Fasting c-peptide and insulin-like growth factor-binding protein-1 levels help to distinguish childhood type 1 and type 2 diabetes at diagnosis

The Predictive Potential of C-Peptide in Differentiating Type 1 Diabetes From Type 2 Diabetes in an Outpatient Population in Abu Dhabi

PURPOSE

We aimed to investigate the predictive potential of plasma connecting peptide (C-peptide) in differentiating type 1 diabetes (T1D) from type 2 diabetes (T2D) and to inform evidence-based diabetes classification criteria.

METHODS

A retrospective review was performed of all the patients with diabetes visiting an outpatient diabetology, endocrinology, general practice and family medicine tertiary health care center between January 2016 and December 2021.

FINDINGS

Two hundred twelve individuals with diabetes were included, 85 (44.8%) with T1D and 127 (55.2%) with T2D. Mean (SD) age at diagnosis was 35.9 (15.1) years, and 112 (52.8%) men. Median (interquartile range [IQR]) duration of diabetes was 3.8 (3.0-4.5) years (T1D, 3.9 [3.5-4.6]; T2D, 3.4 [2.4-4.4]; P = 0.001). Body mass index was <18.5 kg/m2 in 5 (2.5%) individuals (T1D, 5; T2D, none), 18.5 to <25 kg/m2 in 57 (28.5%) (T1D, 32; T2D, 25), 25 to <30 kg/m2 in 58 (29%) (T1D, 28; T2D, 30), and >30 kg/m2 in 80 (40.0%) (T1D, 20; T2D, 60). Median (IQR) glycosylated hemoglobin was 7.4% (6.7%-8.5%) (T1D, 8.3% [7.2%-9.9%]; T2D, 7% [6.3%-7.6%]; P = 0.0001). Median (IQR) C-peptide concentration was 0.59 nmol/L (0.01-1.14 nmol/L) (T1D, 0.01 nmol/L [0.003-0.05 nmol/L]; T2D, 1.03 nmol/L [0.70-1.44 nmol/L]; P = 0.0001). C-peptide concentration of ≤0.16 nmol/L showed 92.9% sensitivity, 1-specificity of 2.4%, and AUC of 97.2% (CI, 94.7%-99.6%; P = 0.0001) in differentiating T1D from T2D.

IMPLICATIONS

To our knowledge, this is the first study in the Middle East and North Africa region highlighting the role of C-peptide in diabetes classification. The estimated cutoff point for C-peptide concentration (≤0.16 nmol/L) will certainly help in accurately classifying the T1D and will rule out the routine clinical judgmental approaches in the region, especially in those scenarios and periods where it is always difficult to diagnose the diabetes type. Quantifying the cutoff for C-peptide is among the vital strengths of this study that will provide a better treatment plan in diabetes care management. Also, we evaluated concomitant glucose levels to rule out the phenomenon of falsely low C-peptide values in the setting of hypoglycemia or severe glucose toxicity. Based on our findings, C-peptide testing could be included in postulating an evidence-based guideline that differentiates T1D from T2D. Despite this, our study has some limitations, including the selection bias due to the retrospective design and low C-peptide levels could be indicative of low pancreatic reserves due to other causes or long-standing T2D, and quantifying these reasons requires additional resources and time.

The application of predictive value of diabetes autoantibody profile combined with clinical data and routine laboratory indexes in the classification of diabetes mellitus

Objective

Currently, distinct use of clinical data, routine laboratory indicators or the detection of diabetic autoantibodies in the diagnosis and management of diabetes mellitus is limited. Hence, this study was aimed to screen the indicators, and to establish and validate a multifactorial logistic regression model nomogram for the non-invasive differential prediction of type 1 diabetes mellitus.

Methods

Clinical data, routine laboratory indicators, and diabetes autoantibody profiles of diabetic patients admitted between September 2018 and December 2022 were retrospectively analyzed. Logistic regression was used to select the independent influencing factors, and a prediction nomogram based on the multiple logistic regression model was constructed using these independent factors. Moreover, the predictive accuracy and clinical application value of the nomogram were evaluated using Receiver Operating Characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and clinical impact curves (CIC).

Results

A total of 522 diabetic patients were included in this study. These patients were randomized into training and validation sets in a 7:3 ratio. The predictors screened included age, prealbumin (PA), high-density lipoprotein cholesterol (HDL-C), islet cells autoantibodies (ICA), islets antigen 2 autoantibodies (IA-2A), glutamic acid decarboxylase antibody (GADA), and C-peptide levels. Based on these factors, a multivariate model nomogram was constructed, which had an Area Under Curve (AUC) of 0.966 and 0.961 for the training set and validation set, respectively. Subsequently, the calibration curves demonstrated a strong accuracy of the graph; the DCA and CIC results indicated that the graph could be used as a non-invasive valid predictive tool for the differential diagnosis of type 1 diabetes mellitus, clinically.

Conclusion

The established prediction model combining patient's age, PA, HDL-C, ICA, IA-2A, GADA, and C-peptide can assist in differential diagnosis of type 1 diabetes mellitus and type 2 diabetes mellitus and provides a basis for the clinical as well as therapeutic management of the disease.

Reference Standards for C-Peptide in Korean Population: A Korean Endocrine Hormone Reference Standard Data Center Study

BACKGRUOUND

The Korean Endocrine Hormone Reference Standard Data Center (KEHRS DC) has created reference standards (RSs) for endocrine hormones since 2020. This study is the first of its kind, wherein the KEHRS DC established RSs for serum Cpeptide levels in a healthy Korean population.

METHODS

Healthy Korean adults were recruited from May 2021 to September 2023. After excluding participants according to our criteria, serum samples were collected; each participant could then choose between fasting glucose only or fasting glucose plus an oral glucose tolerance test (OGTT). If their sample showed high glucose (≥100 mg/dL) or hemoglobin A1c (HbA1c) (≥5.70%), their C-peptide levels were excluded from analyzing the RSs.

