Initial Basal and Bolus Rates and Basal Rate Variability During Pump Treatment in Children and Adolescents

Pump-treated children with type 1 diabetes (T1DM) have widely differing basal insulin (BI) infusion profiles for specific periods of the day. The pattern of BI requirements depends on the timing and magnitude of cortisol and growth hormone secretion within each age group. In adolescents and young adults, a decreased insulin sensitivity is seen, particularly in the early morning (dawn phenomenon) and to a lesser extent, in the late afternoon (dusk phenomenon). Different approaches exist for the inititation of basal rates. However, there is a lack of evidence-based recommendation, especially in young children. Usually the basal rates are set equally throughout day and night or the day is divided into tertiles. The aim of this study was to analyze the change of the initial, equally distributed, BI rates over the first year of standard insulin pump therapy.

A total of 154 patients with T1DM, aged between 0 and <21 years at diagnosis, from a single center were documented. Patients were divided into five age groups according to age at pump initiation: group 1, <5 years (n=36); group 2, 5-8 years (n=20); group 3, 8-15 years (n=74); group 4, 15-18 years, (n=19); and group 5, >18 years, (n=5). Distribution of hourly basal rates at the initiation of the pump and at the end of first year were evaluated.

Median (range) age and diabetes duration was 14.46 (1.91-26.15) and 7.89 (1.16-17.15) years, respectively. Forty-four percent were male, 56% were female. Mean total insulin dose/kg in the whole cohort at the initiation and after one year of pump therapy was 0.86±0.23 U/kg and 0.78±0.19 U/kg, respectively and differed significantly between each age group (p<0.001; p<0.001). Mean daily basal rate/kg showed significant differences between the five groups (p<0.001). Circadian distribution of BI differed markedly among the five age groups.

At the initiation of insulin pump therapy, circadian profiles by age group should be taken into account in pediatric patients to optimize basal rate faster and more easily.