Effect of 48 Months of Closed-Loop Insulin Delivery on Residual C-Peptide Secretion and Glycemic Control in Newly Diagnosed Youth With Type 1 Diabetes: A Randomized Trial.

OBJECTIVE: We evaluated the effect of long-term intensive metabolic control with hybrid closed-loop (CL) on residual C-peptide secretion and glucose control compared with standard insulin therapy in youth with type 1 diabetes over 48 months. RESEARCH DESIGN AND METHODS: Following the 24-month primary phase of a multicenter, randomized, parallel trial of 96 newly diagnosed youth aged 10 to 16.9 years, participants were invited to an extension phase using treatment allocated at randomization. They continued with hybrid CL using the Cambridge algorithm or standard insulin therapy (control) until 48 months after diagnosis. Analysis was by intention-to-treat. RESULTS: At 24 months after diagnosis, 81 participants (mean ± SD age 14 ± 2 years) continued in the extension phase (47 CL, 34 control). There was no difference in fasting C-peptide corrected for fasting glucose at 48 months between groups (CL: 5 ± 9 vs. control: 6 ± 14 pmol/L per mmol/L; mean adjusted difference -2 [95% CI -7, 4; P = 0.54]). Central laboratory HbA1c remained lower in the CL group by 0.9% (10 mmol/mol [95% CI 0.2, 1.5; 3, 17 mmol/mol); P = 0.009). Time in target range of 3.9 to 10.0 mmol/L was 12 percentage points (95% CI 3, 20; P = 0.008) higher in the CL group compared with control. There were 11 severe hypoglycemic events (6 CL, 5 control) and 7 diabetic ketoacidosis events (3 CL, 4 control) during the extension phase. CONCLUSIONS: Improved glycemic control was sustained over 48 months after diagnosis with CL insulin delivery compared with standard therapy in youth with type 1 diabetes. This did not appear to confer a protective effect on residual C-peptide secretion.

The role of automated insulin delivery technology in diabetes.

The role of automated insulin delivery systems in diabetes is expanding. Hybrid closed-loop systems are being used in routine clinical practice for treating people with type 1 diabetes. Encouragingly, real-world data reflects the performance and usability observed in clinical trials. We review the commercially available hybrid closed-loop systems, their distinctive features and the associated real-world data. We also consider emerging indications for closed-loop systems, including the treatment of type 2 diabetes where variability of day-to-day insulin requirements is high, and other challenging applications for this technology. We discuss issues around access and implementation of closed-loop technology, and consider the limitations of present closed-loop systems, as well as innovative approaches that are being evaluated to improve their performance.

Hypoglycemia and Hyperglycemia According to Type of Diabetes: Observations During Fully Closed-Loop Insulin Delivery in Adults With Type 1 and Type 2 Diabetes.

BACKGROUND: CamAPS HX fully closed-loop (FCL) system, with no user input required at mealtimes, has been shown to be safe and effective in adults with type 1 and type 2 diabetes. We assessed whether time spent in hypoglycemia and hyperglycemia during FCL insulin delivery in adults varied by type of diabetes over the 24-hour period. METHODS: We retrospectively analyzed eight weeks of data from 52 participants (adults with type 1 diabetes and adults with insulin-treated type 2 diabetes) recruited to two single-center randomized controlled studies using FCL insulin delivery during unrestricted-living conditions. Key outcomes were time spent in hypoglycemia <70 mg/dL and marked hyperglycemia >300 mg/dL by type of diabetes. RESULTS: The median percentage of time spent in hypoglycemia <70 mg/dL over the 24-hour period was lower for those with type 2 diabetes than for those with type 1 diabetes (median [interquartile range (IQR)] 0.43% [0.20-0.77] vs 0.86%, [0.54-1.46]; mean difference 0.46 percentage points [95% CI 0.23-0.70]; P < .001). Median percentage time in marked hyperglycemia >300 mg/dL was lower for those with type 2 diabetes than for those with type 1 diabetes (median [IQR] 1.8% [0.6-3.5] vs 9.3% [6.9-11.8]; mean difference 7.8 percentage points [95% CI 5.5-10.0]; P < .001). CONCLUSIONS: Using the FCL system, hypoglycemia and marked hyperglycemia exposure were lower in type 2 diabetes than in type 1 diabetes.

