You may be taking too much insulin.

It’s possible that you may be taking too much insulin and don’t even know it. Fortunately, there is a calculation you can do to determine how close your total daily insulin intake is to a target used in clinical practice to determine appropriate levels of insulin.

Here’s how you do it:

1. Weigh yourself and if need be convert into kilograms using the ratio of 2.2lb. = 1kg. An online converter can help you with this.
2. Add up your total daily insulin. If you take shots then keep a logbook. If you are on a pump then look at history.
3. Divide total daily insulin units by weight (in kilograms).
4. Compare to target (below) or in our case, 1.5 u/kg/day of insulin.

Example:

Susie is 13 yrs old and weighs 84 lbs. She takes 30 units of Lantus with dinner as her long acting background insulin (basal). She follows a meal plan of 60g carbohydrate/meal and also remembers to take insulin with any snacks she might choose to have.

Yesterday, she injected 10 units of Humalog with each of her meals (based on and Insulin to Carbohydrate ratio I:C) and took a correction dose (according to her Insulin Sensitivity Factor or ISF) of another 3 units since her blood sugar was still too high 3 hours after lunch. Her total insulin was (10+10+3+10+30 = 63) and that’s a pretty typical day for Susie.

Using the lb to kg converter, I can type 84 in the lb box and hit the Convert! button to learn that she weighs 38.1 kilograms (kg).

So, 63 units total daily insulin (tdi) / 38.1 kg = 1.65 u/kg/day

Armed with this information, we can also see that Susie’s basal insulin of 30 units compares to her 33 units of fast acting insulin which is in the ballpark considering additional guidelines that say 50%-65% should be basal (long acting) vs. 35%-55% bolus (short acting) which is about where we want it to be. We should watch this ratio too as we’re already outside but not too far to change yet. First things first.

Compared to the target of 1.5 u/kg/day it looks like Susie might be taking more insulin than is necessary. Turns out, Susie has been complaining about her meals lately, too much food, full, can’t finish. Looks like a good time to discuss a dosing change with Susie’s doctor.

Case Study:

At camp recently, one of our kids came in with 1.89 u/kg/day. Because we had 24 hour supervision over a full week, we were able to apply intensive management (measure, understand and act) resulting in a decreased insulin requirement by week’s end of 1.37 u/kg/day. Camp is a lot of activity so his insulin requirements will most likely increase slightly when he goes home.

When we reviewed the blood sugar logbook we saw the effects of the current regimen. Oddly enough, mid morning numbers looked OK upon arrival so you wouldn’t think that there was too much insulin just from looking at blood sugars.

One other thing we did was move his NPH from dinner to bedtime to address insulin resistance at breakfast. This move assured us that he had sufficient coverage of his basal insulin throughout the night. With quite possibly a lack of basal insulin in the early morning hours or at a minimum leaving only the evaporating tail of the NPH by breakfast, were able to reduce insulin resistance and lower his breakfast carb ratio.

The results were seen in strategically timed blood sugar checks that highlighted the new fasting and post meal glucose levels. It was clear that a significant percentage of the insulin wasn’t needed after all.

The child was happier with this regimen and his parents shared with me that they thought he was on too much insulin and didn’t like feeding him so many carbs. Hopefully, he was able to stick with the changes after leaving camp, his total carb intake can stay reduced, he’ll lose some of the weight that he’s put on since diagnosis and he’ll feel better.

With simple guidelines and formulas like the ones above, anyone can take advantage of advanced self-management techniques to measure what needs to measured, understand when it’s time for a change from the norm and take the appropriate actions to safely improve blood sugar control with the appropriate dosing of insulin. In this case, to simply have a basis from which to make a call to your physician and discuss the potential for a change in the insulin regimen and meal plan can make a big difference in how you approach your own care.

Note: While many of us make our own adjustments to insulin and carb ratios on a regular basis, this was a fairly complex change and was performed under the supervision and orders of a pediatric endocrinologist.

Reference: “QUICK REFERENCE GUIDE TO DIABETES FOR HEALTH CARE PROVIDERS” A special project of the Michigan Diabetes Outreach Network with additional references from American Diabetes Association (2006). Clinical Practice Recommendations. Diabetes Care, Vol 29 (1).

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This entry was posted on Monday, August 20th, 2007 at 9:29 am and is filed under Clinical, Experiences. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.