Blood Sugar Levels- HgbA1c vs. Current Sugar

[Planktonmd]

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Trying to have a discussion with you is like arguing with a 4-year-old... or some of my ex-girlfriends.

Done with this thread.

-copro

Bye sweetie.

 

[dhb]

Ok lets summarize: high bs = acute event surgery can be postponed (copro).

High HbA1c level but no acute event surgery can proceed although higher morbidity can be expected (copro). Surgery can also be postponed if overall assessment is unfavorable (Plank).

Everybody happy?

What Plank was getting to is that HbA1c is a mesure of glucose control over the past 3 months. If it is high, say 12%, that means the average bg was 300mg/dl over the period. So if you are ready to cancel a case for a single value of 300 then you should definitely do it for a HbA1c of 12% since it means the patients average is at 300.

On a side note i couldn't care less about morbidity in a fatso with DM type 2 (they are morbid by nature) i'll do the case if the price is right.

 

[BLADEMDA]

To explain what an A1c is, think in simple terms. Sugar sticks, and when it's around for a long time, it's harder to get it off. In the body, sugar sticks too, particularly to proteins. The red blood cells that circulate in the body live for about three months before they die. When sugar sticks to these cells, it gives us an idea of how much sugar has been around for the preceding three months. In most labs, the normal range is 4-5.9 %. In poorly controlled diabetes, its 8.0% or above, and in well controlled patients it's less than 7.0%. The benefits of measuring A1c is that is gives a more reasonable view of what's happening over the course of time (3 months), and the value does not bounce as much as finger stick blood sugar measurements.
There is a correlation between A1c levels and average blood sugar levels as follows:

While there are no guidelines to use A1c as a screening tool, it gives a physician a good idea that someone is diabetic if the value is elevated. Right now, it is used as a standard tool to determine blood sugar control in patients known to have diabetes.

A1c(%)Mean blood sugar (mg/dl)6135717082059240102751131012345
The American Diabetes Association currently recommends an A1c goal of less than 7.0%, while other groups such as the American Association of Clinical Endocrinologists recommend a goal of less than 6.5%. Of interest, studies have shown that there is a 10% decrease in relative risk for every 1% eduction in A1c. So, if a patients starts off with an A1c of 10.7 and drops to 8.2, though there are not yet at goal, they have managed to decrease their risk of microvascular complications by about 20%. The closer to normal the A1c, the lower the absolute risk for microvascular complications.

Last Editorial Review: 1/15/2009

Can someone assist with posting the chart below:
http://www.ucsfhealth.org/childrens/medical_services/hdisorder/diabetes/HbA1c_test.html

 

[Planktonmd]

What Plank was getting to is that HbA1c is a mesure of glucose control over the past 3 months. If it is high, say 12%, that means the average bg was 300mg/dl over the period. So if you are ready to cancel a case for a single value of 300 then you should definitely do it for a HbA1c of 12% since it means the patients average is at 300.

On a side note i couldn't care less about morbidity in a fatso with DM type 2 (they are morbid by nature) i'll do the case if the price is right.

Exactly!

If you consider a one time high blood sugar by itself a sufficient reason to cancel a case then you should cancel the case for a high A1c as well.
Unfortunately this concept is commonly misunderstood by many practicing anesthesiologists and obviously some people finish residency and never really give it enough thought or no one actually explains it to them.

 

[Mman]

A high A1C is relatively meaningless as to how I will manage a patient intraoperatively.

It is very meaningful longterm, but I can't change it on the day of surgery. If anybody wants to make a real impact on the patient in regards to timing (or cancellation) of surgery, it has to be the surgeon at the time of scheduling of the case. They can get an A1C in their office and then call the patient up and let them know that the complication rate is higher at their current level of glycemic control and perhaps everybody would be better served if the patient lost some weight and had tighter glucose control for 3-6 months and then scheduled the surgery.


