they're having a
hemorrhage into their eye," says Dr. Carol Teutsch, a diabetes specialist.
Once a diagnosis is made, controlling blood sugar starts with diet and
exercise. Some people also will have to take insulin or medications.
For those without diabetes, some studies suggest that exercise and good
nutrition may prevent people from developing the condition. A large study
now under way should provide a definitive answer in three to four years.
New diabetes guidelines urge testing for all at age 45
By The Associated Press
BOSTON - 06/23/97 - 06:44 PM ET -
New federally endorsed guidelines recommend for the first time that all adults be tested for diabetes by age 45 to try to catch the
disease before it begins its insidious destruction.
The guidelines, written by an international panel of experts, also lower the cutoff for declaring people diabetic and change the way the disease
is classified.
The National Institutes of Health, which endorsed the recommendations, estimates that they could help identify 2 million of the 8 million
Americans who have diabetes but don't know it.
The aim is to get these people started on diets, exercise programs and possibly drug treatment before the disease starts a cascade of
complications that eventually damage the eyes, heart, kidneys and nerves.
The guidelines recommend using the readily available fasting plasma glucose test. The simple blood test costs $5 to $10 and requires that
people not eat for eight hours beforehand.
The guidelines were released Monday at a meeting of the American Diabetes Association, which sponsored them. The World Health
Organization plans to adopt them in slightly different form later this year.
Currently, there is no across-the-board recommendation for screening people for diabetes. Instead, doctors test patients when they have some
reason to suspect they may be diabetic. Symptoms of diabetes can include excessive thirst, frequent urination and weight loss.
"The earlier we diagnose diabetes, the more likely we are to retard its progression and the development of complications," said Dr. James R.
Gavin III of the Howard Hughes Medical Institute in Chevy Chase, Md., who headed the committee that drew up the guidelines.
A high level of sugar in the blood is the hallmark of diabetes. Gavin said that since the last diabetes guidelines were issued in 1979, doctors
have learned that the disease begins its painless destruction at lower sugar levels than had been thought.
About 16 million Americans have diabetes, but only about half of them have been diagnosed with the disease. With the new guidelines, "I
think we will begin to get into the missing 8 million," said Dr. Frank Vinicor of the Centers for Disease Control and Prevention in Atlanta.
The new cutoff on the blood test does not change the total number of Americans with the disease; the 16 million figure was based on a
different type of glucose test.
Among the new guidelines:
- Every adult should have a diabetes test every three years starting at 45. Those who get a high reading should have the test repeated on
another day.
- Those at higher than usual risk may need to be tested earlier or more often. These include American Indians, blacks, Asians, Hispanics
and anyone who is overweight or has high blood pressure, high cholesterol or a strong family history of the disease.
- The cutoff for declaring someone diabetic should be lowered from the current 140 milligrams of glucose per deciliter of blood plasma to
126.
- Doctors should abandon the categories of insulin-dependent and non-insulin-dependent diabetes. Insulin-dependent, which once was
called juvenile diabetes, should be termed type 1. Non-insulin-dependent, traditionally known as adult-onset diabetes, should be called
type 2.
- Contrary to earlier recommendations, pregnant women do not need to be tested routinely if they are white, under 25, of normal size and
have no close family members with the disease.
Dr. George Alberti of the University of Newcastle upon Tyne in England said the WHO will adopt virtually the same guidelines for use
worldwide.
"This is very much a world consensus based on logic," he said.
About 700,000 Americans have type 1 diabetes. It usually results from a malfunction of the immune system that destroys insulin producing
cells in the pancreas. Victims typically lose all ability to make insulin, often as children or young adults.
About 15.3 million people have type 2 diabetes. It is most common among older people and may involve a combination of too little insulin
production and an inability of the body to use insulin properly.
If weight loss and exercise fail to bring the disease under control, it can be treated with a variety of pills or insulin injections.
New Guidelines Issued for Diagnosing Diabetes
NY Times
By Denise Grady
Levels of blood sugar that have long been accepted as normal are actually too high and should be
considered a sign of diabetes, according to new guidelines issued Monday by the American Diabetes
Association and endorsed by federal health authorities.
The guidelines call for testing all healthy people age 45 and older -- about 77 million Americans -- every three
years, and are expected to lead to the detection of 2 million new cases.
Under the guidelines, testing would start earlier and be done more often in people with higher risk, including
those who are obese, black, Hispanic, American Indian or closely related to someone with diabetes.
The new guidelines, announced at a medical conference in Boston, have been endorsed by the Centers for
Disease Control and Prevention and the National Institute of Diabetes and Digestive and Kidney Diseases. A
report on the recommendations will be published in the July issue of the journal Diabetes Care. Doctors usually
follow the association's recommendations.
Dr. K.G.M.M. Alberti, director of the World Health Organization's Collaborating Center for Research and
Development in Laboratory Techniques in Diabetes, said at a press conference that that organization fully
supports the association's recommendations.
The redefinition of diabetes may have a powerful impact. Researchers say they hope that by leading to earlier
detection, the guidelines will improve treatment and prevent complications like cardiovascular disease and
blindness.
But it is not known whether those benefits will be realized, and in the meantime, the scientists say, there are
potential risks in telling a large pool of symptom-free people they have a chronic disease with potentially
devastating consequences. Those individuals would have to deal with employers and insurers, and in some
cases make decisions about taking potent drugs whose long-term effects are not entirely known.
According to the new guidelines, a person has diabetes if two readings, on two different days, reach 126
milligrams per deciliter or higher on a simple blood test called a fasting plasma glucose -- better known as fasting
blood sugar. The previous cutoff, set in 1979, was 140 or higher.
