Browsing by Author "Skyler, Jay S."

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    Consensus guidance for monitoring individuals with islet autoantibody-positive pre-stage 3 type 1 diabetes
    (Springer, 2024-09) Phillip, Moshe; Achenbach, Peter; Addala, Ananta; Albanese-O'Neill, Anastasia; Battelino, Tadej; Bell, Kirstine J.; Besser, Rachel E. J.; Bonifacio, Ezio; Colhoun, Helen M.; Couper, Jennifer J.; Craig, Maria E.; Danne, Thomas; de Beaufort, Carine; Dovc, Klemen; Driscoll, Kimberly A.; Dutta, Sanjoy; Ebekozien, Osagie; Elding Larsson, Helena; Feiten, Daniel J.; Frohnert, Brigitte I.; Gabbay, Robert A.; Gallagher, Mary P.; Greenbaum, Carla J.; Griffin, Kurt J.; Hagopian, William; Haller, Michael J.; Hendrieckx, Christel; Hendriks, Emile; Holt, Richard I. G.; Hughes, Lucille; Ismail, Heba M.; Jacobsen, Laura M.; Johnson, Suzanne B.; Kolb, Leslie E.; Kordonouri, Olga; Lange, Karin; Lash, Robert W.; Lernmark, Åke; Libman, Ingrid; Lundgren, Markus; Maahs, David M.; Marcovecchio, M. Loredana; Mathieu, Chantal; Miller, Kellee M.; O'Donnell, Holly K.; Oron, Tal; Patil, Shivajirao P.; Pop-Busui, Rodica; Rewers, Marian J.; Rich, Stephen S.; Schatz, Desmond A.; Schulman-Rosenbaum, Rifka; Simmons, Kimber M.; Sims, Emily K.; Skyler, Jay S.; Smith, Laura B.; Speake, Cate; Steck, Andrea K.; Thomas, Nicholas P. B.; Tonyushkina, Ksenia N.; Veijola, Riitta; Wentworth, John M.; Wherrett, Diane K.; Wood, Jamie R.; Ziegler, Anette-Gabriele; DiMeglio, Linda A.; Pediatrics, School of Medicine
    Given the proven benefits of screening to reduce diabetic ketoacidosis (DKA) likelihood at the time of stage 3 type 1 diabetes diagnosis, and emerging availability of therapy to delay disease progression, type 1 diabetes screening programmes are being increasingly emphasised. Once broadly implemented, screening initiatives will identify significant numbers of islet autoantibody-positive (IAb+) children and adults who are at risk of (confirmed single IAb+) or living with (multiple IAb+) early-stage (stage 1 and stage 2) type 1 diabetes. These individuals will need monitoring for disease progression; much of this care will happen in non-specialised settings. To inform this monitoring, JDRF in conjunction with international experts and societies developed consensus guidance. Broad advice from this guidance includes the following: (1) partnerships should be fostered between endocrinologists and primary-care providers to care for people who are IAb+; (2) when people who are IAb+ are initially identified there is a need for confirmation using a second sample; (3) single IAb+ individuals are at lower risk of progression than multiple IAb+ individuals; (4) individuals with early-stage type 1 diabetes should have periodic medical monitoring, including regular assessments of glucose levels, regular education about symptoms of diabetes and DKA, and psychosocial support; (5) interested people with stage 2 type 1 diabetes should be offered trial participation or approved therapies; and (6) all health professionals involved in monitoring and care of individuals with type 1 diabetes have a responsibility to provide education. The guidance also emphasises significant unmet needs for further research on early-stage type 1 diabetes to increase the rigour of future recommendations and inform clinical care.