But an A1C on the day of surgery? Who cares? I can already have a discussion with the patient that doesn't keep accurate track of the blood sugar level at home and has a BMI of 40 about their increased risk of perioperative and longterm complications. I would never cancel a case if the surgeon and patient both wanted to proceed solely because the A1C was elevated.

 

[Planktonmd]

A high A1C is relatively meaningless as to how I will manage a patient intraoperatively.

It is very meaningful longterm, but I can't change it on the day of surgery. If anybody wants to make a real impact on the patient in regards to timing (or cancellation) of surgery, it has to be the surgeon at the time of scheduling of the case. They can get an A1C in their office and then call the patient up and let them know that the complication rate is higher at their current level of glycemic control and perhaps everybody would be better served if the patient lost some weight and had tighter glucose control for 3-6 months and then scheduled the surgery.


But an A1C on the day of surgery? Who cares? I can already have a discussion with the patient that doesn't keep accurate track of the blood sugar level at home and has a BMI of 40 about their increased risk of perioperative and longterm complications. I would never cancel a case if the surgeon and patient both wanted to proceed solely because the A1C was elevated.

Would you proceed with the surgery if the blood sugar was 500 as long as the surgeon and the patient are OK with it?

 

[Arch Guillotti]

Over on sermo there is a guy who posts very often on the anesthesia forum who is very entertaining. IIRC he is either actively involved in a lawsuit or was named in a suit in the past for a case when the pt. had a high blood glucose preoperatively (I don't know the number) and later had a bad outcome (at least per the pt.). So while cancelling cases based on a single number may be dumb, unfortunately in todays society there is always a risk of litigation, even if it has no merit.

 

[periopdoc]

Over on sermo there is a guy who posts very often on the anesthesia forum who is very entertaining. IIRC he is either actively involved in a lawsuit or was named in a suit in the past for a case when the pt. had a high blood glucose preoperatively (I don't know the number) and later had a bad outcome (at least per the pt.). So while cancelling cases based on a single number may be dumb, unfortunately in todays society there is always a risk of litigation, even if it has no merit.

Which is exactly why I wouldn't check an A1C. It is just a number that can only get you in trouble. Until there is data that improving A1C decreases perioperative risk, it is just a marker for disease. Right now all we know is that people with high A1Cs have increased risk, but we don't know if we can modify that risk by lowering the A1C (no matter how much it makes sense that it would decrease risk).

Now if somebody else checked and I had that elevated number in front of me in preop clinic the whole game changes.

- pod

 

[Mman]

Would you proceed with the surgery if the blood sugar was 500 as long as the surgeon and the patient are OK with it?

Depends on the case, however a single POC glucose is an acute value in an acute setting. It tells me about the patient right now. A1C is solely a measure of chronic control.

If you want to start cancelling cases for an A1C, do you also cancel them because of LVH on the Echo from longstanding hypertension that has been suboptimally controlled?

 

[jetproppilot]

Depends on the case, however a single POC glucose is an acute value in an acute setting. It tells me about the patient right now. A1C is solely a measure of chronic control.

If you want to start cancelling cases for an A1C, do you also cancel them because of LVH on the Echo from longstanding hypertension that has been suboptimally controlled?

Mman has hit the GRAND SLAM WITH THE BASES LOADE IN THE BOTTOM OF THE NINTH

with that question.

Makes you really ask yourself

how far do we go with cancellations when presented with potentially "SINISTER" preoperative laboratory data?

Or should we, like back in DA OLD DAYS, MAYBE LOOK AT AND CONSIDER THE.....UHHHHH...PATIENT? INSTEAD OF THE TESTS?

Are we really doing the patient a favor by cancelling the case?

WE HAVE ALL seen these situations:

1) 58 year old lady, married, cuppla sons that went to Jesuit, Founder of the Floral Home Gardens of New Orleans, active, gardens daily, walks her dog a cuppla miles every day, jogged-walked the 5k Crescent City Classic with her martini-toting-friends, no salient medical history, doesnt smoke, drinks a cuppla martinis every nite like everyone in New Orleans, needs a knee scope by Tim Finney-the-New-Orleans Saints ortho dude who-is-CDAZY-FAST, EKG ordered, EKS reads "INFERIOR MI, AGE UNDETERMINED."

