Use of Continuous Glucose Sensors by Adolescents With Inadequate Diabetic Control

Management of type 1 diabetes mellitus (T1DM) in adolescents is very difficult and innovative approaches are needed to help them achieve better glycemic control and behavioral outcomes. Continuous glucose sensors (CGS) have been refined progressively and provide acceptably accurate, nearly continuous estimates of glucose levels and trends. This increased quality and quantity of glucose data could be an excellent adjunct to conventional self-monitoring of blood glucose, permitting more informed diabetes decision-making. CGS could yield medical, educational and psychological benefits for adolescents with T1DM, but those with extremely variable self-management habits and suboptimal glycemic control may not realize these benefits readily. We hypothesize that a targeted, family-focused behavioral intervention could optimize benefit from adding CGS to T1DM therapy for youths with glycosylated hemoglobin (HbA1c) > 7.5%. A multi-site sample of 150 adolescents with T1DM and HbA1C of 7.5% to 10.0% will be randomized to either Standard Care for T1DM (SC), or to augmentation of SC with 9 months' use of a CGS device (CGS) or use of a CGS device supplemented with a targeted behavior therapy intervention (CGS+BT). Multiple measures of glycemic control, glycemic variability and health care use will be obtained during the study and there will be periodic assessments of demographic factors, diabetes self-management, family relations and psychological adjustment. Three specific aims will be addressed: 1. Evaluate whether CGS+BT yields more improvement in glycemic outcomes than CGS or SC; 2. Evaluate whether CGS+BT yields more improvement in behavioral outcomes than CGS or SC; and 3. Identify behavioral variables that mediate and moderate glycemic benefit from use of the CGS device. The study will also compare the cost effectiveness of CGS and CGS+BT relative to SC and evaluate the predictive utility of various indices of glycemic variability in youths. We hypothesize that, compared with SC and CGS, CGS+BT will yield significantly better biomedical outcomes (HbA1C; severe hypoglycemia; glycemic variability; proportion of glucose readings in the normal range) and behavioral outcomes (treatment adherence; parent adolescent teamwork; diabetes-related family conflict; quality of life; fear of hypoglycemia; and treatment satisfaction). After the 9 month randomized trial, all youths will be allowed to use the CGS device during an additional 3-month continuation phase. Statistical analyses will be based on individual growth modeling techniques. The application capitalizes on the Principal Investigator's prior and ongoing funded research on family management of T1DM, including trials of family-focused behavioral interventions, intensive therapy regimens, and clinical evaluations of continuous glucose sensors. The proposed study will determine whether a targeted behavioral intervention improves CGS benefits among adolescents with previously inadequate glycemic control. These results could demonstrate that adolescents with previously suboptimal diabetic control could realize multiple benefits from CGS use if they are provided with a specialized behavioral intervention.

Inclusion criteria

• Age of adolescent > 11 years and < 17 years. This age range was chosen because families of adolescents often struggle with diabetes management. Youths > 18 years old may be likely to leave home during the study.
• Diagnosis of type 1 diabetes based on the clinician's best judgment regarding the adolescent's proper diagnostic category.
• Duration of type 1 diabetes > 2 years or > 1 year with negligible stimulated c-peptide level, to exclude those with significant residual pancreatic insulin production.
• Treatment of diabetes for the 6 months prior to enrollment must consist of an intensified regimen including either daily use of an insulin pump or 3 or more daily insulin injections with pre-meal insulin doses calculated using a correction factor that considers prevailing blood glucose levels and planned carbohydrate intake.
• Adolescent must have established diabetes care at a participating Nemours Children's Clinic site as evidenced by at least two diabetes clinic visits within the prior 12 months.
• Most recent HbA1C > 7.5% and < 10.0% or mean HbA1C over the prior 12 months within that same range.
• Intention to remain in the same region and to maintain diabetes care at the enrolling center for 12 months.
• Family has working telephone service.

Exclusion criteria

• Youth has not used a CGM device with real-time glucose feedback for clinical management of diabetes within the prior 6 months. Intermittent or one-time use of "blinded" CGM devices for retrospective analysis only is permissible.
• Absence of any other medical conditions that, in the opinion of the attending endocrinologist, would impede completion of the study protocol.
• Youths may not be on daily glucocorticoid medications due to hyperglycemic effects of these agents.
• Not enrolled in special education for mental retardation, autism or severe behavior disorders.
• Child not in an inpatient psychiatric unit or day treatment program during the 6 months prior to enrollment.
• Primary diabetes caregiver not diagnosed or in treatment for major depression, psychosis, bipolar disorder or substance use disorder within the 6 months prior to enrollment; Child not in an inpatient psychiatric unit or day treatment program during the 6 months prior to enrollment.