Chronic complications in patients with slowly progressing autoimmune type 1 diabetes (LADA)

Adiponectin levels in people with Latent Autoimmune Diabetes-a case control study

Background

To examine adiponectin levels in people with Latent Autoimmune Diabetes in Adults using a matched pair case control study.

Findings

Patients with LADA (n = 64), were matched for sex with type 2 diabetic and non-diabetic controls. A matched paired T-test was used to examine average adiponectin levels in the LADA patients' versus controls. The average adiponectin level for the LADA patients was 9.96 μg/ml compared to 6.4 μg/ml for Type 2 matched controls and 9.6 μg/ml for non-diabetic controls. Mean difference for the LADA-type 2 comparison was calculated after data was log transformed and showed a difference of 1.58 μg/ml (95%CI: 1.28-1.95, p = 0.0001). There was no significant difference between LADA and non-diabetic controls (p = 0.54).

Conclusions

Adiponectin levels are higher among people with LADA compared to those with type 2 diabetes and are equivalent to levels seen in non-diabetic controls. This suggests that risk of complications in LADA, as with type 1 diabetes may be related more to glycaemic control rather than to factors of the metabolic syndrome.

Number of autoantibodies and HLA genotype, more than high titers of glutamic acid decarboxylase autoantibodies, predict insulin dependence in latent autoimmune diabetes of adults

OBJECTIVE

In latent autoimmune diabetes of adults (LADA), the progression into insulin-dependent diabetes is usually faster than in type 2 diabetes (T2D) but the factors influencing this progression are not completely known. In this study, we searched for sensitive markers associated with early development of insulin dependence.

DESIGN

The screening of 5568 T2D patients for glutamic acid decarboxylase autoantibodies (GAD65Ab) identified 276 LADA patients (M=131; F=145) and in 251 of them, tyrosine phosphatase-2 (IA-2Ab) and thyroperoxidase autoantibodies (TPOAbs), some clinical features and genotype variation of the main type 1 diabetes (T1D) disease susceptibility loci (HLA-DRB1 and HLA-DQB1) were analyzed.

RESULTS

Four years after the diagnosis of diabetes, high GAD65Ab titer was not significantly associated with faster progression toward insulin deficiency (P=0.104). Patients with GAD65Ab and TPOAb or IA-2Ab or triple positivity for both islet and TPOAbs (GAD65Ab/IA-2Ab/TPOAb) showed a significantly faster disease progression (P=0.002). Among 104 TPOAb-positive LADA patients, 10 received replacement therapy (l-thyroxine), 43 showed high TSH levels (62.7% developed insulin dependence), and 3 had hyperthyroidism treated with methimazole. Multivariate analysis revealed a significant effect on disease progression only for TPOAb (P=0.022), female gender (P=0.036), low body mass index (BMI; P=0.001), and T1D high/intermediate risk HLA-DRB1/DQB1 genotypes grouped (P=0.020).

CONCLUSIONS

High GAD65Ab titers per se are not a major risk factor for disease progression in LADA, while the number of positive autoantibodies and HLA DRB1-DQB1 genotypes at high risk for T1D are significant predictors. Moreover, clinical characteristics such as low BMI and female gender are more likely to identify patients who will require insulin therapy within 4 years of diagnosis.

Heterogeneity of patients with latent autoimmune diabetes in adults: linkage to autoimmunity is apparent only in those with perceived need for insulin treatment: results from the Nord-Trøndelag Health (HUNT) study

OBJECTIVE

Subjects with the diagnosis of latent autoimmune diabetes in adults (LADA) are more prone to need insulin treatment than those with type 2 diabetes. However, not all patients with LADA develop the need for insulin treatment, indicating the heterogeneity of LADA. We investigated this heterogeneity by comparing phenotypes of LADA with and without perceived need for insulin treatment (data obtained at times when diagnosis of LADA was not investigated) and also compared LADA and type 2 diabetes phenotypes.

RESEARCH DESIGN AND METHODS

We used data from the all population-based Nord-Trøndelag Health study (n = 64,931), performed in 1995-1997. Data were assembled for individuals with LADA (n = 106) and type 2 diabetes (n = 943).

RESULTS

In the comparison of individuals with LADA both with and without the need for insulin, insulin-treated subjects had higher titers of GAD antibodies (P < 0.001) and lower fasting C-peptide levels (P < 0.001). GAD antibodies and C-peptide correlated negatively (r = -0.40; P = 0.009). In the comparison of individuals with LADA and type 2 diabetes, all without the need for insulin, markers of metabolic syndrome were equally prevalent and pronounced. Age, C-peptide, and glucose levels were also similar. In the comparison of insulin-treated individuals with LADA and type 2 diabetes, more patients with LADA received insulin (40 vs. 22%, P < 0.001) and C-peptide levels were lower (P < 0.001). Patients with LADA were leaner but were still overweight (mean BMI 28.7 vs. 30.9 kg/m2 in type 2 diabetes, P < 0.001). In the comparison of type 2 diabetic patients with and without insulin, insulin-treated subjects were more obese and had higher A1C and lower C-peptide levels (P < 0.001).

CONCLUSIONS

Our conclusions are that 1) the need for insulin treatment in LADA is linked to the degree of autoimmunity and beta-cell failure, 2) subjects with LADA and type 2 diabetes without the need for insulin treatment are phenotypically similar, and 3) insulin treatment in type 2 diabetic patients is associated with both insulin resistance and beta-cell insufficiency.

