SummaryBackgroundThe achievement of glycaemic control remains challenging for patients with type 1 diabetes. We assessed the effectiveness of day-and-night hybrid closed-loop insulin delivery compared with sensor-augmented pump therapy in people with suboptimally controlled type 1 diabetes aged 6 years and older.MethodsIn this open-label, multicentre, multinational, single-period, parallel randomised controlled trial, participants were recruited from diabetes outpatient clinics at four hospitals in the UK and two centres in the USA. We randomly assigned participants with type 1 diabetes aged 6 years and older treated with insulin pump and with suboptimal glycaemic control (glycated haemoglobin [HbA1c] 7·5–10·0%) to receive either hybrid closed-loop therapy or sensor-augmented pump therapy over 12 weeks of free living. Training on study insulin pump and continuous glucose monitoring took place over a 4-week run-in period. Eligible subjects were randomly assigned using central randomisation software. Allocation to the two study groups was unblinded, and randomisation was stratified within centre by low (<8·5%) or high (≥8·5%) HbA1c. The primary endpoint was the proportion of time that glucose concentration was within the target range of 3·9–10·0 mmol/L at 12 weeks post randomisation. Analyses of primary outcome and safety measures were done in all randomised patients. The trial is registered with ClinicalTrials.gov, number NCT02523131, and is closed to accrual.FindingsFrom May 12, 2016, to Nov 17, 2017, 114 individuals were screened, and 86 eligible patients were randomly assigned to receive hybrid closed-loop therapy (n=46) or sensor-augmented pump therapy (n=40; control group). The proportion of time that glucose concentration was within the target range was significantly higher in the closed-loop group (65%, SD 8) compared with the control group (54%, SD 9; mean difference in change 10·8 percentage points, 95% CI 8·2 to 13·5; p<0·0001). In the closed-loop group, HbA1c was reduced from a screening value of 8·3% (SD 0·6) to 8·0% (SD 0·6) after the 4-week run-in, and to 7·4% (SD 0·6) after the 12-week intervention period. In the control group, the HbA1c values were 8·2% (SD 0·5) at screening, 7·8% (SD 0·6) after run-in, and 7·7% (SD 0·5) after intervention; reductions in HbA1c percentages were significantly greater in the closed-loop group compared with the control group (mean difference in change 0·36%, 95% CI 0·19 to 0·53; p<0·0001). The time spent with glucose concentrations below 3·9 mmol/L (mean difference in change −0·83 percentage points, −1·40 to −0·16; p=0·0013) and above 10·0 mmol/L (mean difference in change −10·3 percentage points, −13·2 to −7·5; p<0·0001) was shorter in the closed-loop group than the control group. The coefficient of variation of sensor-measured glucose was not different between interventions (mean difference in change −0·4%, 95% CI −1·4% to 0·7%; p=0·50). Similarly, total daily insulin dose was not different (mean difference in change 0·031 U/kg per day, 95% CI −0·005 to 0·067; p=0·09...

CGM technologies enabled collection of verified data under normal living conditions, providing an exceptional vantage point from which to obtain important clinical information. This will facilitate an understanding of the range of euglycemic patterns, provide a sensitive means of detecting impaired glucose tolerance, and help set realistic treatment goals for individuals with diabetes.

CGM detects abnormalities in glycemic control in a manner heretofore impossible to obtain. However, our studies revealed sufficient incongruence between simultaneous laboratory blood glucose levels and interstitial fluid glucose (after calibrations) to question the fundamental assumption that interstitial fluid glucose and blood glucose could be made identical by resorting to algorithms based on concurrent blood glucose levels alone.

To quantify age-related variability of insulin needs during day and night closed-loop insulin delivery. RESEARCH DESIGN AND METHODS We retrospectively analyzed data from hybrid closed-loop studies involving young children (1-6 years old, n 5 20), children (7-12 years, n 5 21), adolescents (13-17 years, n 5 15), and adults (>18 years, n 5 58) with type 1 diabetes. The coefficient of variation quantified variability of insulin needs during 3 weeks of unrestrictedliving hybrid closed-loop use. RESULTS Data from 2,365 nights and 2,367 days in 114 participants were analyzed. The coefficient of variation of insulin delivery was higher in young children compared with adults (mean difference at nighttime 10.7 percentage points [95% CI 2.9-18.4], P 5 0.003; daytime 6.4 percentage points [95% CI 2.0-10.9], P 5 0.002) and compared with adolescents (mean difference at nighttime 10.2 percentage points [95% CI 0.0-20.4], P 5 0.049; daytime 7.0 percentage points [95% CI 1.1-12.8], P 5 0.014). CONCLUSIONS Diabetes management in young children is complicated by higher variability in insulin requirements, supporting fast-track clinical practice adoption of closed-loop in this vulnerable population. With increasing application of insulin pump therapy and continuous glucose monitors, hybrid closed-loop has become a feasible treatment modality for people with type 1 diabetes (1,2). Apart from manual mealtime boluses, insulin delivery is autonomously modulated by a control algorithm based on real-time sensor glucose values. Insulin delivery may vary considerably from day to day and night to night due to varying activity levels, insulin set-changes, meal timings and composition, and other factors (3,4). To date, the association between age and insulin variability has not been assessed. In the present analysis, we investigate whether insulin requirements may be more variable in younger age.

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