Objective: To determine the utility of the continuous glucose monitoring system (CGMS) as an outpatient procedure to improve management of diabetes in adolescents.
Research design and methods: Twelve adolescents (mean age: 16.2 +/- 3 years) with poorly controlled type 1 diabetes (HbA(1c) > 8%) were included in this trial. Mean HbA(1c) during the previous year was 10.1 +/- 1.2%. Insulin treatment consisted of 2 or 3 daily injections in 10 cases and CSII in 2. At the beginning of the study, HbA(1c) was determined and low blood glucose index (LBGI) was calculated. Continuous glucose monitoring was performed for three days. After downloading and analyzing data, results were discussed with the patient and insulin treatment was adjusted. Two months later testing was repeated and all parameters were reassessed.
Results: Initial CGMS profiles demonstrated glycemic excursions unrecognized by capillary measurements in all twelve patients. Glycemia before and after meals varied from<60 mg/dL to > 200 mg/dL in 2 patients (2 episodes). Postprandial hyperglycemia exceeded 200 mg/dL in 10 patients (24 episodes). Prolonged overnight hyperglycemia was observed in 5 patients (7 episodes), dawn phenomenon in 4 patients (6 episodes) and nighttime hypoglycemia in 4 patients (4 episodes). A day-to-day reproducibility of glycemic profiles was observed in 8 patients. Then insulin treatment was adjusted according to CGMS data. Changes involved dose levels in 3 patients, insulin type in 7, number of injections, i.e. 3 instead of 2, in 5 or change from insulin injection to CSII in 1. Reassessment two months later demonstrated a significant reduction of glycemic excursions in 8 patients. HbA(1c) (m +/- SD) decreased from 10.3 +/- 2.1% to 8.75 +/- 1.06% (p<0.05). LBGI increased from 1.7 +/- 0.9 to 2.4 +/- 1.4 but the difference was not significant.
Conclusions: Use of CGMS in diabetic adolescent outpatients achieved a significant improvement in metabolic control not only by providing accurate data for adjustment of insulin treatment but also by promoting patient communication and motivation.