RESULTS

A total of 1,532 participants were recruited; however, only the data of 1,050 participants were analyzed after excluding those whose samples showed hyperglycemia or high HbA1c. Post-30-minute OGTT data from 342 subjects and post-120-minute OGTT data from 351 subjects were used. The means±2 standard deviations and expanded uncertainties of fasting, post-30-minute and 120-minute OGTT C-peptide levels were 1.26±0.82 and 0.34-3.18, 4.74±3.57 and 1.14-8.33, and 4.85±3.58 and 1.25-8.34 ng/mL, respectively. Serum C-peptide levels correlated with obesity, serum glucose levels, and HbA1c levels.

CONCLUSION

The RSs for serum C-peptide levels established in this study are expected to be useful in both clinical and related fields.

Atypical Diabetes: What Have We Learned and What Does the Future Hold?

As our understanding of the pathophysiology of diabetes evolves, we increasingly recognize that many patients may have a form of diabetes that does not neatly fit with a diagnosis of either type 1 or type 2 diabetes. The discovery and description of these forms of "atypical diabetes" have led to major contributions to our collective understanding of the basic biology that drives insulin secretion, insulin resistance, and islet autoimmunity. These discoveries now pave the way to a better classification of diabetes based on distinct endotypes. In this review, we highlight the key biological and clinical insights that can be gained from studying known forms of atypical diabetes. Additionally, we provide a framework for identification of patients with atypical diabetes based on their clinical, metabolic, and molecular features. Helpful clinical and genetic resources for evaluating patients suspected of having atypical diabetes are provided. Therefore, appreciating the various endotypes associated with atypical diabetes will enhance diagnostic accuracy and facilitate targeted treatment decisions.

Utility of Fasting C-Peptide for the Diagnostic Differentiation of Patients with Type 1, Type 2 Diabetes, MODY, and LADA

BACKGROUND

The prevalence of obesity has increased in patients with type 1 diabetes (T1D) and latent autoimmune diabetes of the adult (LADA), limiting the use of clinical features such as the body mass index for its differentiation with type 2 diabetes (T2D). Additionally, some patients with maturity-onset diabetes of the young (MODY) or LADA are misdiagnosed as having T2D. The evaluation of autoantibodies and genetic testing are not fully available. We aimed to evaluate the utility of a widely available and less expensive diagnostic tool such as C-peptide to differentiate between T1D, T2D, MODY, and LADA.

METHODS

Our study included 38 patients with T1D, 49 with T2D, 13 with MODY, and 61 with LADA. We recorded anthropometric measurements, biochemical profiles, and antidiabetic treatment and determined C-peptide, anti-GAD65, and anti-IA2 antibodies.

RESULTS

C-peptide concentration differed significantly among populations (T1D: 0.2 ng/mL; T2D: 2.4 ng/mL; MODY: 1.14 ng/mL; LADA: 1.87 ng/mL). Through a ROC curve, we observed that the C-peptide cut-off point of 0.95 ng/mL allows differentiation between T1D and T2D (sensitivity 82%, specificity 77%); 0.82 ng/mL between T1D and LADA (sensitivity 82%, specificity 77%); and 1.65 ng/mL between T2D and MODY (sensitivity 72%, specificity 72%).

CONCLUSIONS

C-peptide is useful for the diagnostic differentiation of patients with type 1, type 2 diabetes, MODY, and LADA.

High Prevalence of A-β+ Ketosis-Prone Diabetes in Children with Type 2 Diabetes and Diabetic Ketoacidosis at Diagnosis: Evidence from the Rare and Atypical Diabetes Network (RADIANT)

Background

A-β+ ketosis-prone diabetes (KPD) in adults is characterized by presentation with diabetic ketoacidosis (DKA), negative islet autoantibodies, and preserved β-cell function in persons with a phenotype of obesity-associated type 2 diabetes (T2D). The prevalence of KPD has not been evaluated in children. We investigated children with DKA at "T2D" onset and determined the prevalence and characteristics of pediatric A-β+ KPD within this cohort.

Methods

We reviewed the records of 716 children with T2D at a large academic hospital and compared clinical characteristics of those with and without DKA at onset. In the latter group, we identified patients with A-β+ KPD using criteria of the Rare and Atypical Diabetes Network (RADIANT) and defined its prevalence and characteristics.

Results

Mean age at diagnosis was 13.7 ± 2.4 years: 63% female; 59% Hispanic, 29% African American, 9% non-Hispanic White, and 3% other. Fifty-six (7.8%) presented with DKA at diagnosis and lacked islet autoantibodies. Children presenting with DKA were older and had lower C-peptide and higher glucose concentrations than those without DKA. Twenty-five children with DKA (45%) met RADIANT A-β+ KPD criteria. They were predominantly male (64%), African American or Hispanic (96%), with substantial C-peptide (1.3 ± 0.7 ng/mL) at presentation with DKA and excellent long-term glycemic control (HbA1c 6.6% ± 1.9% at follow-up (median 1.3 years postdiagnosis)).

Conclusions

In children with a clinical phenotype of T2D and DKA at diagnosis, approximately half meet criteria for A-β+ KPD. They manifest the key characteristics of obesity, preserved β-cell function, male predominance, and potential to discontinue insulin therapy, similar to adults with A-β+ KPD.

Blood C-peptide concentration as a proxy marker of cardiovascular disease: An observational cross-sectional study

Background and Aims

Cardiovascular diseases (CVDs) are among the leading causes of disability and early death in sub-Saharan Africa. Most of the current blood tests for CVD diagnosis involve performing about three test profiles; often at additional cost to patients. C-peptide, a cleavage product of proinsulin, is a promising marker that has the potential to serve as a proxy marker for diagnosing CVDs in resource-poor settings.

Methodology

The study was an observational cross-sectional one and involved 127 consenting persons diagnosed with CVD and 127 individuals without CVD. The socio-demographic and clinical characteristics of participants were obtained. Blood levels of C-peptide, fasting plasma glucose (FPG), total creatinine kinase (CK), creatine kinase myocardial bound (CKMB), lactate dehydrogenase (LDH), propeptide of brain natriuretic peptide (PBNP), Troponin T, lipids, and biomarkers of kidney and liver function were analyzed using ELISA and an automated analyzer. Insulin resistance was computed using the modified homeostatic model assessment (HOMA-IR).

