Publications by authors named "Tim Vigers"

Background: Elexacaftor/tezacaftor/ivacaftor (ETI) has been highly effective for improving pulmonary disease and nutritional outcomes. However, the effect of this therapy on glycemic control in people with cystic fibrosis related diabetes (CFRD) is unclear. This study aimed to examine real-world effects of ETI on glycemia as captured by hemoglobin A1c (HbA1c) in people with pre-existing CFRD.

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BACKGROUNDIn type 1 diabetes (T1D), impaired insulin sensitivity may contribute to the development of diabetic kidney disease (DKD) through alterations in kidney oxidative metabolism.METHODSYoung adults with T1D (n = 30) and healthy controls (HCs) (n = 20) underwent hyperinsulinemic-euglycemic clamp studies, MRI, 11C-acetate PET, kidney biopsies, single-cell RNA-Seq, and spatial metabolomics to assess this relationship.RESULTSParticipants with T1D had significantly higher glomerular basement membrane (GBM) thickness compared with HCs.

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Article Synopsis
  • Youth with type 1 diabetes often struggle to meet glycemic targets, even with advanced technologies like continuous glucose monitoring (CGM) and hybrid closed-loop (HCL) insulin systems, primarily due to issues like nocturnal alarm fatigue that disrupt sleep.
  • A study involving 76 pediatric patients revealed that the frequency of nighttime alarms increased significantly after starting the HCL system, with an average of 5.4 alarms per night in automated mode, leading to decreased overall device use.
  • Findings suggest that these frequent alarms negatively impact sleep quality and device adherence, indicating a need for further research to explore how diabetes technology affects sleep and ways to enhance sleep quality while using such technologies.
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Objectives: Glycoprotein acetyls (GlycA's) are biomarkers of systemic inflammation and cardiovascular disease, yet little is known about their role in type 1 diabetes (T1D). In this study we examined the associations among GlycA's, central adiposity, insulin resistance, and early kidney injury in youth with T1D.

Methods: Glomerular filtration rate and renal plasma flow by iohexol and p-aminohippurate clearance, urine albumin-to-creatinine ratio (UACR), central adiposity by dual-energy x-ray absorptiometry, and estimated insulin sensitivity were assessed in 50 youth with T1D (16±3.

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Objective: β-Cell dysfunction and insulin resistance magnify the risk of kidney injury in type 2 diabetes. The relationship between these factors and intraglomerular hemodynamics and kidney oxygen availability in youth with type 2 diabetes remains incompletely explored.

Research Design And Methods: Fifty youth with type 2 diabetes (mean age ± SD 16 ± 2 years; diabetes duration 2.

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Background: Two weeks of continuous glucose monitoring (CGM) sampling with >70% CGM use is recommended to accurately reflect 90 days of glycemic metrics. However, minimum sampling duration for CGM use <70% is not well studied. We investigated the minimum duration of CGM sampling required for each CGM metric to achieve representative glycemic outcomes for <70% CGM use over 90 days.

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Underlying molecular mechanisms of the kidney protective effects of sodium glucose co-transporter 2 (SGLT2) inhibitors are not fully elucidated. Therefore, we studied the association between urinary epidermal growth factor (uEGF), a mitogenic factor involved in kidney repair, and kidney outcomes in patients with type 2 diabetes (T2D). The underlying molecular mechanisms of the SGLT2 inhibitor canagliflozin on EGF using single-cell RNA sequencing from kidney tissue were examined.

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Despite evidence of improved diabetes outcomes with diabetes technology such as continuous glucose monitoring (CGM) systems, insulin pumps, and hybrid closed-loop (HCL) insulin delivery systems, these devices are underutilized in clinical practice for the management of insulin-requiring diabetes. This low uptake may be the result of health care providers' (HCPs') lack of confidence or time to prescribe and manage devices for people with diabetes. We administered a survey to HCPs in primary care, pediatric endocrinology, and adult endocrinology practices in the United States.

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Most adolescents with T1D do not meet glycemic recommendations or consistently perform the required self-management behaviors to prevent acute- and long-term deleterious health outcomes. In addition, most youth with T1D do not have access to behavioral health services to address T1D management barriers. Thus, delivering behavioral interventions during routine medical appointments may hold promise for improving T1D outcomes in adolescents.

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Background: Cystic Fibrosis Foundation (CFF) Guidelines recommend annual screening for cystic fibrosis related diabetes (CFRD) with an oral glucose tolerance test (OGTT). However, screening rates remain consistently low. We conducted surveys of 1) US CF center directors and 2) Endocrinologists affiliated with the CFF-sponsored EnVision program to characterize CFRD screening practices, describe provider perceived barriers to screening, and identify strategies for improving screening.

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Background: We developed a novel approach to minimize batch effects when assigning samples to batches. Our algorithm selects a batch allocation, among all possible ways of assigning samples to batches, that minimizes differences in average propensity score between batches. This strategy was compared to randomization and stratified randomization in a case-control study (30 per group) with a covariate (case vs control, represented as β1, set to be null) and two biologically relevant confounding variables (age, represented as β2, and hemoglobin A1c (HbA1c), represented as β3).

