Self-management is important, but difficult, in children with diabetes. A color-coded slide rule containing a color scheme representing a treatment algorithm might help diabetic children with self-management (1). Moving the slide rule to the right moment of the day reveals a color that corresponds to the glucose value. The slide rule will describe the correct action to be undertaken. These actions include taking extra insulin but can also include consuming more carbohydrates, as well as ketone monitoring, blood glucose checking, or consulting a diabetes expert. The amount of insulin taken is individualized to the patient by using a written insert paper with the actual amount recorded.
To determine the effect of a color-coded slide rule, we performed a randomized multi-center trial in three Dutch hospitals. Children with diabetes from ages 1 to 16 years were randomly assigned to the intervention group, where they immediately started to use the slide rule for a period of 6 months, or to the control group, in which they began using the slide rule after 3 months for a period of 3 months. The outcome measures were changes in HbA1c, blood glucose levels, knowledge about glucose values, and quality of life. Informed consent was obtained from the patients and/or their families before entry into the study, which was approved by the medical ethical committees of the three participating hospitals.
A total of 79 children (mean age 11.1 years, mean duration of diabetes 4.9 years) were enrolled in our study. The intervention group had similar outcomes compared with the control group on all outcome measures. However, in the group with a high baseline HbA1c (≥7.7%), there was a significant difference in the decrease in HbA1c. HbA1c decreased 0.4 ± 0.2% in the intervention group and increased 0.1 ± 0.3% in the control group (P = 0.049). No negative side effects were found, i.e., the amount of hypoglycemic episodes was not affected during use. Patients liked using the slide rule and referred to it as a good tool in the day-to-day care of their diabetes.
Metabolic control is linked to a patient’s level of knowledge and their application of this knowledge. Increased knowledge about diabetes and blood glucose levels has been related to better metabolic control (2), although this is not always the case (3,4). We conclude that a color-coded slide rule is safe and that patients liked using it. We also conclude that children with a higher baseline HbA1c might benefit from the slide rule by obtaining better metabolic control. Use of the slide rule did not affect patients’ knowledge of the interpretation of blood glucose levels or their quality of life.
