Accuracy and predictive value of classification schemes for ketosis-prone diabetes

Clinical Utility of Serum C-Peptide Concentration for Hospitalized Patients with Hyperglycemia

Background: Serum C-peptide concentration is often utilized for diagnostic, prognostic, or therapeutic assessment in diabetes mellitus. However, there are limited clinical data regarding diagnostic and predictive value of C-peptide measured during hospitalizations for hyperglycemia. Materials and Methods: Adults admitted to Mayo Clinic inpatient facilities due to an acute hyperglycemic emergency between January 2017 and November 2022 were included in our study. Predictive capacity of C-peptide for discontinuation of therapeutic insulin was examined in the entire cohort and the subgroup of non-autoimmune non-pancreatitis diabetes (NANP-DM). Results: We included 187 patients (63 women) in our study. During hospitalization, patients with type 1 diabetes antibodies displayed diminished serum C-peptide concentration (P = 0.014), correlating inversely with subsequent hemoglobin A1c% [r = (-0.22), P = 0.005]. Initial C-peptide concentrations did not differ between patients requiring insulin therapy during follow-up and those who did not (P = 0.16). C-peptide concentrations showed limited predictive capacity for achieving glycemic control. Subgroup analyses in NANP-DM exhibited similar limited capacity for anticipating therapeutic insulin needs and achieving glycemic controls. Discussion: C-peptide concentration did not exhibit a robust predictive capability for future need of insulin therapy and achieving glycemic control, limiting its utility in clinical practice within inpatient settings.

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.

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.

Phenotype and predictors of insulin independence in adults presenting with diabetic ketoacidosis: a prospective cohort study

AIMS/HYPOTHESIS

The aim of this work was to describe the phenotype of adults presenting with a first episode of diabetic ketoacidosis (DKA) in Cape Town, South Africa, and identify predictors of insulin independence at 12 and 60 months after presentation.

METHODS

A prospective, descriptive cohort study of all individuals, 18 years or older, presenting for the first time with DKA to four public-sector hospitals of the Groote Schuur Academic Health Complex was performed. Clinical, biochemical and laboratory data including GAD antibody and C-peptide status were collected at baseline. Insulin was systematically weaned and stopped in individuals who achieved normoglycaemia within the months after DKA. Individuals were followed for 12 months and then annually until 5 years after initial presentation with ketoacidosis.

RESULTS

Eighty-eight individuals newly diagnosed with diabetes when presenting with DKA were included and followed for 5 years. The mean ± SD age was 35±10 years and the median (IQR) BMI at diagnosis was 28.5 (23.3-33.4) kg/m2. Overall, 46% were insulin independent 12 months after diagnosis and 26% remained insulin independent 5 years after presentation. Forty-one participants (47%) tested negative for anti-GAD and anti-IA-2 antibodies and had C-peptide levels >0.3 nmol/l; in this group, 68% were insulin independent at 12 months and 37% at 5 years after diagnosis. The presence of acanthosis nigricans was strongly associated with insulin independence (OR 27.1 [95% CI 7.2, 102.2]; p<0.001); a positive antibody status was associated with a lower likelihood of insulin independence at 12 months (OR 0.10 [95% CI 0.03, 0.36]; p<0.001). On multivariable analysis only acanthosis (OR 11.5 [95% CI 2.5, 53.2]; p=0.004) was predictive of insulin independence 5 years after diagnosis.

CONCLUSIONS/INTERPRETATION

The predominant phenotype of adults presenting with a first episode of DKA in Cape Town, South Africa, was that of ketosis-prone type 2 diabetes. These individuals presented with obesity, acanthosis nigricans, negative antibodies and normal C-peptide and could potentially be weaned off insulin at follow-up. Classic type 1 diabetes (lower weight, antibody positivity, low or unrecordable C-peptide levels and long-term insulin dependence) was less common. The simple clinical sign of acanthosis nigricans is a strong predictor of insulin independence at 12 months and 5 years after initial presentation.

The challenges of identifying and studying type 1 diabetes in adults

Diagnosing type 1 diabetes in adults is difficult since type 2 diabetes is the predominant diabetes type, particularly with an older age of onset (approximately >30 years). Misclassification of type 1 diabetes in adults is therefore common and will impact both individual patient management and the reported features of clinically classified cohorts. In this article, we discuss the challenges associated with correctly identifying adult-onset type 1 diabetes and the implications of these challenges for clinical practice and research. We discuss how many of the reported differences in the characteristics of autoimmune/type 1 diabetes with increasing age of diagnosis are likely explained by the inadvertent study of mixed populations with and without autoimmune aetiology diabetes. We show that when type 1 diabetes is defined by high-specificity methods, clinical presentation, islet-autoantibody positivity, genetic predisposition and progression of C-peptide loss remain broadly similar and severe at all ages and are unaffected by onset age within adults. Recent clinical guidance recommends routine islet-autoantibody testing when type 1 diabetes is clinically suspected or in the context of rapid progression to insulin therapy after a diagnosis of type 2 diabetes. In this moderate or high prior-probability setting, a positive islet-autoantibody test will usually confirm autoimmune aetiology (type 1 diabetes). We argue that islet-autoantibody testing of those with apparent type 2 diabetes should not be routinely undertaken as, in this low prior-prevalence setting, the positive predictive value of a single-positive islet antibody for autoimmune aetiology diabetes will be modest. When studying diabetes, extremely high-specificity approaches are needed to identify autoimmune diabetes in adults, with the optimal approach depending on the research question. We believe that until these recommendations are widely adopted by researchers, the true phenotype of late-onset type 1 diabetes will remain largely misunderstood.

