Interaction of onset and duration of diabetes on the percent of GAD and IA-2 antibody-positive subjects in the type 1 diabetes genetics consortium database

Exogenous Insulin Antibody Syndrome (EIAS) Presenting in an Elderly, Long-Term Patient with Type 1 Diabetes Mellitus that Resolved with Low-Cost Outpatient Therapy with Mycophenolate Mofetil and Regular Insulin by Pump

Exogenous insulin antibody syndrome (EIAS) has until recently been a rarely described complication of exogenous insulin therapy. EIAS results not only in hyperglycemia, but also in hypoglycemia and occasionally in ketoacidosis (DKA). The incidence of EIAS is increasing probably due to an overall increase in autoimmunity associated with the coronavirus disease 2019 (Covid-19) epidemic resulting in increasing binding of insulin by antibodies. Herein, we describe a case of EIAS occurring in an elderly patient with longstanding type 1 diabetes mellitus (T1DM) who had progressive loss of glycemic control. It responded positively, as we have previously described, to oral mycophenolate mofetil and the use of soluble regular insulin delivered by continuous subcutaneous insulin infusion (CSII). Therefore, EIAS is an increasingly frequent cause of hyperglycemia with and without DKA, and hypoglycemia in subjects with T1DM. Once diagnosed, they can be treated with mycophenolate mofetil and soluble insulin in an outpatient setting, which will decrease the rate of hospitalization and lower the expense of therapy.

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.

Performance of European prediction models for classification of type 1 and type 2 diabetes in Indians

AIM

We aimed to determine the performance of European prediction models in an Indian population to classify type 1 diabetes(T1D) and type 2 diabetes(T2D).

METHODS

We assessed discrimination and calibration of published models of diabetes classification, using retrospective data from electronic medical records of 83309 participants aged 18-50 years living in India. Diabetes type was defined based on C-peptide measurement and early insulin requirement. Models assessed combinations of clinical measurements: age at diagnosis, body mass index(mean = 26.6 kg/m2), sex(male = 64.9 %), Glutamic acid decarboxylase(GAD) antibody, serum cholesterol, serum triglycerides, and high-density lipoprotein(HDL) cholesterol.

RESULTS

67955 participants met inclusion criteria, of whom 0.8 % had T1D, which was markedly lower than model development cohorts. Model discrimination for clinical features was broadly similar in our Indian cohort compared to the European cohort: area under the receiver operating characteristic curve(AUC ROC) was 0.90 vs. 0.90 respectively, but was lower in the subset of young participants with measured GAD antibodies(n = 2404): and an AUC ROC of 0.87 when clinical features, sex, lipids and GAD antibodies were combined. All models substantially overestimated the likelihood of T1D, reflecting the lower prevalence of T1D in the Indian population. However, good model performance was achieved after recalibration by updating the model intercept and slope.

CONCLUSION

Models for diabetes classification maintain the discrimination of T1D and T2D in this Indian population, where T2D is far more common, but require recalibration to obtain appropriate model probabilities. External validation and recalibration are needed before these tools can be used in non-European populations.

New advances in type 1 diabetes

Type 1 diabetes is an autoimmune condition resulting in insulin deficiency and eventual loss of pancreatic β cell function requiring lifelong insulin therapy. Since the discovery of insulin more than 100 years ago, vast advances in treatments have improved care for many people with type 1 diabetes. Ongoing research on the genetics and immunology of type 1 diabetes and on interventions to modify disease course and preserve β cell function have expanded our broad understanding of this condition. Biomarkers of type 1 diabetes are detectable months to years before development of overt disease, and three stages of diabetes are now recognized. The advent of continuous glucose monitoring and the newer automated insulin delivery systems have changed the landscape of type 1 diabetes management and are associated with improved glycated hemoglobin and decreased hypoglycemia. Adjunctive therapies such as sodium glucose cotransporter-1 inhibitors and glucagon-like peptide 1 receptor agonists may find use in management in the future. Despite these rapid advances in the field, people living in under-resourced parts of the world struggle to obtain necessities such as insulin, syringes, and blood glucose monitoring essential for managing this condition. This review covers recent developments in diagnosis and treatment and future directions in the broad field of type 1 diabetes.

