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Browsing by Author "Becker, Dorothy J."
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Item Associations of HbA1c with the Timing of C‐peptide Responses during the Oral Glucose Tolerance Test at the Diagnosis of Type 1 Diabetes(Wiley, 2019) Ismail, Heba M.; Evans-Molina, Carmella; DiMeglio, Linda A.; Becker, Dorothy J.; Libman, Ingrid; Sims, Emily K.; Boulware, David; Herold, Kevan C.; Rafkin, Lisa; Skyler, Jay; Cleves, Mario A.; Palmer, Jerry; Sosenko, Jay; Pediatrics, School of MedicineBackground In new onset type 1 diabetes (T1D), overall C‐peptide measures such as area under the curve (AUC) C‐peptide and peak C‐peptide are useful for estimating the extent of β‐cell dysfunction, and for assessing responses to intervention therapy. However, measures of the timing of C‐peptide responsiveness could have additional value. Objectives We assessed the contribution of the timing of C‐peptide responsiveness during oral glucose tolerance tests (OGTTs) to HbA1c variation at T1D diagnosis. Methods We analyzed data from 85 individuals <18 years with OGTTs and HbA1c measurements at diagnosis. Overall [AUC and peak C‐peptide] and timing measures [30‐0 minute C‐peptide (early); 60 to 120 minute C‐peptide sum‐30 minutes (late); 120/30 C‐peptide; time to peak C‐peptide] were utilized. Results At diagnosis, the mean (±SD) age was 11.2±3.3 years, BMI‐z was 0.4±1.1, 51.0% were male and the HbA1c was 43.54±8.46 mmol/mol (6.1±0.8%). HbA1c correlated inversely with the AUC C‐peptide (p<0.001), peak C‐peptide (p<0.001), early and late C‐peptide responses (p<0.001 each), and 120/30 C‐peptide (p<0.001). Those with a peak C‐peptide occurring at ≤60 minutes had higher HbA1c values than those with peaks later (p=0.003). HbA1c variance was better explained with timing measures added to regression models (R2=11.6% with AUC C‐peptide alone; R2=20.0% with 120/30 C‐peptide added; R2=13.7% with peak C‐peptide alone, R2=20.4% with timing of the peak added). Similar associations were seen between the 2‐hr glucose and the C‐peptide measures. Conclusions These findings show that the addition of timing measures of C‐peptide responsiveness better explains HbA1c variation at diagnosis than standard measures alone.Item Early and late C-peptide responses during oral glucose tolerance testing are oppositely predictive of type 1 diabetes in autoantibody-positive individuals(Wiley, 2020-01-31) Ismail, Heba M.; Becker, Dorothy J.; Libman, Ingrid; Herold, Kevan C.; Redondo, Maria J.; Atkinson, Mark A.; Cleves, Mario A.; Palmer, Jerry; Sosenko, Jay; Pediatrics, School of MedicineWe examined whether the timing of the C-peptide response during an oral glucose tolerance test (OGTT) in relatives of patients with type 1 diabetes (T1D) is predictive of disease onset. We examined baseline 2-h OGTTs from 670 relatives participating in the Diabetes Prevention Trial-Type 1 (age: 13.8 ± 9.6 years; body mass index z score: 0.3 ± 1.1; 56% male) using univariate regression models. T1D risk increased with lower early C-peptide responses (30–0 min) (χ2 = 28.8, P < 0.001), and higher late C-peptide responses (120–60 min) (χ2 = 23.3, P < 0.001). When both responses were included in a proportional hazards model, they remained independently and oppositely associated with T1D, with a stronger overall association for the combined model than either response alone (χ2 = 41.1; P < 0.001). Using receiver operating characteristic curve analysis, the combined early and late C-peptide response was more accurately predictive of T1D than area under the curve C-peptide (P = 0.005). Our findings demonstrate that lower early and higher late C-peptide responses serve as indicators of increased T1D risk.Item Excess BMI Accelerates Islet Autoimmunity in Older Children and Adolescents(American Diabetes Association, 2020-03) Ferrara-Cook, Christine; Geyer, Susan Michelle; Evans-Molina, Carmella; Libman, Ingrid M.; Becker, Dorothy J.; Gitelman, Stephen E.; Jose Redondo, Maria; Medicine, School of