Optimizing Closed-Loop Control of Type 1 Diabetes Mellitus in Adolescents

Inclusion Criteria

• ≥13 and ≤18 years old
• Clinical diagnosis of type 1 diabetes mellitus for at least 2 years as noted by the following:

Criteria for documented hyperglycemia (at least 1 criterion must be met):

• Fasting glucose ≥126 mg/dL - confirmed
• Two-hour Oral Glucose Tolerance Test (OGTT) ≥200 mg/dL - confirmed
• Hemoglobin A1c (HbA1c) ≥6.5% documented by history - confirmed
• Random glucose ≥200 mg/dL with symptoms
• No data at diagnosis is available but the participant has a convincing history of hyperglycemia consistent with diabetes

Criteria for requiring insulin at diagnosis (at least 1 criterion must be met):

• Participant required insulin at diagnosis and continually thereafter
• Participant did not start insulin at diagnosis but upon investigator review likely needed insulin (significant hyperglycemia that did not respond to oral agents) and did require insulin eventually and used continually
• Participant did not start insulin at diagnosis but continued to be hyperglycemic, had positive islet cell antibodies - consistent with Latent Autoimmune Diabetes in Adults (LADA) and did require insulin eventually and used continually
• Use of an insulin pump to treat his/her diabetes for at least 6 months
• Actively using a carbohydrate (CHO) /insulin ratio for insulin bolus adjustments in order to keep blood glucose in a predefined range
• Tanner stage II or greater based on physician exam
• HbA1c between 95 percentile as listed according to age and height percentile in the Harriet Lane Handbook of Pediatrics)
• Conditions which may increase the risk of hypoglycemia such as uncontrolled coronary artery disease during the previous year (e.g. history of myocardial infarction, acute coronary syndrome, therapeutic coronary intervention, coronary bypass or stenting procedure, stable or unstable angina, episode of chest pain of cardiac etiology with documented electrocardiogram (EKG) changes, or positive stress test or catheterization with coronary blockages >50%), congestive heart failure, history of cerebrovascular event, seizure disorder, syncope, adrenal insufficiency, neurologic disease or atrial fibrillation
• History of a systemic or deep tissue infection with methicillin-resistant staph aureus or Candida albicans
• History of arrythmia
• Use of a device that may pose electromagnetic compatibility issues and/or radiofrequency interference with the DexCom CGM (implantable cardioverter-defibrillator, electronic pacemaker, neurostimulator, intrathecal pump, and cochlear implants)
• Anticoagulant therapy other than aspirin
• Oral steroids
• Medical condition requiring use of an acetaminophen-containing medication that cannot be withheld for for 24 hours before CGM insertions until the end of each the study admissions.
• Psychiatric disorders that would interfere with study tasks (e.g. inpatient psychiatric treatment within 6 months prior to enrollment)
• Mental incapacity, unwillingness or language barriers precluding adequate understanding or cooperation
• Known current or recent alcohol or drug abuse
• Medical conditions that would make operating a CGM, the DiAs cell phone, or insulin pump difficult (e.g. blindness, severe arthritis, immobility)
• Any skin condition that prevents sensor or pump placement on the abdomen or arm (e.g. bad sunburn, pre-existing dermatitis, intertrigo, psoriasis, extensive scarring, cellulitis)
• Impaired hepatic function measured as alanine aminotransferase or aspartate aminotransferase ≥ three times the upper reference limit
• Impaired renal function measured as creatinine >1.2 times above the upper limit of normal
• Uncontrolled microvascular (diabetic) complications (other than diabetic non-proliferative retinopathy), such as history of laser coagulation, proliferative diabetic retinopathy, known diabetic nephropathy (other than microalbuminuria with normal creatinine) or neuropathy requiring treatment
• Active gastroparesis requiring current medic