I’m curious if anyone has seen any studies showing that getting an A1C into the normal or near-normal range – aka the low- to mid-5’s – actually results in significant reduction in complications beyond the typical A1C guidelines for type 1s?
I’m guessing there isn’t any research, given that it was difficult to near-impossible to achieve such good numbers prior to the advent of CGMS, but perhaps someone knows of some studies out there?
You should read up on the DCCT/EPIC work. There is not an established “significant” reduction in complications for A1cs below 6%, there are reductions, just not “significant.”
The DCCT ended in 1993. Study is still happening and you can read about it here:
The follow-up study, called Epidemiology of Diabetes Interventions and Complications (EDIC), is assessing the incidence and predictors of cardiovascular disease events such as heart attack, stroke, or needed heart surgery, as well as diabetic complications related to the eye, kidney, and nerves. The EDIC study is also examining the impact of intensive control versus standard control on quality of life. Another objective is to look at the cost-effectiveness of intensive control.
There are many interesting studies by the T1D Exchange organization, although not as specific to A1C and complications as the DCCT was.
@karen57, so I looked at those studies, but it seems like less than 5% of the population achieved a sustained A1C of 6.0 or less in the DCCT, or about 72 people, and I’m having trouble actually figuring out what the relative risk reduction, and the error bars, would be for that small subset of people.
Yes, but in my life with diabetes studies are not really meaningful. I’ve been running with A1c in 5 range for years and years, I am well managed, I live like a ‘normal’ and am sans complications. But no one is studying me, thank goodness.
My personal theory is that complications have more than A1c and BG management to cue the onset of occurrence. Our genes play a huge part in our own morbidity.
I hope you figure it out Tia_G and look forward to your conclusions. Be well!
And of course, we have to remember that the A1C is just an average. For discussion and simplicity, let’s assume the “goal” is an A1C of 5. You could have consistent bg’s of 5, 5, and 5 - your A1C would be 5. But you’d aalsohave an A1C of 5 with readings that were 0, 5 and 10. It’s the steady in range that counts for more. And ofcoure, our DNA directs so many things aside form the direction we get from T1D
@artwoman, yes precisely! I think that’s the issue with analyzing the EDIC or DCCT study results for a sign of how complication rate tracks with average BG. While a small fraction of the participants were able to run sub-6 A1Cs, the rate of hypoglycemia soared with decreasing A1C. So there were probably no examples of people who were managing to maintain 70 - 140 numbers really…probably just people who were swinging between 55 and 180, etc.
I guess the reason I ask is because it’s not clear to me whether it’s worth the tradeoff of trying to keep pushing my son’s numbers into the sub-6 A1C range if it means an increased risk of lows, and wanted to do a cost-benefit analysis somehow.
I’ve been in the low- to mid-5’s for about 15 years now. But I have had a Dexcom dur9ng that time. Lots of micro dosing, adjusting of basal rates to stay within my self-determined range. I have had one Endo (with a very low opinion of PWD’s) that it was impossible for me to manage my T1 that well. (does he think that with a Dx of any kind of D there are two automatic co-morbidities? Stupid and Lazy?) It is a lot of work, even with my CGM I still do 10-15 fingersticks a day, and take appropriate action. I can usually catch things before they get to high or low. And the middle of the night alerts are a pain in the ■■■, but I take pride in how I do. I am not a competitive person, but I do compete with my T1D beast.
[quote=“artwoman, post:9, topic:57224, full:true”] It is a lot of work, even with my CGM I still do 10-15 fingersticks a day, and take appropriate action. I can usually catch things before they get to high or low. And the middle of the night alerts are a pain in the ■■■, but I take pride in how I do. I am not a competitive person, but I do compete with my T1D beast.
[/quote]You know it’s really a pain in the ■■■ that you can’t use the word ■■■ in a post, as it’s such a useful word. And what if you actually need to talk about putting your infusion set on your ■■■? Or someone behaving like an ■■■ to you because of your diabetes? they need a good ■■■-kicking! 
Yeah…it really seems like a much higher level of intervention to keep in the sub-6 range. We have thresholds for “low aversion” based on arrows and numbers on the Dexcom and they prevent almost all lows, but those would likely need to be lowered if my goal was an average BG of 100, not 120. Or we’d need to do really small micro-carbing to nudge my son up 10 or 20 points, rather than giving him a 4g glucose tab and letting him bounce up to 50 points.
Tia - there are many studies of complications and various BG measurements. Based on the DCCT and EDIC studies, as well as some related studies in Europe and Asia (DECODE, DECODA and APCSC plus others), the general consensus is that maintaining an HbA1c at or below 6.5% provides a significantly lower risk for most complications of D, and as the HbA1c value rises, the risk rises - exponentially.
More significantly… the risk of CVD (and related complications) does NOT correlate with HbA1c levels… rather, it correlates with post-prandial glucose levels, or after-meal BG spikes. The IDF makes these observations in their Guideline for Management of Postmeal Glucose (2007):
“Epidemiological studies have shown a strong association
between postmeal and postchallenge glycaemia
and cardiovascular risk and outcomes.
Furthermore, a large and growing body of evidence
clearly shows a causal relationship between postmeal
hyperglycaemia and oxidative stress, carotid IMT
and endothelial dysfunction, all of which are known
markers of cardiovascular disease. Postmeal hyperglycaemia
is also linked to retinopathy, cognitive dysfunction
in elderly people, and certain cancers.”
In other words, allowing post meal BG to spike (above 140 mg/dl, identified else where in the report) puts one at higher risk of cardiovascular complications… even in subjects with “good” HbA1c levels (which are NOT actually a measure of one’s “average” BG level… it’s a measure of the percentage of haemoglobin that has glycosylated (the percentage of blood protein that has bound with sugar molecules), from which an “average” BG level can be INFERRED using a formula based on overall population averages for hematocrit content, rates of glycosylation, and blood composition… which vary in all of us in various details, so it’s by no means “accurate” at the individual level… which is why so many people can’t relate their HbA1c results to their meters results.)
The IDF’s recommended glycemic target levels are:
HbA1c - below 6.5%
Premeal BG - less than 100 mg/dl
Two hour postmeal BG - less than 140 mg/dl
Ultimately, keeping BG levels as close to “normal” (non-D) levels as much as possible is the objective. Non-D’s BG levels range from 90 to 120 mg/dl, with about 70% of the day spent in the 90 - 100 range.
I hope this adds some perspective.
w.
Thank you, @T1Wayne, this is useful additional information. I intuitively suspected that postprandial spikes were bad for people independent of A1C, but I didn’t realize that the gold standard trials actually demonstrated this.