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    Correction to: Consensus guidance for monitoring individuals with islet autoantibody‑positive pre‑stage 3 type 1 diabetes
    (Springer, 2024) Phillip, Moshe; Achenbach, Peter; Addala, Ananta; Albanese-O'Neill, Anastasia; Battelino, Tadej; Bell, Kirstine J.; Besser, Rachel E. J.; Bonifacio, Ezio; Colhoun, Helen M.; Couper, Jennifer J.; Craig, Maria E.; Danne, Thomas; de Beaufort, Carine; Dovc, Klemen; Driscoll, Kimberly A.; Dutta, Sanjoy; Ebekozien, Osagie; Elding Larsson, Helena; Feiten, Daniel J.; Frohnert, Brigitte I.; Gabbay, Robert A.; Gallagher, Mary P.; Greenbaum, Carla J.; Griffin, Kurt J.; Hagopian, William; Haller, Michael J.; Hendrieckx, Christel; Hendriks, Emile; Holt, Richard I. G.; Hughes, Lucille; Ismail, Heba M.; Jacobsen, Laura M.; Johnson, Suzanne B.; Kolb, Leslie E.; Kordonouri, Olga; Lange, Karin; Lash, Robert W.; Lernmark, Åke; Libman, Ingrid; Lundgren, Markus; Maahs, David M.; Marcovecchio, M. Loredana; Mathieu, Chantal; Miller, Kellee M.; O'Donnell, Holly K.; Oron, Tal; Patil, Shivajirao P.; Pop-Busui, Rodica; Rewers, Marian J.; Rich, Stephen S.; Schatz, Desmond A.; Schulman-Rosenbaum, Rifka; Simmons, Kimber M.; Sims, Emily K.; Skyler, Jay S.; Smith, Laura B.; Speake, Cate; Steck, Andrea K.; Thomas, Nicholas P. B.; Tonyushkina, Ksenia N.; Veijola, Riitta; Wentworth, John M.; Wherrett, Diane K.; Wood, Jamie R.; Ziegler, Anette-Gabriele; DiMeglio, Linda A.; Pediatrics, School of Medicine
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    Dysglycemia and Index60 as Prediagnostic End Points for Type 1 Diabetes Prevention Trials
    (American Diabetes Association, 2017-11) Nathan, Brandon M.; Boulware, David; Geyer, Susan; Atkinson, Mark A.; Colman, Peter; Goland, Robin; Russell, William; Wentworth, John M.; Wilson, Darrell M.; Evans-Molina, Carmella; Wherrett, Diane; Skyler, Jay S.; Moran, Antoinette; Sosenko, Jay M.; Type 1 Diabetes TrialNet and Diabetes Prevention Trial–Type 1 Study Groups; Medicine, School of Medicine
    OBJECTIVE: We assessed dysglycemia and a T1D Diagnostic Index60 (Index60) ≥1.00 (on the basis of fasting C-peptide, 60-min glucose, and 60-min C-peptide levels) as prediagnostic end points for type 1 diabetes among Type 1 Diabetes TrialNet Pathway to Prevention Study participants. RESEARCH DESIGN AND METHODS: Two cohorts were analyzed: 1) baseline normoglycemic oral glucose tolerance tests (OGTTs) with an incident dysglycemic OGTT and 2) baseline Index60 <1.00 OGTTs with an incident Index60 ≥1.00 OGTT. Incident dysglycemic OGTTs were divided into those with (DYS/IND+) and without (DYS/IND-) concomitant Index60 ≥1.00. Incident Index60 ≥1.00 OGTTs were divided into those with (IND/DYS+) and without (IND/DYS-) concomitant dysglycemia. RESULTS: The cumulative incidence for type 1 diabetes was greater after IND/DYS- than after DYS/IND- (P < 0.01). Within the normoglycemic cohort, the cumulative incidence of type 1 diabetes was higher after DYS/IND+ than after DYS/IND- (P < 0.001), whereas within the Index60 <1.00 cohort, the cumulative incidence after IND/DYS+ and after IND/DYS- did not differ significantly. Among nonprogressors, type 1 diabetes risk at the last OGTT was greater for IND/DYS- than for DYS/IND- (P < 0.001). Hazard ratios (HRs) of DYS/IND- with age and 30- to 0-min C-peptide were positive (P < 0.001 for both), whereas HRs of type 1 diabetes with these variables were inverse (P < 0.001 for both). In contrast, HRs of IND/DYS- and type 1 diabetes with age and 30- to 0-min C-peptide were consistent (all inverse [P < 0.01 for all]). CONCLUSIONS: The findings suggest that incident dysglycemia without Index60 ≥1.00 is a suboptimal prediagnostic end point for type 1 diabetes. Measures that include both glucose and C-peptide levels, such as Index60 ≥1.00, appear better suited as prediagnostic end points.