Understanding diabetes heterogeneity: key steps towards precision medicine in diabetes

Diabetes is a highly heterogeneous condition; yet, it is diagnosed by measuring a single blood-borne metabolite, glucose, irrespective of aetiology. Although pragmatically helpful, disease classification can become complex and limit advances in research and medical care. Here, we describe diabetes heterogeneity, highlighting recent approaches that could facilitate management by integrating three disease models across all forms of diabetes, namely, the palette model, the threshold model and the gradient model. Once diabetes has developed, further worsening of established diabetes and the subsequent emergence of diabetes complications are kept in check by multiple processes designed to prevent or circumvent metabolic dysfunction. The impact of any given disease risk factor will vary from person-to-person depending on their background, diabetes-related propensity, and environmental exposures. Defining the consequent heterogeneity within diabetes through precision medicine, both in terms of diabetes risk and risk of complications, could improve health outcomes today and shine a light on avenues for novel therapy in the future.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association for Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (HbA1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of HbA1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Type 1 Diabetes Genetic Risk Score Differentiates Subgroups of Ketosis-Prone Diabetes

OBJECTIVE

To determine whether genetic risk for type 1 diabetes (T1D) differentiates the four Aβ subgroups of ketosis-prone diabetes (KPD), where A+ and A- define the presence or absence of islet autoantibodies and β+ and β- define the presence or absence of β-cell function.

RESEARCH DESIGN AND METHODS

We compared T1D genetic risk scores (GRS) of patients with KPD across subgroups, race/ethnicity, β-cell function, and glycemia.

RESULTS

Among 426 patients with KPD (54% Hispanic, 31% African American, 11% White), rank order of GRS was A+β- > A+β+ = A-β- > A-β+. GRS of A+β- KPD was lower than that of a T1D cohort, and GRS of A-β+ KPD was higher than that of a type 2 diabetes cohort. GRS was lowest among African American patients, with a similar distribution across KPD subgroups.

CONCLUSIONS

T1D genetic risk delineates etiologic differences among KPD subgroups. Patients with A+β- KPD have the highest and those with A-β+ KPD the lowest GRS.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association of Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (Hb A1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of Hb A1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

The Rare and Atypical Diabetes Network (RADIANT) Study: Design and Early Results

OBJECTIVE

The Rare and Atypical Diabetes Network (RADIANT) will perform a study of individuals and, if deemed informative, a study of their family members with uncharacterized forms of diabetes.

RESEARCH DESIGN AND METHODS

The protocol includes genomic (whole-genome [WGS], RNA, and mitochondrial sequencing), phenotypic (vital signs, biometric measurements, questionnaires, and photography), metabolomics, and metabolic assessments.

RESULTS

Among 122 with WGS results of 878 enrolled individuals, a likely pathogenic variant in a known diabetes monogenic gene was found in 3 (2.5%), and six new monogenic variants have been identified in the SMAD5, PTPMT1, INS, NFKB1, IGF1R, and PAX6 genes. Frequent phenotypic clusters are lean type 2 diabetes, autoantibody-negative and insulin-deficient diabetes, lipodystrophic diabetes, and new forms of possible monogenic or oligogenic diabetes.

CONCLUSIONS

The analyses will lead to improved means of atypical diabetes identification. Genetic sequencing can identify new variants, and metabolomics and transcriptomics analysis can identify novel mechanisms and biomarkers for atypical disease.

Data Mining Framework for Discovering and Clustering Phenotypes of Atypical Diabetes

CONTEXT

Some individuals present with forms of diabetes that are "atypical" (AD), which do not conform to typical features of either type 1 diabetes (T1D) or type 2 diabetes (T2D). These forms of AD display a range of phenotypic characteristics that likely reflect different endotypes based on unique etiologies or pathogenic processes.

OBJECTIVE

To develop an analytical approach to identify and cluster phenotypes of AD.

METHODS

We developed Discover Atypical Diabetes (DiscoverAD), a data mining framework, to identify and cluster phenotypes of AD. DiscoverAD was trained against characteristics of manually classified patients with AD among 278 adults with diabetes within the Cameron County Hispanic Cohort (CCHC) (Study A). We then tested DiscoverAD in a separate population of 758 multiethnic children with T1D within the Texas Children's Hospital Registry for New-Onset Type 1 Diabetes (TCHRNO-1) (Study B).

RESULTS

We identified an AD frequency of 11.5% in the CCHC (Study A) and 5.3% in the pediatric TCHRNO-1 (Study B). Cluster analysis identified 4 distinct groups of AD in Study A: cluster 1, positive for the 65 kDa glutamate decarboxylase autoantibody (GAD65Ab), adult-onset, long disease duration, preserved beta-cell function, no insulin treatment; cluster 2, GAD65Ab negative, diagnosed at age ≤21 years; cluster 3, GAD65Ab negative, adult-onset, poor beta-cell function, lacking central obesity; cluster 4, diabetic ketoacidosis (DKA)-prone participants lacking a typical T1D phenotype. Applying DiscoverAD to the pediatric patients with T1D in Study B revealed 2 distinct groups of AD: cluster 1, autoantibody negative, poor beta-cell function, lower body mass index (BMI); cluster 2, autoantibody positive, higher BMI, higher incidence of DKA.

CONCLUSION

DiscoverAD can be adapted to different datasets to identify and define phenotypes of participants with AD based on available clinical variables.

Remission in Ketosis-Prone Diabetes

Heterogeneous forms of Ketosis-prone diabetes (KPD) are characterized by patients who present with diabetic ketoacidosis (DKA) but lack the typical features and biomarkers of autoimmune T1D. The A-β+ subgroup of KPD provides unique insight into the concept of "remission" since these patients have substantial preservation of beta-cell function permitting the discontinuation of insulin therapy, despite initial presentation with DKA. Measurements of C-peptide levels are essential to predict remission and guide potential insulin withdrawal. Further studies into predictors of remission and relapse can help us guide patients with A-β+ KPD toward remission and develop targeted treatments for this form of atypical diabetes.

Ketosis-prone diabetes mellitus: A phenotype that hospitalists need to understand

Diabetes has been classified mainly into types 1 and 2. Some type 2 diabetes patients, when developing ketosis, have been labeled as having atypical diabetes. Lately, syndromes of ketosis-prone diabetes, primarily in patients who we previously classified as type 2 diabetics, have emerged, and calls are being made to even reclassify diabetes. This mini-review will extensively deal with the historical, molecular, phenotypical, and clinical basis of why ketosis-prone diabetes is different than the traditional principles of type 1 and 2 diabetes and should be classified as such. Clinicians, especially those who are not diabetologists or endocrinologists, as well as hospitalists, intensivists, and primary care providers, will greatly benefit from this review.

