A1c test Unreliable?

[Kitatonic]

Last July, I had a 150 blood glucose about an hour after eating, so the A1c was added on and reported to be 5.8, pre-diabetic. Although the 5.8, was re-confirmed 3 months later, the lab was found to be reporting high, so 5.5 was reconfirmed twice in the next six months. Home monitoring (only occasionally 120 1pp), 2-hour glucose test (102), fasting levels (82) would reflect a A1c of 5.2, not 5.5 (average 105). I realize that OSA is an independent risk factor for insulin resistance. Since I started CPAP, 16 months ago, the AHI has gone from 50 to 0.2, the oxy sat 65 to 95, so I doubt if I'm spiking glucose in the night. No one can seem to explain why the A1c "not accurate" for me. Do any of you have clues as to why the A1c is inaccurate?

[chunkyfrog]

Usually, the best strategy is to treat diabetes and apnea each with its own regimen;
as any connection may not be as tight as we wish it were.
(can't treat one and hope the other will improve.)
BTW, the term pre-diabetes has been falling into disfavor.

[growing]

I would suggest to check serum c-peptide level (fasting and pp after 75 g glucose load).

[Janknitz]

http://chriskresser.com/why-hemoglobin- ... ble-marker


And in http://chriskresser.com/when-your-“norm ... mal-part-2 he says:
If you’re interested in health and longevity – instead of just slowing the onset of serious disease by a few years – you might consider shooting for these targets. But remember to interpret the numbers together, and also remember that blood sugar is highly variable. If you wake up one morning and have a fasting blood sugar of 95, but your A1c and post-meal numbers are still normal, that’s usually no cause for concern. Likewise, if you see a one-hour post-meal spike of 145 mg/dL, but all of your other numbers are normal, that is also usually no cause for concern.

Ideal:

Fasting blood glucose (mg/dL) <86*
OGGT / post-meal (mg/dL after 2 hours) <120
Hemoglobin A1c (%) <5.3

[RandyJ]

I can't speak to whether A1C levels can be inaccurate, but it sounds like you are on top of it. If your FBS (fasting blood sugar) is in the normal range (under 100) and you are following a low glycemic diet, the A1C might improve after 6 months or so.

If you are not following a low glycemic diet, I would suggest talking to your doctor about starting one and maintaining it for at least 6 months to see what happens to your levels. I think giving your body a break from insulin highs and lows can only help. Getting grains, starches, free sugars and sugar substitutes out of your diet can make you feel better, too.

[Kitatonic]

Thanks for the replies.Should I call this "impaired glucose tolerance"? My c-peptide and insulin levels were normal, but I'll recheck on the timing. I had read Chris' column as to possibly having longer lived RBCs, so the A1c is falsely elevated, no doctor seems to discuss this as a possibility. Just curious if any other apnea sufferers have the same experience with a falsely elevated A1c.

[growing]

Sorry, but, if you are overweight which I do not know, you have more chance of disturbed beta-cell function. However, an elevated insulin or c-peptide level is not a big deal to manage. Let us have the fresh blood tests.
I envy your AHI of 0.2. Congratulations.

[Kitatonic]

The reason I posted the insulin resistance on this board is that my ONLY risk factor is severe OSA. I'm 5'4", 109#, lifetime daily athlete & vegetarian (Chunkyfrog, grew up in Nebr seeing a slaughterhouse!). All of us should be aware of this insulin resistance risk as doctors do not seem to be!

I have cut down on the whole wheat breads and increased the nut snacks. Good suggestion to even better adhere to a low glycemic diet. Perhaps, my downfall is that gallon of milk I drink every week. (?) My concern is that since my meter never reflects a high average BG like the A1c, could I be spiking during the night despite my good numbers? Could insulin resistance like fatigue resolve over years of CPAP use?

[JeffH]

I'm diabetic and have been interested in this for a long time. From what I understand, fasting blood sugar readings first thing in the morning are the last on the list of what to hang your hat on. A1c is a 90 day look at the blood sugar of your red blood cells, the most accurate way of looking at blood sugar.

Since I started eating a Paleo diet three years ago, my A1c has always been in the low to mid fives. I also test my fasting blood sugar and depending on what I ate the night before it is rarely over 100, usually in the 80's and 90's. I test two hours after dinner also. I take 1000mg of Metformin twice a day.

Diet is all important with it comes to blood sugar control in my experience.

FWIW


JeffH

[RandyJ]

Diet is all important with it comes to blood sugar control in my experience.

I think most of us don't realize this. In fact, many people avoid going on blood sugar medications or insulin simply by changing diet. Sometimes the changes are drastic and take getting used to; I eliminated gluten, dairy, and yeast from my diet all at once a year ago. All of a sudden sandwiches were a thing of the past (and a sandwich was my 'go to' quick lunch meal for years). Bread was history because breads that are both gluten free and yeast free are hard to find, and when you do find one, either the taste or cost is prohibitive. But you can get used to it, and feel a lot better in the process.

I think when you do a low glycemic diet by eliminating most sugars (found in starches, grains and dairy), you can minimize spikes in insulin response and gradually see better numbers.

For the OP - you might want to try unsweetened almond milk, or almond/coconut milk blend as a low GI alternative to milk. The taste is different, but not unpleasant. If you must have cow's milk, full fat milk is better because it contains less sugar.

[Janknitz]

India has one of the highest rates of diabetes in the world and most of the population is vegetarian. If you are eating a heavily grain-based diet to make up for the lack of meat, that's a risk for insulin resistance.

I'll bet you're dutifully drinking skim milk which has a high sugar content --12 g per cup. 2 slices of whole wheat bread have a higher glycemic index than a candy bar. People are so busy doing low fat that they forget we NEED fat to use vitamins A,D,K, and E which help us use and absorb other micronutrients from our diet like all the calcium you may think you're getting from the milk you drink.

If you have an objection to meat (even pastured, grass finished?) then consider adding eggs, fish, and seafood to your diet, cutting way back (or eliminating) grains, and adding healthy saturated fats (whole dairy fat, coconut oil, olive oil). That will bring your risk of impaired glucose control down considerably.

[stillo]

Hi

To me saying you are pre diabetic is like saying you have a pre headache you either are or you are not i had this out with my gp and he agreed i was then classed as diabetic

Stillo

[JeffH]

India has one of the highest rates of diabetes in the world and most of the population is vegetarian. If you are eating a heavily grain-based diet to make up for the lack of meat, that's a risk for insulin resistance.

I'll bet you're dutifully drinking skim milk which has a high sugar content --12 g per cup. 2 slices of whole wheat bread have a higher glycemic index than a candy bar. People are so busy doing low fat that they forget we NEED fat to use vitamins A,D,K, and E which help us use and absorb other micronutrients from our diet like all the calcium you may think you're getting from the milk you drink.

If you have an objection to meat (even pastured, grass finished?) then consider adding eggs, fish, and seafood to your diet, cutting way back (or eliminating) grains, and adding healthy saturated fats (whole dairy fat, coconut oil, olive oil). That will bring your risk of impaired glucose control down considerably.

One thing I always get a laugh out of is people that use fat free dressing on a salad. Most of the vitamins in veggies are fat soluble. If you eat them with no fat dressing then your body will just pass the good stuff right on thru. Never eat a salad without a good (olive oil) based dressing.


JeffH

[Kitatonic]

Going to take Janknitz & RandyJ's advise to even further cut grains and dairy as this must be the culprit (not OSA) and I'll report back in six months.

Actually diabetes like so many chronic diseases is on a continuum of insulin resistance or deficiency, so I should refer to it as "impaired glucose tolerance" which without dietary changes transitions with age to blown diabetes requiring meds.

[idamtnboy]

Last July, I had a 150 blood glucose about an hour after eating, so the A1c was added on and reported to be 5.8, pre-diabetic. Although the 5.8, was re-confirmed 3 months later, the lab was found to be reporting high, so 5.5 was reconfirmed twice in the next six months. Home monitoring (only occasionally 120 1pp), 2-hour glucose test (102), fasting levels (82) would reflect a A1c of 5.2, not 5.5 (average 105). I realize that OSA is an independent risk factor for insulin resistance. Since I started CPAP, 16 months ago, the AHI has gone from 50 to 0.2, the oxy sat 65 to 95, so I doubt if I'm spiking glucose in the night. No one can seem to explain why the A1c "not accurate" for me. Do any of you have clues as to why the A1c is inaccurate?