Understanding Islet Autoantibodies in Prediction of Type 1 Diabetes

As screening studies and preventive interventions for type 1 diabetes (T1D) advance rapidly, the utility of islet autoantibodies (IAbs) in T1D prediction comes with challenges for early and accurate disease progression prediction. Refining features of IAbs can provide more accurate risk assessment. The advances in islet autoantibodies assay techniques help to screen out islet autoantibodies with high efficiency and high disease specificity. Exploring new islet autoantibodies to neoepitopes/neoantigens remains a hot research field for improving prediction and disease pathogenesis. We will review the recent research progresses of islet autoantibodies to better understand the utility of islet autoantibodies in prediction of T1D.

The relationship between islet autoantibody status and the genetic risk of type 1 diabetes in adult-onset type 1 diabetes

AIMS/HYPOTHESIS

The reason for the observed lower rate of islet autoantibody positivity in clinician-diagnosed adult-onset vs childhood-onset type 1 diabetes is not known. We aimed to explore this by assessing the genetic risk of type 1 diabetes in autoantibody-negative and -positive children and adults.

METHODS

We analysed GAD autoantibodies, insulinoma-2 antigen autoantibodies and zinc transporter-8 autoantibodies (ZnT8A) and measured type 1 diabetes genetic risk by genotyping 30 type 1 diabetes-associated variants at diagnosis in 1814 individuals with clinician-diagnosed type 1 diabetes (1112 adult-onset, 702 childhood-onset). We compared the overall type 1 diabetes genetic risk score (T1DGRS) and non-HLA and HLA (DR3-DQ2, DR4-DQ8 and DR15-DQ6) components with autoantibody status in those with adult-onset and childhood-onset diabetes. We also measured the T1DGRS in 1924 individuals with type 2 diabetes from the Wellcome Trust Case Control Consortium to represent non-autoimmune diabetes control participants.

RESULTS

The T1DGRS was similar in autoantibody-negative and autoantibody-positive clinician-diagnosed childhood-onset type 1 diabetes (mean [SD] 0.274 [0.034] vs 0.277 [0.026], p=0.4). In contrast, the T1DGRS in autoantibody-negative adult-onset type 1 diabetes was lower than that in autoantibody-positive adult-onset type 1 diabetes (mean [SD] 0.243 [0.036] vs 0.271 [0.026], p<0.0001) but higher than that in type 2 diabetes (mean [SD] 0.229 [0.034], p<0.0001). Autoantibody-negative adults were more likely to have the more protective HLA DR15-DQ6 genotype (15% vs 3%, p<0.0001), were less likely to have the high-risk HLA DR3-DQ2/DR4-DQ8 genotype (6% vs 19%, p<0.0001) and had a lower non-HLA T1DGRS (p<0.0001) than autoantibody-positive adults. In contrast to children, autoantibody-negative adults were more likely to be male (75% vs 59%), had a higher BMI (27 vs 24 kg/m²) and were less likely to have other autoimmune conditions (2% vs 10%) than autoantibody-positive adults (all p<0.0001). In both adults and children, type 1 diabetes genetic risk was unaffected by the number of autoantibodies (p>0.3). These findings, along with the identification of seven misclassified adults with monogenic diabetes among autoantibody-negative adults and the results of a sensitivity analysis with and without measurement of ZnT8A, suggest that the intermediate type 1 diabetes genetic risk in autoantibody-negative adults is more likely to be explained by the inclusion of misclassified non-autoimmune diabetes (estimated to represent 67% of all antibody-negative adults, 95% CI 61%, 73%) than by the presence of unmeasured autoantibodies or by a discrete form of diabetes. When these estimated individuals with non-autoimmune diabetes were adjusted for, the prevalence of autoantibody positivity in adult-onset type 1 diabetes was similar to that in children (93% vs 91%, p=0.4).

CONCLUSIONS/INTERPRETATION

The inclusion of non-autoimmune diabetes is the most likely explanation for the observed lower rate of autoantibody positivity in clinician-diagnosed adult-onset type 1 diabetes. Our data support the utility of islet autoantibody measurement in clinician-suspected adult-onset type 1 diabetes in routine clinical practice.

