Improved glycemic control in subjects with atypical diabetes results from restored insulin secretion, but not improved insulin sensitivity

Predictors of Long-Term Glycemic Remission After 2-Week Intensive Insulin Treatment in Newly Diagnosed Type 2 Diabetes

CONTEXT

Although several studies suggest that improved β-cell function is a key determinant of glycemic remission in type 2 diabetes, other predictors remain unclear.

OBJECTIVE

The aim of this clamp-based study was to identify predictors of 2-year glycemic remission after short-term intensive insulin treatment.

DESIGN

A 2-year follow-up was planned in 124 drug-naive patients with type 2 diabetes who received continuous subcutaneous insulin infusion (CSII) for 2 weeks. Euglycemic-hyperinsulinemic clamps and IV glucose tolerance tests were performed to assess the insulin sensitivity [glucose infusion rate (GIR)] and acute insulin response (AIR) before and after CSII.

RESULTS

First-phase insulin secretion was restored, and the GIR was significantly improved (P < 0.0001) after the 2-week CSII. Glycemic remission rates were 47.6% and 30.7% after 12 and 24 months of follow-up, respectively. Cox analysis revealed that a higher post-CSII glucose level [hazard ratio (HR), 1.38; 95% CI, 1.15 to 1.66; P = 0.0005] and older age at diabetes diagnosis (HR, 1.34; 95% CI, 1.05 to 1.72; P = 0.02) accounted for an increased risk of hyperglycemic relapse. A 1 SD increase in the AIR (HR, 0.75; 95% CI, 0.57 to 0.99; P = 0.04), GIR (HR, 0.67; 95% CI, 0.48 to 0.93; P = 0.016) after CSII, and baseline GIR (HR, 0.71; 95% CI, 0.51 to 0.99; P = 0.047) was inversely associated with this risk.

CONCLUSIONS

Younger age at diabetes diagnosis, higher baseline insulin sensitivity, and lower glucose levels after insulin treatment significantly favored a 2-year glycemic remission. This long-term remission was attributed to both improved insulin sensitivity and enhanced β-cell function after short-term intensive insulin treatment.

Ketosis-Prone Type 2 Diabetes: A Case Series

Ketosis-prone type 2 diabetes ("Flatbush diabetes") carries features of both classical type 1 and type 2 diabetes and is highly prevalent in African populations. The disease, which is highly ketosis-prone, but neither chronically insulinopenic nor autoimmune, is discussed regarding pathogenesis, diagnosis and treatment from a patient case perspective.

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).

Prevalence and clinical characteristics of lower limb atherosclerotic lesions in newly diagnosed patients with ketosis-onset diabetes: a cross-sectional study

BACKGROUND

The clinical features of atherosclerotic lesions in ketosis-onset diabetes are largely absent. We aimed to compare the characteristics of lower limb atherosclerotic lesions among type 1, ketosis-onset and non-ketotic type 2 diabetes.

METHODS

A cross-sectional study was performed in newly diagnosed Chinese patients with diabetes, including 53 type 1 diabetics with positive islet-associated autoantibodies, 208 ketosis-onset diabetics without islet-associated autoantibodies, and 215 non-ketotic type 2 diabetics. Sixty-two subjects without diabetes were used as control. Femoral intima-media thickness (FIMT), lower limb atherosclerotic plaque and stenosis were evaluated and compared among the four groups based on ultrasonography. The risk factors associated with lower limb atherosclerotic plaque were evaluated via binary logistic regression in patients with diabetes.

RESULTS

After adjusting for age and sex, the prevalence of lower limb plaque in the patients with ketosis-onset diabetes (47.6%) was significantly higher than in the control subjects (25.8%, p = 0.013), and showed a higher trend compared with the patients with type 1 diabetes (39.6%, p = 0.072), but no difference was observed in comparison to the patients with non-ketotic type 2 diabetes (62.3%, p = 0.859). The mean FIMT in the ketosis-onset diabetics (0.73 ± 0.17 mm) was markedly greater than that in the control subjects (0.69 ± 0.13 mm, p = 0.045) after controlling for age and sex, but no significant differences were found between the ketosis-onset diabetics and the type 1 diabetics (0.71 ± 0.16 mm, p = 0.373), and the non-ketotic type 2 diabetics (0.80 ± 0.22 mm, p = 0.280), respectively. Age and FIMT were independent risk factors for the presence of lower limb plaque in both the ketosis-onset and non-ketotic type 2 diabetic patients, while sex and age in the type 1 diabetic patients.

