It's The DIet, Stupid

From Musingsofahousewife.com

Remember when "It's the economy, stupid" helped get bill Clinton elected in 1992?

I had a ah-hah moment recently of a similar nature, during a discussion with one of our surgeons about striking differences in post op glucose control, despite two seemingly similar patients. 

Both had Bariatric / metabolic procedures - one had a Sleeve, the other a Bypass.

Both had longstanding histories of DM2,  both had slightly advanced ages (late 50s, early 60's), and both ended up OFF insulin post op; Patient A in the hospital, and Patient B within days of coming home, despite requiring it (as a new medicine to her regimen, needed to control her sugar from perioperatively in the 300s, to mid 100s by POD 2) immediately post op.

Patient A I expected to follow a similar course as with Patient B, namely needing aggressive Novolg scale, initially on a Q2 hr basis, to asses his new insulin needs, with a goal to maintain BGs in the 150s or lower, especially given his preop  Lantus maintenance dose of 144 units (Yes, that's one hundred forty four), last dosed the night before surgery. 

By the way, Patient B came to the day surgery area, an hour before surgery at 110, and with a most recent A1C of 6.2.  And, with his preop 60# weight loss (about double of what was 'required' as his 10% to get to the OR), he was actually off 3 of his other antidiabetic meds, and with a slightly reduced dose of Lantus to boot. Pretty good control heading into his surgery.

Not so similarly, Patient A was the epitome of poor control. She was someone who probably needed insulin long before surgery day, but was reluctant to start it, to say the least.  She was hopeful that the 5-10% weight loss and low calorie diet preop would help her, and she was assumptive that post op she would be fine.

I wasn't so sure, when I saw she arrived at the day surgery unit just 1.5 hr preop at 302 for her BG.  She had stopped her Glucophage 1000 BID about 6 weeks earlier due to slight LFT elevation, aware of her NASH diagnosis (Cirrhotic changes from steatosis, on our intraop liver Bx) as her PCP was following apparently both and didn't want to insult her liver potentially further.

In any event, her most recent A1C before surgery was 12.2, certainly out of control, and for some time. 

She (Patient B) however, was the one that really ended up surprising me.

For both patients, and for that fact any T2 Diabetic patient that has surgery, after a Sleeve or Bypass, due to their beneficial metabolic effects, there are many significant metabolic changes occurring very rapidly, often within the first few hours after surgery, that can make control of BGs post op most challenging at times.

Each patient is a little (or a lot) different, but there are a number of trends we keep in mind for post op monitoring and insulin orders, and we let the patients perioperatively declare themselves as one of 3 general types of post op Diabetics. 

#1 is the patient we do Q 6 hr fingersticks on, have a scale ready, and they don't require much if any insulin coverage.

#2 is the patient we start out the same way, and ends up needing a little insulin, which the patient generally reacts to appropriately in reducing their BGs. We usually send them home after a typical 2 night stay off any further DM meds / their pre op maintenance DM meds, and have them monitor BGs at home, with the goal to keep BGs in the 140-160 range or less.  This hands-off approach prevents potentially overdoing it (with resultant hypoglycemia) with PO or injectable meds while the metabolic changes of improved insulin sensitivity,  advancing diet (still very minimal CHO), and decreasing post operative stress is theoretically diminishing. Those 3 factors make you think of a decreased need for meds anyway. Should they then have spikes in BG or a few readings over 180's, etc. they call their PCP for further management before we see them at a  standard 1 week post op visit.

#3 is the wildcard. These patients are usually under not-so-optimal control preop, and are on multiple meds, often with crazy amounts of insulin (both rapid acting and basal) required; sometimes they even have a pump with total doses of insulin easily in the 200 plus unit range.  We have seen a few of these patients on U500 insulin (5x the potency of standard insulin) as well to minimize the volume needed to control the BGs.

You know you have one of these patients when you monitor their BGS in the PACU just out of surgery, and their BG is already in the 200s, especially if they were closer to euglycemic as they went into surgery.  Another not so subtle tip-off is when the aggressive Novolog scale does nothing (BG substantially rises) when checked about 2 hrs after administered.

These patients will often require a number of 'catch up' rapid-acting doses to get back on top of BGs, the dose dependent upon how they react to the doses being given, which usually approximately the dose that would be given in the outlined 'aggressive' scale.

This is when you start thinking about needing a basal dose of a peakless, once daily insulin (Lantus or Levmir) that evening, to give you some help with some background coverage.  I usually start with a dose in the 0.3 - 0.5 units per KG dosage, and expect to possibly start to see its effect within 6-9 hrs, as far as maintaining BGs and lessening the need for the 'catch up' short-acting doses.  If the patient is already on a basal insulin preop, usually we look at 1/2 to 1/3 of that dose to start.

So, back to Patient B. SHe followed the #3 pathway pretty well, and required 3-4 catch up Novolog dosings Q2 h to get her sugars to the mid 100s, started Lantus close to 40 units, and she did well the following day, with less and less Q6 hr scale requirement.  

Interesting enough, she refused the Lantus when she went home, and reports now (I saw her last week) that her BGs are in the 120s and less at home. Well, I'll be....

Anyway, back to what led to this whole discussion, and the picture at the top of the page.

I suspect her "glucotoxicity" of such poor preoperative control, and longstanding at that, created a post op situation that, even with the rapid immediate BG-beneficial effects from the surgery (as essentially declared to be adequate enough to control her BGs off all meds a week post op) was a significant factor in making her look like she would need at least some short term help from exogenous insulin.

What was the other factor?

Diet.

Yes, a very low CHO diet (especially immediately post op), and the limited quantity that could be eaten due to her restrictive procedure, a sort of 'forced' behavior modification. It provided the consistent background of a fixed amount of calories IN, and likely gave the pancreas a fighting chance to keep the BGs controlled.

Which led myself, and the surgeon I was discussing this with, to think:

"How often does this happen in the real world of Diabetes treatment, that we are acting as if the meds aren't adequate, when they cannot possibly overcome maladaptive diets of poor quality and excess amount, in addition to little to no regular exercise?"

I am not in Primary Care anymore, but I think I know the answer to that one.