Results

The CVD Group had significantly higher levels of C-peptide, CK, CKMB, troponin T, PBNP, FPG, HOMA-IR, and several selected kidney, liver, and lipid parameters compared to the non-CVD Group (p < 0.05 for all). Troponin T recorded a positive correlation (r = 0.34, p < 0.001) with C-peptide among the CVD Group. The sensitivity and specificity of C-peptide in identifying CVD were 96.1% and 91.3% respectively (area under the curve = 0.938, p < 0.001).

Conclusion

C-peptide levels were higher in the CVD Group and appeared to be a valuable (high sensitivity and specificity) biomarker in detecting CVD.

Biomarkers and their Clinical Applications in Pediatrics

Biomarker studies are becoming increasingly interesting for many fields of medicine. The use of biomarkers in medicine is involved in detecting diseases and supporting diagnosis and treatment decisions. New research and new discoveries on the molecular basis of the disease show that there may be a number of promising new biomarkers for use in daily clinical practice. Clinical trials in children lag behind adult research both in quality and quantity. The number of biomarkers validated to optimize pediatric patient management is limited. In the pathogenesis of many diseases, it should not be extrapolated to the pediatric clinical setting, taking into account that biomarkers that are effective in adults are clearly different in children and that ontogeny directly affects disease development and therapeutic response in children. The search for ideal biomarkers or markers that can make an early and definitive diagnosis in neonatal sepsis is still ongoing. The ideal biomarker for pediatric diseases should be costeffective, noninvasive, applicable to pediatric specific diseases, and its results should correspond to age-related physiological changes. Lactate, troponin and B-type natriuretic peptide are valuable biomarkers in the evaluation and management of critically ill children with cardiac disease. Tumor markers in children are biochemical substances used in the clinical treatment of pediatric tumors and to detect the presence of cancer (regression or progression). In this chapter, current and brief information about biomarkers and their clinical applications used in the diagnosis and monitoring of pediatric diseases is presented.;

Practical Clinical Applications of Islet Autoantibody Testing in Type 1 Diabetes

BACKGROUND

The distinction between type 1 diabetes (T1D) and type 2 diabetes (T2D) is extremely important for the choice of therapy, body weight and dietary management, screening for coexistent autoimmune diseases and comorbidities, anticipated prognosis, and risk assessment in relatives. Not uncommonly, the presentation of the patient may not allow an unambiguous discrimination between T1D and T2D. To help resolve this challenge, the detection of islet autoantibodies can support the diagnosis of T1D.

CONTENT

The presence of islet autoantibodies in a person with diabetes indicates an autoimmune etiology therefore establishing the diagnosis of T1D. Presently 5 islet autoantibodies are available for routine clinical use: islet cell cytoplasmic autoantibodies (ICA), insulin autoantibodies (IAA), glutamic acid decarboxylase autoantibodies (GADA), insulinoma associated-2 autoantibodies (IA-2A), and zinc transporter-8 autoantibodies (ZnT8A). There are caveats to the selection of which islet autoantibodies should be measured. Islet autoantibodies can also predict the development of T1D. Therefore, once safe and effective therapies are available to prevent T1D, islet autoantibody testing is expected to become a routine part of medical practice. A very rare cause of autoimmune diabetes is the type B insulin resistance syndrome resulting from antagonistic autoantibodies to the insulin receptor. Rarely hypoglycemia can result from agonistic insulin receptor autoantibodies, or high-titer IAA causing the autoimmune insulin syndrome (i.e., Hirata disease).

SUMMARY

In summary, autoimmune causes of dysglycemia are increasing in clinical importance requiring the scrutiny of laboratorians. The determination of islet autoantibodies can greatly aid in the diagnosis and the prediction of T1D.

Transplant Options for Patients With Diabetes and Advanced Kidney Disease: A Review

Optimal glycemic control in kidney transplant recipients with diabetes is associated with improved morbidity and better patient and allograft survival. Transplant options for patients with diabetes requiring insulin therapy and chronic kidney disease who are suitable candidates for kidney transplantation should include consideration of β-cell replacement therapy: pancreas or islet transplantation. International variation related to national regulatory policies exists in offering one or both options to suitable candidates and is further affected by pancreas/islet allocation policies and transplant waiting list dynamics. The selection of appropriate candidates depends on patient age, coexistent morbidities, the timing of referral to the transplant center (predialysis versus on dialysis) and availability of living kidney donors. Therefore, early referral (estimated glomerular filtration rate < 30 mL/min/1.73 m²) is of the utmost importance to ensure adequate time for informed decision making and thorough pretransplant evaluation. Obesity, cardiovascular disease, peripheral vascular disease, smoking, and frailty are some of the conditions that need to be addressed before acceptance on the transplant list, and ideally before dialysis becoming imminent. This review offers insights into selection of pancreas/islet transplant candidates by transplant centers and an update on posttransplant outcomes, which may have practice implications for referring nephrologists.

Morbidity and Complications of Diabetes Mellitus in Children and Adolescents in Ghana: Protocol for a Longitudinal Study

Background

Diabetes is associated with premature morbidity and mortality from its many complications. There are limited data on the chronic complications of diabetes in children and adolescents in sub-Saharan Africa.

Objective

The study aims to determine the (1) burden and related factors of chronic systemic complications of diabetes, including diabetic and nondiabetic ocular conditions in children and adolescents, and (2) quality of life (QoL) of participants compared to healthy controls. This manuscript describes the study methodology.

Methods

Demographic information, medical history, anthropometric measurements, and laboratory characteristics were collected, and the participants were screened for microvascular and macrovascular complications as well as nondiabetic ocular disease. QoL questionnaires were administered to participants, their caregivers, and controls. Participants were followed up annually up to 3 years to determine the natural history of and trends in these conditions. SPSS Version 25.0 will be used for data analysis. Continuous and categorical data will be presented as mean (SD) and as percentages (%), respectively. t tests and analysis of variance will be used to compare means, and chi-square tests will be used to compare categorical data. Correlation, regression, and logistic regression analyses will be employed to establish linear associations and causal associations as appropriate. Relative risk and odds ratios will be used to estimate risk. QoL outcomes in Ghanaian children and adolescents with diabetes mellitus compared with caregivers and healthy controls will be assessed using the Pediatric Quality of Life inventory. Significance will be set at α=.05.

