Browsing by Author "Bremer, Andrew A."

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    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 Medicine
    AIMS/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.
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    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 Medicine
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    Longitudinal Plasma Metabolomics Profile in Pregnancy—A Study in an Ethnically Diverse U.S. Pregnancy Cohort
    (MDPI, 2021-09-01) Mitro, Susanna D.; Wu, Jing; Rahman, Mohammad L.; Cao, Yaqi; Zhu, Yeyi; Chen, Zhen; Chen, Liwei; Li, Mengying; Hinkle, Stefanie N.; Bremer, Andrew A.; Weir, Natalie L.; Tsai, Michael Y.; Song, Yiqing; Grantz, Katherine L.; Gelaye, Bizu; Zhang, Cuilin; Epidemiology, School of Public Health
    Amino acids, fatty acids, and acylcarnitine metabolites play a pivotal role in maternal and fetal health, but profiles of these metabolites over pregnancy are not completely established. We described longitudinal trajectories of targeted amino acids, fatty acids, and acylcarnitines in pregnancy. We quantified 102 metabolites and combinations (37 fatty acids, 37 amino acids, and 28 acylcarnitines) in plasma samples from pregnant women in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons cohort (n = 214 women at 10-14 and 15-26 weeks, 107 at 26-31 weeks, and 103 at 33-39 weeks). We used linear mixed models to estimate metabolite trajectories and examined variation by body mass index (BMI), race/ethnicity, and fetal sex. After excluding largely undetected metabolites, we analyzed 77 metabolites and combinations. Levels of 13 of 15 acylcarnitines, 7 of 25 amino acids, and 18 of 37 fatty acids significantly declined over gestation, while 8 of 25 amino acids and 10 of 37 fatty acids significantly increased. Several trajectories appeared to differ by BMI, race/ethnicity, and fetal sex although no tests for interactions remained significant after multiple testing correction. Future studies merit longitudinal measurements to capture metabolite changes in pregnancy, and larger samples to examine modifying effects of maternal and fetal characteristics.