A longitudinal assessment of diabetes autoantibodies in the SEARCH for diabetes in youth study

To assess changes in diabetes autoantibodies (DAs) over time in children and young adults with diabetes and determine whether observed changes were associated with demographic characteristics, clinical parameters and diabetes complications. Participants had DAs measured at baseline (10.3 ± 7.1 months after diabetes diagnosis) and at 12, 24 months and ≥5 years after the baseline measurement. At the ≥5-year follow-up, the presence of diabetes complications was assessed. We examined the associations between change in number of positive DAs and changes in individual DA status with the participants' characteristics and clinical parameters over time. Out of 4179 participants, 62% had longitudinal DA data and 51% had complications and longitudinal DA data. In participants with ≥1 baseline positive DA (n = 1699), 83.4% remained positive after 7.3 ± 2.3 years duration of diabetes. Decrease in number of positive DAs was associated with longer diabetes duration (p = 0.003 for 1 baseline positive DA; p < 0.001 for 2 baseline positive DAs) and younger age at diagnosis (p < 0.001 for 2 baseline positive DAs). No associations were found between change in number of positive DAs in participants with ≥1 baseline positive DA (n = 1391) and HbA1c, insulin dose, acute, or chronic complications after 7.7 ± 1.9 years duration of diabetes. DA status likely remains stable in the first 7 years after diabetes diagnosis. Younger age at diabetes diagnosis and longer duration were associated with less persistence of DAs. Measuring DAs after initial presentation may aid in diabetes classification but not likely in predicting the clinical course.

The longitudinal loss of islet autoantibody responses from diagnosis of type 1 diabetes occurs progressively over follow-up and is determined by low autoantibody titres, early-onset, and genetic variants

The clinical usefulness of post-diagnosis islet autoantibody levels is unclear and factors that drive autoantibody persistence are poorly defined in type 1 diabetes (T1D). Our aim was to characterise the longitudinal loss of islet autoantibody responses after diagnosis in a large, prospectively sampled UK cohort. Participants with T1D [n = 577] providing a diagnosis sample [range -1.0 to 2.0 years] and at least one post-diagnosis sample (<32.0 years) were tested for autoantibodies to glutamate decarboxylase 65 (GADA), islet antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A). Select HLA and non-HLA SNPs were considered. Non-genetic and genetic factors were assessed by multivariable logistic regression models for autoantibody positivity at initial sampling and autoantibody loss at final sampling. For GADA, IA-2A, and ZnT8A, 70.8%, 76.8%, and 40.1%, respectively, remained positive at the final sampling. Non-genetic predictors of autoantibody loss were low baseline autoantibody titres (P < 0.0001), longer diabetes duration (P < 0.0001), and age-at-onset under 8 years (P < 0.01--0.05). Adjusting for non-genetic covariates, GADA loss was associated with low-risk HLA class II genotypes (P = 0.005), and SNPs associated with autoimmunity RELA/11q13 (P = 0.017), LPP/3q28 (P = 0.004), and negatively with IFIH1/2q24 (P = 0.018). IA-2A loss was not associated with genetic factors independent of other covariates, while ZnT8A loss was associated with the presence of HLA A*24 (P = 0.019) and weakly negatively with RELA/11q13 (P = 0.049). The largest longitudinal study of islet autoantibody responses from diagnosis of T1D shows that autoantibody loss is heterogeneous and influenced by low titres at onset, longer duration, earlier age-at-onset, and genetic variants. These data may inform clinical trials where post-diagnosis participants are recruited.

Persistence of islet autoantibodies after diagnosis in type 1 diabetes

The presence of islet autoantibodies remains a reliable biomarker to identify individuals at high risk of developing type 1 diabetes. As such, these autoantibodies play a pivotal role in understanding the prodrome of diabetes and selecting individuals for both prevention and intervention clinical trials. Over the last few decades, studies have sought to investigate autoantibody prevalence after diabetes onset to better understand ongoing islet autoimmunity; however, many findings are contradictory, and little is known about factors that may influence autoantibody persistence. Generally, glutamate decarboxylase autoantibodies (GADAs) are the most prevalent autoantibodies after diagnosis, particularly in adults, whilst zinc transporter 8 autoantibodies (ZnT8A) prevalence declines more rapidly. However, when studies with islet autoantibody data at diagnosis are considered, it becomes clear that overall islet antigen-2 autoantibodies (IA-2A) tend to persist for longer than GADA or ZnT8A. In this review, we assess the major studies that have contributed to our understanding of autoantibody persistence after diabetes onset and what factors affect this. Islet autoantibodies may provide biomarkers for long-term β-cell function and insights into how to prevent ongoing islet autoimmunity but larger studies collecting samples at and decades after diabetes onset are required to leverage the information they could provide.