Adult-onset type 1 diabetes: A changing perspective

Type 1 diabetes most commonly presents in adulthood, contrary to the widely held view that it is a disease of childhood. Furthermore, a substantial proportion of cases of adult-onset type 1 diabetes does not require insulin therapy at clinical onset. Recent studies have emphasised the evidence that adult-onset type 1 diabetes is prevalent but often misclassified initially as type 2 diabetes (1, 2). In this review, we discuss that recent literature, highlighting the similarities and differences between adult-onset and childhood-onset type 1 diabetes, exploring recent debates surrounding its epidemiology and genetics, as well as expanding on important issues of diagnostic criteria for individuals presenting with adult-onset diabetes and the subsequent management once identified as having an autoimmune basis. In addition, this review looks at the psychosocial challenges faced by T1D patients and their possible management.

Clinical Significance of Insulin Peptide-specific Interferon-γ-related Immune Responses in Ketosis-prone Type 2 Diabetes

CONTEXT

Unprovoked A-β+ ketosis-prone type 2 diabetes (KPD) is characterized by the sudden onset of diabetic ketosis/ketoacidosis (DK/DKA) without precipitating factors, negative anti-islet autoantibodies ("A-"), and preservation of β-cell function ("β+") after recovery from DKA. Although this phenotype often appears with acute hyperglycemia and DK/DKA just like acute-onset type 1 diabetes (AT1D), the involvement of anti-islet immune responses remains unknown.

OBJECTIVE

We sought to clarify the immunological role of insulin-associated molecules in unprovoked A-β+ KPD.

METHODS

In this cross-sectional study, blood samples from 75 participants (42 with AT1D and 33 with KPD) were evaluated for interferon (IFN)-γ-secreting peripheral blood mononuclear cells (PBMCs) reactive to 4 insulin B-chain amino acid 9-23-related peptides (B:9-23rPep) using an enzyme-linked immunospot (ELISpot) assay.

RESULTS

Overall, 36.4% (12/33) of KPD participants showed positive IFN-γ ELISpot assay results; the positivity rate in KPD was similar to that in AT1D (38.1%; 16/42) and statistically significantly higher than the previously reported rate in type 2 diabetes (8%; 2/25; P < .0167). Moreover, B:9-23rPep-specific IFN-γ-producing PBMC frequency was negatively correlated with age and ad lib serum C-peptide levels in all KPD participants and positively correlated with glycated hemoglobin A1c level in KPD participants with positive IFN-γ ELISpot results.

CONCLUSION

These findings suggest the involvement of B:9-23rPep-specific IFN-γ-related immunoreactivity in the pathophysiology of some unprovoked A-β+ KPD. Moreover, increased immunoreactivity may reflect transiently decreased β-cell function and increased disease activity at the onset of DK/DKA, thereby playing a key role in DK/DKA development in this KPD phenotype.

A Pediatric Case of Ketosis-Prone Type 2 Diabetes Requiring Insulin Therapy

In recent years, cases of diabetic ketoacidosis (DKA) or ketosis as the initial manifestation of diabetes with a similar clinical course to that of type 2 diabetes have been reported. This phenotype has been recognized as ketosis-prone type 2 diabetes (KPD). Most cases of KPD occur in adults, and the typical clinical course is that patients are often able to wean off insulin therapy after initial treatment. We report a pediatric case of ketosis-prone type 2 diabetes requiring insulin therapy with four years of follow-up. Our case suggests that patients with KPD may require strict management, including weight control, compared with patients with typical type 2 diabetes.

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.

Masqueraders: how to identify atypical diabetes in primary care

Diabetes mellitus is a complex set of conditions that impacts 34 million Americans. While type 1 diabetes, type 2 diabetes, and gestational diabetes are most frequently encountered, there are many other types of diabetes with which healthcare providers are less familiar. These atypical forms of diabetes make up nearly 10% of diabetes cases and can masquerade as type 1 or 2 diabetes mellitus (T1DM or T2DM), and the treatment may not be optimized if the diagnosis is not accurate. Atypical forms include monogenic diabetes (formally known as maturity-onset diabetes of the young [MODY]), latent autoimmune diabetes of the adult (LADA), ketosis-prone diabetes, and secondary diabetes. This paper will detail the defining characteristics of each atypical form and demonstrate how they can masquerade as type 1 or 2 diabetes mellitus. Gestational diabetes mellitus will not be discussed in this article.

REPRINT OF: CLASSIFICATION OF DIABETES MELLITUS

Executive Summary This document updates the 1999 World Health Organization (WHO) classification of diabetes. It prioritizes clinical care and guides health professionals in choosing appropriate treatments at the time of diabetes diagnosis, and provides practical guidance to clinicians in assigning a type of diabetes to individuals at the time of diagnosis. It is a compromise between clinical and aetiological classification because there remain gaps in knowledge of the aetiology and pathophysiology of diabetes. While acknowledging the progress that is being made towards a more precise categorization of diabetes subtypes, the aim of this document is to recommend a classification that is feasible to implement in different settings throughout the world. The revised classification is presented in Table 1. Unlike the previous classification, this classification does not recognize subtypes of type 1 diabetes and type 2 diabetes and includes new types of diabetes ("hybrid types of diabetes" and "unclassified diabetes").

Uncommon forms of diabetes

Diabetes mellitus is a common condition which all clinicians will encounter in their clinical practice. The most common form is type 2 diabetes followed by type 1 diabetes. However, there are many other atypical forms of diabetes which are important for a clinician to consider as it can impact on the diagnosis and their management.This article focuses on maturity onset diabetes of the young (MODY), latent autoimmune diabetes in adults (LADA), ketosis-prone diabetes and other secondary forms of diabetes such as pancreatic cancer and haemochromatosis. We briefly describe the key clinical features of these forms of diabetes and their investigations and treatment.