Lived Experience of Fully Closed-Loop Insulin Delivery in Adults with Type 1 Diabetes.

Introduction: The Closing the Loop in Adults With Type 1 Diabetes (CLEAR) randomized crossover study compared a novel fully closed-loop insulin delivery system with no carbohydrate entry or mealtime bolusing (CamAPS HX), with standard insulin pump therapy and glucose sensor in adults with type 1 diabetes and suboptimal glycemic outcomes. This qualitative substudy aimed to understand the psychosocial impact of using the fully automated system. Materials and Methods: Adults participating in the CLEAR study were invited to take part in a virtual semistructured interview after they had completed 8 weeks using the fully closed-loop system. Recruitment continued until there was adequate representation and data saturation occurred. Interviews were anonymized and transcribed for in-depth thematic analysis using an inductive-deductive approach. Study participants were also asked to complete questionnaires assessing diabetes distress, hypoglycemia confidence, and closed-loop treatment satisfaction. Results: Eleven participants (eight male and three female; age range 26-66 years) were interviewed. After an initial adjustment period, interviewees reported enjoying a reduction in diabetes burden, freed-up mental capacity, and improved mood. All were happy with overnight glycemic outcomes, with the majority reporting benefits on sleep. Although experiences of postprandial glucose outcomes varied, all found mealtimes easier and less stressful, particularly when eating out. Negatives raised by participants predominantly related to the insulin pump hardware, but some also reported increased snacking and challenges around resuming carbohydrate counting at trial closeout. Conclusions: In adults with type 1 diabetes, use of a fully closed-loop insulin delivery system had significant quality-of-life benefits and provided a welcome break from the day-to-day demands of living with diabetes. Clinical Trial Registration: NCT04977908.

Cost-Effectiveness of Closed-Loop Automated Insulin Delivery Using the Cambridge Hybrid Algorithm in Children and Adolescents with Type 1 Diabetes: Results from a Multicenter 6-Month Randomized Trial.

BACKGROUND/OBJECTIVE: The main objective of this study is to evaluate the incremental cost-effectiveness (ICER) of the Cambridge hybrid closed-loop automated insulin delivery (AID) algorithm versus usual care for children and adolescents with type 1 diabetes (T1D). METHODS: This multicenter, binational, parallel-controlled trial randomized 133 insulin pump using participants aged 6 to 18 years to either AID (n = 65) or usual care (n = 68) for 6 months. Both within-trial and lifetime cost-effectiveness were analyzed. Analysis focused on the treatment subgroup (n = 21) who received the much more reliable CamAPS FX hardware iteration and their contemporaneous control group (n = 24). Lifetime complications and costs were simulated via an updated Sheffield T1D policy model. RESULTS: Within-trial, both groups had indistinguishable and statistically unchanged health-related quality of life, and statistically similar hypoglycemia, severe hypoglycemia, and diabetic ketoacidosis (DKA) event rates. Total health care utilization was higher in the treatment group. Both the overall treatment group and CamAPS FX subgroup exhibited improved HbA1C (-0.32%, 95% CI: -0.59 to -0.04; P = .02, and -1.05%, 95% CI: -1.43 to -0.67; P < .001, respectively). Modeling projected increased expected lifespan of 5.36 years and discounted quality-adjusted life years (QALYs) of 1.16 (U.K. tariffs) and 1.52 (U.S. tariffs) in the CamAPS FX subgroup. Estimated ICERs for the subgroup were £19 324/QALY (United Kingdom) and -$3917/QALY (United States). For subgroup patients already using continuous glucose monitors (CGM), ICERs were £10 096/QALY (United Kingdom) and -$33 616/QALY (United States). Probabilistic sensitivity analysis generated mean ICERs of £19 342/QALY (95% CI: £15 903/QALY to £22 929/QALY) (United Kingdom) and -$28 283/QALY (95% CI: -$59 607/QALY to $1858/QALY) (United States). CONCLUSIONS: For children and adolescents with T1D on insulin pump therapy, AID using the Cambridge algorithm appears cost-effective below a £20 000/QALY threshold (United Kingdom) and cost saving (United States).