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    Failure to Preserve β-Cell Function With Mycophenolate Mofetil and Daclizumab Combined Therapy in Patients With New- Onset Type 1 Diabetes
    (American Diabetes Association, 2010-04) Gottlieb, Peter A.; Quinlan, Scott; Krause-Steinrauf, Heidi; Greenbaum, Carla J.; Wilson, Darrell M.; Rodriguez, Henry; Schatz, Desmond A.; Moran, Antoinette M.; Lachin, John M.; Skyler, Jay S.; Type 1 Diabetes TrialNet MMF/DZB Study Group; Pediatrics, School of Medicine
    OBJECTIVE This trial tested whether mycophenolate mofetil (MMF) alone or with daclizumab (DZB) could arrest the loss of insulin-producing β-cells in subjects with new-onset type 1 diabetes. RESEARCH DESIGN AND METHODS A multi-center, randomized, placebo-controlled, double-masked trial was initiated by Type 1 Diabetes TrialNet at 13 sites in North America and Europe. Subjects diagnosed with type 1 diabetes and with sufficient C-peptide within 3 months of diagnosis were randomized to either MMF alone, MMF plus DZB, or placebo, and then followed for 2 years. The primary outcome was the geometric mean area under the curve (AUC) C-peptide from the 2-h mixed meal tolerance test. RESULTS One hundred and twenty-six subjects were randomized and treated during the trial. The geometric mean C-peptide AUC at 2 years was unaffected by MMF alone or MMF plus DZB versus placebo. Adverse events were more frequent in the active therapy groups relative to the control group, but not significantly. CONCLUSIONS Neither MMF alone nor MMF in combination with DZB had an effect on the loss of C-peptide in subjects with new-onset type 1 diabetes. Higher doses or more targeted immunotherapies may be needed to affect the autoimmune process.
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    The influence of body mass index and age on C-peptide at the diagnosis of type 1 diabetes in children who participated in the diabetes prevention trial-type 1
    (Wiley, 2018-05) Sosenko, Jay M.; Geyer, Susan; Skyler, Jay S.; Rafkin, Lisa E.; Ismail, Heba M.; Libman, Ingrid M.; Liu, Yuk-Fun; DiMeglio, Linda A.; Evans-Molina, Carmella; Palmer, Jerry P.; Medicine, School of Medicine
    BACKGROUND/OBJECTIVE: The extent of influence of BMI and age on C-peptide at the diagnosis of type 1 diabetes (T1D) is unknown. We thus studied the impact of body mass index Z-scores (BMIZ) and age on C-peptide measures at and soon after the diagnosis of T1D. METHODS: Data from Diabetes Prevention Trial-Type 1 (DPT-1) participants <18.0 years at diagnosis was analyzed. Analyses examined associations of C-peptide measures with BMIZ and age in 2 cohorts: oral glucose tolerance tests (OGTTs) at diagnosis (n = 99) and mixed meal tolerance tests (MMTTs) <6 months after diagnosis (n = 80). Multivariable linear regression was utilized. RESULTS: Fasting and area under the curve (AUC) C-peptide from OGTTs (n = 99) at diagnosis and MMTTs (n = 80) after diagnosis were positively associated with BMIZ and age (P < .001 for all). Associations persisted when BMIZ and age were included as independent variables in regression models (P < .001 for all). BMIZ and age explained 31%-47% of the variance of C-peptide measures. In an example, 2 individuals with identical AUC C-peptide values had an approximate 5-fold difference in values after adjustments for BMIZ and age. The association between fasting glucose and C-peptide decreased markedly when fasting C-peptide values were adjusted (r = 0.30, P < .01 to r = 0.07, n.s.). CONCLUSIONS: C-peptide measures are strongly and independently related to BMIZ and age at and soon after the diagnosis of T1D. Adjustments for BMIZ and age cause substantial changes in C-peptide values, and impact the association between glycemia and C-peptide. Such adjustments can improve assessments of β-cell impairment at diagnosis.
