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From Wisconsin, USA:

I have been told that after a pre meal low, you treat the low first, then reduce the overall meal insulin amount by one-half to one unit depending upon how low it was to start out with. However, I also have read you can give negative corrections according to a certain formula. Another way I know is to treat the low, then just give a normal bolus. Which way is actually correct or all three ways okay to do when treating pre meal lows?


This is a wonderful question. All three responses to a pre meal low (and thus bolus dose of insulin) are reasonable. This shows that there is no single right way to manage diabetes. This also takes into account physicians' as well as patients' preferences. Also, the type(s) of insulin and routes of administration (injections versus pumping) may play roles, too.

The first option you gave (treat the low and then lower the dose of the mealtime insulin) is the most conservative. In my experience, the patient tends to run high later and one ends up chasing numbers. This is not bad, but can be frustrating to the person on injections.

The "negative correction" option is also not my preference. I interpret this option to mean that for the person on a basal-bolus insulin plan either by pump or multiple daily injections (MDI), you adjust the insulin dose in your "correction formula." Let's say that your normal insulin-to-carbohydrate ratio for a meal is one unit for each 10 grams of carbohydrates and you're about to eat 65 grams. Furthermore, your usual insulin correction formula is (glucose minus 120) divided by 50. If, in this example, your glucose were 237 mg/dL [16.2 mmol/L] and you ate the 65 grams of carbohydrates, you would give 8.8 units of rapid-acting insulin by the pump (9 if by injection; 6.5 for the meal and 2.3 to correct for the basal glucose value). But, if your glucose were 47 mg/dl [2.6 mmol/L] at the start, you would give 5 units (6.5 for the meal and then take away the 1.5 units to correct for the low). However, I think this doesn't take into account that you (might) overtreat the low, which is commonly done.

So, personally/professionally, I prefer your option #3 - treat the low. Then, either recheck for a new baseline value after the patient is symptomatically better or after 15 minutes of treating the low, assume that you corrected to a "normal target glucose" (120 mg/dl [6.7 mmol/L] in this example), and then bolus for your meal as you normally would.

None of this takes into account the activities the patient might have done or will be doing, or whether the patient is ill with a gastrointestinal illness (thus inhibiting absorption of food), but that is the routine daily challenge of diabetes care anyway.

Your own diabetes team should work out a correction formula for your child. My example of a target glucose of 120 mg/dL [6.7 mmol/L] and a sensitivity factor of 50, were for teaching purposes only. Your child may need different values.


Original posting 25 Oct 2008
Posted to Insulin and Daily Care


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Last Updated: Tuesday April 06, 2010 15:10:16
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