Carbohydrate counting with a bolus calculator improves post-prandial blood glucose levels in children and adolescents with type 1 diabetes using insulin pumps


Corresponding author:

Ragnar Hanas, MD, PhD,

Department of Pediatrics,

Uddevalla Hospital,

NU Hospital Group,

S-45180 Uddevalla,


Tel: +4652292000;

fax: +4652293149;




Carbohydrate counting (CC) is widely used in insulin pumps. The primary objectives of this study were improvement of HbA1c and meal-related plasma glucose (PG) levels when using CC.


Forty patients with pump treatment, aged 13.8 ± 3.4 yr (range 5.0–19.5) and diabetes duration 8.0 ± 3.8 (1.8–16.8) years completed a 1-yr multi-center study. HbA1c at start was 7.6 ± 0.9% Diabetes Control and Complications Trial (DCCT), 59 ± 10 mmol/mol International Federation for Clinical Chemistry and Laboratory Medicine (IFCC). They were randomized into (A) control group, (B) manual CC, and (C) CC with a bolus calculator in the pump for calculations. (B) and (C) received education in CC while (A) received equal hours of traditional dietary education. Glucose meters were downloaded at visits and the standard deviation (PG-SD) calculated. PG measurements from before and 2 h after meals were registered separately.


We found no difference in HbA1c between the groups. Group C had a non-significant decrease in PG-SD (p = 0.056) compared to start, and a significantly higher number of post-meal PG between 4 and 8 mmol/L at 12 months compared to group A (55.3% vs. 30.6%, p = 0.014). The frequency of hypoglycemia was reduced for the whole study group (p = 0.01), but with no significant difference between groups. (A) significantly increased their basal-insulin dosage at 12 months. In (C), all subjects wanted to continue CC after the study. The insulin:carbohydrate ratio correlated significantly to the insulin-dose/24 h (p = 0.003) and the correction factor to the insulin-dose/24 h (p = 0.035) and age (p < 0.001).


We conclude that CC using a bolus calculator may help decrease PG-fluctuations and increase post-meal PG values within target.