CONCLUSIONS

The prevalence and risk of lower limb atherosclerotic plaque in the ketosis-onset diabetes were remarkably higher than in the control subjects without diabetes. The features and risk factors of lower limb atherosclerotic lesions in the ketosis-onset diabetes resembled those in the non-ketotic type 2 diabetes, but different from those in the type 1 diabetes. Our findings provide further evidences to support the classification of ketosis-onset diabetes as a subtype of type 2 diabetes rather than idiopathic type 1 diabetes.

Pathogenesis of A⁻β⁺ ketosis-prone diabetes

A⁻β⁺ ketosis-prone diabetes (KPD) is an emerging syndrome of obesity, unprovoked ketoacidosis, reversible β-cell dysfunction, and near-normoglycemic remission. We combined metabolomics with targeted kinetic measurements to investigate its pathophysiology. Fasting plasma fatty acids, acylcarnitines, and amino acids were quantified in 20 KPD patients compared with 19 nondiabetic control subjects. Unique signatures in KPD--higher glutamate but lower glutamine and citrulline concentrations, increased β-hydroxybutyryl-carnitine, decreased isovaleryl-carnitine (a leucine catabolite), and decreased tricarboxylic acid (TCA) cycle intermediates--generated hypotheses that were tested through stable isotope/mass spectrometry protocols in nine new-onset, stable KPD patients compared with seven nondiabetic control subjects. Free fatty acid flux and acetyl CoA flux and oxidation were similar, but KPD had slower acetyl CoA conversion to β-hydroxybutyrate; higher fasting β-hydroxybutyrate concentration; slower β-hydroxybutyrate oxidation; faster leucine oxidative decarboxylation; accelerated glutamine conversion to glutamate without increase in glutamate carbon oxidation; and slower citrulline flux, with diminished glutamine amide-nitrogen transfer to citrulline. The confluence of metabolomic and kinetic data indicate a distinctive pathogenic sequence: impaired ketone oxidation and fatty acid utilization for energy, leading to accelerated leucine catabolism and transamination of α-ketoglutarate to glutamate, with impaired TCA anaplerosis of glutamate carbon. They highlight a novel process of defective energy production and ketosis in A⁻β⁺ KPD.

Characteristics of diabetic ketoacidosis in Chinese adults and adolescents -- a teaching hospital-based analysis

OBJECTIVE

To investigate the diabetic ketoacidosis (DKA) episodes occurred in diabetic adults and adolescents.

METHODS

We reviewed diabetic patients of admissions with DKA in West China Hospital in Chengdu from January 1, 2008 to December 31, 2008. Clinical and laboratory data including β-cell function and autoantibody status were collected respectively. Patients were classified as having type 1 or type 2 diabetes or atypical diabetes based on clinical diagnosis and treatment history. And groups were compared for differences in vital statistics and biochemical profiles at presentation.

RESULTS

Detailed and accurate information was obtained in relation to 263 of patients accounted for the 287 admissions admitted for DKA, of whom 41 patients had type 1 diabetes (15.59%) meanwhile 178 patients were diagnosis as T2DM (67.68%), and 37 patients could not be "typed" were classified as atypical DM (14.07%). In addition, there were two gestational diabetes mellitus (GDM) and five patients with other specific types. Sixty admissions (22.81%) were newly diagnosed diabetes, of which 28 admissions (46.67%) were atypical diabetes. The most common contributing factor for DKA was infection (39.16%), followed by noncompliance with anti-diabetes treatment including omission of insulin (25.5%), unknown causes (25.86%) and other medical conditions (11.73%). Of note, these middle-age obese male patients with atypical diabetes often lapse into diabetic ketoacidosis without identifiable precipitating factors.

CONCLUSIONS

DKA could occur not only in T1DM but also in patients with T2DM under infection or stress condition, furthermore without any identifiable precipitant. The prevalence of DKA and its clinical heterogeneity have significant implications for diagnosing and classification of diabetes. More attention and prevention strategies are needed in ketosis-prone atypical diabetes.

Ketosis-prone type 2 diabetes mellitus (review of the literature)

Idiopathic ketosis-prone type 2 diabetes is intermediate between two major forms of diabetes mellitus. The aim of this review is to analyse factors contributingto its development and occurrence and to discuss approaches to differential diagnosis of this pathology.

Syndromes of ketosis-prone diabetes mellitus

Ketosis-prone diabetes (KPD) is a widespread, emerging, heterogeneous syndrome characterized by patients who present with diabetic ketoacidosis or unprovoked ketosis but do not necessarily have the typical phenotype of autoimmune type 1 diabetes. Multiple, severe forms of beta-cell dysfunction appear to underlie the pathophysiology of KPD. Until recently, the syndrome has lacked an accurate, clinically relevant and etiologically useful classification scheme. We have utilized a large, longitudinally followed, heterogeneous, multiethnic cohort of KPD patients to identify four clinically and pathophysiologically distinct subgroups that are separable by the presence or absence of beta-cell autoimmunity and the presence or absence of beta-cell functional reserve. The resulting "Abeta" classification system of KPD has proven to be highly accurate and predictive of such clinically important outcomes as glycemic control and insulin dependence, as well as an aid to biochemical and molecular investigations into novel causes of beta-cell dysfunction. In this review, we describe the current state of knowledge in regard to the natural history, pathophysiology, and treatment of the subgroups of KPD, with an emphasis on recent advances in understanding their immunological and genetic bases.