Acute Metabolic Emergencies in Diabetes: DKA, HHS and EDKA

Emergency admissions due to acute metabolic crisis in patients with diabetes remain some of the most common and challenging conditions. DKA (Diabetic Ketoacidosis), HHS (Hyperglycaemic Hyperosmolar State) and recently focused EDKA (Euglycaemic Diabetic Ketoacidosis) are life-threatening different entities. DKA and HHS have distinctly different pathophysiology but basic management protocols are the same. EDKA is just like DKA but without hyperglycaemia. T1D, particularly children are vulnerable to DKA and T2D, particularly elderly with comorbidities are vulnerable to HHS. But these are not always the rule, these acute conditions are often occur in different age groups with diabetes. It is essential to have a coordinated care from the multidisciplinary team to ensure the timely delivery of right treatment. DKA and HHS, in many instances can present as a mixed entity as well. Mortality rate is higher for HHS than DKA but incidences of DKA are much higher than HHS. The prevalence of HHS in children and young adults are increasing due to exponential growth of obesity and increasing T2D cases in this age group. Following introduction of SGLT2i (Sodium-GLucose co-Transporter-2 inhibitor) for T2D and off-label use in T1D, some incidences of EDKA has been reported. Healthcare professionals should be more vigilant during acute illness in diabetes patients on SGLT2i without hyperglycaemia to rule out EDKA. Middle aged, mildly obese and antibody negative patients who apparently resemble as T2D without any precipitating causes sometime end up with DKA which is classified as KPD (Ketosis-prone diabetes). Many cases can be prevented by following 'Sick day rules'. Better access to medical care, structured diabetes education to patients and caregivers are key measures to prevent acute metabolic crisis.

Disentangling the heterogeneity of adulthood-onset non-autoimmune diabetes: a little closer but lot more to do

Diabetes diagnosed in adults is a highly heterogeneous disorder. It mostly consists of what is referred to as type 2 diabetes but also comprises other entities (i.e. different diseases), including latent autoimmune diabetes, late onset forms of monogenic diabetes and familial diabetes of the adulthood, which has recently been the source of new diabetogenes discovery. Notably, type 2 diabetes is itself heterogeneous as it includes subtypes with onset at the extremes of age and/or weight distributions characterized by different degree of hyperglycemia and cardiovascular risk as compared to common forms of type 2 diabetes occurring in middle-aged, overweight/obese individuals. Understanding whether these are different presentations of one, highly heterogeneous disease or separate nosological entities with different clinical trajectories and requiring different treatments is essential to effectively pursue the path of precision medicine.

Challenges in the diagnosis of diabetes type in pediatrics

The incidence of diabetes, both type 1 and type 2, is increasing. Health outcomes in pediatric diabetes are currently poor, with trends indicating that they are worsening. Minority racial/ethnic groups are disproportionately affected by suboptimal glucose control and have a higher risk of acute and chronic complications of diabetes. Correct clinical management starts with timely and accurate classification of diabetes, but in children this is becoming increasingly challenging due to high prevalence of obesity and shifting demographic composition. The growing obesity epidemic complicates classification by obesity's effects on diabetes. Since the prevalence and clinical characteristics of diabetes vary among racial/ethnic groups, migration between countries leads to changes in the distribution of diabetes types in a certain geographical area, challenging the clinician's ability to classify diabetes. These challenges must be addressed to correctly classify diabetes and establish an appropriate treatment strategy early in the course of disease for all. This may be the first step in improving diabetes outcomes across racial/ethnic groups. This review will discuss the pitfalls in the current diabetes classification scheme that is leading to increasing overlap between diabetes types and heterogeneity within each type. It will also present proposed alternative classification schemes and approaches to understanding diabetes type that may improve the timely and accurate classification of pediatric diabetes type.

Defining and Classifying New Subgroups of Diabetes

An etiologically based classification of diabetes is needed to account for the heterogeneity of type 1 and type 2 diabetes (T1D and T2D) and emerging forms of diabetes worldwide. It may be productive for both classification and clinical discovery to consider variant forms of diabetes as a spectrum. Maturity onset diabetes of youth and neonatal diabetes serve as models for etiologically defined, rare forms of diabetes in the spectrum. Ketosis-prone diabetes is a model for more complex forms, amenable to phenotypic dissection. Bioinformatic approaches such as clustering analyses of large datasets and multi-omics investigations of rare and atypical phenotypes are promising avenues to explore and define new subgroups of diabetes.

Pathophysiology of diabetes: An overview

Diabetes mellitus is a chronic heterogeneous metabolic disorder with complex pathogenesis. It is characterized by elevated blood glucose levels or hyperglycemia, which results from abnormalities in either insulin secretion or insulin action or both. Hyperglycemia manifests in various forms with a varied presentation and results in carbohydrate, fat, and protein metabolic dysfunctions. Long-term hyperglycemia often leads to various microvascular and macrovascular diabetic complications, which are mainly responsible for diabetes-associated morbidity and mortality. Hyperglycemia serves as the primary biomarker for the diagnosis of diabetes as well. In this review, we would be focusing on the classification of diabetes and its pathophysiology including that of its various types.

The clinical consequences of heterogeneity within and between different diabetes types

Advances in molecular methods and the ability to share large population-based datasets are uncovering heterogeneity within diabetes types, and some commonalities between types. Within type 1 diabetes, endotypes have been discovered based on demographic (e.g. age at diagnosis, race/ethnicity), genetic, immunological, histopathological, metabolic and/or clinical course characteristics, with implications for disease prediction, prevention, diagnosis and treatment. In type 2 diabetes, the relative contributions of insulin resistance and beta cell dysfunction are heterogeneous and relate to demographics, genetics and clinical characteristics, with substantial interaction from environmental exposures. Investigators have proposed approaches that vary from simple to complex in combining these data to identify type 2 diabetes clusters relevant to prognosis and treatment. Advances in pharmacogenetics and pharmacodynamics are also improving treatment. Monogenic diabetes is a prime example of how understanding heterogeneity within diabetes types can lead to precision medicine, since phenotype and treatment are affected by which gene is mutated. Heterogeneity also blurs the classic distinctions between diabetes types, and has led to the definition of additional categories, such as latent autoimmune diabetes in adults, type 1.5 diabetes and ketosis-prone diabetes. Furthermore, monogenic diabetes shares many features with type 1 and type 2 diabetes, which make diagnosis difficult. These challenges to the current classification framework in adult and paediatric diabetes require new approaches. The 'palette model' and the 'threshold hypothesis' can be combined to help explain the heterogeneity within and between diabetes types. Leveraging such approaches for therapeutic benefit will be an important next step for precision medicine in diabetes. Graphical abstract.