Diabetic Ketoacidosis at Onset of Type 1 Diabetes and Glycemic Outcomes with Closed-Loop Insulin Delivery.

The presence of diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes (T1D) is associated with higher glycated hemoglobin levels over time. We evaluated whether hybrid-closed loop (HCL) therapy from onset of T1D could prevent the adverse impact of DKA at diagnosis on long-term glycemic outcomes. This was a posthoc analysis from 51 adolescents using HCL from diagnosis of T1D as part of the CLOuD trial (NCT02871089). We compared glycemic and insulin metrics between adolescents with (n = 17) and without (n = 34) DKA at diagnosis. Participants with and without DKA at diagnosis had similar time in target glucose range 3.9-10.0 mmol/L (70-180 mg/dL), time below range (<3.9 mmol/L, <70 mg/dL) and HbA1c at 6, 12, and 24 months. While insulin requirements at 6 months were higher in those with DKA at diagnosis, this was not statistically significant after adjusting for bodyweight. Residual C-peptide secretion was similar between groups. We conclude that HCL therapy may mitigate against the negative glycemic effects of DKA at T1D diagnosis.

Postprandial Glucose Excursions with Ultra-Rapid Insulin Analogs in Hybrid Closed-Loop Therapy for Adults with Type 1 Diabetes.

Objective: To evaluate postprandial glucose control when applying (1) faster-acting insulin aspart (Fiasp) compared to insulin aspart and (2) ultra-rapid insulin lispro (Lyumjev) compared to insulin lispro using the CamAPS FX hybrid closed-loop algorithm. Research Design and Methods: We undertook a secondary analysis of postprandial glucose excursions from two double-blind, randomized, crossover hybrid closed-loop studies contrasting Fiasp to standard insulin aspart, and Lyumjev to standard insulin lispro. Endpoints included incremental area under curve (iAUC)-2h, iAUC-4h, 4 h postprandial time in target range, time above range, and time below range. It was approved by independent research ethics committees. Results: Two trials with 8 weeks of data from 51 adults with type 1 diabetes were analyzed and 7137 eligible meals were included. During Lyumjev compared with insulin lispro, iAUC-2h and iAUC-4h were significantly decreased following breakfast (mean difference 92 mmol/L per 2 h (95% confidence interval [CI]: 56 to 127); P < 0.001 and 151 mmol/L per 4 h (95% CI: 74 to 229); P < 0.001, respectively) and the evening meal (P < 0.001 and P = 0.011, respectively). Mean time in target range (3.9-10.0 mmol/L) for 4 h postprandially significantly increased during Lyumjev with a mean difference of 6.7 percentage points (95% CI: 3.3 to 10) and 5.7 percentage points (95% CI: 1.4 to 9.9) for breakfast and evening meal, respectively. In contrast, there were no significant differences in iAUC-2h, iAUC-4h, and the other measures of postprandial glucose control between insulin aspart and Fiasp during breakfast, lunch, and evening meal (P > 0.05). Conclusion: The use of Lyumjev with CamAPS FX closed-loop system improved postprandial glucose excursions compared with insulin lispro, while the use of Fiasp did not provide any advantage compared with insulin aspart. Clinical Trial Registration numbers: NCT04055480, NCT05257460.

CamAPS FX Hybrid Closed-Loop with Ultra-Rapid Lispro Compared with Standard Lispro in Adults with Type 1 Diabetes: A Double-Blind, Randomized, Crossover Study.

