Closed-Loop Insulin Therapy Improves Glycemic Control in Children Aged <7 Years

A randomized controlled trial

  1. Garry M. Steil, PHD3
  1. 1Division of Endocrinology, Boston Children’s Hospital, Boston, Massachusetts
  2. 2Department of Medicine, Boston Children’s Hospital, Boston, Massachusetts
  3. 3Medicine Critical Care Program, Boston Children’s Hospital, Boston, Massachusetts
  4. 4Department of Nursing, Boston Children’s Hospital, Boston, Massachusetts
  1. Corresponding author: Garry M. Steil, garry.steil{at}


OBJECTIVE To assess the possibility of improving nocturnal glycemic control as well as meal glycemic response using closed-loop therapy in children aged <7 years.

RESEARCH DESIGN AND METHODS This was a randomized controlled crossover trial comparing closed-loop with standard open-loop insulin pump therapy performed in an inpatient clinical research center. Ten subjects aged <7 years with type 1 diabetes for >6 months treated with insulin pump therapy were studied. Closed-loop therapy and standard open-loop therapy were compared from 10:00 p.m. to 12:00 p.m. on 2 consecutive days. The primary outcome was plasma glucose time in range (110–200 mg/dL) during the night (10:00 p.m.–8:00 a.m.). Secondary outcomes included peak postprandial glucose levels, incidence of hypoglycemia, degree of hyperglycemia, and prelunch glucose levels.

RESULTS A trend toward a higher mean nocturnal time within target range was noted for closed versus open-loop therapy, although not reaching statistical significance (5.3 vs. 3.2 h, P = 0.12). There was no difference in peak postprandial glucose or number of episodes of hypoglycemia. There was significant improvement in time spent >300 mg/dL overnight with closed-loop therapy (0.18 vs. 1.3 h, P = 0.035) and the total area under the curve of glucose >200 mg/dL (P = 0.049). Closed-loop therapy returned prelunch blood glucose closer to target (189 vs. 273 mg/dL on open loop, P = 0.009).

CONCLUSIONS Closed-loop insulin delivery decreases the severity of overnight hyperglycemia without increasing the incidence of hypoglycemia. The therapy is better able to reestablish target glucose levels in advance of a subsequent meal. Younger children with type 1 diabetes may reap significant benefits from closed-loop therapy.

  • Received June 7, 2012.
  • Accepted July 29, 2012.

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