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.

Atypical diabetes: a diagnostic challenge

In medical school, we learned how to classify diabetes according to different clinical characteristics. However, at the dawn of the precision medicine era, it is clear that today's clinical reality does not always align well with textbook teachings. The terms juvenile versus elderly-onset diabetes, as well as insulin-dependent versus non-insulin-dependent diabetes, have become obsolete. Contrary to what is often taught severe ketoacidosis may occur in type 2 diabetes. Patients may also suffer from two or more forms of diabetes simultaneously or consecutively. Five authentic cases of diabetes with uncommon characteristics that pose diagnostic challenges are presented here.

Circulating osteocalcin: A potential predictor of ketosis in type 2 diabetes

AIMS

Osteocalcin contributes to the regulation of endocrine system. However, the association between osteocalcin and ketosis has not been evaluated. We thus aimed to explore the relationship between total osteocalcin and risk of ketosis in type 2 diabetes (T2DM).

MATERIALS AND METHODS

We identified 6157 diabetes patients from Shanghai Tenth People's Hospital between 1 January 2011 and 1 March 2017. Six hundred eight subjects were enrolled in the retrospective cross-sectional study: 304 T2DM patients with ketosis whose age, gender, and body mass index were matched with 304 T2DM patients without ketosis. A further retrospective nested case-control study was conducted in 252 T2DM patients without ketosis for a mean duration of 21.58 ± 12.43 months to investigate the occurrence of ketosis.

RESULTS

Osteocalcin levels were negatively correlated with blood ketones (adjusted r = -0.263) and urine ketones (adjusted r = -0.183). The inverse dose-dependent relationship of osteocalcin and risk of ketosis was present across osteocalcin level quintiles (top quintile as the reference, adjusted odds ratio [95% CI] = 2.56 [0.80-8.17], 3.71 [0.90-15.29], 10.77 [2.63-44.15], 23.81 [4.32-131.17] per osteocalcin quintile, respectively). Ketosis occurred in 17 of the 252 T2DM patients during follow-up. The Cox regression analysis indicated that osteocalcin was an independent protective factor against development of ketosis (adjusted hazard ratio [95% CI]: 0.668 [0.460-0.971]).

CONCLUSIONS

Total osteocalcin can be used as a predictor of ketosis in T2DM.

Risk Factors of Ketosis in Obese Ketosis-Prone Diabetic Patients: A Case-Control Study

INTRODUCTION

Different types of ketosis-prone obese diabetic patients are seen in the clinic. At present, the mechanism responsible for ketosis onset in these patients remains unclear, and we do not know how these patients should be optimally treated to prevent recurrent ketosis. Therefore, this study aims to investigate risk factors of ketosis in obese ketosis-prone diabetic (OB-KPD) patients.

METHODS

In an observational case-control study, primary OB-KPD patients [body mass index (BMI) ≥ 28 kg/m²] were selected as the study group (OB-KPD group), and primary obese type 2 diabetes patients served as the control group (OB-T2DM group). Clinical diagnostic assessments of fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), blood lipid, area under curve of serum C-peptide (AUC_C-P) after steamed bread meal, insulin sensitivity index (ISI), β-hydroxybutyric acid (β-HB) and free fatty acid (FFA) vlaues of the subjects were collected. Subjects in the OB-KPD group were followed up for 1 year to determine the likelihood of insulin therapy cessation and whether ketosis recurred by assessing clinical chemistry parameters at 1-year follow-up.

RESULTS

Seventy-five subjects were screened, of which 15 were not included in the study for several identified clinical reasons. On enrollment, the OB-KPD group displayed significantly higher FPG, HbA1c and FFA levels than the OB-T2DM group (p < 0.01), while AUC_C-P and ISI values were significantly lower than in the OB-T2DM group (p < 0.01 and p = 0.03). Statistical analysis showed that increases in β-HB in the OB-KPD group were associated with increased blood glucose and FFA and decreased AUC_C-P and ISI values. Furthermore, decreases in AUC_C-P were closely associated with increased blood glucose values.

CONCLUSION

The occurrence of ketosis in ketosis-prone obese diabetic patients may be related to glucose and lipid metabolism disorders, increased insulin resistance and decreased β-cell secretory functions.

TRIAL REGISTRATION

This work was registered at the Chinese Clinical Trial Registry with trial registration identifier no. ChiCTR1900025909.

Bodyweight threshold for sudden onset of ketosis might exist in ketosis-prone type 2 diabetes patients

Ketosis-prone type 2 diabetes is recognized as atypical diabetes. These patients are often male, characterized by obesity, sudden onset of ketosis and a transient decrease in insulin secretion capacity that can be recovered with temporal insulin therapy. Here, we report a male patient with ketosis-prone type 2 diabetes who was followed up for 8 years. During the follow-up period, his bodyweight fluctuated and he experienced four episodes of critical ketosis recurrence in association with bodyweight gain. He discontinued insulin therapy after each ketosis episode within the first 4 years, but thereafter, he had to continue insulin therapy because of decreased insulin secretion capacity. Interestingly, his peak bodyweight just before the repeated ketosis episode gradually decreased, and the insulin secretion capacity after the recovery from repeated ketosis decreased in parallel with his peak bodyweight. This long-term clinical course might be a clue to understand the pathophysiology of ketosis-prone type 2 diabetes.

Uncommon Association Between Diabetic Ketoacidosis, Thyrotoxicosis, Cutaneous Abscess and Acute Pericarditis in an Immunocompetent Patient: A Single Case Report and Literature Review

INTRODUCTION

The typical factors precipitating diabetic ketoacidosis (DKA) include infections (30%), cessation of antidiabetic medication (20%), and a new diagnosis of diabetes (25%). The etiology remains unknown in 25% of cases. Less frequent causes cited in the literature include severe thyrotoxicosis and, infrequently, pericarditis. Few publications have described the role of human T lymphotropic virus type 1 (HTLV-1) in endocrine and metabolic disorders. Based on a clinical case associated with several endocrine and metabolic disorders, we suggest a potential role for HTLV-1, an endemic virus in the Amazonian area, and review the literature concerning the role of this virus in thyroiditis, pericarditis and diabetes mellitus.