Introduction: To evaluate hybrid closed-loop with ultra-rapid insulin lispro (Lyumjev) compared with hybrid closed-loop with standard insulin lispro in adults with type 1 diabetes. Materials and Methods: In a single-center, double-blind, randomized, crossover study, 28 adults with type 1 diabetes (mean ± standard deviation [SD]: age 44.5 ± 10.7 years, glycated hemoglobin (HbA1c) 7.1 ± 0.9% [54 ± 10 mmol/mol]) underwent two 8-week periods comparing hybrid closed-loop with ultra-rapid insulin lispro and hybrid closed-loop with standard insulin lispro in random order. The same CamAPS FX closed-loop algorithm was used in both periods. Results: In an intention-to-treat analysis, the proportion of time sensor glucose was in target range (3.9-10 mmol/L [70-180 mg/dL]; primary endpoint) was greater with ultra-rapid lispro compared with standard insulin lispro (mean ± SD: 78.7 ± 9.8% vs. 76.2 ± 9.6%; mean difference 2.5 percentage points [95% confidence interval 0.8 to 4.2]; P = 0.005). Mean sensor glucose was lower with ultra-rapid lispro compared with standard insulin lispro (7.9 ± 0.8 mmol/L [142 ± 14 mg/dL] vs. 8.1 ± 0.9 mmol/L [146 ± 16 mg/dL]; P = 0.048). The proportion of time with sensor glucose <3.9 mmol/L [70 mg/dL] was similar between interventions (median [interquartile range] ultra-rapid lispro 2.3% [1.3%-2.7%] vs. standard insulin lispro 2.1% [1.4%-3.3%]; P = 0.33). No severe hypoglycemia or ketoacidosis occurred. Conclusions: The use of ultra-rapid lispro with CamAPS FX hybrid closed-loop increases time in range and reduces mean glucose with no difference in hypoglycemia compared with standard insulin lispro in adults with type 1 diabetes. ClinicalTrials.gov: Trial registration number NCT05257460.

Fully Closed-Loop Glucose Control Compared With Insulin Pump Therapy With Continuous Glucose Monitoring in Adults With Type 1 Diabetes and Suboptimal Glycemic Control: A Single-Center, Randomized, Crossover Study.

OBJECTIVE: We evaluated the safety and efficacy of fully closed-loop with ultrarapid insulin lispro in adults with type 1 diabetes and suboptimal glycemic control compared with insulin pump therapy with continuous glucose monitoring (CGM). RESEARCH DESIGN AND METHODS: This single-center, randomized, crossover study enrolled 26 adults with type 1 diabetes using insulin pump therapy with suboptimal glycemic control (mean ± SD, age 41 ± 12 years, HbA1c 9.2 ± 1.1% [77 ± 12 mmol/mol]). Participants underwent two 8-week periods of unrestricted living to compare fully closed-loop with ultrarapid insulin lispro (CamAPS HX system) with insulin pump therapy with CGM in random order. RESULTS: In an intention-to-treat analysis, the proportion of time glucose was in range (primary end point 3.9-10.0 mmol/L) was higher during closed-loop than during pump with CGM (mean ± SD 50.0 ± 9.6% vs. 36.2 ± 12.2%, mean difference 13.2 percentage points [95% CI 9.5, 16.9], P < 0.001). Time with glucose >10.0 mmol/L and mean glucose were lower during closed-loop than during pump with CGM (mean ± SD time >10.0 mmol/L: 49.0 ± 9.9 vs. 62.9 ± 12.6%, mean difference -13.3 percentage points [95% CI -17.2, -9.5], P < 0.001; mean ± SD glucose 10.7 ± 1.1 vs. 12.0 ± 1.6 mmol/L, mean difference -1.2 mmol/L [95% CI -1.8, -0.7], P < 0.001). The proportion of time with glucose <3.9 mmol/L was similar between periods (median [interquartile range (IQR)] closed-loop 0.88% [0.51-1.55] vs. pump with CGM 0.64% [0.28-1.10], P = 0.102). Total daily insulin requirements did not differ (median [IQR] closed-loop 51.9 units/day [35.7-91.2] vs. pump with CGM 50.7 units/day [34.0-70.0], P = 0.704). No severe hypoglycemia or ketoacidosis occurred. CONCLUSIONS: Fully closed-loop insulin delivery with CamAPS HX improved glucose control compared with insulin pump therapy with CGM in adults with type 1 diabetes and suboptimal glycemic control.