It's not the A1c that is inaccurate, it's the BG test with the monitor that is inaccurate. And then in a sense, it really is not inaccurate, it just does not give a reliable number about the longer term average blood sugar level. Put 90% faith in the A1c number and 10% faith in the home BG tests.

I'm surprised the doc reacted at a 150 postprandial number. Depending on what you ate for lunch I would say that is a very usual and likely reading for anyone. If you have lots of test strips available w/o having to be overly concerned about the cost, do this. Some day that you know in the morning will be a pretty much usual day for activities and eating, test your BG once every hour. It'll be a real education about how your BG fluctuates throughout the day, fluctuations that are quite normal.

The best way, in my opinion, to use BG meter testing is to test your BG at the same time every day, preferably when you first get up. Test it for about 7 or 14 days and calculate the average. 7 or 14 days encompasses all the usual variations throughout a week. Then repeat the test cycle about every six or eight weeks and compare the averages. If the averages start to move up over about a year's time frame, then you know you need to watch things. This approach follows what is known as statistical process monitoring wherein the group of individual readings captures the normal variation for a set time period, and the averages show changes over time. The reason for the morning test is that during the night your body stabilizes your BG level as you sleep at a level that reflects how well your cells are absorbing the glucose. If you snack during the night then all bets are off.

The A1c number is a running average and smooths out all the ups and downs in your BG level. The indicator, which I don't recall the name of just now, has a half life of about 90 days. The indicator concentration changes rapidly, and directly, in relation to the glucose level, but disappears over time, with about 1/2 of it gone after 90 days. That's why it's a good average indicator. The home BG test is only a measure of your BG at the specific time of the test. Since your BG moves up and down, and it normally spikes after eating, a single BG monitor number is not reliable for any long term measure.

I'd have to look it up to be absolutely certain, but "impaired glucose tolerance" is an older term used to indicate your BG level is creeping toward the official threshold for diabetes diagnosis. Contrary to the opinion above about pre-diabetes being a bogus term, it is a measure of your current BG level. Prior to about 2001 diabetes threshold was defined as a glucose tolerance test BG level of 140. Impaired glucose tolerance was 120, I believe. Then the official diagnosis level was changed to 126 being diabetic, and 110 to 125 being pre-diabetic. Below 100 is considered normal non-diabetic. 101 to 109 is non-diabetic but "keep a watch on it."

With your A1c numbers don't get wrapped around the axle about trying to lower them. But do stay on top by regular monitoring, and do continue to pay attention to your diet. If you can keep them where they're at, good.

A book I would suggest you read is "Sugar Busters." The author gets a little carried away, IMO, with his condemnation of starchy foods like potatoes and carrots, but he does a good job of explaining how sugar and insulin work in your body. I think the glycemic index is worth paying attention to, but it is not the end all, be all, in diet guidance. I also believe your body will process foods like grains and starches differently from your neighbor's body. Don't be too quick to get rid of grains from your diet, but do try to move away from refined grains. Interestingly enough, contrary to the usual thinking about pastas being refined and high glycemic, I've seen some relatively low spikes after eating pasta.

About BG spiking - one thing I have not found is a good discussion of the relative longer term impact of the peak of the spike vs the time span it covers. In other words, I'm not sure that a high, but very short term, spike may not have less impact on your body over the long term than does a lower spike that lasts longer. The lower but longer spike is what you get with a low glycemic food. The reason for thinking this is the overall amount of insulin the pancreas secretes to process the glucose may be less in the former case than in the latter. I don't know, but I sure do wonder. Insulin is necessary for your body to function, but too much of it and it can be a poison, or cause you to get fat.

Keep in mind the saying, "For every problem there is a solution, easy, straightforward, simple, and wrong!" There are no pat, fits all, answers with regard to diet and diabetes. Look for the answer that works for you, and ignore everything and everyone else.