Autoimmune diabetes in adults: lessons from the UKPDS

Diagnostic Dilemmas and Current Treatment Approaches in Latent Onset Autoimmune Diabetes in Adults: A Concise Review

Latent Onset Autoimmune Diabetes in Adults (LADA) is an autoimmune disorder between T1DM and T2DM and is often misdiagnosed as T2DM due to its late-onset. The disease is characterized by β-cell failure and slow progression to insulin dependence. Early diagnosis is significant in limiting disease progression. C-peptide levels and autoantibodies against β-cells are the most critical diagnostic biomarkers in LADA. The review aims to provide an overview of the biomarkers used to diagnose LADA, and the following treatment approaches. We have summarized LADA's pathophysiology and the autoantibodies involved in the condition, diagnostic approaches, and challenges. There are clear shortcomings concerning the feasibility of autoantibody testing. Finally, we have explored the treatment strategies involved in the management of LADA. In conclusion, the usual management includes treatment with metformin and the addition of low doses of insulin. Newer oral hypoglycaemic agents, such as GLP-1RA and DPP-4 inhibitors, have been brought into use. Since the disease is not entirely understood at the research level and in clinical practice, we hope to encourage further research in this field to assess its prevalence. Large randomized controlled trials are required to compare the efficacy of different available treatment options.

Latent Autoimmune Diabetes in Adults in the United Arab Emirates: Clinical Features and Factors Related to Insulin-Requirement

AIMS

To describe and to characterize clinical features of latent autoimmune diabetes in adults (LADA) compared to type 1 and type 2 diabetes in the UAE.

METHODS

In this cross-sectional study a dataset including 18,101 subjects with adult-onset (>30 years) diabetes was accessed. 17,072 subjects fulfilled the inclusion/exclusion criteria. Data about anthropometrics, demographics, autoantibodies to Glutamic Acid Decarboxylase (GADA) and to Islet Antigen 2 (anti-IA2), HbA1c, cholesterol and blood pressure were extracted. LADA was diagnosed according to GADA and/or anti-IA2 positivity and time to insulin therapy.

RESULTS

437 (2.6%) patients were identified as LADA and 34 (0.2%) as classical type 1 diabetes in adults. Mean age at diagnosis, BMI, waist circumference, systolic blood pressure and HbA1c significantly differed between, LADA, type 2 and type 1 diabetes, LADA showing halfway features between type 2 and type 1 diabetes. A decreasing trend for age at diagnosis and waist circumference was found among LADA subjects when subdivided by positivity for anti-IA2, GADA or for both antibodies (p=0.013 and p=0.011 for trend, respectively). There was a gradual downward trend in autoantibody titre in LADA subjects requiring insulin within the first year from diagnosis to subjects not requiring insulin after 10 years of follow-up (p<0.001).

CONCLUSIONS

This is the first study describing the clinical features of LADA in the UAE, which appear to be different from both type 1 and type 2 diabetes. Furthermore, we showed that the clinical phenotype of LADA is dependent on different patterns of antibody positivity, influencing the time to insulin requirement.

Latent autoimmune diabetes in adults in Asians: similarities and differences between East and West

Latent autoimmune diabetes in adults (LADA) is a form of autoimmune diabetes with features of both type 1 and type 2 diabetes and in the middle of the diabetes spectrum. Scientists clash on the question of whether this type of diabetes is a unique diabetes subtype. Multicenter studies have been performed in different countries, including the Korea National Diabetes Program (KNDP) collaboratory group, the Ehime study in Japan, the Not Insulin-Requiring Autoimmune Diabetes (NIRAD) study in Italy, the Nord-Trøndelag Health (HUNT) study in Norway, the UK Prospective Diabetes Study (UKPDS) in the UK, the Action LADA study in Europe and the LADA China study in China. These studies found universal immunogenetic effects associated with LADA, but with some ethnic differences. Herein we summarize those multicenter studies and compare the ethnic similarities and differences between East and West from epidemiological, clinical, immune, and genetic viewpoints.

Determinants and consequences of insulin initiation for type 2 diabetes in France: analysis of the National Health and Wellness Survey

BACKGROUND

The aim of the study was to identify the intrinsic patient characteristics and extrinsic environmental factors predicting prescription and use and, more specifically, early initiation (up to 5 years of disease duration) of insulin for type 2 diabetes in France. A secondary objective was to evaluate the impact of insulin therapy on mental and physical quality of life and patient adherence.