So ya getta call from the PA in pre op about the EKG.

He faxes it to you.

Theres definitely Q waves in III, aVF; the lead II Qs border on significance.

In a lady who EXCEEDS metabolic equivalents cardiac-classification criteria with her activity/exercise.

Case is for TOMORROW.

Oh, and its 4PM on the day before surgery.

WHADDYA DO NOW?

 

[Planktonmd]

The point I am trying to make is that A1c is more relevant to periop complications than a single pre-op blood sugar.
Many anesthesiologists are taught to cancel a surgery based on one high pre-op blood sugar number while they would ignore A1c.
A high A1c means that although the BS is OK now it might be 500 in 1 hour when you expose the patient to surgical stress and catecholamines start doing their thing.
So, We should not cancel any case based on one single number but if you think an elevated blood sugar is enough to not proceed then you should consider a high A1c as a reason to cancel as well.

Mman has hit the GRAND SLAM WITH THE BASES LOADE IN THE BOTTOM OF THE NINTH

with that question.

Makes you really ask yourself

how far do we go with cancellations when presented with potentially "SINISTER" preoperative laboratory data?

Or should we, like back in DA OLD DAYS, MAYBE LOOK AT AND CONSIDER THE.....UHHHHH...PATIENT? INSTEAD OF THE F U KKING TESTS?

Are we really doing the patient a favor by cancelling the case?

WE HAVE ALL seen these situations:

1) 58 year old lady, married, cuppla sons that went to Jesuit, Founder of the Floral Home Gardens of New Orleans, active, gardens daily, walks her dog a cuppla miles every day, jogged-walked the 5k Crescent City Classic with her martini-toting-friends, no salient medical history, doesnt smoke, drinks a cuppla martinis every nite like everyone in New Orleans, needs a knee scope by Tim Finney-the-New-Orleans Saints ortho dude who-is-CDAZY-FAST, EKG ordered, EKS reads "INFERIOR MI, AGE UNDETERMINED."

So ya getta call from the PA in pre op about the EKG.

He faxes it to you.

Theres definitely Q waves in III, aVF; the lead II Qs border on significance.

In a lady who EXCEEDS metabolic equivalents cardiac-classification criteria with her activity/exercise.

Case is for TOMORROW.

Oh, and its 4PM on the day before surgery.

WHADDYA DO NOW?

 

[Mman]

The point I am trying to make is that A1c is more relevant to periop complications than a single pre-op blood sugar.

Is it?

If a patient has an A1C of 9.0 and comes in with a glucose of 147 on the day of surgery, is he more likely to get a wound infection in the first week after surgery compared to a patient with an A1C of 7 and a glucose of 400 on the day of surgery?

To me, it's a question of whether or not the patient is in as good a shape as we can reasonably expect for the procedure. If a patient comes in with DKA, I don't care how low their A1C is, the case needs to be postponed. But if they just don't take their insulin or check their blood sugar very often, that is quite unlikely to change any time soon.

I think the whole question of A1Cs needs to be left to primary care physicians and/or the surgeon scheduling the case. They can discuss it with the patient and implications for periop risk. I'm happy to inform the patient of why it's important, but as long as they look OK on the day of surgery I can't imagine cancelling a case because of an A1C.

 

[Planktonmd]

Is it?

If a patient has an A1C of 9.0 and comes in with a glucose of 147 on the day of surgery, is he more likely to get a wound infection in the first week after surgery compared to a patient with an A1C of 7 and a glucose of 400 on the day of surgery? .

Yes, because the one with normal A1c and high blood sugar is telling you that his elevated blood sugar today is rather the exception not the rule while the one with the high A1c is telling you that he frequently has elevated blood sugar although you caught him on a good day when his blood sugar was not too high.