Time Spent in Hypoglycemia According to Age and Time of Day: Observations During Closed-Loop Insulin Delivery.

Objective: We aimed to assess whether percentage of time spent in hypoglycemia during closed-loop insulin delivery differs by age group and time of day. Methods: We retrospectively analyzed data from hybrid closed-loop studies involving young children (2-7 years), children and adolescents (8-18 years), adults (19-59 years), and older adults (≥60 years) with type 1 diabetes. Main outcome was time spent in hypoglycemia <3.9 mmol/L (<70 mg/dL). Eight weeks of data for 88 participants were analyzed. Results: Median time spent in hypoglycemia over the 24-h period was highest in children and adolescents (4.4% [interquartile range 2.4-5.0]) and very young children (4.0% [3.4-5.2]), followed by adults (2.7% [1.7-4.0]), and older adults (1.8% [1.2-2.2]); P < 0.001 for difference between age groups. Time spent in hypoglycemia during nighttime (midnight-05:59) was lower than during daytime (06:00-23:59) across all age groups. Conclusion: Time in hypoglycemia was highest in the pediatric age group during closed-loop insulin delivery. Hypoglycemia burden was lowest overnight across all age groups.

Hybrid Closed-Loop with Faster Insulin Aspart Compared with Standard Insulin Aspart in Very Young Children with Type 1 Diabetes: A Double-Blind, Multicenter, Randomized, Crossover Study.

We evaluated the use of hybrid closed-loop (HCL) insulin delivery with faster insulin aspart (Fiasp) in very young children with type 1 diabetes (T1D). In a double-blind, multicenter, randomized, crossover study, children aged 2-6 years with T1D underwent two 8-week periods of HCL using CamAPS FX with Fiasp and standard insulin aspart (IAsp), in random order. Primary endpoint was between-treatment difference in time in target range 3.9-10.0 mmol/L. We randomized 25 participants: mean (±standard deviation) age 5.1 ± 1.3 years, baseline HbA1c 55 ± 9 mmol/mol. Time in range was not significantly different between interventions (64% ± 9% vs. 65% ± 9% for HCL with Fiasp vs. IAsp; mean difference -0.33% [95% confidence interval: -2.13 to 1.47; P = 0.71]). There was no significant difference in time with glucose <3.9 mmol/L. No post-randomization severe hypoglycemia or diabetic ketoacidosis events occurred. Use of Fiasp with CamAPS FX HCL demonstrated no significant difference in glycemic outcomes compared with IAsp in very young children with T1D. Clinical trials registration: NCT04759144.

Implementation of fully closed-loop insulin delivery for inpatients with diabetes: Real-world outcomes.

AIMS: Fully closed-loop insulin delivery has been shown in clinical trials to be safe and improve glucose control compared with standard insulin therapy in the inpatient setting. We investigated the feasibility of implementing the approved CamAPS HX fully closed-loop system in a hospital setting. METHODS: This implementation project was conducted in a large teaching hospital in Cambridge, UK. Healthcare professional training was multimodal including face-to-face workshops, online learning modules and supported by standard operating procedures. Set-up and maintenance of closed-loop devices were undertaken by the inpatient diabetes team. Selection of suitable patients was multidisciplinary and prioritised those with more challenging diabetes management. Demographic and clinical data were collected from electronic health records and diabetes data management platforms. RESULTS: In the 12 months since the closed-loop system was implemented, 32 inpatients (mean ± SD age 61 ± 16 years, 8 females, 24 males) used closed-loop insulin delivery during their admission, across medical and surgical wards in the hospital with a total of 555 days of closed-loop glucose control (median [IQR]: 14 [6, 22] days per inpatient). The time spent in target glucose range 3.9-10.0 mmol/L was 53.3 ± 18.3%. Mean glucose was 10.7 ± 1.9 mmol/L with 46.0 ± 18.2% of time spent with glucose >10.0 mmol/L. Time spent with sensor glucose below 3.9 mmol/L was low (median [IQR]: 0.38 [0.00, 0.85]). There were no episodes of severe hypoglycaemia or diabetic ketoacidosis during closed-loop use. CONCLUSIONS: We have demonstrated that the fully closed-loop system can be safely and effectively implemented by a diabetes outreach team in complex medical and surgical inpatients with challenging glycaemic control.

