Insulin Sensitivity, Impaired Counterregulation, and Glucose Variability

Inclusion Criteria

• Type I diabetes mellitus (TIDM) (as defined by the American Diabetes Association criteria or judgment of a physician) for at least two years prior to the enrollment in the study.
• Use of an insulin pump to treat their diabetes for at least six months prior to the study.
• Ability to use a bolus calculator function with the current insulin pump with pre-defined parameters for glucose goal, carbohydrate ratio, and insulin sensitivity factor.
• Age 21 - 64 years. Adults age 65 and over are likely to have medical exclusions for the follow-up Phase 2 study, which involves induced hypoglycemia.
• Completed Phase 1 of the Institutional Review Board (IRB) #14956 "Development of a Behavioral Observer for Type 1 Diabetes Mellitus"
• Willingness to use lispro (Humalog) insulin two days prior to and during inpatient admission.
• Willingness to perform Self-Monitoring Blood Glucose (SMBG) 4 times per day at times before meals and bedtime.
• Demonstration of proper mental status and cognition for completion of the study.

Exclusion Criteria

• Pregnancy
• Psychiatric disorders that would interfere with study tasks (e.g. mental retardation, substance abuse)
• History of a systemic deep tissue infection with methicillin-resistant staph aureus or Candida albicans
• Known bleeding diathesis or dyscrasia
• Active enrollment in another clinical trial
• Medical condition that would make operating an insulin pump difficult (e.g. blindness, severe arthritis, extensive scar tissue at sites where devices are inserted).
• Anemia (hematocrit 1.5) or uncontrolled hypertension (resting blood pressure >140/90).