To me, it's a question of whether or not the patient is in as good a shape as we can reasonably expect for the procedure. If a patient comes in with DKA, I don't care how low their A1C is, the case needs to be postponed. But if they just don't take their insulin or check their blood sugar very often, that is quite unlikely to change any time soon.

I am not saying that you should cancel a case because of a high A1c (I wouldn't) I am simply suggesting that if you happen to be someone who thinks that a one time morning of surgery high blood sugar is a good enough reason to cancel (I don't but many people do) then you need to also cancel for high A1c.
We are not talking about DKA or any acute complication of diabetes, we are talking about a patient with high blood sugar let's say 500 without any other acute problems versus someone with high A1c without any other problems, I wouldn't cancel for either reason.

 

[proman]

With the changes in Medicare (not) reimbursing for surgical site infections, the surgeons will probably become very interested in long-term glycemic control being documented prior to an operation.

 

[BLADEMDA]

With the changes in Medicare (not) reimbursing for surgical site infections, the surgeons will probably become very interested in long-term glycemic control being documented prior to an operation.

Exactly. Plus, you now know that if a diabetic relative/loved one is going to have major surgery perhaps checking a hgbA1C is warranted. If your mother was a diabetic and scheduling an elective AortoBifem would you want her HgbA1c at 9 or 7.0? Would you care?

As Perioperative Physicians we should know the peer reviewed data; what you decide to do with it is up to you.

BLade

 

[Mman]

Yes, because the one with normal A1c and high blood sugar is telling you that his elevated blood sugar today is rather the exception not the rule while the one with the high A1c is telling you that he frequently has elevated blood sugar although you caught him on a good day when his blood sugar was not too high.

Actually, an A1C just tells you what his average gluocse was at home from the period from 4 weeks ago to 12 weeks ago.

It doesn't tell you what the glucose will be in the OR, or in the first few days after surgery as an inpatient. Plenty of people don't really check their glucose very often (if at all), but if they get admitted it will be checked every 6 hours for the entirety of their stay in the hospital and they will have far better glucose control immediately and in the first 1-2 weeks after discharge if they can keep with the routine.

 

[Planktonmd]

Actually, an A1C just tells you what his average gluocse was at home from the period from 4 weeks ago to 12 weeks ago.

It doesn't tell you what the glucose will be in the OR, or in the first few days after surgery as an inpatient. Plenty of people don't really check their glucose very often (if at all), but if they get admitted it will be checked every 6 hours for the entirety of their stay in the hospital and they will have far better glucose control immediately and in the first 1-2 weeks after discharge if they can keep with the routine.

So, If the average blood sugar at home was elevated doesn't that mean that this is most likely a poorly controlled diabetes that most likely will continue to be poorly controlled or worsen when you expose the patient to surgical stress?
Do you really think that hospitalizing a poorly controlled diabetic and exposing him to surgical stress and post-op pain will improve his diabetes control or you are just saying that for the sake of arguing (I hope it's the second possibility).
Do you agree that poorly controlled diabetes means most likely more significant diabetic vasculopathy and as a result more likelihood of poor healing and more surgical wound infection among other things?

 

[dhb]

or in the first few days after surgery

I disagree it will tell you exactly this.

if they get admitted it will be checked every 6 hours for the entirety of their stay in the hospital and they will have far better glucose control immediately

For patients with a very poor control this is often not the case i've seen patients admitted for glucose control that had numbers all over the place for days.

 

[Mman]

The vast majority of poorly controlled type 2 diabetics with elevated A1Cs do not have some super difficult version of the disease process that is difficult to control. They just don't check their glucose regularly and don't take the right amount of insulin regularly. It's quite simple, at least in the patients that I see with this (poor, lack of education, etc).

When they get admitted to a hospital (for surgery or anything else), they get a nurse checking finger stick glucose 4 times a day and they are regularly receiving scheduled plus sliding scale insulin.