The management of type 1 diabetes in adults. A consensus report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) convened a writing group to develop a consensus statement on the management of type 1 diabetes in adults. The writing group has considered the rapid development of new treatments and technologies and addressed the following topics: diagnosis, aims of management, schedule of care, diabetes self-management education and support, glucose monitoring, insulin therapy, hypoglycaemia, behavioural considerations, psychosocial care, diabetic ketoacidosis, pancreas and islet transplantation, adjunctive therapies, special populations, inpatient management and future perspectives. Although we discuss the schedule for follow-up examinations and testing, we have not included the evaluation and treatment of the chronic microvascular and macrovascular complications of diabetes as these are well-reviewed and discussed elsewhere. The writing group was aware of both national and international guidance on type 1 diabetes and did not seek to replicate this but rather aimed to highlight the major areas that healthcare professionals should consider when managing adults with type 1 diabetes. Though evidence-based where possible, the recommendations in the report represent the consensus opinion of the authors. Graphical abstract.

The Management of Type 1 Diabetes in Adults. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) convened a writing group to develop a consensus statement on the management of type 1 diabetes in adults. The writing group has considered the rapid development of new treatments and technologies and addressed the following topics: diagnosis, aims of management, schedule of care, diabetes self-management education and support, glucose monitoring, insulin therapy, hypoglycemia, behavioral considerations, psychosocial care, diabetic ketoacidosis, pancreas and islet transplantation, adjunctive therapies, special populations, inpatient management, and future perspectives. Although we discuss the schedule for follow-up examinations and testing, we have not included the evaluation and treatment of the chronic microvascular and macrovascular complications of diabetes as these are well-reviewed and discussed elsewhere. The writing group was aware of both national and international guidance on type 1 diabetes and did not seek to replicate this but rather aimed to highlight the major areas that health care professionals should consider when managing adults with type 1 diabetes. Though evidence-based where possible, the recommendations in the report represent the consensus opinion of the authors.

Adult-onset type 1 diabetic patients with less severe clinical manifestation have less risk DR-DQ genotypes than childhood-onset patients

BACKGROUND

The aim of this study was to investigate differences in clinical features and HLA genotypes between adult-onset and childhood-onset patients with type 1 diabetes in a Chinese population.

MATERIALS AND METHODS

This study enrolled 716 Han Chinese patients with type 1 diabetes from Guangdong (258 childhood-onset and 458 adult-onset) to compare their clinical features. Of them 214 patients with classical type 1 diabetes (100 childhood-onset and 114 adult-onset) were selected for HLA DR and DQ genotyping by next-generation sequencing.

RESULTS

Adult-onset patients were characterized by longer duration of symptoms before diagnosis, lower frequency of DKA at disease onset, less frequent autoantibody positivity, higher serum C-peptide concentrations, and better glycemic control. These findings were replicated in the restricted cohort of 214 patients with classical type 1 diabetes. Compared with childhood-onset patients, adult-onset patients had a lower frequency of the DR9 haplotype, as well as lower frequency of high-risk DR3/DR4 and DR3/DR9 genotypes, but higher frequency of DR3/DR3 genotype and DR3/X, DR4/X or DR9/X (X, non-risk) genotypes.

CONCLUSIONS

Adult-onset type 1 diabetic patients with susceptible haplotypes (DR3, DR4 or DR9) were more likely to carry protective DR-DQ haplotypes than childhood-onset patients, which suggested the association between less risk DR-DQ genotypes and the less severe clinical manifestation in adult-onset patients.

Postexercise Glycemic Control in Type 1 Diabetes Is Associated With Residual β-Cell Function

OBJECTIVE

To investigate the impact of residual β-cell function on continuous glucose monitoring (CGM) outcomes following acute exercise in people with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Thirty participants with T1D for ≥3 years were recruited. First, participants wore a blinded CGM unit for 7 days of free-living data capture. Second, a 3-h mixed-meal test assessed stimulated C-peptide and glucagon. Peak C-peptide was used to allocate participants into undetectable (Cpep_und <3 pmol/L), low (Cpep_low 3-200 pmol/L), or high (Cpep_high >200 pmol/L) C-peptide groups. Finally, participants completed 45 min of incline treadmill walking at 60% VO_2peak followed by a further 48-h CGM capture.

