Insulin/Carb Ratios

Today I visited Mike Taylor, the diabetic education nurse at Howard County General Hospital in Columbia., Maryland. Mike looked at my log of Humalog injections, carbs eaten, and blood sugar readings and agreed that my results have been somewhat inconsistent.

The main problem, we both agreed, seems to be that my "basal" blood sugar levels are uncontrolled. The Humalog I am taking, which is intended to control post-meal ("bolus") elevations in blood sugar, has to fight in addition the changes in my blood sugar that occur independently of mealtimes. That is throwing off the results I am getting with mealtime insulin.

Mike will contact my doctor, Dr. Moore, with a suggestion that I be put on basal insulin as well as Humalog. He feels I need to inject perhaps 18 units of basal insulin each morning. Then I would also continue using Humalog, but in smaller mealtime doses. At that point, he suggested, I would start by using an insulin/carb ratio of 1:15 — 1 unit of insulin for every 15 grams of carbs.

That ratio might later have to be adjusted. Proper I/C ratios for "bolus" insulin such as Humalog are generally between 1:5 and 1:15, depending on the individual.

In addition, at each meal there would possibly be a "correction factor" needed: 1 extra unit of Humalog for every 50 mg/dL by which my blood sugar exceeds the midpoint of my target range for basal blood sugar level. For instance, if my target range was 70-100 mg/dL, the midpoint would be 85. If the measured level prior to a meal was 135-184, I would add 1 unit of insulin to my pre-meal dose. If it were 185-234, 2 extra units. And so on.

Mike also told me that things like eggs and bacon, which I often eat for breakfast, count as 0, carb-wise, even though for purposes of calorie counting they do have some carbohydrates in them. So a bacon-and-eggs breakfast would require no insulin injection, if I skipped having orange juice with it!

O.J. is not a good idea, Mike said, because it gets into the blood stream faster than even fast-acting insulin like Humalog can match it. Better I should eat a muffin, a bagel, or a piece of bread with my bacon and eggs, because those complex carbs take longer to enter the blood stream.

Mike set up an appointment for me with the dietitian in his office three days from now.

For now, Mike suggested I use an I/C ratio of 1:5, with the proviso that I count only those carbs that really count, diabetes-wise.