Aims/hypothesisThe 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.MethodsChildren 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.ResultsSeventy-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).Conclusions/interpretationContinuous 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 registrationClinicalTrials.gov registration no. NCT00598663.FundingThe study was funded by Medtronic International Trading Sarl Switzerland.

To investigate the impact of continuous glucose monitoring (CGM) on health-related quality of life (HRQOL), treatment satisfaction (TS) medical resource use, and indirect costs in the SWITCH study. SWITCH was a multicentre, randomized, crossover study. Patients with type 1 diabetes (n = 153) using continuous subcutaneous insulin infusion (CSII) were randomized to a 12 month sensor-On/Off or sensor-Off/On sequence (6 months each treatment), with a 4-month washout between periods. HRQOL in children and TS in adults were measured using validated questionnaires. Medical resource utilization data were collected. In adults, TS was significantly higher in the sensor-On arm, and there were significant improvements in ratings for treatment convenience and flexibility. There were no clinically significant differences in children’s HRQOL or parents’ proxy ratings. The incidence of severe hypoglycaemia, unscheduled visits, or diabetes-related hospitalizations did not differ significantly between the two arms. Adult patients made fewer telephone consultations during the sensor-On arm; children’s caregivers made similar numbers of telephone consultations during both arms, and calls were on average only 3 min longer during the sensor-On arm. Regarding indirect costs, children with >70 % sensor usage missed fewer school days, compared with the sensor-Off arm (P = 0.0046) but there was no significant difference in the adults days of work off. The addition of CGM to CSII resulted in better metabolic control without imposing an additional burden on the patient or increased medical resource use, and offered the potential for cost offsets.

When paediatric patients used CSII, the bolus insulin dose calculated using the Bolus Wizard was more effective in improving pre- and postprandial glycaemic control with fewer correction boluses, without differences in the prandial insulin requirements and without restriction in the carbohydrate content of meals. The use of the Bolus Wizard was easy and was associated with a high level of satisfaction in these patients.

CSII was safe and effective in improving short- and medium-term metabolic control in young adults, adolescents and younger children with DM.