MedicineObjective: Sustained excess BMI increases the risk of type 1 diabetes (T1D) in autoantibody-positive relatives without diabetes of patients. We tested whether elevated BMI also accelerates the progression of islet autoimmunity before T1D diagnosis. Research design and methods: We studied 706 single autoantibody-positive pediatric TrialNet participants (ages 1.6-18.6 years at baseline). Cumulative excess BMI (ceBMI) was calculated for each participant based on longitudinally accumulated BMI ≥85th age- and sex-adjusted percentile. Recursive partitioning analysis and multivariable modeling defined the age cut point differentiating the risk for progression to multiple positive autoantibodies. Results: At baseline, 175 children (25%) had a BMI ≥85th percentile. ceBMI range was -9.2 to 15.6 kg/m2 (median -1.91), with ceBMI ≥0 kg/m2 corresponding to persistently elevated BMI ≥85th percentile. Younger age increased the progression to multiple autoantibodies, with age cutoff of 9 years defined by recursive partitioning analysis. Although ceBMI was not significantly associated with progression from single to multiple autoantibodies overall, there was an interaction with ceBMI ≥0 kg/m2, age, and HLA (P = 0.009). Among children ≥9 years old without HLA DR3-DQ2 and DR4-DQ8, ceBMI ≥0 kg/m2 increased the rate of progression from single to multiple positive autoantibodies (hazard ratio 7.32, P = 0.004) and conferred a risk similar to that in those with T1D-associated HLA haplotypes. In participants <9 years old, the effect of ceBMI on progression to multiple autoantibodies was not significant regardless of HLA type. Conclusions: These data support that elevated BMI may exacerbate islet autoimmunity prior to clinical T1D, particularly in children with lower risk based on age and HLA. Interventions to maintain normal BMI may prevent or delay the progression of islet autoimmunity.Item 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 MedicineBACKGROUND: 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.Item The Role of Age and Excess Body Mass Index in Progression to Type 1 Diabetes in At-Risk Adults(Oxford University Press, 2017-12-01) Ferrara, Christine T.; Geyer, Susan M.; Evans-Molina, Carmella; Libman, Ingrid M.; Becker, Dorothy J.; Wentworth, John M.; Moran, Antoinette; Gitelman, Stephen E.; Redondo, Maria J.; Medicine, School of MedicineBackground: Given the global rise in both type 1 diabetes incidence and obesity, the role of body mass index (BMI) on type 1 diabetes pathophysiology has gained great interest. Sustained excess BMI in pediatric participants of the TrialNet Pathway to Prevention (PTP) cohort increased risk for progression to type 1 diabetes, but the effects of age and obesity in adults remain largely unknown. Objective: To determine the effect of age and sustained obesity on the risk for type 1 diabetes in adult participants in the TrialNet PTP cohort (i.e., nondiabetic autoantibody-positive relatives of patients with type 1 diabetes). Research Design and Methods: Longitudinally accumulated BMI >25 kg/m2 was calculated to generate a cumulative excess BMI (ceBMI) for each participant, with ceBMI values ≥0 kg/m2 and ≥5 kg/m2 representing sustained overweight or obese status, respectively. Recursive partitioning analysis yielded sex- and age-specific thresholds for ceBMI that confer the greatest risk for type 1 diabetes progression. Results: In this cohort of 665 adults (age 20 to 50 years; median follow-up, 3.9 years), 49 participants developed type 1 diabetes. Age was an independent protective factor for type 1 diabetes progression (hazard ratio, 0.95; P = 0.008), with a threshold of >35 years that reduced risk for type 1 diabetes. In men age >35 years and women age <35 years, sustained obesity (ceBMI ≥5 kg/m2) increased the risk for type 1 diabetes. Conclusions: Age is an important factor for type 1 diabetes progression in adults and influences the impact of elevated BMI, indicating an interplay of excess weight, age, and sex in adult type 1 diabetes pathophysiology.