title: Automated overnight closed-loop glucose control in young children with type 1 diabetes.
abstract: BACKGROUND
  We evaluated the effectiveness of automated overnight closed-loop (AOCL) insulin delivery and the influence of timing of initiation on glucose control overnight in young children with type 1 diabetes (T1D).
  
  
  METHODS
  Eight children with T1D (four boys, four girls) (mean ± SD: 9.4 ± 2.7 years old; body mass index, 18.3 ± 2.3 kg/m(2); duration of diabetes, 3.9 ± 2.5 years; total daily insulin dose, 0.7 ± 0.1 U/kg/day; glycosylated hemoglobin, 7.9 ± 0.9%) were studied in a clinical research facility on two separate occasions. Subjects had a meal at 18:00 (77 ± 8 g of carbohydrate [CHO]) and snack at 21:00 (21 ± 6 g of CHO), both accompanied by a prandial insulin bolus. In random order, AOCL was started at 18:00 or 21:00 h and ran until 08:00 h the next day. Subcutaneous continuous glucose monitoring data were fed automatically into the model predictive control algorithm. Calculated subcutaneous insulin infusion rates were sent wirelessly to an insulin pump. Plasma glucose was measured to assess closed-loop performance.
  
  
  RESULTS
  No rescue CHOs were administered. Time spent with plasma glucose in the target range from 3.9 to 8.0 mmol/L was 50.7% (29.0%, 72.2%), and it did not differ on the two occasions: median (interquartile range), 42% (18%, 64%) versus 58% (32%, 79%) (P = 0.161). Time when plasma glucose was above 8.0 mmol/L (42% [25%, 82%] vs. 29% [14%, 64%], P = 0.093), time below 3.9 mmol/L (0% [0%, 11%] vs. 8% [0%, 17%], P = 0.500), low blood glucose index (0.1 [0.0, 2.5] vs. 1.7 [0.4, 3.3], P = 0.380), plasma glucose at the start of AOCL (12.5 ± 2.7 vs. 11.6 ± 4.2 mmol/L, P = 0.562), and mean overnight plasma glucose (8.3 ± 2.1 vs. 7.5 ± 2.2 mmol/L, P = 0.246) were also similar.
  
  
  CONCLUSIONS
  AOCL is feasible in young children with T1D. Comparable results were obtained when closed-loop was initiated at 18:00 or 21:00 h.
authors.affiliation: Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Daniela
authors.initials: D
authors.lastname: Elleri
authors.forename: Janet M
authors.initials: JM
authors.lastname: Allen
authors.forename: Marianna
authors.initials: M
authors.lastname: Nodale
authors.forename: Malgorzata E
authors.initials: ME
authors.lastname: Wilinska
authors.forename: Jasdip S
authors.initials: JS
authors.lastname: Mangat
authors.forename: Anne Mette F
authors.initials: AM
authors.lastname: Larsen
authors.forename: Carlo L
authors.initials: CL
authors.lastname: Acerini
authors.forename: David B
authors.initials: DB
authors.lastname: Dunger
authors.forename: Roman
authors.initials: R
authors.lastname: Hovorka
mesh_terms: D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D015918:Infusion Pumps, Implantable; D007328:Insulin / Q000008:administration & dosage*; D007332:Insulin Infusion Systems; D008297:Male; D018709:Statistics, Nonparametric
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin