Bolus Calculator Settings in Well-Controlled Prepubertal Children Using Insulin Pumps Are Characterized by Low Insulin to Carbohydrate Ratios and Short Duration of Insulin Action Time

Abstract

The use of continuous subcutaneous insulin infusion (CSII) in young children is increasing in many countries, and is in Sweden currently 60% in preschool children. 1 An international consensus group has recommended CSII in the young age group. 2 The bolus calculator in the pump gives the individual the opportunity to use features that simplify the calculation of bolus doses, correcting for the current glucose level. Although a meta-analysis from 2013 found limited evidence for the use of carbohydrate counting in adults, 3 recent pediatric studies have found possible beneficial effects in decreasing HbA1c, both with CSII 4,5 and multiple daily injections (MDI), 6 and increasing the percentage of postmeal glucose readings within target. 7 Furthermore, learning about carbohydrates and carbohydrate counting can also result in overall increased knowledge regarding other components of the diet, which can lead to other benefits. The pharmacodynamic effect of 0.2 U/kg of subcutaneously injected insulin aspart was found to last approximately 4 hours in pubertal and 5 hours in prepubertal children in 1 study, 8 and similar results were found in another study using 0.15 U/kg. 9 If anything, these clamp studies lengthen the duration of insulin action, since the patient is resting in a bed, and the given dose will often have supplied both the basal 1348D STXXX10.

Prospective evaluation of insulin‐to‐carbohydrate ratio in children and adolescents with type 1 diabetes using multiple daily injection therapy

“…This study found that bolus insulin requirements estimated by the 500 rule were lower than the actual bolus doses used by the study participants. These results confirmed the findings of other studies, which demonstrated that the 500 rule underestimated the insulin requirements for children and adolescents with T1DM …”

“…Moreover, using a formula that assumes that ICR is stable throughout the day may be inappropriate due to the circadian change in insulin sensitivity . Some studies conducted on children with T1DM demonstrated that ICR had diurnal variation with higher bolus insulin requirement at morning meal than for other meals . Although this diurnal variation in ICR was not found in other studies, it is essential to assess the ICR for each meal separately.…”

ISPAD Clinical Practice Consensus Guidelines 2018: Diabetes technologies

“…Determination of insulin to carbohydrate ratios If using a carbohydrate ratio prior to transition to the pump, start with the usual factor. Otherwise, carbohydrate ratio can be determined by dividing 500 by the TDD Young children may need more aggressive meal coverage and a 350 rule may be employed …”

Managing diabetes in preschool children

“…Preschool children often need proportionally larger bolus doses than older children, often constituting 60% to 80% of the total daily insulin dose (TDD). The often used rule of 500 (500/TDD = how many grams of CHO is covered by 1 U of insulin) for bolus calculations, as detailed in the ISPAD guidelines on insulin therapy rarely fits the youngest children as it often underestimates the insulin dose . Different strategies can be used; either use a 330 or 250 rule (gives 50%‐100% more insulin) instead of 500, or, which is preferable, to observe and calculate the correct proportion between insulin and CHO from real life meals.…”

“…Thus, the total basal rate can be relatively low, around 20% to 40% of TDD. In preschool children, it is often estimated that the effect of a subcutaneous bolus of rapid‐acting insulin analogs (eg, as lispro, aspart, or glulisine) lasts for only 2 to 3 hours (active insulin time in pumps) …”