Government Labels IGT as “Pre-Diabetes”

 

Tommy Thompson said that people with pre-diabetes can take meaningful

steps now to reduce their risks and avoid having diabetes."

 

The new message is that most middle-aged people should be tested during their next visit to the doctor to find if they have "pre-diabetes," a type of high blood sugar that puts them at super high risk of getting full-blown diabetes, say new guidelines.

 

The government yesterday for the first time urged overweight Americans to get tested for a newly defined condition called "pre-diabetes" as part of a campaign to stem a growing epidemic of diabetes in the United States.

 

The recommendation was prompted by the recent recognition that people who are at risk of developing diabetes can be identified and their risk of going on to develop the full-blown disease can be cut substantially by weight loss and exercise.

 

The rising incidence of diabetes in the United States is the result of a dramatic increase in obesity, as well as the aging of the population. The latest figures show that in addition to the estimated 17 million Americans who have full-blown diabetes, at least an additional 16 million have "pre-diabetes," Thompson said.

 

People with pre-diabetes have levels of glucose (a sugar in the bloodstream) that are higher than normal but not high enough to be classified as diabetes. It causes no symptoms, but without treatment most people with the condition go on to develop diabetes, which is the sixth leading cause of death in the United States and a major contributing cause of heart disease, stroke, kidney failure, high blood pressure and blindness.

 

A new campaign, sponsored by HHS and the American Diabetes Association (ADA), seeks to inform the public and health care professionals about the need to identify and treat pre-diabetes.

"Some people have . . . become fatalistic, believing diabetes is inescapable," said Judith Fradkin of the National Institutes of Health. "Those are the people we most need to reach with this message that diabetes can be stopped."

 

Thompson said HHS will also try to persuade health insurers and employers to pay for testing and treatment to prevent diabetes, a disease that is estimated to cost the U.S. economy $100 billion annually. Except for certain screening tests mandated by Congress, the federal Medicare program does not pay for preventive treatment.

 

According to the new recommendations, pre-diabetes can be diagnosed by either of two blood tests. A fasting plasma glucose (FPG) test measures the level of glucose in the bloodstream after an overnight fast. A two-hour oral glucose tolerance test (OGTT) includes the FPG test and measures the glucose level two hours after the person being tested drinks a solution containing glucose.

 

The guidelines state that testing is strongly recommended for anyone who is 44 or older and overweight (defined as a Body Mass Index of 25 or higher). They say doctors should also consider testing people older than 44 who have no risk factors, as well as younger adults who are overweight and who have at least one other risk factor for diabetes.

If the test for pre-diabetes is normal, it should be repeated every three years, according to the recommendations. If pre-diabetes is diagnosed, the patient should receive counseling on weight loss and increasing exercise and should be monitored every year or two for possible diabetes.

"Just 30 minutes of walking a day, five days a week, can significantly reduce the risk of developing diabetes," Thompson said.

In the Finnish study, the goal was to have participants lose 5 percent of their body weight and exercise moderately for 150 minutes each week. In the U.S. study, the exercise goal was the same but the weight loss goal was 7 percent of body weight.

 

Participants in both studies received considerable incentives, such as nutritional counseling, exercise classes, meal plans and sometimes gifts such as exercise equipment or gym memberships. Even so, in the U.S. study only 50 percent reached the weight loss goal and in the Finnish study, only 43 percent. Seventy-four percent of participants in the U.S. study and 36 percent in the Finnish study reached their exercise goal.

 

Thompson and other speakers at the briefing acknowledged that such lifestyle changes are difficult for many people. Thompson promised to recruit actors and athletes to help in the campaign against diabetes and to send the administration's new surgeon general, Richard H. Carmona, "out on the road" if his appointment is confirmed.  The guidelines are published in the April issue of the journal Diabetes Care

 

Impaired Glucose Tolerance- A Call for Action

Barbara Lesperance, MSN, RN-CS. APRN. CDE

Impaired glucose tolerance (IGT), frequently a precursor to Type 2 Diabetes, has received more attention recently in the medical community due to the national focus on preventing heart disease. IGT, defined as a 2-hour postload value in the Oral Glucose Tolerance Test of >140 but <200, is now shown to place individuals at an increased risk for cardiovascular disease ^1,2.

Approximately 8-11% of the US population³ have IGT. Fully 25% of this group³ are likely to progress to frank Diabetes, increasing their risk of microvascular and macrovascular complications. 

Certain ethnic groups (American Indian, Hispanic, African-American) carry a higher risk of progression from IGT to Type 2 Diabetes as do individuals with metabolic syndrome (excess weight with central obesity, elevated blood pressure, dyslipidemia, and insulin resistance⁵). Frank diabetes is generally the end point of several progressive steps⁴:

1.      Metabolic syndrome leads to insulin resistance at the cellular level, forcing the pancreas to work harder to produce enough insulin to maintain blood glucose at close to normal ranges.