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    Interleukin-1 antagonism in type 1 diabetes of recent onset: two multicentre, randomised, double-blind, placebo-controlled trials
    (Elsevier, 2013) Moran, Antoinette; Bundy, Brian; Becker, Dorothy J.; DiMeglio, Linda A.; Gitelman, Stephen E.; Goland, Robin; Greenbaum, Carla J.; Herold, Kevan C.; Marks, Jennifer B.; Raskin, Philip; Sanda, Srinath; Schatz, Desmond; Wherrett, Diane K.; Wilson, Darrell M.; Krischer, Jeffrey P.; Skyler, Jay S.; Pickersgill, Linda; de Koning, Eelco; Ziegler, Anette-G; Böehm, Bernhard; Badenhoop, Klaus; Schloot, Nanette; Bak, Jens Friis; Pozzilli, Paolo; Mauricio, Didac; Donath, Marc Y.; Castaño, Luis; Wägner, Ana; Lervang, Hans Henrik; Perrild, Hans; Poulsen, Thomas Mandrup; Pediatrics, School of Medicine
    Background: Innate immunity contributes to the pathogenesis of autoimmune diseases, such as type 1 diabetes, but until now no randomised, controlled trials of blockade of the key innate immune mediator interleukin-1 have been done. We aimed to assess whether canakinumab, a human monoclonal anti-interleukin-1 antibody, or anakinra, a human interleukin-1 receptor antagonist, improved β-cell function in recent-onset type 1 diabetes. Methods: We did two randomised, placebo-controlled trials in two groups of patients with recent-onset type 1 diabetes and mixed-meal-tolerance-test-stimulated C peptide of at least 0·2 nM. Patients in the canakinumab trial were aged 6-45 years and those in the anakinra trial were aged 18-35 years. Patients in the canakinumab trial were enrolled at 12 sites in the USA and Canada and those in the anakinra trial were enrolled at 14 sites across Europe. Participants were randomly assigned by computer-generated blocked randomisation to subcutaneous injection of either 2 mg/kg (maximum 300 mg) canakinumab or placebo monthly for 12 months or 100 mg anakinra or placebo daily for 9 months. Participants and carers were masked to treatment assignment. The primary endpoint was baseline-adjusted 2-h area under curve C-peptide response to the mixed meal tolerance test at 12 months (canakinumab trial) and 9 months (anakinra trial). Analyses were by intention to treat. These studies are registered with ClinicalTrials.gov, numbers NCT00947427 and NCT00711503, and EudraCT number 2007-007146-34. Findings: Patients were enrolled in the canakinumab trial between Nov 12, 2010, and April 11, 2011, and in the anakinra trial between Jan 26, 2009, and May 25, 2011. 69 patients were randomly assigned to canakinumab (n=47) or placebo (n=22) monthly for 12 months and 69 were randomly assigned to anakinra (n=35) or placebo (n=34) daily for 9 months. No interim analyses were done. 45 canakinumab-treated and 21 placebo-treated patients in the canakinumab trial and 25 anakinra-treated and 26 placebo-treated patients in the anakinra trial were included in the primary analyses. The difference in C peptide area under curve between the canakinumab and placebo groups at 12 months was 0·01 nmol/L (95% CI -0·11 to 0·14; p=0·86), and between the anakinra and the placebo groups at 9 months was 0·02 nmol/L (-0·09 to 0·15; p=0·71). The number and severity of adverse events did not differ between groups in the canakinumab trial. In the anakinra trial, patients in the anakinra group had significantly higher grades of adverse events than the placebo group (p=0·018), which was mainly because of a higher number of injection site reactions in the anakinra group. Interpretation: Canakinumab and anakinra were safe but were not effective as single immunomodulatory drugs in recent-onset type 1 diabetes. Interleukin-1 blockade might be more effective in combination with treatments that target adaptive immunity in organ-specific autoimmune disorders.
