Browsing by Author "Weinzimer, Stuart A."
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Item Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial.(Elsevier, 2022-04) Ware, Julia; Boughton, Charlotte K.; Allen, Janet M.; Wilinska, Malgorzata E.; Tauschmann, Martin; Denvir, Louise; Thankamony, Ajay; Campbell, Fiona M.; Wadwa, R. Paul; Buckingham, Bruce A.; Davis, Nikki; DiMeglio, Linda A.; Mauras, Nelly; Besser, Rachel E. J.; Ghatak, Atrayee; Weinzimer, Stuart A.; Hood, Korey K.; Fox, D. Steven; Kanapka, Lauren; Kollman, Craig; Sibayan, Judy; Beck, Roy W.; Hovorka, Roman; Pediatrics, School of MedicineBackground Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population. Methods In a multicentre, multinational, parallel randomised controlled trial, participants aged 6–18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0–10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299. Findings Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference −3·5 mmol/mol (95% CI −6·5 to −0·5 [–0·32 percentage points, −0·59 to −0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26–53]), but consistently high with CamAPS FX (93% [88–96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis. Interpretation The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.Item CGM-measured glucose values have a strong correlation with C-peptide, HbA1c and IDAAC, but do poorly in predicting C-peptide levels in the two years following onset of diabetes(Springer-Verlag, 2015-06) Buckingham, Bruce; Cheng, Peiyao; Beck, Roy W.; Kollman, Craig; Ruedy, Katrina J.; Weinzimer, Stuart A.; Slover, Robert; Bremer, Andrew A.; Fuqua, John; Tamborlane, William; Diabetes Research in Children Network (DirecNet) and Type 1 Diabetes TrialNet Study Groups; Department of Pediatrics, IU School of MedicineAIMS/HYPOTHESIS: The aim of this work was to assess the association between continuous glucose monitoring (CGM) data, HbA1c, insulin-dose-adjusted HbA1c (IDAA1c) and C-peptide responses during the first 2 years following diagnosis of type 1 diabetes. METHODS: A secondary analysis was conducted of data collected from a randomised trial assessing the effect of intensive management initiated within 1 week of diagnosis of type 1 diabetes, in which mixed-meal tolerance tests were performed at baseline and at eight additional time points through 24 months. CGM data were collected at each visit. RESULTS: Among 67 study participants (mean age [± SD] 13.3 ± 5.7 years), HbA1c was inversely correlated with C-peptide at each time point (p < 0.001), as were changes in each measure between time points (p < 0.001). However, C-peptide at one visit did not predict the change in HbA1c at the next visit and vice versa. Higher C-peptide levels correlated with increased proportion of CGM glucose values between 3.9 and 7.8 mmol/l and lower CV (p = 0.001 and p = 0.02, respectively) but not with CGM glucose levels <3.9 mmol/l. Virtually all participants with IDAA1c < 9 retained substantial insulin secretion but when evaluated together with CGM, time in the range of 3.9-7.8 mmol/l and CV did not provide additional value in predicting C-peptide levels. CONCLUSIONS/INTERPRETATION: In the first 2 years after diagnosis of type 1 diabetes, higher C-peptide levels are associated with increased sensor glucose levels in the target range and with lower glucose variability but not hypoglycaemia. CGM metrics do not provide added value over the IDAA1c in predicting C-peptide levels.Item Effects of Frequency of Sensor-Augmented Pump Use on HbA1c and C-Peptide Levels in the First Year of Type 1 Diabetes(American Diabetes Association, 2016-04) Triolo, Taylor M.; Maahs, David M.; Pyle, Laura; Slover, Robert; Buckingham, Bruce; Cheng, Peiyao; DiMeglio, Linda A.; Bremer, Andrew A.; Weinzimer, Stuart A.; Chase, H. Peter; Pediatrics, School of MedicineItem Lived experience of CamAPS FX closed loop system in youth with type 1 diabetes and their parents(Wiley, 2022) Hood, Korey K.; Garcia-Willingham, Natasha; Hanes, Sarah; Tanenbaum, Molly L.; Ware, Julia; Boughton, Charlotte K.; Allen, Janet M.; Wilinska, Malgorzata E.; Tauschmann, Martin; Denvir, Louise; Thankamony, Ajay; Campbell, Fiona; Wadwa, R. Paul; Buckingham, Bruce A.; Davis, Nikki; DiMeglio, Linda A.; Mauras, Nelly; Besser, Rachel E. J.; Ghatak, Atrayee; Weinzimer, Stuart A.; Fox, D. Steven; Kanapka, Lauren; Kollman, Craig; Sibayan, Judy; Beck, Roy W.; Hovorka, Roman; DAN05 ConsortiumAim: To examine changes in the lived experience of type 1 diabetes after use of hybrid closed loop (CL), including the CamAPS FX CL system. Materials and methods: The primary study was conducted as an open-label, single-period, randomized, parallel design contrasting CL versus insulin pump (with or without continuous glucose monitoring). Participants were asked to complete patient-reported outcomes before starting CL and 3 and 6 months later. Surveys assessed diabetes distress, hypoglycaemia concerns and quality of life. Qualitative focus group data were collected at the completion of the study. Results: In this sample of 98 youth (age range 6-18, mean age 12.7 ± 2.8 years) and their parents, CL use was not associated with psychosocial benefits overall. However, the subgroup (n = 12) using the CamAPS FX system showed modest improvements in quality of life and parent distress, reinforced by both survey (p < .05) and focus group responses. There were no negative effects of CL use reported by study participants. Conclusions: Closed loop use via the CamAPS FX system was associated with modest improvements in aspects of the lived experience of managing type 1 diabetes in youth and their families. Further refinements of the system may optimize the user experience.