2.      When insulin resistance increases and the pancreas loses its ability to respond adequately to the mealtime glucose load, post-prandial levels of glucose are found to be 140-200 (while fasting glucose levels remain less than 110). This stage is IGT.

3.      Further resistance at the cellular level forces response from the liver, increasing glucose production. At this point there is a rise in fasting glucose levels, with eventual rises in both post-prandial and fasting levels diagnostic of diabetes.

Terms such as “borderline diabetes” or “mild diabetes” truly undermine the serious nature of glucose intolerance. Unfortunately, once postprandial and fasting glucose rise to levels diagnostic for Diabetes, 20% of individuals already have confirmed retinopathy³. Evidence of stroke, angina, and myocardial infarction are also more frequently present in this previously undiagnosed group at the time of diagnosis. Early identification of IGT allows aggressive treatment of the macrovascular components (coronary artery, peripheral vascular, and cerebrovascular disease) to avoid the life threatening consequences of these problems as well as delay the onset of frank diabetes. Recognition of glucose intolerance may indeed allow timely interventions to encourage lifestyle changes including healthy eating, regular exercise, strict control of lipids to achieve recommended targets, and blood pressure within the 130/80 limit. 

Will primary care providers (physicians, nurse practitioners, and physician assistants) identify glucose intolerance in the high risk groups and take the time to encourage lifestyle changes and follow progress until targets are reached? At the current time, many primary care providers do not even attempt to reach targeted glucose, lipid, or blood pressure goals in those already diagnosed with Type 2 Diabetes. An informed consumer may indeed embrace preventive therapy if told directly about the consequences of Type 2 diabetes, and the benefits of prevention. Diabetologists and diabetes educators certainly promote prevention strategies, but their audience is smaller than the greater numbers cared for by primary providers. The media has been helpful in presenting current research on linking glucose control and obesity to cardiovascular events, and revealing the near epidemic proportions of obesity in younger age groups leading to glucose intolerance and frank diabetes.  Until physicians, trusted by their patients, make a concerted effort to identify high risk patients, explain the dangers of diabetes and the significance of IGT, and outline reasonable, patient-specific therapies, there is likely to be little impact on embracing the needed lifestyle changes. 

Barbara J. Lesperance, MSN, RN-CS, APRN, CDE, is serving as clinical specialist and diabetes educator, and as manager for special projects related to JCAHO survey for the Danbury Hospital, Danbury, CT. She received her masters degree in nursing from Western Connecticut State University and has a degree in psychology from Mount Holyoke College. She recently presented “Diabetes: The impact on Hospitalized Patients-Not ‘Just a Little Sugar’” at the AACN annual conference in Boston, MA. 

References:

1.       O’Keefe, J., Miles, J., Harris, W., Moe, R, & McCallister, B. Improving the adverse cardiovascular prognosis of type 2 diabetes. Reprint Mayo Clinic Proc, February 1999;74:171-180.

2.       American Diabetes Association. Impaired Glucose tolerance (IGT) and impaired fasting glucose (IFG). Diabetes Care (Suppl)25:5S.2002.

3.       Edelman, S. & Henry, R. Diagnosis and management of Type 2 Diabetes. 4^th edition.2001. Professional Communications. Caddo, OK:25-9.

4.       Quinn, L. ed. “Type 2 Diabetes: Epidemiology, pathophysiology, and diagnosis.  The Nursing Clinics of North America.2001:36,2:178-182.

5.       Leahy, J, Clark, N., & Cefalu, W.  Medical management of diabetes mellitus. 2000. Marcel Dekker:New York:44, 116.

 

Diabetes-- A Confusing Diagnosis

 

A Special interview by our Publisher, Stephen Freed, R.Ph., Diabetes Educator 

IGT, IFG, DIABETES, 110, 140, 126, 200, Pre-Diabetes, Confusing?

“The use of a single measurement cut-off for diagnosis of diabetes and altered glucose tolerance misclassifies many people with abnormal glucose tolerance as being normal,” says Dr. Doi, Faculty member of the Divisions of Medicine, Endocrinology and Metabolic Medicine, Jahra Hospital, Jabriya, Kuwait.

Why are 30% of people with diabetes walking around with normal fasting blood glucose undiagnosed and untreated?

Why do most people with diabetes get diagnosed after they have had diabetes for up to 12 years?

Why do most people at diagnosis of diabetes already have one or more of the complications?

Why are we spending over 100 Billion dollars on diabetes?

The use of a single measurement cut-off for diagnosis of diabetes and altered glucose tolerance misclassifies many people with abnormal glucose tolerance as being normal.