Results

Institutional approval from the Ethical and Protocol Review Committee of the University of Ghana Medical School was received on August 22, 2014 (Protocol Identification Number: MS-Et/M.12-P4.5/2013-2014). Funding for the project was received from the University of Ghana Research Fund (#UGRF/9/LMG-013/2015-2016) in March 2016. Patient recruitment, clinical examination, and data collection commenced in August 2016 and was completed in September 2019. A total of 58 children and adolescents with diabetes mellitus have been recruited. Blood samples were stored at –80 °C for analysis, which was completed at the end of July 2020. Data analysis is ongoing and will be completed by the end of December 2020. Investigators plan to submit the results for publication by the end of February 2021.

Conclusions

The prevalence, natural history, trends in diabetic complications and nondiabetic ocular disease, and QoL will be provided. Our data may inform policies and interventions to improve care given to children and adolescents with diabetes.

International Registered Report Identifier (IRRID)

DERR1-10.2196/21440

Pediatric Type 2 Diabetes: Not a Mini Version of Adult Type 2 Diabetes

Pediatric type 2 diabetes mellitus (T2DM) is increasing in incidence, with risk factors including obesity, puberty, family history of T2DM in a first-degree or second-degree relative, history of small-for-gestational-age at birth, child of a gestational diabetes pregnancy, minority racial group, and lower socioeconomic status. The pathophysiology of T2DM consists of insulin resistance and progression to pancreatic beta-cell failure, which is more rapid in pediatric T2DM compared with adult T2DM. Treatment options are limited. Treatment failure and nonadherence rates are high in pediatric T2DM; therefore, early diagnosis and treatment and new pharmacologic options and/or effective behavioral interventions are needed.

Challenges in the classification and management of Asian youth-onset diabetes mellitus- lessons learned from a single centre study

It remains widely perceived that early-onset Type 2 Diabetes (T2D) in children and adolescents is rare and clinically distinct from Type 1 Diabetes (T1D). We studied the challenges of classifying subtypes of early-onset diabetes using clinical features and biomarkers, and management of these patients. We reviewed retrospectively the record of patients < 25 years old who attended the diabetes clinic in Penang General Hospital, Malaysia between 1^st December 2012 and 30^th June 2015. We examined their clinical features, C-peptide and pancreatic autoantibodies. Comparisons were made between T1D and T2D for magnitude, demographics, metabolic status and complications. We studied 176 patients with a mean age of 20 ± 3.7 years, 43.2% had T1D, 13.6% had T2D, and 13.6% had mixed features of both. When tested, pancreatic autoantibodies were positive in 59.4% of the T1D. T2D presented two years later than T1D at 14.3 years, 20% were asymptomatic at presentation, and 50% required insulin supplementation despite fasting c-peptide of > 250 pmol/L. HbA_1C of ≤ 8.0% (64 mmol/mol) was achieved in 30.3% of T1D, 58.3% of T2D on OAD and 16.7% of T2D on insulin. The T2D had greater cardiovascular risk with higher body mass index, more dyslipidaemia, higher blood pressure and earlier onset of nephropathy. The overlapping clinical features, variable autoimmunity, and beta-cell loss complicate classification of young diabetes. Pancreatic autoantibodies and C-peptide did not always predict diabetes subtypes nor respond to insulin. The poor metabolic control and high cardiovascular risk burden among the T2D highlight the need for population-based study and focused intervention.

Insulin-Like Growth Factor Binding Proteins in Autoimmune Diseases

Insulin-like growth factor binding proteins (IGFBPs) are a family of proteins binding to Insulin-like growth factors (IGFs), generally including IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, and IGFBP6. The biological functions of IGFBPs can be classified as IGFs-dependent actions and IGFs-independent effects. In this review, we will discuss the structure and function of various IGFBPs, particularly IGFBPs as potential emerging biomarkers and therapeutic targets in various autoimmune diseases, and the possible mechanisms by which IGFBPs act on the pathogenesis of autoimmune diseases.

Urinary C-Peptide/Creatinine Ratio Can Distinguish Maturity-Onset Diabetes of the Young from Type 1 Diabetes in Children and Adolescents: A Single-Center Experience

BACKGROUND

The urinary C-peptide/creatinine ratio (UCPCR) and fasting C-peptide level can assess beta-cell function in clinical practice. In the present study, the use of the UCPCR and fasting C-peptide levels was investigated in the differential diagnosis between maturity-onset diabetes of the young (MODY) and type 1 diabetes mellitus (T1DM).

METHODS

Twenty-seven patients with genetically confirmed MODY by next-generation sequence analysis and 42 children with T1DM were included. C-peptide levels were measured after an overnight fast before breakfast, and urine samples were collected 2 h after a standard lunch in the hospital.

RESULTS

The UCPCR in the T1DM group was 0.17 ± 0.5 nmol/mmol, and in the MODY group it was 1.27 ± 1.03 nmol/mmol (p = 0.001). The receiver operating characteristic (ROC) curves showed excellent discrimination (area under the curve 0.93). A UCPCR ≥0.22 nmol/mmol yielded a 96.3% sensitivity and an 85.7% specificity. The fasting C-peptide level in the T1DM group was lower than that in the MODY group (p = 0.001). The fasting C-peptide cutoff determined by ROC curve analysis was 0.62 ng/ml, with a sensitivity of 93% and a specificity of 90% for discriminating between MODY and T1DM.

CONCLUSIONS

We showed that the UCPCR and fasting C-peptide levels in children and adolescents can distinguish patients with MODY from patients with T1DM with high specificity and sensitivity. A value of UCPCR ≥0.22 nmol/mmol may indicate further genetic testing for MODY.

