Are Doctors Over-Diagnosing Pre-Diabetes?

by admin  - 
Are Doctors Over-Diagnosing Pre-Diabetes?

So, your were told by your Doc you have “pre-diabetes”. What does that mean? It sound scary….I get it. It’s a diagnosis that is made by looking at a fasting blood sugar or another test called the A1C, which is an indiator of the glucose levels over the past 3 months. Let’s take a deep dive into this diagnosis, and I GUARANTEE this will be more time than is given to the topic that was discussed in todays world of Corporate Medicine. First, understand that Pre-diabetes is NOT Type 2 diabetes. The Pre-diabetes lebal was designed to identify high risk people who may progress to diabetes….”May” is NOT “Will”.

The HbA1C test, also called “Hemoglobin A1C” came into practice in 1978. It was  test of convenience to follow the status of the diabetic patient, because it doesn’t require fasting for the morning blood work, and like I said before, it’s a 3-month reflection of how well the glucose control has been going. Around 23 years later, the American Diabetes Association [“ADA”] coined the label “pre-diabetes” and numerous organizations felt that a HbA1C > 6.5  equaled diabetes…but they just couldn’t all agree on the prediabetes range of an abnormal test. They went with 5.7%-6.4% range as the prediabetes range, but the World Health Organization recommended it should be higher at 6.0%-6.4%.

So, this test got added to the “older tests” that were being used, that being a Fasting AM blood glucose and an Oral Glucose Tolerance Test, where you drink a sweet drink and they follow your glucose level over the next 2 hours. How well do these test agree with each other? One word….POORLY.

FALSE and INACCURATE READINGS:

One concern is that there are many things that can affect the HbA1C level. First, why 3 months or 90 days? Because HbA1C is a measure that comes from your red blood cells, that’s the “Hb” part of the name.  It implies the role of hemoglobin, the protein that makes your blood red in color. If you live in a high-altitude location like Denver, the test can be False LOW. Pregnant Women can also have a False Low reading. Taking Vitamin C? That can affect the test EITHER WAY, either Up or Down.  Kidney and Liver disease, which can both affect the lifespan of a red blood cell, can alter your test result. So can alcoholism.

Let’s say you are diagnosed with anemia and the anemia is due to a low iron level….that can may HbA1C False High reading. If you are low on B12, it can also make the test a False High. Same if your triglycerides are too high. To use A1c to conform diabetes, it is recommended that the test be performed twice.

Diabetes diagnosis based only on an A1C reading will actually miss a large proportion of asymptomatic early cases of diabetes that can only be identified by the Oral Glucose Tolerance Test, which is the 75 gram sugar drink test.

 

Test Don’t Always Agree:
     The fasting morning blood glucose level can often be unreliable. When they draw the tube of blood, there are cells present in that tube, and they are living cells using energy. They draw on the glucose in the blood for that energy. If the tube does not have a substance in it to impede the cell’s use of glucose for energy, by the time the tube gets to the machine, the HbA1C may be falsely low. This fasting glucose level can be as high as 10% of the actual number.
Which Test Best Predicts Cardiovascular Concerns?

  We, it’s not the morning fasting blood glucose level.  An elevated fasting blood glucose level does not tell you anything about the risk of you having a cardiovascular “event” related to diabetes. The A1C and the 2 hour Oral Glucose Tolerance Test are better predictors of that….and comparing them to each other, the 2 hour Oral Glucose Tolerance Test is superior.

 

Will I Get Diabetes?

This is a tough question and the literature is literally all over the place. After an extensive review, this is what I believe;

  •   Woman are at a higher risk of progression vs. Men.
  •   Aging, blood conditions and ethnic differences can affect the HbA1C level
  •   The 10-year risk in women is 14% and in men is 9%, starting at age 45, if one goes by the ADA definition of pre-diabetes, and higher is using the WHO definition.

Take Home Points:

 

  1. Fasting Morning Blood Glucose levels are NOT that great of a test to see if you have diabetes. It corresponds to the lowest glucose level during the day and it reflects the long night-time period when there is ZERO intake of food and no particular stress on the pancreas to make insulin.  However, humans spend most of their time in “after-eating” states  or postabsorptive states that are not working well in diabetes.
  2. In the Finnish Diabetes Prevention Study, the sensitivity of A1C ≥6.5% to diagnose diabetes was only 39%!!   61% of new diagnosed diabetes cases actually had A1C <6.5%. So, using a HbA1C to make a diagnosis of diabetes is pretty bad.
  3. Your HbA1C increases with age, 0.15% in men and 0.19% in women, per decade.
  4. The World Health Organization does not recognize “pre-diabetes”. Many people with this diagnosis will simply never develop diabetes. They do recognize impaired glucose tolerance.and fasting hyperglycemia.
  5. The 2 hour Oral Glucose Tolerance Test IS the gold standard and the HbA1C has poor sensitivity and specificity in comparison, especially in obese and overweight Black American and Caribbean children, where the sensitivity and specificity is about 70% /48%. In a study in Turkey, the sensitivity of HbA1C in making a diagnosis of diabetes was only 50%.
  6.  In Whites and Hispanics, the HbA1C and the oral Glucose Tolerance Test do not match-up well in making the diagnosis. Using A1C alone will incorrectly diagnose too may people with diabetes.

Disclaimer: This post is for entertainment purposes only. Do not make personal medical decision based on this post. The accuracy of the information cannot be ascertained to be 100% correct and you should not make any personal medical decisions based on what you have read here. No doctor-patient relationship is established nor implied by reading and/or interacting with this website or this post. Personal health/medical decisions are to be made strictly between you and your health care provider.