RESULTS

CGM parameters were comparable across groups during the free-living observation week. In the 12- and 24-h postexercise periods (12 h and 24 h), the Cpep_high group had a significantly greater amount of time spent with glucose 3.9-10 mmol/L (12 h, 73.5 ± 27.6%; 24 h, 76.3 ± 19.2%) compared with Cpep_low (12 h, 43.6 ± 26.1%, P = 0.027; 24 h, 52.3 ± 25.0%, P = 0.067) or Cpep_und (12 h, 40.6 ± 17.0%, P = 0.010; 24 h, 51.3 ± 22.3%, P = 0.041). Time spent in hyperglycemia (12 h and 24 h glucose >10 and >13.9 mmol/L, P < 0.05) and glycemic variability (12 h and 24 h SD, P < 0.01) were significantly lower in the Cpep_high group compared with Cpep_und and Cpep_low. Change in CGM outcomes from pre-exercise to 24-h postexercise was divergent: Cpep_und and Cpep_low experienced worsening (glucose 3.9-10 mmol/L: -9.1% and -16.2%, respectively), with Cpep_high experiencing improvement (+12.1%) (P = 0.017).

CONCLUSIONS

Residual β-cell function may partially explain the interindividual variation in the acute glycemic benefits of exercise in individuals with T1D. Quantifying C-peptide could aid in providing personalized and targeted support for exercising patients.

Different interaction of onset age and duration of type 1 diabetes on the dynamics of autoantibodies to insulinoma-associated antigen-2 and zinc transporter 8

Aims/Introduction

This study aimed to investigate the dynamics associated with autoantibodies to insulinoma‐associated antigen‐2 (IA‐2A) and zinc transporter 8 (ZnT8A) relating to the onset age and disease duration in patients with type 1 diabetes.

Methods

Using bridging‐type enzyme‐linked immunosorbent assay, IA‐2A, ZnT8A and glutamic acid decarboxylase autoantibodies were evaluated in 269 patients with type 1 diabetes (median onset age 18.2 years, range 0.8–86 years; median diabetes duration 7 years, range 0–58 years). We then compared the prevalence of these autoantibodies among the different age groups, along with the duration of diabetes using the Cochran–Armitage trend test and multivariate logistic regression analysis.

Results

The prevalence of IA‐2A, ZnT8A and glutamic acid decarboxylase autoantibodies in patients with duration of ≤3 years was 41.1, 36.7 and 72.2%, respectively, with 80.0% expressing one or more of these autoantibodies. This prevalence declined according to the disease duration (P < 0.005). Both IA‐2A and ZnT8A were more frequently observed in younger patients, whereas glutamic acid decarboxylase autoantibodies was more common in older patients. Multivariate logistic regression analysis showed that there was a significant interaction between the onset age and duration of diabetes in patients diagnosed when aged ≤10 years regarding all anti‐islet autoantibodies (P < 0.05). However, for patients diagnosed in the middle tertile (aged 11–30 years), the interaction was significant only for ZnT8A, and for those with late‐onset diabetes (aged ≥31 years) only for IA‐2A.

Conclusions

The current study showed that the rate of disappearance of anti‐islet autoantibodies is faster in patients aged ≤10 years, and that even though both proteins are localized in the insulin granule membrane, humoral autoimmunity to IA‐2 and ZnT8 differs according to the age of onset.

Clinical and genetic correlates of islet-autoimmune signatures in juvenile-onset type 1 diabetes

AIMS/HYPOTHESIS

Heterogeneity in individuals with type 1 diabetes has become more generally appreciated, but has not yet been extensively and systematically characterised. Here, we aimed to characterise type 1 diabetes heterogeneity by creating immunological, genetic and clinical profiles for individuals with juvenile-onset type 1 diabetes in a cross-sectional study.

METHODS

Participants were HLA-genotyped to determine HLA-DR-DQ risk, and SNP-genotyped to generate a non-HLA genetic risk score (GRS) based on 93 type 1 diabetes-associated SNP variants outside the MHC region. Islet autoimmunity was assessed as T cell proliferation upon stimulation with the beta cell antigens GAD65, islet antigen-2 (IA-2), preproinsulin (PPI) and defective ribosomal product of the insulin gene (INS-DRIP). Clinical parameters were collected retrospectively.

RESULTS

Of 80 individuals, 67 had proliferation responses to one or more islet antigens, with vast differences in the extent of proliferation. Based on the multitude and amplitude of the proliferation responses, individuals were clustered into non-, intermediate and high responders. High responders could not be characterised entirely by enrichment for the highest risk HLA-DR3-DQ2/DR4-DQ8 genotype. However, high responders did have a significantly higher non-HLA GRS. Clinically, high T cell responses to beta cell antigens did not reflect in worsened glycaemic control, increased complications, development of associated autoimmunity or younger age at disease onset. The number of beta cell antigens that an individual responded to increased with disease duration, pointing to chronic islet autoimmunity and epitope spreading.

