People with blood glucose levels that are higher than normal but not yet in the diabetic range have `prediabetes`. Doctors sometimes call this condition impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), depending on the test used to diagnose it. Insulin resistance and prediabetes usually have no symptoms. You may have one or both conditions for several years without noticing anything.

How is prediabetes detected?
At present, the fasting plasma glucose (FPG) and the 2-h oral glucose tolerance test (OGTT) are the tests of choice to identify all states of hyperglycemia. Either test is suitable, and each has advantages and disadvantages, such as convenience, cost, and reproducibility. Identification of individuals with IGT can be made only with a 2-hour OGTT; the fasting plasma glucose (FPG) alone will miss approximately 30% of patients with isolated IGT. A recent consensus statement issued by the American Diabetes Association has recommended that if pharmacotherapy is used, both IFG and IGT should be documented. If only lifestyle modification is planned, a confirmatory test is not required.

1. IGT is detected when blood glucose levels are elevated (140-199 mg/dL) two hours after an Oral Glucose Tolerance Test is administered.
2. IFG is detected when blood glucose levels are elevated (100-125 mg/dL) after a fast of at least eight hours.

Do risk factors for prediabetes differ from type 2 diabetes?
No, risk factors for prediabetes do not differ from type 2 diabetes. Both conditions share the same risk factors, and prediabetes is itself a risk factor for type 2 diabetes.

While prediabetes and type 2 diabetes share the same risk factors, persons with prediabetes can reduce their blood glucose levels to normal values and reduce their risk for developing type 2 diabetes. Currently, there is not enough information to warrant distinguishing prediabetes and diabetes` risk factors. As we learn more about the differing pathophysiologies of IGT and IFG and their relation to the onset of type 2 diabetes, as well as preventive interventions, distinguishing prediabetes and type 2 diabetes risk factors might become possible.

What is the risk of a person`s prediabetes converting into type 2 diabetes?
The risk of progressing to diabetes depends on the type of prediabetes that a person has (IFG only, IGT only, or both), as well as other diabetes risk factors. Individuals with prediabetes who are older, overweight, and have a family history of diabetes and gestational diabetes are more likely to progre-ss to diabetes.5 Individuals with prediabetes are 5-15 times more likely to develop type 2 diabetes than are people with normal glucose values.4 Individuals with both IFG and IGT develop diabetes approximately twice as often as individuals with just one of the two conditions.

Annual progression to diabetes
Studies in the United States and abroad show that, for persons with IGT, between 2% and 34% will develop type 2 diabetes annually; for persons with IFG, between 1.5% and 23% will develop diabetes annually.4 Two randomized controlled trials of diabetes prevention, the Diabetes Prevention Program (DPP) and the Finish Diabetes Prevention Study, demonstrated that 3-5% of individuals with IGT who lost weight and engaged in moderate physical activity progressed to diabetes annually. For persons with prediabetes who did not lose weight and engage in moderate physical activity, 11% progressed to diabetes annually.

Prolonged progression to diabetes
The natural history of prediabetes (both IGT and IFG) indicates that about 25% of persons with prediabetes progress to diabetes within three to five years. With longer observation, the majority of individuals with IFG or IGT go on to develop diabetes within about 10 years, unless they lose weight through moderate changes in diet and physical activity.12 Over the course of a lifetime, as many as 83% of persons with prediabetes (IGT) who neither lose weight nor engage in moderate physical activity will develop diabetes.13 Over the course of a lifetime, approximately 65% of persons with prediabetes who lose weight and engage in moderate physical activity will go on to develop diabetes.

Text courtesy: www.cdc.gov