 

One day we will have a test just like the pregnancy tests that will tell you that if it shows a plus (+) you have diabetes and if it shows a (-) you don’t, but if it shows (0) then you are pre-diabetic or maybe red for diabetes and blue for normal and yellow for IGT.

 

But we don’t have that test yet.  So what can we do today to make a real difference?

I recently had a chance to review a study by the lead doctors from the faculty of Medicine, Division of Endocrinology and Metabolic Medicine in Kuwait.  I found the results to be factual and intriguing.    Why are we not diagnosing people with IGT and diabetes much earlier?  Why do people get a fasting BG in the office to diagnose diabetes when we know that 50% of the time a person can have a normal FBG and still have diabetes? The answer could be right before us. 

I asked Dr. Doi if he would write a summary for our readers to further explain the results from a study he recently completed.  As you will see the study defined 2 cut off points to diagnose IGT, Diabetes and Normal. 

Diagnostic Criteria for Diabetes, IGT and IFG Revisited: Use of Combined Criteria
 
SUMMARY

We know that existing cut-offs for the fasting plasma glucose (FPG) and post-load glucose (2hPG) criteria are not equivalent in the diagnosis of diabetes and glucose intolerance: A sizable proportion of subjects with diagnostic 2hPG concentrations (≥ 11.1 mmol/L or 199 mg/dL) have fasting glucose values below the level defined as diagnostic by the WHO (FPG <7.8 mmol/L or 140 mg/dL) or the ADA (FPG <7.0 mmol/L or 126 mg/dL). This proportion varies in different populations and ranges from one-thirds to three-quarters. In fact, it has also been shown, from pooled analysis of 20 studies conducted in different European countries, that as many as one-third (31%) of those who are diabetic, according to the 2hPG, have normal fasting values (<6.1 mmol/L or 110 mg/dL) and therefore, would only be detected by a screening procedure based essentially on post load glucose measurements. On the other hand, fasting glucose is of little help in diagnosing impaired glucose tolerance (IGT) since evidence is accumulating that most people with IGT (from 54 to 67%) have fasting glucose in the normal range (<6.1 mmol/L or 110 mg/dL).

It seems clear therefore, that not only are these cutoffs not equivalent in their definition of diabetes. The increased emphasis given by the expert committee on the fasting values is not entirely optimal since it has been demonstrated that isolated post load hyperglycemia is a strong predictor of mortality and progression to diabetes, and it is possible to prevent the progression to overt diabetes in this group. Based on this data, workers have tried to improve on the fasting glucose threshold for diagnosis of this group by lowering it to 5.5 mmol/l or 100mg/dL, (thus detecting 93% of all those with diabetes diagnosed on the basis of 2hPG). However it was still clear that at this cut-off, its ability to identify IGT (sensitivity) does not improve substantially. It has therefore been concluded that the FPG, while being useful to confirm the overtly diabetic state, misclassifies many people with abnormal glucose tolerance as being normal.

In short, the 2hPG clearly points out normality and the FPG clearly points out diabetes with excessive overlap of other groups. This is corroborated by studies where approximately two thirds of individuals diagnosed as having diabetes by a 2hPG concentration of 11.1–13.3 mmol/L or 200-240 mg/dL on an oral glucose tolerance test have normal HBA1c levels. At the same time, patients with IFG usually have a normal glycemic status rather than an intermediate level of glycemia and are very distinct from diabetics. It is clear that the FPG of 6.1-6.9 mmol/L or 110 – 124 mg/dL provides no reliable information on whether an individual is normal or is at risk from future diabetes or future cardiovascular, eye or kidney disease related to diabetes. In a similar fashion, the 2hPG provides poor discrimination of those at intermediate risk from the overtly diabetic patients with ongoing risk. This is confirmed by the Funagata Diabetes Study in Japan, where the hazard ratios for all cause and cardiovascular mortality were higher for subjects diagnosed with diabetes according to the FPG than for subjects diagnosed according to the 2hPG. However subjects with IGT had a higher risk of cardiovascular mortality than subjects with IFG. These observations suggest that a diagnostic fasting value represents a level of glycemia that provides a high level of clinical certainty that the patient does indeed have diabetes, especially if it is elevated on two occasions, whereas the 2-hour criterion does not. In the same vein, a normal 2hPG provides a high level of clinical certainty that a patient needs no intervention, whearas the fasting criterion does not. It then becomes clear that to diagnose normality, impaired glucose tolerance and diabetes, we need a combination of these two criteria: One that favors sensitivity to exclude diabetes and the other that favors specificity to diagnose diabetes. The same result can not be achieved by adjusting cut-offs of single measurements.

