Balancing the daily meal plan with the dosages of insulin is crucial for maintaining serum glucose concentrations within the target range and avoiding hypoglycemia or hyperglycemia. The content and schedule of meals vary according to the type of insulin regimen used. It is recommended that carbohydrates contribute 50% to 65% of the total calories, protein 12% to 20%, and fat <30%. Saturated fat should contribute <10% of the total caloric intake, and cholesterol intake should be less than 300 mg/24 hours. High fiber content is recommended.
Patients using multiple daily injections or the insulin pump can maintain a more flexible meal schedule with regard to the timing of meals and the carbohydrate content. These patients give an injection of insulin before or immediately after each meal with the total dose calculated according to the carbohydrate content of the meal. Further adjustments in the dose can be made based on the measured serum glucose concentration and plans for activity during the day. Children using a twice-aday combination of intermediate-acting and fast-acting insulins need to maintain a relatively consistent meal schedule so that carbohydrate absorption and insulin action peaks correspond. A typical meal schedule for a patient using this type of regimen involves three meals and three snacks daily. The total carbohydrate content of the meals and snacks should be kept constant.
Blood glucose should be routinely monitored before each meal and at bedtime. Hypoglycemia during the night or excessive variability in the morning glucose concentrations should prompt additional testing at 2 or 3 am to ensure that there is no consistent hypoglycemia or hyperglycemia. During periods of illness or when blood glucose concentrations are higher than 300 mg/dL, urine ketones also should be tested. Continuous glucose monitors, which provide minute-to-minute blood glucose concentration information, can be useful in following
Table 171-2 Representative Profiles of Insulin INSULIN ONSET PEAK ACTION DURATION Very Short Acting Lispro, aspart, glulisine 5−15 minutes 30−90 minutes 3−5 hours
Data from Wolfsdorf JI, editor: Intensive Diabetes Management, ed 4, Alexandria, VA, 2009, American Diabetes Associations.
trends of blood glucose concentrations but should not be used in calculations of mealtime insulin doses.
Measurements of glycohemoglobin or hemoglobin A1c (HgbA1c) reflect the average blood glucose concentration over the preceding 3 months and provide a means for assessing long-term glycemic control. HgbA1c should be measured four times a year, and the results should be used for counseling of patients. The American Diabetes Association has set HgbA1c targets based on age with children less than 6 years having an HgbA1c target of 7.5% to 8.5%, ages 6 to 13 years HgbA1c target of less than 8%, and ages 13 to 18 years HgbA1c target of less than 7.5%. Measurements of HgbA1c are inaccurate in patients with hemoglobinopathies. Glycosylated albumin or fructosamine can be used in these cases.
Patients with DM1 for more than 3 to 5 years should receive an annual ophthalmologic examination for retinopathy. Urine should be collected annually for assessment of microalbuminuria, which suggests early renal dysfunction and indicates a high risk of progression to nephropathy. Treatment with angiotensin-converting enzyme inhibitors may halt the progression of microalbuminuria. In children with DM1, annual cholesterol measurements and periodic assessment of blood pressure are recommended. Early detection of hypertension and hypercholesterolemia with appropriate intervention can help limit future risk of coronary disease.