The association also decided that the fasting plasma glucose test was sufficient to make the diagnosis, and
could replace a more expensive, time-consuming and unpleasant procedure, the oral glucose-tolerance test,
which requires that patients drink a glucose solution and then have blood drawn two hours later. (The dipsticks
used to test urine samples for glucose in many doctor's offices are not adequate for diagnosing diabetes.)
The association said it recommends lowering the blood-sugar cut-off to 126 because research has shown that
people with readings in the low- to mid-120s develop complications of diabetes, including blood-vessel damage
that can eventually lead to heart disease, stroke, kidney failure, blindness, nerve damage and amputation of the
feet and legs.
The American Diabetes Association estimates that each year, the disease results in 54,000 amputations, 12,000 to
24,000 cases of blindness and 178,000 deaths from diabetes and its complications.
But in its early stages, high blood sugar produces no symptoms, and many adults have diabetes for 7 years or
more before it is diagnosed. By that time, irreversible damage to the circulatory system and organs may already
have occurred.
"Damage is occurring earlier than we previously thought," said Dr. James Gavin, senior scientific officer at the
Howard Hughes Medical Institute in Chevy Chase, Md. He was the chairman of a group of international experts
that developed the guidelines after analyzing 15 years of research.
"The earlier we pick up the disease and the more aggressive we are in treating it, the greater the likelihood we'll
be able to avoid these kinds of complications," Gavin said. "This is an attempt to raise public awareness."
Although he thinks the new guidelines will ultimately benefit patients, Gavin said he did not expect the changes
to be unanimously welcomed. He said many people fear a diagnosis of diabetes, not only because of what it
means medically but also because it may expose them to insurance or employment discrimination. Cases of
discrimination have occurred, he said.
"But diabetes has earned those negative connotations because we've been picking it up and trying to intervene
late in its course when the complications have had a chance to get off to a running start," he said. "The sting is
taken away if we can avoid complications."
Eight million Americans have been diagnosed with diabetes, and another 8 million are thought to have the
disease without knowing it. The new guidelines won't change the combined total, but are expected to shift 2
million people who don't know they are diabetic into the group that does know.
Nearly all the new cases will be adult-onset or type 2 diabetes, which affects 90 percent to 95 percent of diabetics
and which tends to develop after age 40. Type 1, which is more severe, usually develops in childhood or
adolescence and is caused by a severe deficiency of the hormone insulin. Type 2 patients are more likely than
type 1 to be overweight and to have high blood pressure and other risk factors for heart disease.
People with type 2 diabetes have high levels of blood sugar because their bodies cannot use insulin properly,
and in some cases do not make enough of it to metabolize glucose and control its levels in the blood. The
immediate goal of treatment is to keep blood sugar within the normal range. Although the benefit of that strategy
has not been proved for type 2 diabetics, many researchers think it must exist.
Unlike people with type 1 diabetes, who require insulin shots to control the disease, those with type 2 don't
always have to take drugs, Gavin said. Obesity and lack of exercise are major risk factors for type 2 diabetes, and
it can sometimes be controlled with weight loss, exercise and attention to diet.
If those methods fail, or if blood sugar is very high, insulin shots or oral medications may be needed. The
American Diabetes Association estimates that 10 percent to 20 percent of type 2 patients are treated with diet
and exercise, 30 percent to 40 percent with oral drugs, and 30 percent to 40 percent with insulin or insulin and
oral medications.
Dr. Richard C. Eastman, of the National Institute of Diabetes and Digestive and Kidney Diseases, who wrote an
editorial accompanying the report on the new guidelines in Diabetes Care, said: "Many of the people who are
newly diagnosed won't require any specific therapy because their level of blood sugar is not very high. But it
goes up with time, and they need to be followed closely and therapy begun earlier."
A researcher who did not work on the new guidelines, Dr. David Nathan, director of the diabetes center at the
Massachusetts General Hospital and Harvard Medical School, agreed that undiagnosed diabetes is a major
health problem because millions of Americans don't realize they have it.
"The question that remains unresolved is, by screening, do we actually do them a favor?" Nathan said. "Will
they have a better health status? It makes sense that they should, but there have never been studies to prove
the case."
Just making the diagnosis does not guarantee patients better health care, Nathan said. "One problem in the U.S.
is that physicians are not aggressive enough in treating type 2 diabetes," he said.
But if they were, he added, that might lead to another set of problems. Even though high blood sugar is
dangerous, and patients would almost certainly be healthier if it could be lowered, he is concerned about the
safety of the drugs used to lower it in type 2 diabetics.
Studies have suggested that some of the drugs may contribute to heart disease, and some are dispensed with
warnings of the increased risk.
"We start with diet and exercise and rather rapidly move into a number of drugs, without data to suggest that's
good for patients over a long time," Nathan said. "We must be careful we don't cause some mischief, don't make
their heart disease worse."
Nonetheless, Nathan said, "On balance, I probably agree with the recommendations. But there is a cautionary
side to this story."
In addition to establishing a fasting blood sugar of 126 as the cutoff for diabetes, the guidelines also designate
normal as below 110, and identify a danger zone of 110 to 125 in which the body's ability to process glucose is
considered to be impaired.
Gavin said people in that zone should be tested more frequently and counseled about ways to lower their blood
sugar and reduce the risk of heart disease.
"That might include losing weight or not gaining any, increasing physical activity, stopping smoking, and
aggressively treating high blood pressure or high blood fat," he said.
A nationwide study, still enrolling patients, is attempting to determine whether drugs or life style changes can
prevent diabetes in people in this category, Nathan said.
[Results of this study, the DPP, were announced on August 8, 2001, and are discussed at
Diabetes Prevention Program]
Also see
Diabetes Diagnosis
From the
National Diabetes Information Clearinghouse
Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus
At PubMed. Unfortunately, no abstract is available.
Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus
At ADA. Full-text available.
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