CONCLUSIONS/INTERPRETATION

Collectively, these data provide new insights into type 1 diabetes disease heterogeneity and highlight the importance of stratifying patients on the basis of their genetic and autoimmune signatures for immunotherapy and personalised disease management.

Development and validation of multivariable clinical diagnostic models to identify type 1 diabetes requiring rapid insulin therapy in adults aged 18-50 years

OBJECTIVE

To develop and validate multivariable clinical diagnostic models to assist distinguishing between type 1 and type 2 diabetes in adults aged 18-50.

DESIGN

Multivariable logistic regression analysis was used to develop classification models integrating five pre-specified predictor variables, including clinical features (age of diagnosis, body mass index) and clinical biomarkers (GADA and Islet Antigen 2 islet autoantibodies, Type 1 Diabetes Genetic Risk Score), to identify type 1 diabetes with rapid insulin requirement using data from existing cohorts.

SETTING

UK cohorts recruited from primary and secondary care.

PARTICIPANTS

1352 (model development) and 582 (external validation) participants diagnosed with diabetes between the age of 18 and 50 years of white European origin.

MAIN OUTCOME MEASURES

Type 1 diabetes was defined by rapid insulin requirement (within 3 years of diagnosis) and severe endogenous insulin deficiency (C-peptide <200 pmol/L). Type 2 diabetes was defined by either a lack of rapid insulin requirement or, where insulin treated within 3 years, retained endogenous insulin secretion (C-peptide >600 pmol/L at ≥5 years diabetes duration). Model performance was assessed using area under the receiver operating characteristic curve (ROC AUC), and internal and external validation.

RESULTS

Type 1 diabetes was present in 13% of participants in the development cohort. All five predictor variables were discriminative and independent predictors of type 1 diabetes (p<0.001 for all) with individual ROC AUC ranging from 0.82 to 0.85. Model performance was high: ROC AUC range 0.90 (95% CI 0.88 to 0.93) (clinical features only) to 0.97 (95% CI 0.96 to 0.98) (all predictors) with low prediction error. Results were consistent in external validation (clinical features and GADA ROC AUC 0.93 (0.90 to 0.96)).

CONCLUSIONS

Clinical diagnostic models integrating clinical features with biomarkers have high accuracy for identifying type 1 diabetes with rapid insulin requirement, and could assist clinicians and researchers in accurately identifying patients with type 1 diabetes.

Relationship between islet autoantibody status and the clinical characteristics of children and adults with incident type 1 diabetes in a UK cohort

OBJECTIVES

To describe the characteristics of children and adults with incident type 1 diabetes in contemporary, multiethnic UK, focusing on differences between the islet autoantibody negative and positive.

DESIGN

Observational cohort study.

SETTING

146 mainly secondary care centres across England and Wales.

PARTICIPANTS

3312 people aged ≥5 years were recruited within 6 months of a clinical diagnosis of type 1 diabetes via the National Institute for Health Research Clinical Research Network. 3021 were of white European ethnicity and 291 (9%) were non-white. There was a small male predominance (57%). Young people <17 years comprised 59%.

MAIN OUTCOME MEASURES

Autoantibody status and characteristics at presentation.

RESULTS

The majority presented with classical osmotic symptoms, weight loss and fatigue. Ketoacidosis was common (42%), especially in adults, and irrespective of ethnicity. 35% were overweight or obese. Of the 1778 participants who donated a blood sample, 85% were positive for one or more autoantibodies against glutamate decarboxylase, islet antigen-2 and zinc transporter 8. Presenting symptoms were similar in the autoantibody-positive and autoantibody-negative participants, as was the frequency of ketoacidosis (43%vs40%, P=0.3). Autoantibody positivity was less common with increasing age (P=0.0001), in males compared with females (82%vs90%, P<0.0001) and in people of non-white compared with white ethnicity (73%vs86%, P<0.0001). Body mass index was higher in autoantibody-negative adults than autoantibody-positive adults (median, IQR 25.5, 23.1-29.2vs23.9, 21.4-26.7 kg/m²; P=0.0001). Autoantibody-negative participants were more likely to have a parent with diabetes (28%vs16%, P<0.0001) and less likely to have another autoimmune disease (4%vs8%, P=0.01).

CONCLUSIONS

Most people assigned a diagnosis of type 1 diabetes presented with classical clinical features and islet autoantibodies. Although indistinguishable at an individual level, autoantibody-negative participants as a group demonstrated features more typically associated with other diabetes subtypes.