It doesn't matter if they have surgery, their glucose control is still better in the hospital with nurses and physicians managing it than they do at home when they don't check it. It's not even close. I can't remember the last time I saw a patient on POD #1 or POD #2 with a glucose above 300 or 400, even when their A1C suggests that is almost an average level for them at home.



The bottom line is that the poorly controlled diabetics just can't/don't/won't manage their disease at home. There are exceptions, but they are exceedingly rare. Cancelling a case and sending them home to control it better and come back in 3-6 months doesn't improve their disease management, it just allows them to come back again in 3-6 months in even worse shape.

If somebody could do an RCT comparing these patients in regards to cancelling the case vs not cancelling the case and show an outcome difference, I would truly be amazed. I would hazard a guess that you would be much more likely to find a number needed to harm.

 

[Mman]

For patients with a very poor control this is often not the case i've seen patients admitted for glucose control that had numbers all over the place for days.

Keep in mind we are talking about patients that show up on the day of surgery with an acceptable glucose level (pretend it's <200), but that they have an elevated Hgb A1C (9, 10, whatever). These patients don't get admitted for glucose control because they are controlled at the moment, but they are chronically poorly controlled.

 

[BLADEMDA]

Keep in mind we are talking about patients that show up on the day of surgery with an acceptable glucose level (pretend it's <200), but that they have an elevated Hgb A1C (9, 10, whatever). These patients don't get admitted for glucose control because they are controlled at the moment, but they are chronically poorly controlled.

Like it or not the current data strongly suggest that this Group of patients with a high HgbA1c (definitely greater than 9) will have a worse outcome with Cardiac/Major Vascular Surgery. If the surgery is elective then some (e.g. Plaintiff's lawyer) would make a sound argument that the operation should have been delayed for 2 months in order to decrease the perioperative risk.

Like most on this board I just check the glucose preoperatively; but, should I be checking the HgbA1C in the preop clinic? Should the Cardiac/Vascular Surgeon be checking the HgbA1c before the ELECTIVE Case and ATTEMPT to convince the patient that better glucose control just might help him/her survive the operation or avoid a complication?

 

[Mman]

Like it or not the current data strongly suggest that this Group of patients with a high HgbA1c (definitely greater than 9) will have a worse outcome with Cardiac/Major Vascular Surgery. If the surgery is elective then some (e.g. Plaintiff's lawyer) would make a sound argument that the operation should have been delayed for 2 months in order to decrease the perioperative risk.

Like most on this board I just check the glucose preoperatively; but, should I be checking the HgbA1C in the preop clinic? Should the Cardiac/Vascular Surgeon be checking the HgbA1c before the ELECTIVE Case and ATTEMPT to convince the patient that better glucose control just might help him/her survive the operation or avoid a complication?

I am completely 100% in agreement that the surgeon should be checking this in clinic, and perhaps even a preop clinic if it's more than just one day before surgery. The patient should be counseled on the risks.

That's a no brainer. It's also plainly obvious that it makes a difference in their post-op outcome if you compare well controlled diabetics vs poorly controlled.

But I am yet to be convinced that a surgeon that thinks surgery is indicated and a patient who wants surgery and who shows up with an elevated A1C on the morning of surgery (but a relatively normal glucose that day) should be cancelled. And I'm willing to bet that cancelling the case on the day of surgery just because they are chronically poorly controlled will not improve any outcome because they will still be poorly controlled 3 months from now.

 

[BLADEMDA]

The evidenvce for cancelling a case based on HgA1C is still weak. Previuosly in this thread I posted peer reviewed articles showing a lonk between major surgery and bad outcome with a HgbA1C; however, others studies have failed to show that link.

A High blood glucose level is another story. Wound infection and poor wound healing amoth other thing have been linked to poor glucose control. Thus, an obesed IDDM patient undergoing a total knee replacement with a Blood sugar of 450 probably should be cancelled; but, what if the patient states her HgbA1C is 6 and that sugar is just a one time event?

 

[killerleaf]

Being a diabetic, may I throw one little thought in here?

