Hi all -
I just got the results of my 72-hour CGMS (it was actually 4 days, tho) and wanted to get your comments back.
I commute to and from work each day by bicycle, and it shows in my BG profile, but the 4th day I took the car and you can see my BG was higher that day.
There is a bizarre thing there in the early a.m. of the 1st morning (Tuesday): my BG dropped about 50 pts rapidly at about 3:30 a.m.
My doctor mentioned "insulin antibodies" and said that in some cases we are making antibodies that resist our external insulin, and then if our pH chemistry changes it can neutralize the antibodies thus "freeing up" the on-board insulin suddenly ....
He did caveat that by saying the build-up of insulin anti-bodies occurs in old-timers who have been taking low-quality insulin for years ....
Any comments please? I'd love to hear your feedback ....
Sorry forgot to say: you can see a scan of the CGMS graph in the attachments (look for the link called “Capture1.jpg”
Also I probably violated a hundred rules of “Elements of Style” by putting 4-hyphenated-words in the last paragraph …
It could of been a sensor issue. The senors are not 100% accurate. It may of had a brain cramp at that point in time and your BS wasn’t changing at all. I guess I would want to see if that was a trend. For those of us who use CGMs daily, this is not unusual.
I’ve never heard of the antibodies, but that sounds interesting.
Insulin antibodies don’t just occur in people using low-quality insulins, it’s really the product of how strongly your immune system reacts to insulin it considers “foreign”… it can happen with anything you inject into your body.
There is a simple blood test to check to see if you have insulin antibodies and they may be impacting your BG levels.
Sarah is right. Insulin antibodies reflect your body’s natural defense foreign substances. It used to be common to generate insulin antibodies from animal insulins, but these days it generally occurs with the insulin analogs (like Lantus or Humalog). I don’t believe you develop insulin antibodies for the human insulins (Novolin/Humulin NPH/R) as these employ insulin molecules that are bioidentical to human insulin.
Insulin antibodies are generated by your body as an immune response and they attach to the insulin and essentially deactivate it. This results in essentially an insulin resistance. I have never heard of pH changes affecting the response, but that may well be true. I really doubt that was the cause of your sudden drop. It just seems unlikely that in the middle of the night your body would suddenly change pH.
I think it is unnecessary to start invoking “insulin antibodies” as a reason for a shift in a diabetic’s blood sugar. It’s a cop-out by the medical community to say “it’s not my fault, it’s the patient’s”.
BTW, overall, your graphs look wonderful. That’s excellent control.
Your basal is something like Lantus, right? To pretend that absorption of Lantus is perfectly flat is something the advertising likes to do but it simply isn’t true in the real world.
Your doc did have a point about pH. Lantus absorption rate is very much related to the pH at the injection site. I don’t fully understand the chemistry but a slow pH change is what enables it to be a long-lasting insulin with a fairly flat activity curve.
Long term insulin users also have some issues with lipohypotrophy at injection sites which can disturb the normal absorption rate and efficacy.
For a long time the medical community assumed that lipohypotrophy was caused by animal-source (maybe what your doc was calling “low quality insulin”) insulin but there are studies that show that the modern insulins do not automatically prevent it.
All that said, understanding variation in real bg (which may or may not be what the CGMS was reporting but may be the best we have!) is a very valuable tool. You don’t have to really understand the source of every little bump or drop in bg but noticing patterns in variations and correlating them with what you can control, is the absolutely basic and important tool.
Thanks everyone for your remarks so far. I appreciate the insight about the sensor performance, too, and judging the CGMS results based on trend not details …
When I’m not on the bike, my insulin sensitivity lessens and I run higher BG’s and get higher post-prandial spikes… but the more I look on the Web about insulin antibodies the more I suspect that could be a problem with me … I know exercise enhances insulin sensitivity but in my case the drop-off is so exaggerated when I lay off the bike that it makes me think something else is the culprit …
Next visit to the doc I will ask for the antibodies blood test!
As Jim saidd. Also, the CGM measures interstital fluid, and the last place the body puts glucose is in the interstitial fluid that isn’t moving. So, it youwere laying on that area, it is posable that that part of your boddy wasn’t supplied with as much glucose. That is why we do fingerstickss to calibrate, and why alternative sites are not advised when treating a low, or a high BG. If you poke vaious fingers at the same time, and also a leg or toe or two, you will very likely come up with different numbers.
There’s nothing wrong with you.
Exercise can have a profound effect on insulin needs. (Or maybe more appropriately for 30-50 years ago when I was diagnosed “manual labor” would be a better word than exercise.) That’s just how it works in the real world.
The textbooks, and popular internet sites? Way way oversimplified. Don’t feel that because the books and websites and medical journals are too simplistic, that there is anything wrong with you.
BTW, I look at your CGM graphs, and you have completely excellent control.
Thanks Tim. Encouraging words. I'll take yours at face value and settle down .... Here is an excerpt re: antibodies (my emphasis added):
http://www.sydpath.stvincents.com.au/tests/InsulinAb.htm
Antibodies to Exogenous Insulin
The development of low levels of antibodies to exogenous insulin is an expected consequence of insulin treatment in diabetes mellitus. In some cases they may lead to higher post-prandial glucose levels and increased risk of delayed hypoglycaemia. Very rarely this condition may cause extreme insulin resistance leading to very high daily insulin requirements.
So much for crazy theories .... I guess my best gig is to stay on the bike.... but after a while (and a some fatigue!) I have to lay off and then my BG is harder to control ... I feel like I'm a slave to the bike, as well as Big D!