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    Persistence of b-Cell Responsiveness for Over Two Years in Autoantibody-Positive Children With Marked Metabolic Impairment at Screening
    (American Diabetes Association, 2022-12-01) Sims, Emily K.; Cuthbertson, David; Felton, Jamie L.; Ismail, Heba M.; Nathan, Brandon M.; Jacobsen, Laura M.; Paprocki, Emily; Pugliese, Alberto; Palmer, Jerry; Atkinson, Mark; Evans-Molina, Carmella; Skyler, Jay S.; Redondo, Maria J.; Herold, Kevan C.; Sosenko, Jay M.; Pediatrics, School of Medicine
    OBJECTIVE We studied longitudinal differences between progressors and nonprogressors to type 1 diabetes with similar and substantial baseline risk. RESEARCH DESIGN AND METHODS Changes in 2-h oral glucose tolerance test indices were used to examine variability in diabetes progression in the Diabetes Prevention Trial–Type 1 (DPT-1) study (n = 246) and Type 1 Diabetes TrialNet Pathway to Prevention study (TNPTP) (n = 503) among autoantibody (Ab)+ children (aged <18.0 years) with similar baseline metabolic impairment (DPT-1 Risk Score [DPTRS] of 6.5–7.5), as well as in TNPTP Ab− children (n = 94). RESULTS Longitudinal analyses revealed annualized area under the curve (AUC) of C-peptide increases in nonprogressors versus decreases in progressors (P ≤ 0.026 for DPT-1 and TNPTP). Vector indices for AUC glucose and AUC C-peptide changes (on a two-dimensional grid) also differed significantly (P < 0.001). Despite marked baseline metabolic impairment of nonprogressors, changes in AUC C-peptide, AUC glucose, AUC C-peptide–to–AUC glucose ratio (AUC ratio), and Index60 did not differ from Ab− relatives during follow-up. Divergence between nonprogressors and progressors occurred by 6 months from baseline in both cohorts (AUC glucose, P ≤ 0.007; AUC ratio, P ≤ 0.034; Index60, P < 0.001; vector indices of change, P < 0.001). Differences in 6-month change were positively associated with greater diabetes risk (respectively, P < 0.001, P ≤ 0.019, P < 0.001, and P < 0.001) in DPT-1 and TNPTP, except AUC ratio, which was inversely associated with risk (P < 0.001). CONCLUSIONS Novel findings show that even with similarly abnormal baseline risk, progressors had appreciably more metabolic impairment than nonprogressors within 6 months and that the measures showing impairment were predictive of type 1 diabetes. Longitudinal metabolic patterns did not differ between nonprogressors and Ab− relatives, suggesting persistent β-cell responsiveness in nonprogressors.
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    Rituximab, B-lymphocyte depletion, and preservation of beta-cell function
    (Massachusetts Medical Society, 2009-11-26) Pescovitz, Mark D.; Greenbaum, Carla J.; Krause-Steinrauf, Heidi; Becker, Dorothy J.; Gitelman, Stephen E.; Goland, Robin; Gottlieb, Peter A.; Marks, Jennifer B.; McGee, Paula F.; Moran, Antoinette M.; Raskin, Philip; Rodriguez, Henry; Schatz, Desmond A.; Wherrett, Diane; Wilson, Darrell M.; Lachin, John M.; Skyler, Jay S.; Type 1 Diabetes TrialNet Anti-CD20 Study Group; Medicine, School of Medicine
    BACKGROUND: The immunopathogenesis of type 1 diabetes mellitus is associated with T-lymphocyte autoimmunity. However, there is growing evidence that B lymphocytes play a role in many T-lymphocyte-mediated diseases. It is possible to achieve selective depletion of B lymphocytes with rituximab, an anti-CD20 monoclonal antibody. This phase 2 study evaluated the role of B-lymphocyte depletion in patients with type 1 diabetes. METHODS: We conducted a randomized, double-blind study in which 87 patients between 8 and 40 years of age who had newly diagnosed type 1 diabetes were assigned to receive infusions of rituximab or placebo on days 1, 8, 15, and 22 of the study. The primary outcome, assessed 1 year after the first infusion, was the geometric mean area under the curve (AUC) for the serum C-peptide level during the first 2 hours of a mixed-meal tolerance test. Secondary outcomes included safety and changes in the glycated hemoglobin level and insulin dose. RESULTS: At 1 year, the mean AUC for the level of C peptide was significantly higher in the rituximab group than in the placebo group. The rituximab group also had significantly lower levels of glycated hemoglobin and required less insulin. Between 3 months and 12 months, the rate of decline in C-peptide levels in the rituximab group was significantly less than that in the placebo group. CD19+ B lymphocytes were depleted in patients in the rituximab group, but levels increased to 69% of baseline values at 12 months. More patients in the rituximab group than in the placebo group had adverse events, mostly grade 1 or grade 2, after the first infusion. The reactions appeared to be minimal with subsequent infusions. There was no increase in infections or neutropenia with rituximab. CONCLUSIONS: A four-dose course of rituximab partially preserved beta-cell function over a period of 1 year in patients with type 1 diabetes. The finding that B lymphocytes contribute to the pathogenesis of type 1 diabetes may open a new pathway for exploration in the treatment of patients with this condition.
