James Yong

Home Use of an Artificial Beta Cell in Type 1 Diabetes

BACKGROUND The feasibility, safety, and efficacy of prolonged use of an artificial beta cell (closed-loop insulin-delivery system) in the home setting have not been established. METHODS In two multicenter, crossover, randomized, controlled studies conducted under free-living home conditions, we compared closed-loop insulin delivery with sensor-augmented pump therapy in 58 patients with type 1 diabetes. The closed-loop system was used day and night by 33 adults and overnight by 25 children and adolescents. Participants used the closed-loop system for a 12-week period and sensor-augmented pump therapy (control) for a similar period. The primary end point was the proportion of time that the glucose level was between 70 mg and 180 mg per deciliter for adults and between 70 mg and 145 mg per deciliter for children and adolescents. RESULTS Among adults, the proportion of time that the glucose level was in the target range was 11.0 percentage points (95% confidence interval [CI], 8.1 to 13.8) greater with the use of the closed-loop system day and night than with control therapy (P<0.001). The mean glucose level was lower during the closed-loop phase than during the control phase (difference, -11 mg per deciliter; 95% CI, -17 to -6; P<0.001), as were the area under the curve for the period when the glucose level was less than 63 mg per deciliter (39% lower; 95% CI, 24 to 51; P<0.001) and the mean glycated hemoglobin level (difference, -0.3%; 95% CI, -0.5 to -0.1; P=0.002). Among children and adolescents, the proportion of time with the nighttime glucose level in the target range was higher during the closed-loop phase than during the control phase (by 24.7 percentage points; 95% CI, 20.6 to 28.7; P<0.001), and the mean nighttime glucose level was lower (difference, -29 mg per deciliter; 95% CI, -39 to -20; P<0.001). The area under the curve for the period in which the day-and-night glucose levels were less than 63 mg per deciliter was lower by 42% (95% CI, 4 to 65; P=0.03). Three severe hypoglycemic episodes occurred during the closed-loop phase when the closed-loop system was not in use. CONCLUSIONS Among patients with type 1 diabetes, 12-week use of a closed-loop system, as compared with sensor-augmented pump therapy, improved glucose control, reduced hypoglycemia, and, in adults, resulted in a lower glycated hemoglobin level. (Funded by the JDRF and others; AP@home04 and APCam08 ClinicalTrials.gov numbers, NCT01961622 and NCT01778348.).

Closing the Loop in Adults, Children and Adolescents With Suboptimally Controlled Type 1 Diabetes Under Free Living Conditions: A Psychosocial Substudy

Objective: The objective was to explore psychosocial experiences of closed loop technology for adults, children, and adolescents with type 1 diabetes and their parents taking part in two multicenter, free-living, randomized crossover home studies. Methods: Participants using insulin pump therapy were randomized to either 12 weeks of automated closed-loop glucose control, then 12 weeks of sensor augmented insulin pump therapy (open loop), or vice versa. Closed loop was used for 24 hours by adults and overnight only by children and adolescents. Participants completed the Diabetes Technology Questionnaire (DTQ) periodically and shared their views in semistructured interviews. This analysis characterizes the impact of the technology, positive and negative aspects of living with the device, alongside participants’ expectations, hopes, and anxieties. Results: Participants were 32 adults, age 38.6 ± 9.6 years, 55% male, and 26 children, mean age 12 years (range 6-18 years), 54% male. DTQ results indicated moderately favorable impact of, and satisfaction with, both open and closed loop interventions, but little evidence of a comparative advantage of either. Key positive themes included perceived improved blood glucose control, improved general well-being, particularly on waking, improved sleep, reduced burden of diabetes, and visibility of data. Key negative themes included having to carry around the equipment and dislike of the pump and second cannula (ie, sensor) inserted. Conclusions: Overall, participants reported a positive experience of the closed loop technology. Results are consistent with previous research with size of equipment continuing to be a problem. Progress is being made in the usability of the closed-loop system.

G474(P) Review of glycaemic control, complications and outcome following transfer to adult services in adolescents and young adults with childhood onset type 1 diabetes mellitus

Aims To review glycaemic control and rate of microvascular complications in adolescents and young adults with childhood onset type 1 diabetes and to investigate glycaemic control before and after transfer to adult services. Methods All patients aged 17 to 23 years with childhood onset type 1 diabetes at a single tertiary centre were included. Patients were identified using our clinic database. Details of treatment control and complications were obtained from the database. Results A total of 104 (male=55) patients with a median age of 19.2 (17.15 to 23.0) years were identified with mean (±SD) duration of diabetes of 9.7 (±4.4) years. Treatment consisted of multiple daily injections in 66.3%, pump therapy in 27.9% and twice daily insulin regimen in 5.8%. Mean HbA1c was 77.3 ± 17.9 mmol/mol, comparable to results seen in similar studies. Hypothyroidism and coeliac disease was detected in 6.7% and 3.8%, respectively. Microalbuminuria was noted in 8.6% and retinopathy in 43.2%, with one patient requiring laser therapy. Mean LDL was 2.3 ± 0.67 mmol/l with one patient on statin therapy. The mean systolic and diastolic blood pressures were 122 ± 11 and 71.4 ± 8.9 mmHg, respectively. The mean age of transfer to adult services was 18.5 ± 1.2 years. Mean HbA1c in the year before transfer was 77.8 ± 18.1 mmol/mol with similar levels one year post transfer at 78.3 ± 18.3 mmol/mol. Only 12.5% of individuals achieved target HbA1c of <58 mmol/mol. There was a reduction in average number of clinics attended post transfer (3.2 Vs 2.4 in one calendar year) with three patients lost to follow up after transfer. Hospital admissions halved post transfer from 6 admissions over 3 years before transfer to 3 admissions after transfer. Conclusions Diabetes control in adolescent and young adults with type 1 diabetes is inadequate and is not affected by transfer to adult services, despite a reduction in the number of clinic attendance. The rate of microvascular complications in this group is relatively high, although advanced complications were evident only in a minority. Future work is needed to improve glycaemic control in young people with diabetes to encourage engagement and develop new strategies for self management.