Clinical and Laboratory Characteristics of Childhood Diabetes Mellitus: A Single-Center Study from 2000 to 2013

We examined the clinical and laboratory characteristics of children newly diagnosed with diabetes mellitus (DM) in a single-center study. We retrospectively reviewed the data of 155 children with DM between January 2000 and December 2013. Of 155 diabetic children, 87 (56.1%) were diagnosed with type 1 DM (T1DM) and 68 (43.9%) with type 2 DM (T2DM). Mean ages at diagnosis were 8.95±3.89 years (T1DM) and 13.76±2.23 years (T2DM), respectively (p<0.001). There were significant differences in HbA1c, C-peptide, and glutamic acid decarboxylase antibody levels between the T1DM and T2DM groups. Annual numbers of children with DM have increased, and since 2011 the number of children with T2DM has surpassed the number with T1DM. The most common clinical symptom in T1DM was polyuria, and 26.4% of children with T1DM presented initially with diabetic ketoacidosis. In contrast, 60.3% of T2DM children showed glucosuria in a school urine screening, and only 19.1% presented with polydipsia. The rate of positivity for at least more than one islet autoantibody was 77.1% in T1DM and 26.3% in T2DM. Serum C-peptide levels in T2DM were increased up to 12 months after onset and remained >3.59 ng/mL for 36 months. However, serum C-peptide levels in T1DM were slightly increased up to 6 months after onset and gradually decreased to 0.32 ng/mL for 36 months. The prevalence of children with DM has increased over the last 14 years, and the proportion of T2DM patients has rapidly increased since 2009. Because childhood DM is associated with several metabolic and cardiovascular complications, children should be screened for early detection of DM, especially asymptomatic T2DM in children and adolescents.

Fasting serum C-peptide is useful for initial classification of diabetes mellitus in children and adolescents

PURPOSE

With rising obesity rates in children, it is increasingly difficult to differentiate between type 1 and type 2 diabetes mellitus (T1DM, T2DM) on clinical grounds alone. Using C-peptide as a method of classifying diabetes mellitus (DM) has been suggested. This study aimed to find a correlation between fasting C-peptide level and DM types in children and adolescents.

METHODS

A total of 223 diabetic children, newly diagnosed at 5 hospitals between January 2001 and December 2012, were enrolled in this study. Initial DM classification was based on clinical and laboratory data including fasting C-peptide at diagnosis; final classification was based on additional data (pancreatic autoantibodies, human leukocyte antigen type, and clinical course).

RESULTS

Of 223 diabetic children, 140 were diagnosed with T1DM (62.8%) and the remaining 83 with T2DM (37.2%). The mean serum C-peptide level was significantly lower in children with T1DM (0.80 ng/mL) than in children with T2DM (3.91 ng/mL). Among 223 children, 54 had a serum C-peptide level <0.6 ng/mL; they were all diagnosed with T1DM. The proportion of children with T2DM increased in accordance with C-peptide level. Forty-nine of 223 children had a C-peptide level >3.0 ng/mL; 48 of them (97.9%) were diagnosed with T2DM.

CONCLUSION

In this study, we found that if the C-peptide level was <0.6 ng/mL at diagnosis, T2DM could be excluded; if C-peptide level was >3.0 ng/mL, a T1DM diagnosis is unlikely. This finding suggests that serum fasting C-peptide level is useful for classifying DM type at the time of diagnosis in youth.

Epigenetic analyses of the insulin-like growth factor binding protein 1 gene in type 1 diabetes and diabetic nephropathy

Background

Clinical observations have demonstrated that high levels of circulating insulin-like growth factor binding protein-1 (IGFBP-1) are associated with type 1 diabetes (T1D), whereas low serum IGFBP-1 levels are associated with the risk of type 2 diabetes (T2D). Recently, we reported that increased DNA methylation levels in the IGFBP1 gene were associated with T2D. In the present study, we evaluated the epigenetic changes of IGFBP1 in T1D and diabetic nephropathy (DN).

Results

In total, 778 Swedish individuals, including T1D patients with or without DN and subjects with the normal glucose tolerance (NGT), were involved in the study. IGFBP1 methylation levels in genomic DNA extracted from peripheral blood were analyzed with bisulfite pyrosequencing. Serum IGFBP-1 levels were measured with radioimmunoassay. We found that DNA methylation levels in the IGFBP1 gene were decreased (15.6% versus 16.9%; P < 0.001), whereas serum IGFBP-1 levels were increased (31 versus 24 μg/L, P = 0.003) in T1D patients compared with NGT subjects. Furthermore, T1D patients with DN had increased circulating IGFBP-1 concentration compared with the patients without DN (52 versus 28 μg/L; P = 0.006). However, no difference of the IGFBP1 DNA methylation levels between T1D patients with and without DN was observed.

Conclusions

This study shows for the first time that T1D patients had decreased DNA methylation levels in the IGFBP1 gene and further implies that increased circulating IGFBP-1 levels are associated with T1D and DN.

Population-based survey of the prevalence of type 1 and type 2 diabetes in school children in Philadelphia

BACKGROUND

Population-based (PB) registries of type 1 diabetes mellitus (T1DM) in children have been essential in determining the geographic, racial, and temporal patterns of the disease. There is a paucity of PB data on the prevalence of type 1 and type 2 diabetes (T2DM) in youth.

METHODS

The prevalence of diabetes in children was determined using a PB survey of the 628 schools in Philadelphia. Data obtained included type of diabetes, date of birth, race, gender, date of diagnosis, diabetes treatment, and most recent height and weight.

RESULTS

The survey was completed by nurses at 510 schools (81% of schools) representing 252,896 children (70% of children in Philadelphia). Prevalence (per 1000) was computed. The survey identified 492 cases (355 T1DM, 88 T2DM, 49 type unknown). The overall prevalence of T1DM was 1.58 (0.73 White, 0.56 African American, 0.50 Hispanic); of T2DM was 0.35 (0.03 White, 0.28 African American, 0.05 Hispanic). Mean age at diagnosis was 8.6 and 11.9 years for T1DM and T2DM, respectively. The prevalence of T1DM was higher in boys--T2DM was higher in girls. Of children with T2DM, 25% were treated with insulin. BMI was ≥95th percentile in 20% of children weighed (10% of T1DM, 57% of T2DM).

