Results of a Randomised Controlled Cross-Over Trial on the Effect of Continuous Subcutaneous Glucose Monitoring (CGMS) on Glycaemic Control in Children and Adolescents with Type 1 Diabetes

Abstract

Objective: To study the feasibility and the influence on glycaemic control of continuous glucose monitoring (CGMS) in young patients with type 1 diabetes. Design and Methods: A double-blinded, cross-over study was performed in 30 children (median age 11.1 years [range: 2.3 - 16.3], diabetes duration 2.1 years [0.2 - 7.1]). Patients were randomised into an open (A) or blind study arm (B). Both groups performed standardised self-monitoring blood glucose (SMBG) and received CGMS at the beginning of the study, at 3 and 6 months, each. In the blinded arm, patients and investigator were concealed from CGMS data. After 3 months, open and blinded study arms crossed over. Average glucose values and area under the glucose curve (AUC) per 24 h, above 180 and below 60 mg/dl were calculated from CGMS. Haemoglobin A1c (HbA1c) was measured at each study point. Results: Despite comparable clinical characteristics between the 15 patients of each arm, mean HbA1c was slightly lower in arm A than in B at baseline (7.8 ± 1.2 % vs. 8.4 ± 1.1 %, p = 0.148), at 3 months (7.8 ± 1.1 % vs. 8.3 ± 1.1 %, p = 0.233), and significantly lower at 6 months (7.6 ± 1.1 % vs. 8.5 ± 0.9 %, p = 0.026). However, no significant change of HbA1c occurred within each arm (A, p = 0.183 and B, p = 0.823), irrespectively whether CGMS data were blinded or not. Likewise, mean glucose and hyper- or hypoglycaemia values did not change significantly. Conclusions: In this setting, CGMS did not decisively influence glycaemic control of a total study cohort. More frequent use of CGMS at shorter intervals in single patients with hyper- or hypoglycaemic problems may be of greater value than SMBG.

Key words

Continuous glucose monitoring - CGMS - children - diabetes - prepubertal - pubertal

References

• 1 Bode B, Gross K, Rikalo N, Schwartz S, Wahl T, Page C, Gross T, Mastrototaro J J. Alarms based on real-time sensor glucose values alert patients to hypo- and hyperglycemia. The Guardian Continuous Monitoring System.  Diabetes Technol Therapeutics. 2004;  6 105-113
• 2 Bode B W, Gross T M, Thorton K R, Mastrototaro J J. Continuous glucose monitoring used to adjust diabetes therapy improves glycosylated hemoglobin: a pilot study.  Diabetes Res Clin Pract. 1999;  46 183-190
• 3 Boland E, Monsod T, Delucia M, Brandt C A, Fernando S, Tamborlane W V. Limitations of conventional methods of self-monitoring of blood glucose: lessons learned from 3 days of continuous glucose sensing in pediatric patients with type 1 diabetes.  Diabetes Care. 2001;  24 1858-1862
• 4 Chase H P, Kim L M, Owen S L, MacKenzie T A, Klingensmith G J, Murtfeld R, Garg S K. Continuous subcutaneous glucose monitoring in children with type 1 diabetes.  Pediatrics. 2001;  2 222-226
• 5 Chase H P, Roberts M D, Wightman C, Klingensmith G, Garg S K, Van Wyhe M. et al . Use of the GlucoWatch biographer in children with type 1 diabetes.  Pediatrics. 2003;  111 790-794
• 6 Chico A, Vidal-Rios P, Subira M, Novialis A. The continuous glucose monitoring system is useful for detecting unrecognized hypoglycemias in patients with type 1 and type 2 diabetes but is not better than frequent capillary glucose measurements for improving metabolic control.  Diabetes Care. 2003;  26 1153-1157
• 7 Deiss D, Hartmann R, Hoeffe J, Kordonouri O. Assessment of glycemic control by continuous glucose monitoring system in 50 children with type 1 diabetes starting on insulin pump therapy.  Pediatric Diabetes. 2004;  5 117-121
• 8 Deiss D, Kordonouri O, Meyer K, Danne T. Long hypoglycaemic periods detected by subcutaneous continuous glucose monitoring in toddlers and pre-school children with diabetes mellitus.  Diabet Med. 2001;  18 337-338
• 9 DirecNet Study Group . The accuracy of the CGMS in children with type 1 diabetes: results of the Diabetes Research in Children Network (DirecNet) Accuracy Study.  Diabetes Technol Therapeutics. 2003;  5 781-789
• 10 Gross T M, Bode B W, Einhorn D, Kayne D M, Reed C, White N H, Mastrototaro J J. Performance evaluation of the MiniMed continuous glucose monitoring system during patients home use.  Diabetes Technol Ther. 2000;  2 49-56
• 11 Kaufman F R, Austin J, Neinstein A, Jeng L, Halvorson M, Devoe D J. et al . Nocturnal hypoglycemia detected with the Continuous Glucose Monitoring System in pediatric patients with type 1 diabetes.  J Pediatr. 2002;  141 625-630
• 12 Kaufman F R, Gibson L C, Halvorson M, Carpenter S, Fisher L K, Pitukcheewanont P. A pilot study of the the Continuous Glucose Monitoring System - clinical decisions and glycemic control after its use in pediatric type 1 diabetic subjects.  Diabetes Care. 2001;  24 2030-2034
• 13 Ludvigsson J, Hanas R. Continuous subcutaneous glucose monitoring improved metabolic control in pediatric patients with type 1 diabetes: a controlled crossover study.  Pediatrics. 2003;  111 933-938
• 14 Mastrototaro J. The MiniMed Continuous Glucose Monitoring System (CGMS).  J Pediatr Endocrinol Metab. 1999;  12 (Suppl 3) 751-758
• 15 Mastrototaro J J, Bode B, Peters Harmel A, Lane W, Levetan C, Mestman J, Tanenberg R, Tobian J, Gross T M. Therapy adjustments based on CGMS data lower HbA1c with less hypoglycemia than blood glucose meter data alone.  Diabetologia. 2003;  46 (Suppl 2) A45
• 16 Salardi S, Zucchini S, Santoni R. et al . The glucose area under the profiles obtained with continuous glucose monitoring system relationships with HbA1 c in pediatric type 1 diabetic patients.  Diabetes Care. 2002;  25 1840-1844
• 17 Schaepelynck-Belicar P, Vague P, Simonin G, Lassmann-Vague V. Improved metabolic control in diabetic adolescents using the continuous glucose monitoring system (CGMS).  Diabetes Metab. 2003;  29 608-612