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In recent years, continuous glucose monitor (CGM) use is increasing in people without diabetes to promote healthy lifestyle. CGM metrics such as glucose management indicator (GMI), a statistical formula to estimate glycated hemoglobin (HbA1c) from sensor glucose, is commonly used to approximate HbA1c. This study was aimed to evaluate discordance between GMI and HbA1c in people without diabetes.

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Malglycemia in pediatric, adolescent and young adult (AYA) patients who undergo hematopoietic stem cell transplant (HSCT) is associated with increased infection and mortality rate. Continuous glucose monitoring (CGM) has been safely used in pediatric/AYA HSCT recipients, but there is a need for a composite metric that can easily be used in clinical settings to assess the glycemic control and identify high-risk patients who needs therapeutic intervention. Composite metrics derived from CGM have not been studied in pediatric/AYA HSCT patients.

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Background: Glomerular filtration rate (GFR) is a key measure of kidney function but often inaccurately ascertained by serum creatinine and cystatin C in pediatrics. In this pilot trial, we evaluated the relationship between GFR calculated by using phase-contrast MRI (PC-MRI) biomarkers and GFR by I-iothalamate clearance in youth undergoing bone marrow transplantation (BMT).

Methods: A total of twenty-one pediatric BMT candidates (8-21 years of age) were recruited for a research kidney PC-MRI.

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To evaluate influence of daytime versus nighttime continuous glucose monitoring (CGM)-based metrics on A1C in adults with type 1 diabetes (T1D). CGM data from 407 adults with T1D (age 39 ± 15 years, diabetes duration 20 ± 12 years, A1C 7.3% ± 1.

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Aims: To understand morning biopsychosocial factors that predict glycemia, adherence, and goal attainment in adolescents and young adults (AYA) with type 1 diabetes (T1D) on a daily basis.

Methods: Eight-eight AYA (mean 17.6 ± 2.

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Fear of hypoglycemia (FOH) is anxiety or extreme worry about having a low blood glucose and its consequences. FOH is common in individuals with type 1 diabetes (T1D) of all ages, as well as their caregivers, and can lead to inappropriate T1D self-management and suboptimal health outcomes. Despite its prevalence and serious health consequences, there has been very little attention focused on developing interventions to reduce FOH and its associated maladaptive T1D management behaviors.

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Objective: Type 2 diabetes (T2D) is a leading cause of end-stage kidney disease worldwide. Recent studies suggest a more aggressive clinical course of diabetic kidney disease in youth-onset compared with adult-onset T2D. We compared kidney structural lesions in youth- and adult-onset T2D to determine if youth onset was associated with greater early tissue injury.

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Hybrid Closed-Loop (HCL) systems aid individuals with type 1 diabetes in improving glycemic control; however, sustained use over time has not been consistent for all users. This study developed and validated prognostic models for successful 12-month use of the first commercial HCL system based on baseline and 1- or 3-month data. Data from participants at the Barbara Davis Center ( = 85) who began use of the MiniMed 670G HCL were used to develop prognostic models using logistic regression and Lasso model selection.

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Context: Early glucose abnormalities in people with cystic fibrosis (PwCF) are commonly detected by continuous glucose monitoring (CGM). Relationships between these CGM abnormalities and oral glucose tolerance testing (OGTT) in PwCF have not been fully characterized.

Objective: This work aimed to determine the relationship between CGM and common OGTT-derived estimates of β-cell function, including C-peptide index and oral disposition index (oDI) and to explore whether CGM can be used to screen for OGTT-defined prediabetes and cystic fibrosis-related diabetes (CFRD).

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Cgmanalysis is an open-source software based on the R programming language for data management and descriptive analysis of data from continuous glucose monitoring (CGM). We sought to validate the summary measures calculated by cgmanalysis against the results from proprietary software associated with four CGM commercially available models. Two weeks of data from 188 patients with type 1 diabetes using commercially available CGMs.

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Environmental factors including viruses, diet, and the metabolome have been linked with the appearance of islet autoimmunity (IA) that precedes development of type 1 diabetes (T1D). We measured global DNA methylation (DNAm) and untargeted metabolomics prior to IA and at the time of seroconversion to IA in 92 IA cases and 91 controls from the Diabetes Autoimmunity Study in the Young (DAISY). Causal mediation models were used to identify seven DNAm probe-metabolite pairs in which the metabolite measured at IA mediated the protective effect of the DNAm probe measured prior to IA against IA risk.

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Objective: To determine whether the use of an inhaled insulin would improve HbA1c.

Methods: This study was performed in 20 type 2 diabetes mellitus (T2DM) participants with HbA1c values ≥7.5 (58) to ≤11.

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Individuals with type 1 diabetes (T1D) must engage in a variety of complex and burdensome self-management behaviors daily to maintain near normal blood glucose levels and prevent complications. There is a need for interventions to improve use of sophisticated diabetes technologies, such as insulin pumps, during adolescence - a very high-risk developmental period for individuals with T1D. All diabetes devices, including insulin pumps, store large amounts of behavioral data that can be downloaded and analyzed to evaluate adherence to recommended T1D self-management behaviors.

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Background: Alternate methods for characterizing oral glucose tolerance tests (OGTT) have emerged as superior to the 2-hour glucose in identifying individuals at risk for type 2 diabetes. The significance of these methods in cystic fibrosis (CF) is unclear. We compared 3 OGTT classifications in youth with CF: 1.

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