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    The effect of age on longitudinal measures of beta cell function and insulin sensitivity during the progression of early stage type 1 diabetes
    (Springer, 2023) Ferrannini, Ele; Mari, Andrea; Monaco, Gabriela S. F.; Skyler, Jay S.; Evans-Molina, Carmella; Pediatrics, School of Medicine
    Aim/hypothesis: The risk of progressing from autoantibody positivity to type 1 diabetes is inversely related to age. Separately, whether age influences patterns of C-peptide loss or changes in insulin sensitivity in autoantibody-positive individuals who progress to stage 3 type 1 diabetes is unclear. Methods: Beta cell function and insulin sensitivity were determined by modelling of OGTTs performed in 658 autoantibody-positive participants followed longitudinally in the Diabetes Prevention Trial-Type 1 (DPT-1). In this secondary analysis of DPT-1 data, time trajectories of beta cell function and insulin sensitivity were analysed in participants who progressed to type 1 diabetes (progressors) to address the impact of age on patterns of metabolic progression to diabetes. Results: Among the entire DPT-1 cohort, the highest discriminant age for type 1 diabetes risk was 14 years, with participants aged <14 years being twice as likely to progress to type 1 diabetes as those aged ≥14 years. At study entry, beta cell glucose sensitivity was impaired to a similar extent in progressors aged <14 years and progressors aged ≥14 years. From study entry to stage 3 type 1 diabetes onset, beta cell glucose sensitivity and insulin sensitivity declined in both progressor groups. However, there were no significant differences in the yearly rate of decline in either glucose sensitivity (-13.7 [21.2] vs -11.9 [21.5] pmol min-1 m-2 [mmol/l]-1, median [IQR], p=0.52) or insulin sensitivity (-22 [37] vs -14 [40] ml min-1 m-2, median [IQR], p=0.07) between progressors aged <14 years and progressors aged ≥14 years. Conclusions/interpretation: Our data indicate that during progression to stage 3 type 1 diabetes, rates of change in declining glucose and insulin sensitivity are not significantly different between progressors aged <14 years and progressors aged ≥14 years. These data suggest there is a predictable course of declining metabolic function during the progression to type 1 diabetes that is not influenced by age.
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    The Transition From a Compensatory Increase to a Decrease in C-peptide During the Progression to Type 1 Diabetes and Its Relation to Risk
    (American Diabetes Association, 2022-10) Ismail, Heba M.; Cuthbertson, David; Gitelman, Stephen E.; Skyler, Jay S.; Steck, Andrea K.; Rodriguez, Henry; Atkinson, Mark; Nathan, Brandon M.; Redondo, Maria J.; Herold, Kevan C.; Evans-Molina, Carmella; DiMeglio, Linda A.; Sosenko, Jay; DPT-1 and TrialNet Study Groups; Pediatrics, School of Medicine
    OBJECTIVE To define the relationship between glucose and C-peptide during the progression to type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS We longitudinally studied glucose and C-peptide response curves (GCRCs), area under curve (AUC) for glucose, and AUC C-peptide from oral glucose tolerance tests (OGTTs), and Index60 (which integrates OGTT glucose and C-peptide values) in Diabetes Prevention Trial–Type 1 (DPT-1) (n = 72) and TrialNet Pathway to Prevention Study (TNPTP) (n = 82) participants who had OGTTs at baseline and follow-up time points before diagnosis. RESULTS Similar evolutions of GCRC configurations were evident between DPT-1 and TNPTP from baseline to 0.5 years prediagnosis. Whereas AUC glucose increased throughout from baseline to 0.5 years prediagnosis, AUC C-peptide increased from baseline until 1.5 years prediagnosis (DPT-1, P = 0.004; TNPTP, P = 0.012) and then decreased from 1.5 to 0.5 years prediagnosis (DPT-1, P = 0.017; TNPTP, P = 0.093). This change was mostly attributable to change in the late AUC C-peptide response (i.e., 60- to 120-min AUC C-peptide). Median Index60 values of DPT-1 (1.44) and TNPTP (1.05) progressors to T1D 1.5 years prediagnosis (time of transition from increasing to decreasing AUC C-peptide) were used as thresholds to identify individuals at high risk for T1D in the full cohort at baseline (5-year risk of 0.75–0.88 for those above thresholds). CONCLUSIONS A transition from an increase to a decrease in AUC C-peptide ∼1.5 years prediagnosis was validated in two independent cohorts. The median Index60 value at that time point can be used as a pathophysiologic-based threshold for identifying individuals at high risk for T1D.