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Feasibility of automated insulin delivery guided by continuous glucose monitoring in preterm infants
  1. Kathryn Beardsall1,2,
  2. Lynn Thomson1,
  3. Daniela Elleri1,
  4. David B Dunger1,
  5. Roman Hovorka1
  1. 1 Department of Paediatrics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, Cambridgeshire, UK
  2. 2 Neonatal Unit, Cambridge University Hospitals NHS Trust, Cambridge
  1. Correspondence to Dr Kathryn Beardsall, Department of Paediatrics, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 2QQ, UK; kb274{at}


Objective Closed-loop systems have been used to optimise insulin delivery in children with diabetes, but they have not been tested in neonatal intensive care. Extremely preterm infants are prone to hyperglycaemia and hypoglycaemia; both of which have been associated with adverse outcomes. Insulin sensitivity is notoriously variable in these babies and glucose control is time-consuming, with management requiring frequent changes of dextrose-containing fluids and careful monitoring of insulin treatment. We aimed to evaluate the feasibility of closed-loop management of glucose control in these infants.

Design and setting Single-centre feasibility study with a randomised parallel design in a neonatal intensive care unit. Eligibility criteria included birth weight <1200 g and <48 hours of age. All infants had subcutaneous continuous glucose monitoring for the first week of life, with those in the intervention group receiving closed-loop insulin delivery in a prespecified window, between 48 and 72 hours of age during which time the primary outcome was percentage of time in target (sensor glucose 4–8 mmol/L).

Results The mean (SD) gestational age and birth weight of intervention and control study arms were 27.0 (2.4) weeks, 962 (164) g and 27.5 (2.8) weeks, 823 (282) g, respectively, and were not significantly different. The time in target was dramatically increased from median (IQR) 26% (6-64) with paper guidance to 91% (78-99) during closed loop (p<0.001). There were no serious adverse events and no difference in total insulin infused.

Conclusions Closed-loop glucose control based on subcutaneous glucose measurements appears feasible as a potential method of optimising glucose control in extremely preterm infants.

  • glucose
  • preterm
  • insulin
  • continuous glucose monitoring
  • closed loop

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  • Contributors KB was the principal investigator who had the original idea for the study and contributed to the study design, to the acquisition and analysis of the data prior to drafting the initial manuscript and subsequent critical revisions. LT contributed to the design of the study, to the acquisition of the data and drafting of the manuscript. DE contributed to the analysis of the data collected during the study, and critically reviewed the manuscript. RH contributed to the design of the study and in particular the model predictive computer algorithm, to the interpretation of the data, critical revision of the initial drafts of the manuscript. DBD contributed to the design of the study, evaluation of the data, critical review and revision of the manuscript. All authors have approved the final manuscript prior to submission and are accountable for the integrity of the study.

  • Funding Funding was provided by the Evelyn Trust, the National Institute of Health Research EME Programme and the National Institute of Health Research Cambridge Biomedical Research Centre. Medtronic provided the continuous glucose monitoring systems and sensors.

  • Disclaimer Medtronic had no role in design of the study, the gathering of data, access to data, preparation of the manuscript or decision to publish the results.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Requests for anonymised data should be made to the corresponding author.

  • Patient consent for publication Not required.

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