ADA (2003)

FPG >7.0

Abbreviations: DM, diabetes mellitus; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; NGT, normal glucose tolerance. Source: From Refs. 1, 3, and 4.

Abbreviations: DM, diabetes mellitus; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; NGT, normal glucose tolerance. Source: From Refs. 1, 3, and 4.

glucose criteria for diagnosis were considered by the ADA to have good reproducibility, small variability, and easy application in clinical practice. IGT is defined by the WHO as a 2-hour plasma glucose concentration between 7.8 and 11.0mmol/L. The ADA (3) also introduced a category of IFG, defined as fasting plasma glucose between 5.6 and 6.9 mmol/L, to replace IGT. IFG and IGT were considered to be metabolic stages intermediate between normal glucose homeostasis and diabetes. However, it is possible that IFG differs from IGT with respect to the relative contribution of insulin secretion defect and hepatic and peripheral insulin resistance. IFG and IGT are not clinical entities, but rather risk categories for future diabetes and/or cardiovascular disease. Normoglycemia is defined as plasma fasting glucose < 6.1 (WHO) (1) and 5.6 mmol/L (ADA) (3) and a 2-hour glucose < 7.8 mmol/L in an oral glucose tolerance test. The changes in diagnostic criteria for diabetes recognized results of epidemiological studies indicating that the risks of both retinopathy and cardiovascular disease start to increase at fasting plasma glucose values of about 6.0 mmol/L (10).

Both the ADA and WHO recommend a fasting plasma glucose concentration of 7.0 mmol/L for the diagnosis of diabetes, but according to the WHO criteria (1), diabetes can be also diagnosed if the 2-h glucose concentration is at least 11.1 mmol/L. For the asymptomatic person, at least one additional glucose test result with a value in the diabetic range is essential, from a random (casual) sample, or from the oral glucose tolerance test.

A number of studies summarized by Shawn et al. (11) have compared the WHO and ADA criteria for DM using fasting and 2-h definitions. These studies demonstrate both an increase and a decrease in people as having nearly diagnosed diabetes depending on the population studied. Compared to the WHO criteria, fasting glucose-based ADA criteria may underestimate glucose abnormalities more in older age than in younger age (12). Also the Cardiovascular Health Study demonstrated a 50% underestimation of diabetes prevalence in older adults (> 65 years) comparing the ADA criteria with the WHO criteria (13). Furthermore, IGT may have higher sensitivity over IFG for predicting progression to type 2 diabetes (14).

In general the fasting criterion identifies different people as being diabetic compared to those identified by the 2-h criterion (15). In subjects without previously diagnosed diabetes, the DECODE study group from 16 different European populations (16) found that all subjects diagnosed by either the fasting or 2-h criteria, only 29% qualified as diabetic according to both criteria. This result was confirmed in the DECODA study group (17) including existing epidemiological data from 11 population-based studies collected from Asian people (n=17,666) between 30 and 89 years of age. The authors concluded that it would be inappropriate to use the ADA criteria alone for screening diabetes in Asian populations.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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