We therefore evaluated their combined use for diagnosis against mean levels of hemoglobin A1c (HbA1c) in our patient groups. We defined the combined criteria as the upper limit for the FPG (specific test) combined with the lower limit for the 2hPG (sensitive test). Normality was based on the 2hPG value (<7.8 mmol/Lor 140 mg/dL) so long as the fasting value was concordant (<7 mmol/L or 126 mg/dL). In the same way, a fasting value was used to define diabetes (≥ 7 mmol/Lor 126 mg/dL) so long as the 2hPG value was concordant (≥ 7.8 mmol/L or 140mg/dL). A discordant fasting and 2hPG value defines combined criteria IGT (cIGT). As expected, we were able to demonstrate three distinct groups of patients (by HBA1c) with the combined criteria: Normal, impaired and diabetic. With the FPG or the 2hPG only two groups could be demonstrated: Diabetic and others OR normals and others. Both fail to define the important group of impaired glucose tolerance as a distinct group.

We therefore conclude, that to diagnose diabetes or glucose intolerance, we need a formal 2h OGTT with a fasting and 2h value and the cut-off points specified above for diagnostic characterization. We look forward to retrospective application of these criteria to current databases in terms of its impact on diabetic endpoints such as microvascular disease or mortality.

Ali Parappil , Suhail AR Doi and Kamal AS Al-Shoumer
Division of Medicine, Jahra Hospital, Kuwait  Division of Endocrinology and Metabolic Medicine, faculty of medicine, Kuwait
Mubarak Al-Kabeer Hospital, Jabriya, Kuwait  BMC Endocrine Disorders 2002 2: 1
To view complete Study: http://www.biomedcentral.com/1472-6823/2/1 

 

Physicians World Wide Complacent About Tight Blood Glucose Control

 

When physicians are complacent, so are their patients.  "Diabetes could become the AIDS of the 21st century"

The International Diabetes Federation (IDF) has called for urgent action to stem the growing epidemic of type 2 diabetes by identifying those at high-risk and prevent complications by more aggressive management of blood glucose control.

Many physicians have been too complacent about the need for tight blood glucose control. This complacency has been passed on to patients, who are often poorly motivated to control their condition. "Type 2 diabetes is not a 'mild' form of diabetes" says IDF President, Professor Sir George Alberti, speaking today at a Federation meeting in Montreux. "More aggressive control of the whole blood glucose profile is essential if we are to prevent the life-threatening complications of diabetes".

Diabetes remains the industrialised world's leading cause of blindness, end-stage renal disease, and non-traumatic limb amputations. Type 2 diabetes increases the risk of cardiovascular diseases by two or three fold, and eight out of ten people with the condition will die from a cardiovascular disease.

The key to preventing diabetic complications is to achieve tight control of blood glucose as well as meticulous control of other cardiovascular disease risk factors. The UK Prospective Diabetes Study showed that if HbA1c (a marker of blood glucose control) is reduced by 1%, the risk of heart attack is reduced by 14%, and the risk of eye and kidney damage by up to nearly 45%. Yet the vast majority of patients with type 2 diabetes do not achieve adequate control of their blood glucose levels, particularly their post-meal glucose.

Early detection of the condition is also vital. "Affluent nations should be screening high-risk groups, such as people who are obese, have a family history, or are from ethnic groups pre-disposed to the condition" says Professor Alberti. Earlier detection and treatment would not only reduce the suffering caused by diabetic complications, but would reduce the huge burden that diabetes places on healthcare services. Type 2 diabetes already accounts for 10-15% of European healthcare budgets and this is set to rise.

It is essential that more resources be devoted to diabetes prevention programs. Unless significant efforts are made to stem the rise in diabetes, healthcare services across the world will soon be crippled by the costs of treating the diseases and its complications. "Diabetes could become the AIDS of the 21st century" warns Professor Alberti. "The importance of diabetes prevention cannot be underestimated".

Type 2 diabetes currently affects 1 in 20 European adults (22.5 million). A further 1 in 7 adults over 40 years of age have a condition known as impaired glucose tolerance (IGT), which confers a high risk of diabetes and a significantly increased risk of cardiovascular disease. Approximately half of people with IGT will develop diabetes within ten years, but the vast majority of people with IGT will never be diagnosed, or offered advice on how to reduce their risk of progressing to diabetes.

Recent large-scale clinical trials have shown that frequent lifestyle advice, delivered by a health professional, is effective at reducing diabetes incidence in people at high risk. Clinical trials are also underway to investigate whether drugs that improve insulin secretion or insulin sensitivity reduce the risk of diabetes and cardiovascular disease in high-risk groups. The largest of these is the NAVIGATOR trial launched in November 2001, which will involve 7,500 people with IGT in 41 countries across the world.

Professor Alberti today called for people with impaired glucose tolerance to be managed much more aggressively with lifestyle change and weight control and drug therapy for lifestyle advice failures. 

 

Back to Top Stories for 2002

 

 

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