According to my doctor, my A1c of 7.1 is where she wants it at, for fear of lows, according to her, I do have good control...my fasting numbers are usually in 80's. All good, right? EXCEPT when I am sick, in pain, or stressed to the max, then they go up. Sometimes way up. Once the event is over, then they go back down where they are supposed to be. So shouldn't you listen to the patient, and take both the BS reading that morning and the A1c documented in the chart into consideration?

 

[BLADEMDA]

Being a diabetic, may I throw one little thought in here?

According to my doctor, my A1c of 7.1 is where she wants it at, for fear of lows, according to her, I do have good control...my fasting numbers are usually in 80's. All good, right? EXCEPT when I am sick, in pain, or stressed to the max, then they go up. Sometimes way up. Once the event is over, then they go back down where they are supposed to be. So shouldn't you listen to the patient, and take both the BS reading that morning and the A1c documented in the chart into consideration?

Of course. But. most don't have a HgbA1C in their chart or can't recall the last date of the test or the number. This means some Anesthesiologists may cancel the case for a very high blood sugar. I've seen this happen on more than one occasion for a big surgery.


https://www.accu-chek.com/us/glucose-monitoring

 

[BLADEMDA]

1. Khaw (2001) BMJ 322:15
2. Background
   1. Glycosylated Hemoglobin is not equivalent to A1C
      1. Hemoglobin A1C is 70% total glycosylated Hemoglobin
3. Approximating Serum Glucose
4. Hemoglobin A1C of 6% represents mean glucose of 130
5. Each 1% increase in A1C, glucose increases 30
6. Interpretation: Correlation to Mean Serum Glucose
7. Hemoglobin A1C: 5.5% represents mean glucose of 100
8. Hemoglobin A1C: 7.0% represents mean glucose of 150
9. Hemoglobin A1C: 8.0% represents mean glucose of 180
10. Hemoglobin A1C: 9.0% represents mean glucose of 220
11. Hemoglobin A1C: 10.0% represents mean glucose of 250
12. Hemoglobin A1C: 11.5% represents mean glucose of 300
13. Hemoglobin A1C: 13.0% represents mean glucose of 350

 

[BLADEMDA]

1. Khaw (2001) BMJ 322:15
2. Background
   1. Glycosylated Hemoglobin is not equivalent to A1C
      1. Hemoglobin A1C is 70% total glycosylated Hemoglobin
3. Approximating Serum Glucose
4. Hemoglobin A1C of 6% represents mean glucose of 130
5. Each 1% increase in A1C, glucose increases 30
6. Interpretation: Correlation to Mean Serum Glucose
7. Hemoglobin A1C: 5.5% represents mean glucose of 100
8. Hemoglobin A1C: 7.0% represents mean glucose of 150
9. Hemoglobin A1C: 8.0% represents mean glucose of 180
10. Hemoglobin A1C: 9.0% represents mean glucose of 220
11. Hemoglobin A1C: 10.0% represents mean glucose of 250
12. Hemoglobin A1C: 11.5% represents mean glucose of 300
13. Hemoglobin A1C: 13.0% represents mean glucose of 350

So, maybe if your partner wants to cancel that Total Knee because the BS is 400 you should check a HgbA1c and if it is only "8.5" then treat the high sugar and do the case.
The HgbA1c of 8.5 shows the average BS was only 200 during the previous 3 months.

http://www.quickmedical.com/metrika/index.html

The monitor costs $190 plus the strips. Immediate result in holding area.


With the Bayer A1CNow+ Multi-Test A1C System, you can get your A1c test results in just five minutes. The Bayer pager-sized A1CNow+ is the first technology to provide healthcare professionals with immediate access to quantitative A1C status -- the gold standard indicator of diabetes management -- without the time, high cost and complexity of reference labs or instrument-based systems.


It looks like each bed side test costs $10.00 So, is it worth $10 to avoid cancelling a major, expensive surgery? Or, confirm that cancellation was reasonable?