METHODS

The data used in this study were derived from the 2008, 2010, and 2011 France National Health and Wellness Survey. This survey is an annual, cross-sectional, self-administered, Internet-based questionnaire among a nationwide representative sample of adults (aged 18 years or older). Of the total of 45,958 persons recruited in France, 1,933 respondents (deduped) were identified as diagnosed with type 2 diabetes. All unique respondents from the three waves, currently using insulin or oral bitherapy or tritherapy at the time of assessment, were included in this analysis.

RESULTS

Early (versus late) initiation of insulin therapy was 9.9 times more likely to be prescribed by an endocrinologist or diabetologist than by a primary care physician (P < 0.0001). Younger age at diagnosis and current smoking habits were significant predictors of early (versus late) insulin initiation (odds ratio [OR] 1.031, 95% confidence interval [CI] 1.005-1.059, P = 0.0196, and OR 2.537, 95% CI 1.165-5.524, P = 0.0191, respectively). Patients with a yearly income ≥€50,000 were less likely to be put on insulin early (P = 0.0399). A link between insulin prescription and complications was shown only in univariate analysis. Mental quality of life was lower in patients on early (versus late) insulin, but only in patients with diabetes-related complications. Insulin users (versus oral bitherapy or tritherapy users) had 3.0 times greater odds of being adherent than uncontrolled oral bitherapy or tritherapy users (OR 2.983, 95% CI 1.37-6.495, P = 0.0059).

CONCLUSION

This study confirms the role of specialists in early initiation of insulin, and the data presented herein reflect the fact that early initiation is more frequent in younger patients, patients with diabetes-related complications, and current smokers, and less frequent in patients with a higher income. Moreover, we observed that being treated with insulin was not associated with deterioration in quality of life, and insulin-treated patients were more often adherent than uncontrolled oral bitherapy or tritherapy users. These data suggest that doctors' concerns about patient adherence and detrimental effects on quality of life should not be a barrier to their decision regarding early initiation of insulin therapy. Due to the nature of this cross-sectional survey (eg, inability to assess treatment flow), further research is needed to confirm its findings.

Insulin autoantibody could help to screen latent autoimmune diabetes in adults in phenotypic type 2 diabetes mellitus in Chinese

Latent autoimmune diabetes in adults (LADA) is characterized by a relatively mild diabetes onset, autoantibody positivity, and eventual requirement for insulin therapy. Glutamic acid decarboxylase autoantibodies (GADA) or cytoplasmic islet cell autoantibodies (ICA) play a key role in distinguishing LADA from type 2 diabetes mellitus (T2DM) in clinical practice. The aim of our research was to determine whether insulin autoantibody (IAA) has some additional value in diagnosing LADA. We analyzed IAA, GADA, and IA-2A (antibodies to insulinoma-associated antigen-2) in 1,003 newly diagnosed phenotypic T2DM patients, 110 type 1 diabetes mellitus (T1DM) patients, and 317 normal controls to survey the prevalence of IAA in phenotypic T2DM patients and the overlapping positivity of IAA with other autoantibodies. Sera were drawn within 7 days from the start of insulin therapy. Results showed that 3.39% of the newly diagnosed phenotypic T2DM, 0.95% of normal control (χ(2) = 5.3, P < 0.05), and 21.82% of T1DM (χ(2) = 68.2, P < 0.001) were positive for IAA at diagnosis. The combination frequency of three antibodies was 10.47%, which was higher than any single antibody testing. Combination testing of IAA with GADA and IA-2A could improve LADA diagnose rate by 2.39% than that of GADA and IA-2A. IAA-positive subjects had diabetes family history more common compared to its matched group (67.6% vs. 14.7%, P = 0.000). Postprandial C-peptide in IAA-positive group tended to be lower, but the difference was not statistically significant (P = 0.084). We concluded that IAA can be used to screen LADA in phenotypic T2DM in the Chinese population.

Interventions for latent autoimmune diabetes (LADA) in adults

BACKGROUND

Latent autoimmune diabetes in adults (LADA) is a slowly developing type 1 diabetes.

OBJECTIVES

To compare interventions used for LADA.

SEARCH STRATEGY

Studies were obtained from searches of electronic databases, supplemented by handsearches, conference proceedings and consultation with experts. Date of last search was December 2010.

SELECTION CRITERIA

Randomised controlled trials (RCT) and controlled clinical trials (CCT) evaluating interventions for LADA or type 2 diabetes with antibodies were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Studies were summarised using meta-analysis or descriptive methods.