CASE REPORT

A fifty-year-old Surinamese woman without any medical history was admitted for diabetic ketoacidosis. No specific anti-pancreatic autoimmunity was observed, and the C-peptide level was low, indicating atypical type-1 diabetes mellitus. DKA was associated with thyrotoxicosis in the context of thyroiditis and complicated by nonbacterial pericarditis and a Staphylococcus aureus subcutaneous abscess. The patient was infected with HTLV-1.

CONCLUSION

To our knowledge, this uncommon association is described for the first time. Few studies have analyzed the implications of HTLV-1 infection in thyroiditis and diabetes mellitus. We did not find any reports describing the association of pericarditis with HTLV-1 infection. Additional studies are necessary to understand the role of HTLV-1 in endocrine and cardiac disorders.

Uncommon Presentations of Diabetes: Zebras in the Herd

The majority of patients with diabetes are diagnosed as having either type 1 or type 2 diabetes. However, when encountered in clinical practice, some patients may not match the classic diagnostic criteria or expected clinical presentation for either type of the disease. Latent autoimmune, ketosis-prone, and monogenic diabetes are nonclassical forms of diabetes that are often misdiagnosed as either type 1 or type 2 diabetes. Recognizing the distinguishing clinical characteristics and understanding the diagnostic criteria for each will lead to appropriate treatment, facilitate personalized medicine, and improve patient outcomes.

Two cases of ketosis-prone diabetes mellitus in Korean adolescents

In recent years, reports of diabetes mellitus (DM) cases that do not fit the traditional classification system have increased in prevalence. While insulin deficiency appears as type 1 DM (T1DM), the new type also has the clinical features of type 2 DM (T2DM); as such, this new type of DM is called ketosis-prone diabetes (KPD) and is correlated with findings of severe hyperglycemia and ketoacidosis. To provide a clear, clinical classification of DM, new classification systems are being studied. Among these, the Aβ system demonstrates the highest sensitivity and specificity in predicting clinical features and prognosis. We report 2 cases of KPD in Korean pediatric patients. The first patient was referred while in a state of diabetic ketoacidosis (DKA) and was considered to have T1DM. However, their blood glucose was well-controlled even with small doses of insulin, and the treatment was able to be changed to metformin therapy. The second patient seemed to be a typical case of T2DM because of his obesity and strong family history. However, blood glucose was not well-controlled with a regular diet, and ketosis occurred. After performing a glucagon stimulation test, both patients showed different clinical features that were finally diagnosed as type A-β+ KPD. The rapid and accurate diagnosis of KPD can reduce the duration of inappropriate insulin use and improve patients&apos; quality of life. Further, the treatment of KPD children should be individualized according to each patient's lifestyle to preventing recurrent DKA.

Atypical forms of diabetes mellitus in Africans and other non-European ethnic populations in low- and middle-income countries: a systematic literature review

BACKGROUND

Atypical presentations of diabetes mellitus (DM) have been reported in non-European ethnic populations under various names. It is unclear whether those names are used for the same or different clinical phenotypes. Unclear terminology may lead to inappropriate treatment and an underestimation of the burden caused by atypical diabetes phenotypes overlapping with classic types of diabetes. This review aimed to describe the terms used for atypical forms of diabetes and to investigate whether the terms are used for similar or different phenotypes.

METHODS

PubMed and Scopus were searched for relevant publications in French or English available before 15 September 2015 using the terms: "Atypical diabetes", "Malnutrition Related Diabetes Mellitus (MRDM)", "Fibro-calculus pancreatic diabetes (FCPD)", Protein deficient Pancreatic Diabetes (PDPD)", "African diabetes", "Ketosis prone-type 2 diabetes", "tropical diabetes", "Flatbush diabetes", "J-type diabetes". Titles, abstracts screening and quality assessment were performed by two independent authors. Observational studies addressing atypical diabetes in humans aged 14 years and above were included. One author extracted data from selected articles.

RESULTS

22 articles among 350 identified articles were retained for data extraction. Two atypical diabetes phenotypes were identified, each of them with a variety of names but similar definitions. One phenotype occurred in very thin people less than 30 years of age, typically from poor socio-economic backgrounds and requires insulin for life. It differs from type 1 diabetes in the tolerance of high blood glucose without ketosis in the absence of exogenous insulin. The second phenotype resembles type1 diabetes as it presents with ketosis at onset but responds well, as type2 diabetes, to oral hypoglycemic drugs after initial stabilization with insulin. It occurs in individuals who are usually over 30 years of age, with normal or overweight and absence of auto antibodies mainly found in type 1 diabetes.

CONCLUSION

The scarce existing literature used various terms for similar diabetes phenotypes. Agreement on nomenclature for the various forms of diabetes using the above reported characteristics are needed in populations where atypical forms of diabetes exist as well as better characterization of phenotypes and genotypes to inform evidence based treatment.

Setting the Stage for Islet Autoimmunity in Type 2 Diabetes: Obesity-Associated Chronic Systemic Inflammation and Endoplasmic Reticulum (ER) Stress

Islet autoimmunity has been identified as a component of both type 1 (T1D) and type 2 (T2D) diabetes, but the pathway through which islet autoimmunity develops in T1D and T2D may be different. Acknowledging the presence of islet autoimmunity in the pathophysiology of T2D, a historically nonautoimmune metabolic disease, would pave the way for important changes in classifications of and therapeutic options for T2D. In order to fully appreciate the importance of islet autoimmunity in T2D, the underlying mechanisms for immune system activation need to be explored. In this review, we focus on the potential origin of immune system activation (innate and adaptive) leading to the development of islet autoimmunity in T2D.

Ketosis-prone diabetes mellitus in an obese adolescent: A case report

RATIONALE

In recent years, there are more new insights into the clinical susceptibility, pathophysiological mechanism, and progression of classification and treatment of ketosis-prone diabetes mellitus (KPDM), which was once described as Idiopathic Type 1 Diabetes, Type 1B Diabetes or Flatbush Diabetes. ketosis-prone diabetes mellitus is still a heterogeneous syndrome reported in African-American or western Sub-Sahara-African, Hispanic descendant, and recently in Asian.

