Advanced Carbohydrate Counting and Medications

Patients using split-mixed insulin regimens that consists of an insulin that peaks within a set timeframe after being injected (usually a few hours, Humulin 70/30 or Humalog 75/25), may require meals to be consumed at a preset time in order to avoid hypoglycemia.

 

Patients injecting a fixed dose of rapid-acting insulin with meals manage their diabetes by injecting a fixed dose of rapid-acting insulin, such as lispro (Humalog) or aspart (Novolog), which begins working 10-20 minutes after injection and peaks within 40-50 minutes, may require a pre-determined amount of carbohydrate at mealtime.

With Advanced Carbohydrate Counting, rapid-acting insulin (in most cases) is matched to the amount of carbohydrate eaten. Using this approach, the type and amount of carbohydrate can vary, which allows more freedom of choice in the meal choice. These patients should be counseled on making good nutrition choices, otherwise this added flexibility will be wasted and unintended weight gain could be the result.

Matching carbohydrate intake to medications   Can be used in cases of patients using multiple daily injections

Matching Medications to Carbs

But matching a rapid-acting insulin dose to carbohydrates eaten may be a more accurate way to make sure the amount of insulin taken won't cause the blood glucose level to drop too low. Patients are taught to match their insulin dose (rapid-acting insulin given at mealtime) with their carbohydrate consumption based on an insulin-to-carbohydrate ratio (ICR). The ICR is the ratio that works for them to achieve a stable blood glucose level. This might mean that instead of a standard 1:15 ratio (1 unit of insulin for every 15 grams of carbs eaten), the ratio might be 1:10, or 1:20. Once this ratio is known, the insulin dose is adjusted according to the grams of carbohydrate eaten. A dietitian or certified diabetic educator can teach the patient about the basal-bolus insulin concept and how to achieve their target blood glucose level. (6)

Blood glucose should be measured before meals to determine if additional insulin should be added using a sensitivity factor (SF). And then about two hours following the meal blood glucose needs to be taken again to determine if the ICR is still accurate. This only needs to be done after each meal in the initial stages of setting the ICR, once it is decided to be accurate, periodic checks are all that is needed.

Insulin-to-carbohydrate ratio (ICR) Sensitivity factor (SF)