Fully automated closed-loop insulin delivery in adults with type 2 diabetes: an open-label, single-center, randomized crossover trial.

In adults with type 2 diabetes, the benefits of fully closed-loop insulin delivery, which does not require meal bolusing, are unclear. In an open-label, single-center, randomized crossover study, 26 adults with type 2 diabetes (7 women and 19 men; (mean ± s.d.) age, 59 ± 11 years; baseline glycated hemoglobin (HbA1c), 75 ± 15 mmol mol-1 (9.0% ± 1.4%)) underwent two 8-week periods to compare the CamAPS HX fully closed-loop app with standard insulin therapy and a masked glucose sensor (control) in random order, with a 2-week to 4-week washout between periods. The primary endpoint was proportion of time in target glucose range (3.9-10.0 mmol l-1). Analysis was by intention to treat. Thirty participants were recruited between 16 December 2020 and 24 November 2021, of whom 28 were randomized to two groups (14 to closed-loop therapy first and 14 to control therapy first). Proportion of time in target glucose range (mean ± s.d.) was 66.3% ± 14.9% with closed-loop therapy versus 32.3% ± 24.7% with control therapy (mean difference, 35.3 percentage points; 95% confidence interval (CI), 28.0-42.6 percentage points; P < 0.001). Time > 10.0 mmol l-1 was 33.2% ± 14.8% with closed-loop therapy versus 67.0% ± 25.2% with control therapy (mean difference, -35.2 percentage points; 95% CI, -42.8 to -27.5 percentage points; P < 0.001). Mean glucose was lower during the closed-loop therapy period than during the control therapy period (9.2 ± 1.2 mmol l-1 versus 12.6 ± 3.0 mmol l-1, respectively; mean difference, -3.6 mmol l-1; 95% CI, -4.6 to -2.5 mmol l-1; P < 0.001). HbA1c was lower following closed-loop therapy (57 ± 9 mmol mol-1 (7.3% ± 0.8%)) than following control therapy (72 ± 13 mmol mol-1 (8.7% ± 1.2%); mean difference, -15 mmol mol-1; 95% CI, -11 to -20 mmol l-1 (mean difference, -1.4%; 95% CI, -1.0 to -1.8%); P < 0.001). Time < 3.9 mmol l-1 was similar between treatments (a median of 0.44% (interquartile range, 0.19-0.81%) during the closed-loop therapy period versus a median of 0.08% (interquartile range, 0.00-1.05%) during the control therapy period; P = 0.43). No severe hypoglycemia events occurred in either period. One treatment-related serious adverse event occurred during the closed-loop therapy period. Fully closed-loop insulin delivery improved glucose control without increasing hypoglycemia compared with standard insulin therapy and may represent a safe and efficacious method to improve outcomes in adults with type 2 diabetes. This study is registered with ClinicalTrials.gov (NCT04701424).

Consensus Recommendations for the Use of Automated Insulin Delivery Technologies in Clinical Practice.

The significant and growing global prevalence of diabetes continues to challenge people with diabetes (PwD), healthcare providers, and payers. While maintaining near-normal glucose levels has been shown to prevent or delay the progression of the long-term complications of diabetes, a significant proportion of PwD are not attaining their glycemic goals. During the past 6 years, we have seen tremendous advances in automated insulin delivery (AID) technologies. Numerous randomized controlled trials and real-world studies have shown that the use of AID systems is safe and effective in helping PwD achieve their long-term glycemic goals while reducing hypoglycemia risk. Thus, AID systems have recently become an integral part of diabetes management. However, recommendations for using AID systems in clinical settings have been lacking. Such guided recommendations are critical for AID success and acceptance. All clinicians working with PwD need to become familiar with the available systems in order to eliminate disparities in diabetes quality of care. This report provides much-needed guidance for clinicians who are interested in utilizing AIDs and presents a comprehensive listing of the evidence payers should consider when determining eligibility criteria for AID insurance coverage.

