| Diagnosis |
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| The New American Diabetes Association Criteria For Diagnosis of Diabetes: Clarity Or Confusion? |
| - Dr. S. M. Sadikot |
Consultant Physician & Endocrinologist
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| The criteria and the methods used in the diagnosis are familiar to all of us. These are the WHO method and criteria which were formalised by experts in the late 1980's. |
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| Before the early 1970's, there were no widely accepted criteria or methods laid down for the diagnosis of diabetes leading to utter confusion with different investigators using differing criteria. Then the WHO and the National Diabetes Data Group (NDDG) of the American Diabetes Association (ADA) came up with norms to diagnose diabetes. Unfortunately, the two norms had some significant differences and the confusion, though less than before remained. In 1985, the WHO modified their norms doing away with some discrepancies between the two. Later, the NDDG also followed suit and changed their norms so that for once we had a universal method and criteria for diagnosing diabetes. |
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| Confusion changed to Clarity! |
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| The world now had the norms for diagnosis, which were universally accepted. |
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| Briefly, the Oral Glucose Tolerance Test (OGTT) was the recommended procedure. The test was usually carried out in the morning after an over night fast of 8-12 hours. After collecting the fasting sample for glucose (FPG), the individual was given 75gm of anhydrous glucose (diluted in water in about 200-250 cc of water and drunk over a 3-5 minutes). Blood was then collected after 2 hours to give a 2 hours post glucose (2 hour-PG) value. |
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| But within a decade, we are now faced with the fact that the Expert Committee of the American Diabetes Association has seen it fit to "unilaterally" recommended a new set of diagnostic criteria which has substantially changed the values used for the diagnosis of diabetes. |
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| This term microalbuminuria was coined in 1982 at Guy’s Hospital, London. |
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| The criteria proposed by the ADA expert Committee is as follows: |
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| Although on the face of it, it seems that the only change recommended by the ADA is a lowering of the fasting criteria from 140mg% to 126mg%, a closer scrutiny shows that the new recommendations have a much larger implications. Although they have not done away completely with the need for carrying out an OGTT, for all practical purposes, the diagnostic implications of an OGTT have been minimised and more focus has been placed on the Fasting plasma Glucose (FPG). The minimising of the OGTT can be seen by the fact that they have now introduced a new category called impaired Fasting Glucose (IFG) and have almost given up on the impaired Glucose Tolerance (IGT) category. |
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| The results (venous plasma glucose in mg/100ml) were classified as follows |
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Fasting |
2 hours-PG |
| Diabetes |
³ 140 |
> 200 |
| Impaired Glucose Tolerance (IGT) |
< 140 |
140-199 |
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Plasma |
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Venous |
Capillary |
Venous |
Diabetes Mellitus
Fasting
or
2-hour post glucose load or both |
>=110
>180 |
>=110
>200 |
>=126
>200 |
Impaired Glucose Tolerance
Fasting (if measured)
and
2-hour post glucose load |
<110
>=120 and 180 |
<110
>=140 and <200
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<126
>=140 and <200 |
Impaired Fasting Glycaemia
Fasting
2 hour PG (if measured) |
>=100 and <110
<120 |
>=100 and <110
<140
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>=110 and <126
<140 |
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| From Clarity we move to Confusion! |
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| In view of this, the WHO has now set up an expert committee to look into the need for, and if necessary, review the norms for the diagnosis of diabetes. They may or may not accept the recommendations made by the ADA. |
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| Firstly, and most importantly, is there a need for a change in the norms? And even if there is, is the ADA justified in its unilateral recommendations? Would it not have been better for it to have started a dialogue for a consensus before making its declaration? |
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| Should the world now blindly follow suit? What are the implications of the new norms, especially for our people with diabetes? What is the significance of IFG vis a vis IGT? |
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| WHAT DOES THE ADA DESERVE? BOUQUETS OR BRICKBATS |
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| It is generally accepted that diabetes is a major health problem all over the world, and especially so in the developing countries. India has the dubious distinction of being home to one in five persons with diabetes worldwide. The WHO predicts that the number of people with diabetes is likely to double in the next couple of decades and that the major brunt of this will be borne by the developing countries. In fact, diabetes has long passed the stage of being an epidemic in India, but can be said to have reached "pandemic" proportions. |
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| In a recent all-India survey carried out by the members of the Indian Task Force on Diabetes Care, the first of its kind ever considering that data was collected from more than 200 centers from all over India, cities, towns, villages and even tribal areas in the hinterland, the interim results show that the overall percentage of people with diabetes is frightening, to say the least. |
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| But when one talks of number of people with diabetes, it is presumed that the diagnosis of diabetes is based on criteria and methods which have evolved based on the scientific data which is presently available, and not on abstract assumptions. One must feel confident that the diagnosis is correct, fully established and reproducible. After all, the diagnosis of diabetes is something which will "stick" with a person throughout one's life. As it has been so aptly said, "once a diabetic, always a diabetic!" |
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| The changes made in the criteria as well as the proposed change in the methodology by the ADA has created considerable controversy in the diabetic world. If the WHO Working Group also recommends the new criteria than it becomes essential for all of us to critically examine the need for the change in the diagnostic criteria. |
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