MAIN RESULTS

Searches identified 13,306 citations. Fifteen publications (ten studies) were included, involving 1019 participants who were followed between three months to 10 years (1060 randomised). All studies had a high risk of bias. Sulphonylurea (SU) with insulin did not improve metabolic control significantly more than insulin alone at three months (one study, n = 15) and at 12 months (one study, n = 14) of treatment and follow-up. SU (with or without metformin) gave poorer metabolic control compared to insulin alone (mean difference in glycosylated haemoglobin A1c (HbA1c) from baseline to end of study, for insulin compared to oral therapy: -1.3% (95% confidence interval (CI) -2.4 to -0.1; P = 0.03, 160 participants, four studies, follow-up/duration of therapy: 12, 30, 36 and 60 months; however, heterogeneity was considerable). In addition, there was evidence that SU caused earlier insulin dependence (proportion requiring insulin at two years was 30% in the SU group compared to 5% in conventional care group (P < 0.001); patients classified as insulin dependent was 64% (SU group) and 12.5% (insulin group, P = 0.007). No intervention influenced fasting C-peptide, but insulin maintained stimulated C-peptide better than SU (one study, mean difference 7.7 ng/ml (95% CI 2.9 to 12.5)). In a five year follow-up of GAD65 (glutamic acid decarboxylase formulated with aluminium hydroxide), improvements in fasting and stimulated C-peptide levels (20 μg group) were maintained after five years. Short term (three months) follow-up in one study (n = 74) using Chinese remedies did not demonstrate a significant difference in improving fasting C-peptide levels compared to insulin alone (0.07 µg/L (95% CI -0.05 to 0.19). One study using vitamin D with insulin showed steady fasting C-peptide levels in the vitamin D group but declining fasting C-peptide levels (368 to 179 pmol/L, P = 0.006) in the insulin alone group at 12 months follow-up. Comparing studies was difficult as there was a great deal of heterogeneity in the studies and in their selection criteria. There was no information regarding health-related quality of life, complications of diabetes, cost or health service utilisation, mortality and limited evidence on adverse events (studies on oral agents or insulin reported no adverse events in terms of severe hypoglycaemic episodes).

AUTHORS' CONCLUSIONS

Two studies show SU leading to earlier insulin dependence and a meta-analysis of four studies with considerable heterogeneity showed poorer metabolic control if SU is prescribed for patients with LADA compared to insulin. One study showed that vitamin D with insulin may protect pancreatic beta cells in LADA. Novel treatments such as GAD65 in certain doses (20 μg) have been suggested to maintain fasting and stimulated C-peptide levels. However, there is no significant evidence for or against other lines of treatment of LADA.

Identification of autoantibody-negative autoimmune type 2 diabetic patients

OBJECTIVE

Islet autoimmunity has long been recognized in the pathogenesis of type 1 diabetes and is becoming increasingly acknowledged as a component in the pathogenesis of type 2 diabetes. Islet reactive T cells and autoantibodies have been demonstrated in type 1 diabetes, whereas islet autoimmunity in type 2 diabetes has been limited to islet autoantibodies. In this study, we investigated whether islet reactive T cells might also be present in type 2 diabetic patients and how islet reactive T cells correlate with β-cell function.

RESEARCH DESIGN AND METHODS

Adult phenotypic type 2 diabetic patients (n = 36) were screened for islet reactive T-cell responses using cellular immunoblotting and five islet autoantibodies (islet cell antibody, GADA, insulin autoantibody, insulinoma-associated protein-2 autoantibody, and zinc transporter autoantibody).

RESULTS

We identified four subgroups of adult phenotypic type 2 diabetic patients based on their immunological status (Ab(-)T(-), Ab(+)T(-), Ab(-)T(+), and Ab(+)T(+)). The Ab(-)T(+) type 2 diabetic patients demonstrated T-cell responses similar to those of the Ab(+)T(+) type 2 diabetic patients. Data were adjusted for BMI, insulin resistance, and duration of diabetes. Significant differences (P < 0.02) were observed among groups for fasting and glucagon-stimulated C-peptide responses. T-cell responses to islet proteins were also demonstrated to fluctuate less than autoantibody responses.

CONCLUSIONS

We have identified a group of adult autoimmune phenotypic type 2 diabetic patients who are Ab(-)T(+) and thus would not be detected using autoantibody testing alone. We conclude that islet autoimmunity may be more prevalent in adult phenotypic type 2 diabetic patients than previously estimated.

The presence of GAD and IA-2 antibodies in youth with a type 2 diabetes phenotype: results from the TODAY study

OBJECTIVE

To determine the frequency of islet cell autoimmunity in youth clinically diagnosed with type 2 diabetes and describe associated clinical and laboratory findings.

RESEARCH DESIGN AND METHODS

Children (10-17 years) diagnosed with type 2 diabetes were screened for participation in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study. Measurements included GAD-65 and insulinoma-associated protein 2 autoantibodies using the new National Institute of Diabetes and Digestive and Kidney Diseases/National Institutes of Health (NIDDK/NIH) standardized assays, a physical examination, and fasting lipid, C-peptide, and A1C determinations.

