The International Diabetes Federation (IDF), in a position statement, has recommended the adoption of a test measuring blood sugar one hour (1-h PG) after the load of Oral Glucose Tolerance Test (OGTT) has been administered to check for diabetes risk. They have also recommended revising glycaemic thresholds to measure and predict the risk of developing diabetes.
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The measure of blood sugar one hour after a 75 gm sugar solution is consumed will be a far more sensitive and practical method to screen for intermediate hyperglycaemia (IH), earlier known as pre-diabetes, and type 2 diabetes (T2D) in people at risk. It recommends the use of the cut-off points of 155 mg/dL for measuring IH, and 209 mg/dL for T2D, meaning any figure higher than specified would indicate a higher chance of diabetes, even if the individual’s fasting and two-hour values were normal.
The oral glucose test is the best for detecting the onset of diabetes at a future date, and if it is not employed, many remain undiagnosed and untreated. A “wealth of epidemiological data” guided the confirmation of the superior purpose in using the 1-h PG (plasma glucose) over even fasting PG (FPG), HbA1c and 2-hour PG across ethnicity, sex and age categories.
Michael Bergman, who co-chaired the expert panel with Jaakko Tuomilehto, said: “There are many people who would not be diagnosed through an HbA1c or FPG test but who would, if given an OGTT, be more likely to be detected as having IH or T2D. The 1-h PG has been found to be a more sensitive biomarker for the earlier identification of these high-risk individuals.”
The statement was prepared by an international panel of 22 experts from 15 countries and presented recently at the 17th International Conference on Advanced Technologies, Treatments for Diabetes in Florence, Italy and published online in Diabetes Research and Clinical Practice.
V. Mohan, Chairman, Madras Diabetes Research Foundation, whose organisation represented India on this panel, explained that the one-hour value used to be measured up until the 1980s.
“In fact, we used five values measured at different points of the OGTT. Over the years it was pared down to fasting and the two-hour value. We continued to do the one-hour sample at our centre, and that is when we discovered that 155 mg/dL is the crucial cut-off value.”
In interactions with other experts across the world, including Michael Bergman, it emerged that globally there was agreement over 155 mg/dL at one hour after OGTT being the cut-off value.
“The higher it goes from 155 mg/dL the higher are a person’s chances of moving into IH,” Dr. Mohan explained. Any value over 209 mg/dL and it is considered that the person has diabetes, the statement said.