CONCLUSIONS

Although the Philadelphia Pediatric Diabetes Registry is the longest ongoing US registry of its kind, these are the first PB diabetes prevalence data of children in Philadelphia. PB studies in schools are able to capture children with diabetes who are diagnosed and treated in a variety of settings.

Epidemiological pattern of newly diagnosed children with type 1 diabetes mellitus, Taif, Saudi Arabia

Introduction and Aim. Type-1-diabetes mellitus (T1DM) is the most commonly diagnosed type of DM in children and adolescents. We aim to identify the epidemiological profile, risk factors, clinical features, and factors related to delayed diagnosis or mismanagement in children with newly diagnosed T1DM in Taif, Saudi Arabia. Patients and Methods. Ninety-nine newly diagnosed patients were included in the study along with 110 healthy controls. Patients were classified into 3 groups (I: >2 years, II: 2–>6 years, and III: 6–12 years). Both patients and controls were tested for C-peptide, TSH, and autoantibodies associated with DM and those attacking the thyroid gland. Results. Diabetic ketoacidosis was present in 79.8%. Delayed and missed diagnoses were recorded in 45.5%, with significant correlation to age and district of origin. Severity at presentation showed significant correlation with age and cow's milk feeding. Group I, those with misdiagnosis or positive DM related autoantibodies, had more severe presentations. The correlation of C-peptide and TSH levels in patients and controls was significant for C-peptide and nonsignificant for TSH. Conclusion. Misdiagnosis and mismanagement are common and account for more severe presentation, especially in young children >2 years. Early introduction of cow's milk appears to be a risk factor for the development of T1DM.

The clinical utility of C-peptide measurement in the care of patients with diabetes

C-peptide is produced in equal amounts to insulin and is the best measure of endogenous insulin secretion in patients with diabetes. Measurement of insulin secretion using C-peptide can be helpful in clinical practice: differences in insulin secretion are fundamental to the different treatment requirements of Type 1 and Type 2 diabetes. This article reviews the use of C-peptide measurement in the clinical management of patients with diabetes, including the interpretation and choice of C-peptide test and its use to assist diabetes classification and choice of treatment. We provide recommendations for where C-peptide should be used, choice of test and interpretation of results. With the rising incidence of Type 2 diabetes in younger patients, the discovery of monogenic diabetes and development of new therapies aimed at preserving insulin secretion, the direct measurement of insulin secretion may be increasingly important. Advances in assays have made C-peptide measurement both more reliable and inexpensive. In addition, recent work has demonstrated that C-peptide is more stable in blood than previously suggested or can be reliably measured on a spot urine sample (urine C-peptide:creatinine ratio), facilitating measurement in routine clinical practice. The key current clinical role of C-peptide is to assist classification and management of insulin-treated patients. Utility is greatest after 3-5 years from diagnosis when persistence of substantial insulin secretion suggests Type 2 or monogenic diabetes. Absent C-peptide at any time confirms absolute insulin requirement and the appropriateness of Type 1 diabetes management strategies regardless of apparent aetiology.

Home urine C-peptide creatinine ratio (UCPCR) testing can identify type 2 and MODY in pediatric diabetes

BACKGROUND

Making the correct diabetes diagnosis in children is crucial for lifelong management. Type 2 diabetes and maturity onset diabetes of the young (MODY) are seen in the pediatric setting, and can be difficult to discriminate from type 1 diabetes. Postprandial urinary C-peptide creatinine ratio (UCPCR) is a non-invasive measure of endogenous insulin secretion that has not been tested as a diagnostic tool in children or in patients with diabetes duration <5 yr. We aimed to assess whether UCPCR can discriminate type 1 diabetes from MODY and type 2 in pediatric diabetes.

METHODS

Two-hour postprandial UCPCR was measured in 264 patients aged <21 yr (type 1, n = 160; type 2, n = 41; and MODY, n = 63). Receiver operating characteristic curves were used to identify the optimal UCPCR cutoff for discriminating diabetes subtypes.

RESULTS

UCPCR was lower in type 1 diabetes [0.05 (<0.03-0.39) nmol/mmol median (interquartile range)] than in type 2 diabetes [4.01 (2.84-5.74) nmol/mmol, p < 0.0001] and MODY [3.51 (2.37-5.32) nmol/mmol, p < 0.0001]. UCPCR was similar in type 2 diabetes and MODY (p = 0.25), so patients were combined for subsequent analyses. After 2-yr duration, UCPCR ≥ 0.7 nmol/mmol has 100% sensitivity [95% confidence interval (CI): 92-100] and 97% specificity (95% CI: 91-99) for identifying non-type 1 (MODY + type 2 diabetes) from type 1 diabetes [area under the curve (AUC) 0.997]. UCPCR was poor at discriminating MODY from type 2 diabetes (AUC 0.57).

CONCLUSIONS

UCPCR testing can be used in diabetes duration greater than 2 yr to identify pediatric patients with non-type 1 diabetes. UCPCR testing is a practical non-invasive method for use in the pediatric outpatient setting.

Elevated C-peptide and insulin predict increased risk of colorectal adenomas in normal mucosa

BACKGROUND

Lower concentrations of the insulin-like growth factor binding protein-1 (IGFBP-1) and elevated concentrations of insulin or C-peptide have been associated with an increase in colorectal cancer risk (CRC). However few studies have evaluated IGFBP-1 and C-peptide in relation to adenomatous polyps, the only known precursor for CRC.

METHODS

Between November 2001 and December 2002, we examined associations between circulating concentrations of insulin, C-peptide, IGFBP-1 and apoptosis among 190 individuals with one or more adenomatous polyps and 488 with no adenomatous polyps using logistic regression models.