TRIAL REGISTRATION NUMBER

ISRCTN66496918; Pre-results.

Four-year clinical remission of type 1 diabetes mellitus in two patients treated with sitagliptin and vitamin D3

Type 1 diabetes mellitus (T1DM) is a chronic disease characterized by autoimmune destruction of pancreatic beta cells and inadequate insulin production. Remission criteria in T1DM take into account serum levels of C-peptide and glycosylated hemoglobin, as well as the dose of insulin administered to the patient. However, remission of T1DM lasting longer than 1 year is rare. We describe here the cases of two young women who presented with positive glutamic acid decarboxylase (GAD) antibody and classic clinical manifestations of T1DM. Both patients had a prior history of Hashimoto’s thyroiditis. They were initially treated with a basal-bolus regimen of insulin (glargine and lispro/glulisine). Once their blood glucose levels were controlled, they were started on oral sitagliptin 100 mg and vitamin D3 5000 IU daily. After this therapy, both patients achieved clinical diabetes remission for 4 years, along with a decrease in anti-GAD antibody levels. These benefits were probably associated with immunological effects of these medications. Inhibition of dipeptidyl peptidase 4 (DPP-4) in animal models deregulates Th1 immune response, increases secretion of Th2 cytokines, activates CD4⁺CD25⁺FoxP3⁺ regulatory T-cells and prevents IL-17 production. Vitamin D3 also activates CD4⁺CD25⁺FoxP3⁺ regulatory T-cells, and these medications combined can improve the immune response in patients with new-onset T1DM and probably promote sustained clinical remission.

Islet Autoantibodies

Islet autoantibodies are the main markers of pancreatic autoimmunity in type 1 diabetes (T1D). Islet autoantibodies recognize insulin (IAA), glutamic acid decarboxylase (GADA), protein phosphatase-like IA-2 (IA-2A), and ZnT8 (ZnT8A), all antigens that are found on secretory granules within pancreatic beta cells. Islet antibodies, measured by sensitive and specific liquid phase assays, are the key parameters of the autoimmune response monitored for diagnostics or prognostics in patients with T1D or for disease prediction in at-risk individuals before T1D onset. Islet autoantibodies have been the main tool used to explore the natural history of T1D; this review summarizes the current knowledge about the autoantigens and the phenotype of islets autoantibodies acquired in large prospective studies from birth in children at risk of developing T1D.

Professional continuous glucose monitoring for the identification of type 1 diabetes mellitus among subjects with insulin therapy

The identification of type 1 diabetes in diabetic subjects receiving insulin therapy is sometimes difficult. The purpose of this study is to evaluate whether results of professional continuous glucose monitoring can improve the identification of type 1 diabetes.From 2007 to 2012, 119 adults receiving at least twice-daily insulin therapy and professional continuous glucose monitoring were recruited. Type 1 diabetes was diagnosed by endocrinologists according to American Diabetes Association standards, including a very low C-peptide level (<0.35  pg/mL) or the presence of diabetic ketoacidosis. Continuous glucose monitoring was applied for 3 days.Among 119 subjects, 86 were diagnosed with type 1 diabetes. Subjects with type 1 diabetes were younger (33.8 vs 52.3 years old, P < 0.001), had lower body mass index (BMI, 21.95 vs 24.42, P = 0.003), lower serum creatinine (61.77  vs 84.65 μmol/L, P = 0.001), and higher estimated glomerular filtration rate (108.71 vs 76.48 mg/mL/min/1.73m2, P < 0.001) than subjects with type 2 diabetes. Predictive scores for identification of type 1 diabetes were constructed, including age, BMI, average mean amplitude of glucose excursion in days 2 and 3, and the area under the curve of nocturnal hyperglycemic and hypoglycemic states. The area under the receiver operating characteristic curve was 0.90. With the cutoff of 0.58, the sensitivity was 86.7% and the specificity was 80.8%. The good performance was validated by the leave-one-out method (sensitivity 83.3%, specificity 73.1%).Professional continuous glucose monitoring is a useful tool that improves identification of type 1 diabetes among diabetic patients receiving insulin therapy.

Factors associated with the presence of glutamic acid decarboxylase and islet antigen-2 autoantibodies in patients with long-standing type 1 diabetes

AIM

Glutamic acid decarboxylase (GAD) and/or islet antigen-2 (IA-2) autoantibodies (ab) are present in 90% of patients at the onset of type 1 diabetes (T1D). Few studies have shown that they may persist in the long-term. We analysed the frequency of GADab and IA-2ab and the factors associated with their persistency in patients with long-lasting T1D.