Safety of User-Initiated Intensification of Insulin Delivery Using Cambridge Hybrid Closed-Loop Algorithm.

OBJECTIVE: Many hybrid closed-loop (HCL) systems struggle to manage unusually high glucose levels as experienced with intercurrent illness or pre-menstrually. Manual correction boluses may be needed, increasing hypoglycemia risk with overcorrection. The Cambridge HCL system includes a user-initiated algorithm intensification mode ("Boost"), activation of which increases automated insulin delivery by approximately 35%, while remaining glucose-responsive. In this analysis, we assessed the safety of "Boost" mode. METHODS: We retrospectively analyzed data from closed-loop studies involving young children (1-7 years, n = 24), children and adolescents (10-17 years, n = 19), adults (≥24 years, n = 13), and older adults (≥60 years, n = 20) with type 1 diabetes. Outcomes were calculated per participant for days with ≥30 minutes of "Boost" use versus days with no "Boost" use. Participants with <10 "Boost" days were excluded. The main outcome was time spent in hypoglycemia <70 and <54 mg/dL. RESULTS: Eight weeks of data for 76 participants were analyzed. There was no difference in time spent <70 and <54 mg/dL between "Boost" days and "non-Boost" days; mean difference: -0.10% (95% confidence interval [CI] -0.28 to 0.07; P = .249) time <70 mg/dL, and 0.03 (-0.04 to 0.09; P = .416) time < 54 mg/dL. Time in significant hyperglycemia >300 mg/dL was 1.39 percentage points (1.01 to 1.77; P < .001) higher on "Boost" days, with higher mean glucose and lower time in target range (P < .001). CONCLUSIONS: Use of an algorithm intensification mode in HCL therapy is safe across all age groups with type 1 diabetes. The higher time in hyperglycemia observed on "Boost" days suggests that users are more likely to use algorithm intensification on days with extreme hyperglycemic excursions.

Evaluating the Impact of Applying Personal Glucose Targets in a Closed-Loop System for People With Type 1 Diabetes.

BACKGROUND: CamAPS FX is a hybrid closed-loop smartphone app used to manage type one diabetes. The closed-loop algorithm has a default target glucose of 5.8 mmol/L (104.5 mg/dL), but users can select personal glucose targets (adjustable between 4.4 mmol/L and 11.0 mmol/L [79 mg/dL and 198 mg/dL, respectively]). METHOD: In this post-hoc analysis, we evaluated the impact of personal glucose targets on glycemic control using data from participants in five randomized controlled trials. RESULTS: Personal glucose targets were widely used, with 20.3% of all days in the data set having a target outside the default target bin (5.5-6.0 mmol/L [99-108 mg/dL]). Personal glucose targets >6.5 mmol/L (117 mg/dL) were associated with significantly less time in target range (3.9-10.0 mmol/L [70-180 mg/dL]; 6.5-7.0 mmol/L [117-126 mg/dL]: mean difference = -3.2 percentage points [95% CI: -5.3 to -1.2; P < .001]; 7.0-7.5 mmol/L [126-135 mg/dL]: -10.8 percentage points [95% CI: -14.1 to -7.6; P < .001]). Personal targets >6.5 mmol/L (117 mg/dL) were associated with significantly lower time (<3.9 mmol/L [<70 mg/dL]; 6.5-7.0 mmol/L [117-126 mg/dL]: -1.85 percentage points [95% CI: -2.37 to -1.34; P < .001]; 7.0-7.5 mmol/L [126-135 mg/dL]: -2.68 percentage points [95% CI: -3.49 to -1.86; P < .001]). CONCLUSIONS: Discrete study populations showed differences in glucose control when applying similar personal targets.