RESULTS

Of the 1,206 subjects screened and considered clinically to have type 2 diabetes, 118 (9.8%) were antibody positive; of these, 71 (5.9%) were positive for a single antibody, and 47 were positive (3.9%) for both antibodies. Diabetes autoantibody (DAA) positivity was significantly associated with race (P < 0.0001), with positive subjects more likely to be white (40.7 vs. 19%) (P < 0.0001) and male (51.7 vs. 35.7%) (P = 0.0007). BMI, BMI z score, C-peptide, A1C, triglycerides, HDL cholesterol, and blood pressure were significantly different by antibody status. The antibody-positive subjects were less likely to display characteristics clinically associated with type 2 diabetes and a metabolic syndrome phenotype, although the range for BMI z score, blood pressure, fasting C-peptide, and serum lipids overlapped between antibody-positive and antibody-negative subjects.

CONCLUSIONS

Obese youth with a clinical diagnosis of type 2 diabetes may have evidence of islet autoimmunity contributing to insulin deficiency. As a group, patients with DAA have clinical characteristics significantly different from those without DAA. However, without islet autoantibody analysis, these characteristics cannot reliably distinguish between obese young individuals with type 2 diabetes and those with autoimmune diabetes.

High-titer GAD65 autoantibodies detected in adult diabetes patients using a high efficiency expression vector and cold GAD65 displacement

Adult type 2 diabetes patients with GAD65 autoantibodies (GADA) are known as latent autoimmune diabetes in adults (LADA). It has been suggested that GADA in LADA patients preferentially bind to the N-terminal end of GAD65. Using the N-terminal end extension of ³⁵S-GAD65 generated by the pEx9 plasmid, we tested the hypothesis that GADA in LADA patients preferentially react with ³⁵S-GAD65 from the pEx9 plasmid compared to the normal length pThGAD65 plasmid. Healthy control subjects (n = 250) were compared with type 1 (n = 23), type 2 (n = 290), and unspecified (n = 57) diabetes patients. In addition, radio-binding assays for GADA with ³⁵S-GAD65 generated from both the pEx9 and pThGAD65 plasmids were used in displacement assays with an excess of recombinant human GAD65 (2 μg/mL) to correct for non-specific binding. ³⁵S-GAD65 produced by either pEx9 or pThGAD65 did not differ in binding among the healthy controls and among the type 1 diabetes patients. Among the type 2 and unspecified patients, there were 4/290 and 3/57 patients, respectively, with binding to the pEx9 but not to the pThGAD65 generated ³⁵S-GAD65. In the displacement assay, we discovered 14 patients with very high-titer GADA among the type 1 (n = 3, 12,272-29,915 U/mL), type 2 (n = 7; 12,398-334,288 U/mL), and unspecified (n = 4; 20,773-4,053,580 U/mL) patients. All samples were fully displaced following appropriate dilution. We conclude that pThGAD65 is preferred for the coupled in vitro transcription translation of ³⁵S-GAD65 and that displacement with recombinant GAD65 may detect very high-titer GADA with possible clinical relevance.

Individualizing therapies in type 2 diabetes mellitus based on patient characteristics: what we know and what we need to know

OBJECTIVE

Type 2 diabetes is heterogeneous in its clinical features, pathogenesis, and predisposing or causal genetic factors. This report examines what is known and what needs to be learned about the potential to individualize glycemic therapies in type 2 diabetes, based on phenotypes and genotypes.

PARTICIPANTS

A 29-member international working group with expertise in diabetes epidemiology, physiology, genetics, clinical trials, and clinical care participated in formal presentations and discussions at a conference on April 16-17, 2009. A writing group subsequently prepared this summary and recommendations. The conference was coendorsed by The Endocrine Society and the American Diabetes Association and was supported by an unrestricted educational grant from Novo Nordisk.

EVIDENCE

Participants reviewed and discussed published literature, plus their own unpublished data.

CONSENSUS PROCESS

The summary and recommendations were supported unanimously by the writing group as representing the majority or unanimous opinions of the working group.

CONCLUSIONS

Recent advances in genetics, such as the identification of Kir6.2 mutations and the responsible genes for several forms of maturity onset diabetes of the young (MODY), have established precedents linking specifically effective therapies to defined diabetes subtypes. The recent increase in identified polygenic factors related to type 2 diabetes and our understanding of the pathogenesis of diabetes provide potential opportunities to individualize therapy. To further this process, we recommend expanded analysis of existing data sources and the development of new basic and clinical research studies, including a greater focus on identifying type 2 diabetes subtypes, their response to different therapies, and quantitation of cost-effectiveness.