Table 3.

Key real-world and qualitative studies of closed-loop insulin delivery using commercialised systems.

Type of study	Population	Study duration	CL system	Main findings	Key reference
Real-world studies
Prospective observational	N=79 9-61 years	12 months	670G HCL	CL use declined from median 82% at 1 week to 17% at 12 months 46% of participants stopped using CL by 12 months Utilization of CL correlated with improved glycaemic control	Lal 2019 [72]
Retrospective observational	N=7813 6+ years	12 months	Control IQ	CL use was high at median 94% over the entire 12-month period TIR was 74%, TBR was 1% and GMI 6.9% at 12 months TIR was lower in children and adolescents (65%) compared with adults (≥73%) Those with sub-optimal baseline glycemic control had larger increases in TIR at 12 months	Breton 2021 [33]
Prospective observational	N=1435 14+ years	2 months	Control IQ	CL use was high at median 96% at 2 months TIR was 77% and TBR 1.2% at 2 months Sleep activity was used 33% of the time	Pinsker 2021 [77]
Prospective observational	N=558	6 months	Loop DIY	CL use was median 83% TIR consistent at 73% and TBR at 3%, mean HbA1c 6.5% 14% stopped providing data, of which 3% officially discontinued 51 severe hypoglycaemia events [18.7 per 100 person years]	Lum 2021 [90]
Retrospective observational	N=12870 7+ years	6 months	780G AHCL	CL use was high at median 92% across age-groups TIR was sustained at 74% in children (n=790) and at 78% in adults (n=1642) over 6 months	Arrieta 2022 [74]
Qualitative studies
Interviews	N=16 Pregnancy	Part of 4-week RCT	CamAPS FX	Improved glucose control giving peace of mind with CL More flexible lifestyle and better sleep with CL Device problems, particularly connectivity issues, were seen as burdensome	Farrington 2018 [129]
Interviews	N=39 (18 newly diagnosed adolescents + 21 parents)	Part of 4-year RCT: after first 12 months of CL use	CamAPS FX	Little family conflict about food / checking glucose levels with CL Leading a ‘normal’ life and fitting in with peers with CL Increased independence incl time away from home with CL Concerns about visibility of devices on body and alarms in public	Rankin 2021 [126]
Questionnaires	N=135 12-25 years	Part of 6-month RCT	670G HCL	Improved diabetes-specific quality of life with CL No difference in diabetes distress or hypoglycaemia fear between CL and usual care	Abraham 2021 [32]
Questionnaires	N=113 14-29 years	Part of 3-month RCT	780G AHCL	No significant differences across any PROs Reduction in emotional and behavioural burden subscales of the diabetes distress questionnaire with AHCL	Hood 2021 [134]
Questionnaires	N=101 6-13 years	Part of 4-month RCT + 3-month extension	Control IQ	No significant differences across any PROs at the end of 4 months or the end of the extension phase	Cobry 2021 [131]
Questionnaires	N=168 14+ years	Part of 6-month RCT	Control IQ	Reduction in hypoglycaemia fear with CL at 6 months Improved confidence in managing hypoglycaemia with CL High system usability scores with high perceived benefit with CL	Kudva 2021 [135]
Interviews	N=33 Parents of children 1-7 years	Part of 4-month RCT	CamAPS FX	Parents reported initial apprehension about using CL and required a period of time to adjust to and trust the CL system CL reduced management burden with more ‘normality’ Better sleep, less distress for child, more time for siblings, and more able to outsource care with CL Particular benefit to bolusing from a smartphone Device size and connectivity issues can be problematic	Kimbell 2022 [107]

[CL – closed-loop. HCL – hybrid closed-loop. TIR – time in range (3.9-10.0mmol/L). TBR – time below range (<3.9mmol/L). GMI – glucose management indicator (estimated HbA1c). HbA1c – glycated haemoglobin. AHCL – advanced hybrid closed-loop. RCT – randomized controlled trial.]