Frequency of mealtime insulin bolus predicts glycated hemoglobin in youths with type 1 diabetes.

BACKGROUND Within pediatric diabetes management, two electronic measures of adherence exist: frequency of daily blood glucose monitoring (BGM) and the BOLUS score, a measure of frequency of mealtime insulin bolusing. Past research has demonstrated that the BOLUS score is superior to daily BGM in predicting youths' glycated hemoglobin (HbA1c) in a cross-sectional study. We present data comparing the two adherence measures in predicting HbA1c using a prospective, longitudinal design. SUBJECTS AND METHODS Blood glucose meter data and insulin pump records were collected from a clinical database of 175 youths with type 1 diabetes (mean age, 11.7 ± 3.6 years at baseline). Youths' HbA1c levels occurring at the download time and at 3, 6, 9, and 12 months post-downloads were also collected. We calculated youths' mean BGM and BOLUS score using a standardized protocol. RESULTS Intraclass correlations (ICCs) revealed significant absolute equivalence between youths' predicted HbA1c values using BOLUS and BGM scores and future actual HbA1c values up to 12 months post-download. However, the ICCs of BOLUS scores with future HbA1c values were consistently higher than those of the BGM scores. Also, the predictions of the BOLUS scores were significantly more accurate (P ≤ 0.002) than those of the BGM scores based on the root mean squared error of predictions. CONCLUSIONS In a prospective, longitudinal design, youths' BOLUS scores were superior to youths' daily BGM in predicting future values of HbA1c. Calculating a BOLUS score versus BGM can help researchers and clinicians achieve a better prediction of youths' HbA1c.