PATIENT CONCERNS

An obese 17-year-old student was admitted to a tertiary referral hospital (teaching hospital), presenting with thirst, polyuria fatigue, and a 9 kg weight loss in the preceding two weeks.

DIAGNOSES

Physical examination showed body mass index (BMI) was 32.77 kg/m, arterial blood gas revealed a pH of 7.31. Serum glucose was 27.8 mmol/L with strong positive uric ketones (++++). Hemoglobin A1c (HbA1c) was 13.6%. The glucose disposal ratio (GDR) during the steady-state of euglycemic clamp test was 5.62 mg/kg/min and M value was 2.87 mg/kg/min during hyperglycemic clamp test. Those findings were sufficient to establish a diagnosis of ketosis-prone diabetes mellitus.

INTERVENTIONS

This obese patient with KPDM received intensive insulin therapy and fluids infusion, and during the remainder of hospitalization his insulin requirement was approximately 1.5 U per kilogram of body weight per day. Blood glucose monitoring was rigorous until the diabetic ketoacidosis under control.

OUTCOMES

He achieved the near-nomalglycemic remission uneventfully. At 12-month follow-up, his treatment was adjusted from insulin subcutaneous injection to oral hypoglycemic drugs.

LESSON

The present study of this obese adolescent with negative auto-antibodies but unprovoked diabetic ketoacidosis and partially preserved beta cell functional reserve after the acute of diabetic ketosis suggested that he has the phenotype of "A-β" KPDM. Further study of this syndrome will help illustrate the inadequacy of current classification and targeted therapies.

Islet autoantibody positivity in overweight and obese adults with type 2 diabetes

Islet autoantibodies are typically associated with type 1 diabetes, but have been found in patients diagnosed with type 2 diabetes in whom they are associated with lower adiposity. The significance of autoantibody positivity in overweight and obese patients is not well understood. The aim of this study was to determine the prevalence and clinical significance of islet autoantibodies in overweight/obese adults diagnosed with type 2 diabetes. This study includes 204 participants at one site of the multicenter Look AHEAD (Action for Health in Diabetes) trial (ClinicalTrials.gov identifier: NCT00017953) which randomized overweight/obese adults diagnosed with type 2 diabetes to an intensive lifestyle intervention or diabetes support and education. We measured antibodies to glutamic acid decarboxylase, insulinoma antigen-2, and zinc transporter 8. Participants with and without autoantibodies were compared with respect to baseline clinical features, and longitudinal changes in weight, hemoglobin A1c, and antihyperglycemic medications. We found that 13 participants (6.4%) were autoantibody positive, including six of 47 participants (12.8%) with BMI ≥40 kg/m². At baseline, autoantibody positive participants had higher HDL cholesterol (1.27 vs. 1.09 mmol/L, p = .034) and lower fasting C-peptide (0.32 vs. 0.57 nmol/L, p = .049). Over four years, autoantibody positive participants lost 5.1 kg more weight than autoantibody negative participants (p = .056). Longitudinal changes in hemoglobin A1c did not differ by autoantibody status, though autoantibody positive participants were more likely to increase the number of antihyperglycemic medications or initiate insulin (p = .011). In conclusion, islet autoantibodies were present in 6.4% of overweight/obese adults with type 2 diabetes including those with severe obesity, and were associated with distinct clinical features. The effect of autoantibody positivity on weight loss interventions requires further study.

Evaluation and management of ketosis-prone diabetes

INTRODUCTION

Patients presenting with diabetic ketoacidosis (DKA) who lack the classic phenotype of autoimmune type 1 diabetes have become increasingly identified in recent decades. This has led to the recognition of heterogeneous syndromes of 'ketosis-prone diabetes' (KPD). Evaluation and optimal management of KPD differs from that of 'typical' type 1 or type 2 diabetes. Awareness of these differences and a systematic approach to diagnosis and treatment can improve glycemic control and prevent both acute and chronic complications of diabetes.

AREAS COVERED

This article reviews the Aß classification scheme ('A' for autoantibody status and 'ß' for beta cell functional reserve) which accurately delineates subgroups of KPD, and addresses the relevance of defining these subgroups for clinical outcomes and long-term insulin dependence. Subsequently, the detailed evaluation and management of KPD patients after their index DKA episode is described.

EXPERT COMMENTARY

Among patients presenting with DKA, it is important to diagnose specific subgroups of KPD and not assume that they represent exclusively patients with autoimmune type 1 diabetes. The Aß classification is an accurate aid to diagnosis, and permits optimal management of the subgroups (e.g., insulin treatment for the ß- subgroups; follow-up testing and a range of treatment options for the ß+ subgroups).

A Comparison of Biomarkers in the Assessment of Glycemic Control in Diabetes: Reviewing the Evidence

BACKGROUND

Diabetes Mellitus (DM) is a chronic life-long progressive multisystem heterogeneous metabolic disorder with complex pathogenesis.

INTRODUCTION

Hyperglycemia is not only one of the classical signs of DM, but it also serves as the pivotal prerequisite for the diagnosis of the disease. However, with the advancement in the field of analytical biochemistry, a number of alternative and specific biomarkers have been discovered which can be used for better diagnosis of the DM. In this review, we have discussed various aspects of DM and different biomarkers used in assessing glycemia.

METHODOLOGY

A thorough literature survey was conducted to identify various studies that reported the use of conventional and non-conventional markers for the assessment of glycemia in DM patients.

CONCLUSION

The accurate detection and hence diagnosis of DM has become easy and more specific with the use of various biomarkers.

Autoantibodies to the IA-2 Extracellular Domain Refine the Definition of "A+" Subtypes of Ketosis-Prone Diabetes

OBJECTIVE

Autoantibodies directed against tyrosine phosphatase IA-2 antibody (IA-2 Ab) are diagnostic for autoimmune type 1 diabetes. Conventional assays target the intracellular domain of IA-2. Among patients with ketosis-prone diabetes (KPD), characterized by presentation with diabetic ketoacidosis (DKA), >60% of adults lack three classic islet autoantibodies-IA-2, GAD65, and ZnT8 Abs-associated with type 1 diabetes. We aimed to determine whether apparently autoantibody-negative ("A-") KPD patients possess occult IA-2 Ab directed against full-length IA-2 (IA-2FL) or its extracellular domain (IA-2EC).

