December 19, 2011

Another Dangrously Misleading Study Promoting High A1cs as Healthy

A presentation given at the recent 44th annual meeting of the American Society of Nephrology claims that patients on dialysis have better outcomes when they have higher A1cs. As reported in Medscape, the chief researcher says, "The range from 6% to 9% seems to be the lower range of risk. There's even an impression that you could say that from 7% to 9% is the lowest risk."

You can read the report of the presentation here. It also got some play in the medical news and newsletters directed to doctors and appears summarized on quite a few diabetes sites. The Medscape article gives the best summary. Signing up is free:

Medscape:Diabetics on Dialysis Do Better With Higher Hemoglobin A1c.

It is all too likely that busy family doctors who encounter this information will add it to the rest of the bad research that has convinced them that it's dangerous for people with Type 2 Diabetes to lower their blood sugars to normal levels. (You can read about how misinterpreted studies have led this toxic recommendation HERE.)

To understand the real meaning of the paper given at American Society of Nephrology you have to know that other research looking into the blood sugars of people on dialysis has found that because of the impact of dialysis on their red blood cells, the A1cs of people on dialysis do not correlate to their blood sugars.

In a published review of the research that discovered the inapplicability of the A1c test to people on dialysis, the author writes
We expected maybe the hemoglobin A1c would be slightly impacted by the shortened red cell survival when we went into the study, but the results were shocking to us in that the hemoglobin A1c levels were significantly lower to where they would affect patient care and outcomes.
You can read this report here:

HbA1c Inaccurate in Diabetic Patients on Hemodialysis, Study Says Hogan, Michelle. Nephrology Times: April 2008 - Volume 1 - Issue 4. doi: 10.1097/01.NEP.0000334255.74897.99

The crucial findings of this study were:
Compared with patients who did not have kidney disease, patients with end-stage renal disease had higher mean serum glucose concentrations-172 mg/dL vs 146 mg/dL-and higher percent glycated albumin-18.7% vs 15.3%-but lower hemoglobin A1c-6.8% vs 7.3%.

For a glucose level of 150 mg/dL, for example, hemoglobin A1c was about 6.5% in the dialysis group but 7.5% in the normal renal function group.
There is another test that gives a better idea of blood sugar control over a longer time period, but it isn't available in the U.S.. What is available is testing with your blood sugar meter--which is more accurate in predicting health outcomes than the A1c ever was.

Test your blood sugar 1 hour after eating. If your level is under 140 mg/dl (7.7 mmol/L) you are in the range that research suggests will avoid diabetic complications. If you are staying over 140 mg/dl (7.7 mmol/L) for more than an hour or two you are raising your risk of complications. The more time spent over that level, the more likely it is that you are damaging your organs.

The damage doesn't start immediately, and most of us will see occasional readings over that level from time to time that, if they are isolated events, aren't likely to cause damage. But if we are seeing them every day, it's time to take action.

If you are on dialysis, you will want to rely on what you see when you test your blood sugar after meals, not the A1c, to ensure that you aren't worsening whatever other diabetic complications you already have by maintaining damaging high blood sugar levels.

And if you aren't on dialysis and want to keep your nerves, kidneys, eyes and heart healthy, don't let any doctor tell you that it's dangerous to lower your A1c below 6.5%. The evidence suggests that it is not only safe, but very healthy to lower your blood sugar to normal levels, as long as you aren't doing it using Avandia, Actos, Glipizide or Glimiperide all of which have been shown to damage the heart.. The one other "dangerous" way to lower blood sugar is to use insulin in such a way that you balance high blood sugars with hypos. If you are using insulin but never see hypos below 60 mg/dl (3.3 mmol/L) you have nothing to fear.

If you avoid these known dangerous drugs and use carb restriction, metformin, and/or insulin dosed correctly to lower your blood sugar, especially if you start close to diagnosis (or in the pre-diabetic stage) before long term exposure to high blood sugars have damaged your heart, nerves, and blood vessels, your long term outlook should be very good.

And if your doctor disagrees, find a new doctor. Only doctors whose knowledge of diabetes is gleaned only from dumbed down one-paragraph newsletter summaries--or from perky drug company reps who encourage doctors to keep patients at high A1cs because their expensive new drugs only achieve higher than normal A1cs--believe that lowering A1c to normal levels is dangerous.



Unknown said...

"There is another test that gives a better idea of blood sugar control over a longer time period, but it isn't available in the U.S."

What test are you referring to in the above quote?

Jenny said...

Javed, The test is discussed in the second study linked in this post which says, "the glycated albumin assay, which is not currently available in the United States but is available in Japan, more accurately reflected glycemic control than hemoglobin A1c in patients with diabetes who are on hemodialysis."

Unknown said...


bsc said...

Are you referring to the Diazyme technique? It was approved by the FDA in May 2011, but is not yet available. The Fructosamine test has been available in the US for quite some time and is a glycated serum protein (or glycated albumin) test.

I have a "distorted" A1c, presumably I am a high glycator. My A1c does not correspond to my blood sugar meter readings. However, my fructosamine test results are more consistent with my meter readings

Jenny said...

I am not certain about the details of the Japanese test. I'd always heard that the fructosamine test was a good option for people who had hemoglobin varients that made the A1c unreliable, but I don't know what the impact of dialysis would be on whatever it is that test is testing.