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pre diabetic? BG and HbA1c disagree



I am male 53 years from India and suffering from hypertension since 1990 and currently on Norvasc Toprol XL 100 and Cozaar 100

In 2007, I had my blood profile wherein my HbA1c was 7.7 In 2008 it was 7.1 and currently it is 8.20. My fasting sugar levels remain around 110 112 114 121. I have undergone OGTT thrice during 3 years latest being last month where the value was Fasting 112 after one hour it was 180 and after 2 hours it was 152. I was doing walking. Mu thyroid profile lipid profile ( HDL 34 LDL 67 Triglyceride 97 S Cholestrol 109 VLDL 24 Creatinine 0.90 ) all are within normal limits.

Despite elevated HbA 1C and impaired fasting glucose I am still not on medication But I read from your responses that medications over and above life style medications are vital in the control of pre diabetic stage. I am deeply worried rather very much scared to have a new disease. Can U guide me what should I do. Today, I had my post prandial which was 181 which is alarming.

I am staying away from family and worried Can you guide me what should I do to improve my glucose level. I shall be greatly obliged by your guidance.


The generalizable issue here is a discordance between two different sets of data regarding your blood glucose status: If the HbA1c results are to be taken at face value, one would argue that you have diabetes. If the GTT results are to be taken at face value you either don't have it or it is under better control than what the HbA1c would indicate. In essence, you and your doctor need to determine whether you in fact have diabetes or not. This issue of situations where there may be disagreement between HbA1c and blood glucose is the subject of my research - here are some scientific references you can bring to your doctors attention on the subject. It looks like more information is needed to resolve this - more intensive blood glucose sampling and perhaps some tests whether the red blood cells and hemoglobin molecule are normal. I would be very interested in communicating directly with your doctor, as I suspect there are people who can have normal blood sugar control and HbA1c results like yours that have not yet been described. However, the likeliest result will be that the blood sugars are an underestimation of the true blood sugar.

Cohen, R.M. A1C: does one size fit all? (Invited Editorial) Diabetes Care 30: 2756-2758, 2007

Cohen RM, Joiner CH, Franco RS. Discordant HbA1c - the Hoofbeats Increase (invited editorial). J. Pediatrics 153:7-9, 2008

Cohen RM, Ciraolo P, Palascak MB, Lindsell CJ, Khera PK, Smith EP, Joiner CH, Franco RS. Red cell lifespan heterogeneity in hematologically normal people sufficient to alter the apparent HbA1c. Blood 112: p. 4284-4291, 2008

Khera PK, Joiner CH, Carruthers A, Lindsell CJ, Franco RS, Holmes YR, Smith EP, Cohen RM. Evidence for Inter-Individual Variation in the Glucose Gradient Across the Human RBC Membrane and Its Relationship to Hb Glycation. Diabetes, 57:2445-2552, 2008.

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Response by:

Robert M Cohen, MD Robert M Cohen, MD
Professor of Clinical Medicine
College of Medicine
University of Cincinnati