development of a behavioral observer for type 1 diabetes mellitus

Conditions: Diabetes Mellitus, Type 1

Summary: development of a bio-behavioral stochastic model-predictive controller (smpc) for use as an artificial pancreas in t1dm requires fundamental behavioral and physiology studies, as well as translational modeling and engineering development. in order to be successful, closed-loop control in type 1 diabetes mellitus (t1dm) must adapt to individual physiologic characteristics and to the behavioral profile of each person. an essential part of this adaptation is biosystem (patient) observation. the investigators propose to lay the foundation for a closed-loop control system which will include algorithmic observers of patients' behavior and metabolic state.

this intensive descriptive study will follow 60 adults with t1dm who are currently experienced with insulin pump use for a two-week training period plus a one month active study period during which the dexcom seven® plus continuous glucose monitor (cgm) will be used in tandem with the omnipod® insulin management system. the omnipod® has a built in freestyle glucometer that allows tagging of food and activity-related treatment behaviors with each self-monitoring blood glucose (smbg) value. the omnipod® personal digital assistant (pda) also stores information about insulin delivery and meal size in relation to the carbohydrate content. parallel recording of cgm and behavioral data, as well as psychometric instruments will produce a rich synchronized data set for each person that will ultimately lead to the development of a behavioral event generator for use in future open-loop and closed-loop control algorithms for intelligent insulin dosing.

Eligibility criteria:
inclusion criteria: * type 1 diabetes mellitus (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. * actively using a bolus calculator function with the current insulin pump with pre-defined parameters for glucose goal, carbohydrate ratio, and insulin sensitivity factor. * age 21 - 65 years. the investigators will not be studying children since the dexcom seven® plus is not approved for use in children. adults over age 65 are likely to have medical exclusions for the follow-up phase 2 study, which involves induced hypoglycemia. * willingness to participate in the study for 6 weeks wearing a dexcom seven® plus cgm and omnipod® insulin pump, performing self-monitoring blood glucose (smbg) with the integral freestyle glucometer 4 times per day (before meals and bedtime) in addition to smbg required to calibrate the cgm or to validate a low or high bg alarm (\ 300 mg/dl), and recording behavioral events by tagging smgb values throughout the study with meal and activity descriptors. * willingness to avoid consumption of acetaminophen-containing products for the duration of the study. * 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 requirement for acetaminophen-containing products during the study period for more than 1 week * medical condition that would make operating a cgm or insulin pump difficult (e.g. blindness, severe arthritis, extensive scar tissue at sites where devices are inserted). * need for magnetic resonance imaging (mri)/magnetic resonance angiogram (mra) during the study.