RESULTS

Individuals with the highest concentrations of C-peptide were more likely to have adenomas (OR = 2.2, 95% CI 1.4-4.0) than those with the lowest concentrations; associations that appeared to be stronger in men (OR = 4.4, 95% CI 1.7-10.9) than women. Individuals with high insulin concentrations also had a higher risk of adenomas (OR = 3.5, 95% CI 1.7-7.4), whereas higher levels of IGFBP-1 were associated with a reduced risk of adenomas in men only (OR = 0.3, 95% CI 0.1-0.7). Overweight and obese individuals with higher C-peptide levels (>1(st) Q) were at increased risk for lower apoptosis index (OR = 2.5, 95% CI 0.9-7.1), an association that remained strong in overweight and obese men (OR = 6.3, 95% CI 1.0-36.7). Higher levels of IGFBP-1 in overweight and obese individuals were associated with a reduced risk of low apoptosis (OR = 0.3, 95% CI 0.1-1.0).

CONCLUSIONS

Associations between these peptides and the apoptosis index in overweight and obese individuals, suggest that the mechanism by which C-peptide could induce adenomas may include its anti-apoptotic properties. This study suggests that hyperinsulinemia and IGF hormones predict adenoma risk, and that outcomes associated with colorectal carcinogenesis maybe modified by gender.

Glycemic control in youth with type 2 diabetes declines as early as two years after diagnosis

OBJECTIVES

To determine the course of glycemic decline in a pediatric cohort with type 2 diabetes mellitus (T2DM) by defining longitudinal changes in hemoglobin A1c (HbA1c) and insulin requirement. We also followed markers of insulin reserve (fasting C-peptide and IGFBP-1) over time.

STUDY DESIGN

Participants included two groups: (1) T2DM Nonacidotic (NA) (n = 46); and (2) T2DM diabetic ketoacidosis (n = 13). HbA1c, insulin dose, and fasting C-peptide and IGFBP-1 were obtained at baseline and every 6 months for 4 years.

RESULTS

At baseline, Mann Whitney tests demonstrated that the diabetic ketoacidosis group had higher HbA1c (P = .002), required more insulin (P = .036), and had lower C-peptide (P = .003) than the NA group. Baseline insulin dose (Spearman r = -0.424, P = .009) and baseline IGFBP-1 (Spearman r = -0.349, P = .046) correlated negatively with C-peptide. Over time, HbA1c, insulin dose, and C-peptide changed significantly in a complex manner, with group differences. HbA1c reached a nadir at 6 to 12 months and began to rise after 1.5 years. Insulin requirements reached a nadir at 1 year and began to rise after 2 years.

CONCLUSIONS

Unlike adults, children with T2DM require increasing insulin doses over a 4-year period, and diabetic ketoacidosis at diagnosis predicts greater β-cell decline over time.

Approach to the obese adolescent with new-onset diabetes

The prevalence of both type 1 and type 2 diabetes among children and adolescents has been steadily increasing over the last few decades. However, as the general pediatric population becomes more obese and more ethnically diverse, reliance on phenotypic characteristics for distinguishing between these types of diabetes is becoming increasingly untenable. Yet, the recognition of differences in treatment strategies, associated disorders, and both short- and long-term diabetes and cardiovascular outcomes supports the importance of diagnostic efforts to make a distinction between diabetes types. An approach to determination of diabetes type is discussed, focused on the presence or absence of autoimmunity and assessment of β-cell function. At the time of diagnosis, it is generally not possible to be certain of diabetes type, and therefore, initial treatment decisions must be made based on aspects of the presenting physiology, with adjustments in treatment approach made as the individual's course proceeds and additional information becomes available. The apparent overlap between type 1 and type 2 diabetes that occurs in obese adolescents has resulted in some controversy regarding mixed forms of diabetes that are ultimately semantic, but this does raise interesting questions about the treatment of type 1 diabetes in the presence of an insulin-resistant phenotype. Finally, the lack of information about the efficacy of treatment of cardiovascular risk factors, such as dyslipidemia and hypertension, along with the well-documented challenges in adherence to chronic illness treatment in this population, creates substantial challenges.

Sleeping during the day: effects on the 24-h patterns of IGF-binding protein 1, insulin, glucose, cortisol, and growth hormone

BACKGROUND

Disturbed sleep is a major risk factor for metabolic disturbances, including type 2 diabetes, but the involved mechanisms are still poorly understood. We investigated how an acute shift of sleep to the daytime affected IGF-binding protein 1 (IGFBP1), which is a risk factor for diabetes.

METHODS

Seven healthy men (age, 22-32 years) participated in a night sleep condition (sleep 2300-0700 h) and a day sleep condition (0700-1500 h) with hourly blood samples taken for 25 h (starting at 1900 h) and isocaloric meals every 4th hour awake. The blood samples were analyzed for IGFBP1, insulin, GH, glucose, and cortisol.

RESULT

The acute shift of sleep and meal timing (to 8 h) shifted the 24-h patterns of IGFBP1, glucose, insulin, and GH to a similar degree. However, the day sleep condition also resulted in elevated levels of IGFBP1 (area under curve (AUC)+22%, P<0.05), and reduced glucose levels (AUC-7%, P<0.05) compared with nocturnal sleep. Sleeping during the day resulted in elevated cortisol levels during early sleep and reduced levels in late sleep, but also in increased levels the subsequent evening (P's<0.05).

CONCLUSION

Sleep-fasting seems to be the primary cause for the elevation of IGFBP1, irrespective of sleep timing. However, sleeping during the day resulted in higher levels of IGFBP1 than nocturnal sleep, suggesting altered metabolism among healthy individuals, which may have implications for other groups with altered sleep/eating habits such as shift workers. Moreover, sleep and meal times should be accounted for while interpreting IGFBP1 samples.