Modestly increased beta cell apoptosis but no increased beta cell replication in recent-onset type 1 diabetic patients who died of diabetic ketoacidosis

AIMS/HYPOTHESIS

Type 1 diabetes is characterised by a deficit in beta cell mass thought to be due to immune-mediated increased beta cell apoptosis. Beta cell turnover has not been examined in the context of new-onset type 1 diabetes with diabetic ketoacidosis.

METHODS

Samples of pancreas were obtained at autopsy from nine patients, aged 12 to 38 years (mean 24.3+/-3.4 years), who had had type 1 diabetes for less than 3 years before death due to diabetic ketoacidosis. Samples of pancreas obtained at autopsy from nine non-diabetic cases aged 11.5 to 38 years (mean 24.2+/-3.4 years) were used as control. Fractional beta cell area (insulin staining), beta cell replication (insulin and Ki67 staining) and beta cell apoptosis (insulin and TUNEL staining) were measured.

RESULTS

In pancreas obtained at autopsy from recent-onset type 1 diabetes patients who had died of diabetic ketoacidosis, the beta cell deficit varied from 70 to 99% (mean 90%). The pattern of beta cell loss was lobular, with almost all beta cells absent in most pancreatic lobules; islets in lobules not devoid of beta cells had reduced or a near-normal complement of beta cells. Beta cell apoptosis was increased in recent-onset type 1 diabetes, but to a surprisingly modest degree given the marked hyperglycaemia (30 mmol/l), acidosis and presumably high NEFA. Beta cell replication, scattered pancreatic beta cells and beta cells in exocrine ducts were not increased in recent-onset type 1 diabetes.

CONCLUSIONS/INTERPRETATION

These findings do not support the notion of active beta cell regeneration by replication in new-onset type 1 diabetes under conditions of diabetic ketoacidosis. The gluco-lipotoxicity reported in isolated human islets may be less evident in vivo.

Comparison of type 1, type 2, and atypical ketosis-prone diabetes at 4 years of diabetes duration

CONTEXT

Atypical ketosis-prone diabetes (KPD) is frequently detected in obese individuals at diagnosis of diabetes, yet its precise pathophysiology is not understood.

AIM

The hypothesis tested in this study states that while individuals with atypical KPD are phenotypically similar to those with type 2 diabetes, metabolically, they behave more like individuals with autoimmune type 1 diabetes.

METHODS

Thirty-seven individuals of Black, Hispanic, or White background and a diagnosis of diabetes mellitus for an average duration of 4 years participated in this cross-sectional study. Ten, 12, and 15 subjects had type 1, atypical, and type 2 diabetes, respectively. Insulin secretion was evaluated by a mixed-meal test. Insulin sensitivity and fuel oxidation were assessed by simultaneous euglycemic hyperinsulinemic clamp and indirect calorimetry. Lastly, a 12-h insulin withdrawal test was performed.

RESULTS

Insulin secretion, insulin sensitivity, and the insulin withdrawal tests yielded significant differences for type 1 vs. atypical diabetes and type 1 vs. type 2 diabetes, while there were no significant differences between atypical vs. type 2 diabetes. The indirect calorimetry showed higher-than-normal basal nonprotein respiratory quotients (RQs) and lower-than-normal insulin-stimulated nonprotein RQs across the three study groups.

CONCLUSIONS

After 4 years from diabetes diagnosis and while far from optimal glycemic control, atypical KPD resembles type 2 diabetes phenotypically and metabolically as well. Therefore, this study supports the classification of atypical KPD as ketosis-prone type 2 diabetes, and the concept that metabolic inflexibility occurs in the presence of insulin resistance in type 1 and type 2 diabetes.

Type 2 diabetes mellitus in youth: the complete picture to date

Type 2 diabetes mellitus is a heterogeneous condition in which the clinical manifestation of hyperglycemia is a reflection of the impaired balance between insulin sensitivity and insulin secretion. Clinical experience and research in youth type 2 diabetes mellitus are in an early stage because of the relative novelty of the condition in pediatrics. This article discusses the amassed information in type 2 diabetes mellitus of youth to date with respect to the epidemiology, pathophysiology, risk factors, clinical presentation, screening, and management strategies.