RESEARCH DESIGN AND METHODS

We developed an assay that targets IA-2FL and IA-2EC and used it to analyze 288 subjects with A- KPD.

RESULTS

Ten A- KPD patients were positive for IA-2EC Ab (3.5%), and three were also positive for IA-2FL Ab (1.0%), similar to frequencies in type 1 and type 2 diabetes.

CONCLUSIONS

Measurement of IA-2FL Ab and IA-2EC Ab improves the accuracy of the Aβ classification of KPD patients.

Risperidone-induced type 2 diabetes presenting with diabetic ketoacidosis

A 28-year-old male presented with 2 days of vomiting and abdominal pain, preceded by 2 weeks of thirst, polyuria and polydipsia. He had recently started risperidone for obsessive-compulsive disorder. He reported a high dietary sugar intake and had a strong family history of type 2 diabetes mellitus (T2DM). On admission, he was tachycardic, tachypnoeic and drowsy with a Glasgow Coma Scale (GCS) of 10/15. We noted axillary acanthosis nigricans and obesity (BMI 33.2 kg/m²). Dipstick urinalysis showed ketonuria and glycosuria. Blood results were consistent with diabetic ketoacidosis (DKA), with hyperosmolar state. We initiated our DKA protocol, with intravenous insulin, fluids and potassium, and we discontinued risperidone. His obesity, family history of T2DM, acanthosis nigricans and hyperosmolar state prompted consideration of T2DM presenting with ‘ketosis-prone diabetes’ (KPD) rather than T1DM. Antibody markers of beta-cell autoimmunity were subsequently negative. Four weeks later, he had modified his diet and lost weight, and his metabolic parameters had normalised. We reduced his total daily insulin dose from 35 to 18 units and introduced metformin. We stopped insulin completely by week 7. At 6 months, his glucometer readings and glycated haemoglobin (HbA1c) level had normalised.

Elevated unmethylated and methylated insulin DNA are unique markers of A+β+ ketosis prone diabetes

A+β+ ketosis prone diabetes (KPD) is associated with slowly progressive autoimmune beta cell destruction. Plasma unmethylated and methylated insulin DNA (biomarkers of ongoing beta cell damage and systemic inflammation, respectively) were elevated in A+β+ KPD compared to all other KPD subgroups.

Precision medicine in diabetes: an opportunity for clinical translation

Metabolic disorders present a public health challenge of staggering proportions. In diabetes, there is an urgent need to better understand disease heterogeneity, clinical trajectories, and related comorbidities. A pressing and timely question is whether we are ready for precision medicine in diabetes. Some biological insights that have emerged during the last decade have already been used to direct clinical decision making, especially in monogenic forms of diabetes. However, much work is necessary to integrate high-dimensional explorations into complex disease architectures, less penetrant biological alterations, and broader phenotypes, such as type 2 diabetes. In addition, for precision medicine to take hold in diabetes, reproducibility, interpretability, and actionability remain key guiding objectives. In this review, we examine how mounting data sets generated during the last decade to understand biological variability are now inspiring new venues to clarify diabetes nosology and ultimately translate findings into more effective prevention and treatment strategies.

Ketosis-prone diabetes and SLE co-presenting in an African lady with previous gestational diabetes

We describe the case of an African woman who was diagnosed with ketosis-prone diabetes with diabetes-associated autoantibodies, after being admitted for diabetic ketoacidosis (DKA) precipitated by her first presentation of systemic lupus erythematosus (SLE). She had a seven-year history of recurrent gestational diabetes (GDM) not requiring insulin therapy, with return to normoglycaemia after each pregnancy. This might have suggested that she had now developed type 2 diabetes (T2D). However, the diagnosis of SLE prompted testing for an autoimmune aetiology for the diabetes, and she was found to have a very high titre of GAD antibodies. Typical type 1 diabetes (T1D) was thought unlikely due to the long preceding history of GDM. Latent autoimmune diabetes of adults (LADA) was considered, but ruled out as she required insulin therapy from diagnosis. The challenge of identifying the type of diabetes when clinical features overlap the various diabetes categories is discussed. This is the first report of autoimmune ketosis-prone diabetes (KPD) presenting with new onset of SLE.

Clinical characteristics, beta-cell dysfunction and treatment outcomes in patients with A-β+ Ketosis-Prone Diabetes (KPD): The first identified cohort amongst Asian Indians

OBJECTIVE

Ketosis-prone diabetes (KPD), an atypical form of diabetes, has emerged as a heterogeneous syndrome in multiple ethnic groups. The objectives of this study were to look into the clinical characteristics of adult Asian Indian patients with recently diagnosed, antibody negative diabetes presenting with unprovoked ketoacidosis (A-β+ KPD) and to determine the natural course of recovery of beta-cell functions on serial follow-up over one year.

RESEARCH DESIGN AND METHODS

Newly diagnosed adult diabetes patients (n=11) with suspected KPD (A-β+) were prospectively studied over a period of 1-year with serial evaluations of clinical, biochemical and beta-cell secretion characteristics. These were compared with a control group (n=23) of KPD (A+β-) (classical Type 1A diabetes) with similar presentation. Beta-cell secretion was assessed by fasting and stimulated C-peptide values after a standard mixed meal challenge. Glycaemic control and treatment outcomes were also documented.

RESULTS

In comparison to the A+β- KPD controls, the A-β+ KPD patients had a significantly older age, higher BMI, stronger family history of type 2 diabetes, more severe ketoacidosis and higher fasting and stimulated C-peptide level at presentation. On serial follow-up, the patients with KPD achieved complete recovery of their beta-cell function with remission from insulin-dependence within 3-4months without further recurrences of DKA.

CONCLUSIONS

This is the first reported series of A-β+ KPD from India. The phenotype of Indian A-β+ KPD patients differs from their Western counterparts in that they are relatively younger and leaner, though the male preponderance and natural history of recovery of beta-cell dysfunction bears similarity.