title: Feasibility of automating insulin delivery for the treatment of type 1 diabetes.
abstract: An automated closed-loop insulin delivery system based on subcutaneous glucose sensing and subcutaneous insulin delivery was evaluated in 10 subjects with type 1 diabetes (2 men, 8 women, mean [+/-SD] age 43.4 +/- 11.4 years, duration of diabetes 18.2 +/- 13.5 years). Closed-loop control was assessed over approximately 30 h and compared with open-loop control assessed over 3 days. Closed-loop insulin delivery was calculated using a model of the beta-cell's multiphasic insulin response to glucose. Plasma glucose was 160 +/- 66 mg/dl at the start of closed loop and was thereafter reduced to 71 +/- 19 by 1:00 p.m. (preprandial lunch). Fasting glucose the subsequent morning on closed loop was not different from target (124 +/- 25 vs. 120 mg/dl, respectively; P > 0.05). Mean glucose levels were not different between the open and closed loop (133 +/- 63 vs. 133 +/- 52 mg/dl, respectively; P > 0.65). However, glucose was within the range 70-180 mg/dl 75% of the time under closed loop versus 63% for open loop. Incidence of biochemical hypoglycemia (blood glucose <60 mg/dl) was similar under the two treatments. There were no episodes of severe hypoglycemia. The data provide proof of concept that glycemic control can be achieved by a completely automated external closed-loop insulin delivery system.
authors.affiliation: Medtronic MiniMed, 18000 Devonshire St., Northridge, CA 91325, USA. garry.steil@medtronic.com
authors.forename: Garry M
authors.initials: GM
authors.lastname: Steil
authors.forename: Kerstin
authors.initials: K
authors.lastname: Rebrin
authors.forename: Christine
authors.initials: C
authors.lastname: Darwin
authors.forename: Farzam
authors.initials: F
authors.lastname: Hariri
authors.forename: Mohammed F
authors.initials: MF
authors.lastname: Saad
mesh_terms: D000328:Adult; D001331:Automation / Q000379:methods*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D015992:Body Mass Index; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy*; D004333:Drug Administration Routes; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D007263:Infusions, Parenteral / Q000379:methods*; D007328:Insulin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin