, Volume 55, Issue 12, pp 3155-3162

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

The use and efficacy of continuous glucose monitoring in type 1 diabetes treated with insulin pump therapy: a randomised controlled trial

  • T. BattelinoAffiliated withUMC - University Children’s Hospital, Faculty of Medicine, University of Ljubljana Email author 
  • , I. CongetAffiliated withDiabetes Unit, ICMDM Hospital Clínici Universitari
  • , B. OlsenAffiliated withGlostrup Hospital
  • , I. Schütz-FuhrmannAffiliated withHospital Hietzing
  • , E. HommelAffiliated withSteno Diabetes Center
  • , R. HoogmaAffiliated withGroene Hart Ziekenhuis
  • , U. SchierlohAffiliated withClinique Pediatrique, Centre Hospitalier de Luxembourg
  • , N. SulliAffiliated withClinica Pediatrica, Servizio Diabetologia, Policlinico Umberto I
  • , J. BolinderAffiliated withDepartment of Medicine, Karolinska University Hospital Huddinge, Karolinska Institutet



The aim of this multicentre, randomised, controlled crossover study was to determine the efficacy of adding continuous glucose monitoring (CGM) to insulin pump therapy (CSII) in type 1 diabetes.


Children and adults (n = 153) on CSII with HbA1c 7.5–9.5% (58.5–80.3 mmol/mol) were randomised to (CGM) a Sensor On or Sensor Off arm for 6 months. After 4 months’ washout, participants crossed over to the other arm for 6 months. Paediatric and adult participants were separately electronically randomised through the case report form according to a predefined randomisation sequence in eight secondary and tertiary centres. The primary outcome was the difference in HbA1c levels between arms after 6 months.


Seventy-seven participants were randomised to the On/Off sequence and 76 to the Off/On sequence; all were included in the primary analysis. The mean difference in HbA1c was –0.43% (–4.74 mmol/mol) in favour of the Sensor On arm (8.04% [64.34 mmol/mol] vs 8.47% [69.08 mmol/mol]; 95% CI −0.32%, −0.55% [−3.50, −6.01 mmol/mol]; p < 0.001). Following cessation of glucose sensing, HbA1c reverted to baseline levels. Less time was spent with sensor glucose <3.9 mmol/l during the Sensor On arm than in the Sensor Off arm (19 vs 31 min/day; p = 0.009). The mean number of daily boluses increased in the Sensor On arm (6.8 ± 2.5 vs 5.8 ± 1.9, p < 0.0001), together with the frequency of use of the temporary basal rate (0.75 ± 1.11 vs 0.26 ± 0.47, p < 0.0001) and manual insulin suspend (0.91 ± 1.25 vs 0.70 ± 0.75, p < 0.018) functions. Four vs two events of severe hypoglycaemia occurred in the Sensor On and Sensor Off arm, respectively (p = 0.40).


Continuous glucose monitoring was associated with decreased HbA1c levels and time spent in hypoglycaemia in individuals with type 1 diabetes using CSII. More frequent self-adjustments of insulin therapy may have contributed to these effects.

Trial registration registration no. NCT00598663.


The study was funded by Medtronic International Trading Sarl Switzerland.


Continuous glucose monitoring Diabetes mellitus type 1 Glycaemic control Insulin pump therapy Randomised controlled trial Sensor-augmented insulin pump therapy