METHODS

This cross-sectional study included 430 adult patients with T1D of at least 10-year duration, consecutively seen over one year. GADab and IA-2ab were determined by radio-binding assays. Autoantibodies to thyroperoxydase, gastric parietal cells and transglutaminase were assessed in 418 patients, and HLA DRB1 genotyping in 359. Parameters associated with the persistency of antibodies were studied by multivariate analysis.

RESULTS

Median age at diagnosis of T1D was 12 years, and median diabetes duration was 19 years. Extrapancreatic autoimmunity was present in 38% of the patients, and associated autoimmune diseases in 21%. GADab and/or IA-2ab were found in 56% of the patients, and in 32% in those with more than 25-year diabetes duration. GADab were more frequent than IA-2ab. Female sex, an older age at diagnosis, and a shorter duration of diabetes were independently associated with the presence of ab. The same factors and the DR3 allele were associated with GADab, while only diabetes duration and the DR4 allele were associated with IA-2ab.

CONCLUSION

In a large proportion of the patients with T1D, the long-term persistency of diabetes-associated antibodies allows aetiological diagnosis, even far from the onset of hyperglycaemia.

The increasing onset of type 1 diabetes in children

OBJECTIVE

To identify trends in the recent onset of type 1 diabetes (T1D) in Colorado youth seen at the Barbara Davis Center (BDC) and compare these changes over time.

STUDY DESIGN

A retrospective chart review was performed of patients ages 0-20 years at diagnosis of T1D and type 2 diabetes who were seen at the BDC, were living within Colorado at diagnosis, and were seen within 1 month of diagnosis between 1996 and 2010. The review included age of onset, sex, month and season of onset, islet autoantibodies, diabetes type, hemoglobin A1c level, and body mass index.

RESULTS

Newly diagnosed youth with diabetes (n = 2841) were seen at the BDC between 1996 and 2010. Of these, 2686 (94.4%) had T1D. The number of newly diagnosed youth increased over the 15 years by 5.71% per year when adjusted for population (P < .0001). When analyzed in 5-year periods, the average number of new onset T1D cases, age-adjusted to the population, increased by 9.46% per year from 1996-2000 to 2001-2005. The increase was only 4.86% per year from 2001-2005 to 2006-2010. Islet autoimmune markers appeared to correlate with changes in T1D new onset cases.

CONCLUSION

T1D in youth increased significantly from the late 1990s-2005 and has increased at a lesser rate more recently. Data suggests that even though T1D has increased in all age groups, the greatest increase was in the 5-9 year age category.

Pancreatic exocrine function in patients with diabetes

BACKGROUND

Decreased function of the exocrine pancreas is frequent in patients with diabetes. Our aim was to investigate clinical correlates of pancreatic exocrine failure in patients with diabetes.

PATIENTS AND METHODS

We investigated exocrine function by assaying both elastase-1 concentration and chymotrypsin activity in 667 patients. We conducted separate analysis on patients with Type 1 diabetes and patients with Type 2 diabetes. Patients were separated into three groups according to whether both elastase-1 concentration and chymotrypsin activity were normal, or one or both were altered.

RESULTS

A total of 667 consecutive patients were analysed, including 195 with Type 1 and 472 with Type 2 diabetes. Elastase-1 concentration was <200 μg/g in 23% of the patients. Chymotrypsin activity was <6 U/g in 26% of the patients. In 66% of the patients elastase-1 concentration was >200 ug/g and chymotrypsin activity >6 U/g. One test was below threshold in 19%, both in 15%. In patients with Type 1 diabetes, the three groups defined by results of elastase-1 concentration and chymotrypsin activity differed with regard to duration of diabetes and prevalence of glutamic acid decarboxylase antibodies, but not BMI or HbA(1c) , or prevalence of retinopathy, neuropathy, nephropathy or vascular disease. In patients with Type 2 diabetes, the three groups differed with regard to BMI, use of insulin and vascular disease, but not known duration.

CONCLUSION

Factors associated with pancreatic exocrine failure differ in patients with Type 1 diabetes compared with patients with type 2 diabetes. In patients with Type 2 diabetes, association of decreased pancreatic exocrine function with BMI and vascular disease suggests a role of pancreatic arteriopathy.