Intermediate states of hyperglycemia
IFG, IGT, and diabetes mellitus are seen as progressive stages of the same disease process, and treatment at earlier stages has been shown to prevent progression to later stages (by diet, exercise and lifestyle management). Not all patients with IGT have IFG, so it is considered a separate category. As well, the implications of the two states are slightly different.
Impaired Fasting Hyperglycemia (IFG) is a state of higher than normal fasting blood (or plasma) glucose concentration, but lower than the diagnostic cut-off for diabetes.
Impaired Glucose Tolerance (IGT) is a state of higher than normal blood (or plasma) glucose concentration 2 hours after 75 gram oral glucose load but less than the diagnostic cut-off for diabetes.
Patients usually have no symptoms and are diagnosed because a test is done upon patient request or because he/she falls into a high risk category.
- IFG: fasting plasma glucose >=6.1 mmol/L (110 mg/dL) and <7 mmol/L (126 mg/dL) per WHO 1999 criteria. (ADA has chosen a lower cutoff of 5.6mmol/L or 100mg/dL).
- IGT: fasting plasma glucose (if available) <7.0 mmol/L (126 mg/dL) AND 2 hour post 75g glucose drink of >= 7.8 mmol/L (140 mg/dL) and <11.1 mmol/L (200 mg/dL).
- lifestyle modifications (diet, physical activity, weight loss) are the mainstay of treatment, although sometimes medications are used.
- large, population-based studies in China , Finland and USA have recently demonstrated the feasibility of preventing, or delaying, the onset of diabetes in overweight subjects with mild glucose intolerance (IGT).
- studies suggest that even moderate reduction in weight and only half an hour of walking each day reduces the incidence of diabetes by more than one half.