Update on nonautoimmune diabetes in children

Over the last two decades, nonautoimmune-mediated type 2 diabetes mellitus (T2DM) has become a clinical entity of increasing importance among adolescents. Yet, research specific to adolescent T2DM is in its infancy. Our understanding of the epidemiology of T2DM among adolescents is complicated by variability in definition, incomplete knowledge of novel autoimmune epitopes, the presence of individuals with phenotypic overlap between type 1 and type 2 diabetes, and inadequate understanding of the contribution of common single-gene defects. Furthermore, a higher ratio of diagnosed to undiagnosed cases and a strong relationship with the onset of puberty suggest unique aspects of the pathophysiology in adolescents. Investigators have begun to address these areas while also identifying important relationships with the intrauterine development. Well-designed clinical studies are currently examining the adolescent-specific challenges in prevention and treatment of T2DM, whereas a number of associations struggle to provide screening and treatment guidelines to practitioners based on limited understanding of the phenomenon. Finally, there is growing understanding of medium- and long-term morbidity and mortality in early adulthood. Given the likelihood that early-onset T2DM will have important implications for future public health, continued attention to all aspects of this complex social, economic, and physiological disorder is critical.

Proteomic profiling of amniotic fluid in preterm labor using two-dimensional liquid separation and mass spectrometry

OBJECTIVE

Simultaneous analysis of the protein composition of biological fluids is now possible. Such an approach can be used to identify biological markers of disease and to understand the pathophysiology of disorders that have eluded classification, diagnosis, and treatment. The purpose of this study was to analyze the differences in protein composition of the amniotic fluid of patients in preterm labor.

STUDY DESIGN

Amniotic fluid was obtained by amniocentesis from three groups of women with preterm labor and intact membranes: (1) women without intra-amniotic infection/inflammation (IAI) who delivered at term, (2) women without IAI who delivered a preterm neonate, and (3) women with IAI. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin (IL)-6 (> or =2.3 ng/mL). Two-dimensional (2D) chromatography was used for analysis. The first dimension separated proteins by isoelectric point, while the second, by the degree of hydrophobicity. 2D protein maps were generated using different experimental conditions (reducing agents as well as protein concentration). The maps were used to discern subsets of isoelectric point/hydrophobicity containing differentially expressed proteins. Protein identification of differentially expressed fractions was conducted with mass spectrometry. Enzyme-linked immunosorbent assays (ELISA) as well as surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS)-based on-chip antibody capture immunoassays were also used for confirmation of a specific protein that was differentially expressed.

RESULTS

(1) Amniotic fluid protein composition can be analyzed using a combination of 2D liquid chromatography and mass spectrometry for the identification of proteins differentially expressed in patients in preterm labor. (2) While total insulin-like growth factor-binding protein-1 (IGFBP-1) concentration did not change, IGFBP-1 fragments at about 13.5 kDa were present in patients with IAI. (3) Proteins that were over-expressed in group 1 included von Ebner gland protein precursor, IL-7 precursor, apolipoprotein A1, tropomyosin sk1 (TPMsk1) fragment, ribosomal protein S6 kinase alpha-3, and alpha-1-microglobulin/bikunin precursor (AMBP). (4) Proteins that were over-expressed in group 3 included fibrinopeptide B, transferrin, major histocompatibility complex (MHC) class 1 chain-related A antigen fragment, transcription elongation factor A, sex-determining region Y (SRY) box 5 protein, Down syndrome critical region 2 protein (DSCR2), and human peptide 8 (HP8). (5) One protein, retinol-binding protein, was over-expressed in women who delivered preterm, regardless of the presence of IAI.

CONCLUSIONS

A combination of techniques involving 2D chromatography, mass spectrometry, and immunoassays allows identification of proteins that are differentially regulated in the amniotic fluid of patients with preterm labor. Specifically, the amount of the IGFBP-1 fragments at approximately 13.5 kDa was found to be increased in patients with IAI, while the amount of the intact form of IGFBP-1 was decreased.

Randomized, controlled, parallel-group prospective study to investigate the clinical effectiveness of early insulin treatment in patients with latent autoimmune diabetes in adults

BACKGROUND

Latent autoimmune diabetes in adults [LADA] is a type 1 diabetes that is slowly developing. This means many people are treated as having type 2 diabetes at diagnosis as they are adults who are not immediately insulin dependent. LADA can be distinguished from type 2 diabetes by antibody tests. Patients who are antibody positive have an autoimmune reaction which is similar to that of type 1 diabetes and is not found in type 2 diabetes. We would like to examine the best way of treating LADA in the early phase of the conditions, with tablets (similar to type 2 diabetes) or with insulin (similar to type 1 diabetes).

METHODS/DESIGN

This is an open parallel group prospective randomised trial. Participants need to have a GAD antibody test results of 101 WHO units or more and a diagnosis of diabetes not requiring insulin at diagnosis. Participants will need to have been diagnosed within 12 months and not treated with insulin at study entry. They will be randomised to receive either insulin (NovoMix 30) or tablets (diet treated followed by metformin followed by glitazone (with or without metformin) followed by insulin). Primary outcome assessment will be for change in HbA1c and change in fasting C-peptide over 24 months. Secondary outcome measures will include Quality of life, GAD antibody levels, adverse events, inflammatory markers, insulin resistance, and markers of the metabolic syndrome.

DISCUSSION

This study seeks the best treatment for early LADA in terms of maintaining glycaemic control and maintaining natural insulin production.

TRIAL REGISTRATION

ISRCTN63815121.

Prevalence and clinical features of type 1.5 diabetes mellitus in children

AIM

To classify children with diabetes mellitus as type 1, 1.5 or 2, based on strict criteria, and then compare their features and treatment.

METHODS

In this retrospective study, all children with diabetes mellitus in our clinic with antibody status available (n = 120) were reclassified as type 1, 1.5 or type 2 based on status of antibodies to the pancreas and presence of obesity and/or acanthosis nigricans, and their features compared.

RESULTS

Sixty-four percent of type 2 patients were reclassified as type 1.5. Type 1.5 patients had significantly lower BMI SDS, blood pressure and acanthosis nigricans than type 2 patients. They had a higher insulin requirement (0.82 +/- 0.44 U/kg/day) than type 1 (0.72 +/- 0.35 U/kg/day) or type 2 (0.28 +/- 0.3 U/kg/day) patients. Total cholesterol, HDL-cholesterol, ALT and AST significantly worsened from type 1 to 1.5 to type 2 patients.

CONCLUSIONS

Type 1.5 diabetes mellitus should be considered among obese adolescents presenting as type 2, as their clinical course is more aggressive and insulin requirement higher.