Chronic complications and mortality in community-based patients with latent autoimmune diabetes in adults: the Fremantle Diabetes Study

AIMS

To compare (i) the prevalence and incidence of chronic complications and (ii) cardiac and all-cause mortality in community-based patients with latent autoimmune diabetes in adults (LADA) with those in Type 2 diabetic patients without antibodies to glutamic acid decarboxylase (GAD).

METHODS

Of the 1294 patients with clinically-defined Type 2 diabetes recruited to the longitudinal, observational Fremantle Diabetes Study between 1993 and 1996, 1255 (97%) had GAD antibodies measured at baseline. Complications were ascertained using standard criteria in patients returning for annual assessments until November 2001. Data on hospital admissions and mortality were available to the end of June 2006. Cox proportional hazards modelling was used to determine independent predictors of first occurrence of complications and cardiac and all-cause mortality.

RESULTS

Forty-five (3.6%) subjects had LADA. Compared with the GAD antibody-negative patients, they had a similar prevalence and incidence of coronary heart (P = 0.48 and 0.80, respectively) and cerebrovascular (P = 0.64 and 0.29) disease and cardiac and all-cause mortality (P = 0.62 and 0.81, respectively). There was also a similar prevalence and incidence of retinopathy (P = 0.22 and 0.64, respectively) and neuropathy (P = 0.25 and 0.95), but microalbuminuria was less frequent both at baseline and during follow-up in the LADA subgroup in unadjusted models (P = 0.046) and after adjustment for other risk factors (P = 0.014 and 0.013).

CONCLUSIONS

Except for a lower prevalence and incidence of nephropathy, LADA patients have a similar risk of complications and death to patients with clinically-diagnosed Type 2 diabetes without GAD antibodies. Cardiovascular risk factor management in LADA should, therefore, be as intensive as that for GAD antibody-negative patients.

Latent autoimmune diabetes in adults (LADA): usefulness of anti-GAD antibody titers and benefit of early insulinization

OBJECTIVE

To determine the clinical and laboratory parameters and the progression to insulin requirement in two groups of LADA patients separated according to GADA titers, and to evaluate the benefit of early insulinization in patients at high risk of premature beta-cell failure (high GADA titers).

METHODS

Among the diabetic adults seen at our service and screened for GADA at diagnosis, 54 were diagnosed with LADA and classified as having low (> 1 U/ml and < 17.2 U/ml) or high (> 17.2 U/ml) GADA titers. Fifty-four patients with type 2 diabetes (GADA-) were selected for comparison. In addition, 24 patients who had GADA titers > 20 U/ml and who were not initially insulinized were compared to 16 patients who were insulinized at diagnosis.

RESULTS

Insulin resistance was higher in the GADA- group, followed by patients with low GADA titers. BMI and the frequency of arterial hypertension, elevated triglycerides and reduced HDL cholesterol were lower in the high GADA+ group, with no difference between the GADA- or low GADA+ groups. The high GADA+ group showed a greater reduction and lower levels of C-peptide and required insulin earlier during follow-up. Patients with GADA titers > 20 U/ml and insulinized early presented no significant variation in C-peptide levels, had better glycemic control and required a lower insulin dose than patients who were insulinized later.

CONCLUSION

We agree that patients with LADA should be differentiated on the basis of GADA titers and that patients with GADA titers > 20 U/ml benefit from early insulinization.

Time to insulin initiation cannot be used in defining latent autoimmune diabetes in adults

OBJECTIVE

Latent autoimmune diabetes in adults is type 1 diabetes presenting as non-insulin dependent diabetes. One feature of the selection criteria is time independent of insulin treatment. We examine the validity of this criterion.

RESEARCH DESIGN AND METHODS

Patients were recruited in nine European centers, and clinicians reported on criteria for initiating insulin. All patients were tested for GAD antibodies (GADAs) in a central laboratory. We examined time to insulin treatment for GADA-positive patients in six participating centers.

RESULTS

There was intercenter variation in the criteria used to initiate insulin. Median time to insulin was 16.15 months (interqartile range 6.7-25.5) in centers with GADA testing compared with 45.6 months (29.5-61.8) in centers without routine GADA testing (P < 0.002).

CONCLUSION

Time to insulin should not be used to define patients with LADA because it is dependent on local clinical judgment and the use of laboratory tests for GADA.

Clinical and biochemical characteristics of nonobese type 2 diabetic patients with glutamic acid decarboxylase antibody in Korea

We evaluated the prevalence of glutamic acid decarboxylase autoantibody (GADA) in nonobese patients with type 2 diabetes mellitus in Korea and investigated the characteristics of GADA-positive and GADA-negative patients. Two years later, we assessed the progression of beta-cell function in these patients. Of the 647 nonobese patients with type 2 diabetes mellitus enrolled in the study, 10.1% was positive for GADA. Glutamic acid decarboxylase antibody-positive patients had lower fasting and stimulated C-peptide levels compared with GADA-negative patients (1.70 +/- 0.72 vs 1.24 +/- 0.59 microg/L, P < .001; 2.59 +/- 1.51 vs 1.99 +/- 0.82 microg/L, P < .001). Patients treated with insulin had lower fasting and stimulated C-peptide levels than those not treated (1.13 +/- 0.52 vs 1.66 +/- 0.73 microg/L, P = .002; 1.85 +/- 0.69 vs 2.49 +/- 0.91 microg/L, P = .004) and had higher titers of GADA (30.5 +/- 7.3 vs 6.0 +/- 4.8 U/mL, P < .001). In terms of progression of beta-cell function, fasting and stimulated C-peptide levels were significantly lower in GADA-positive patients after 2 years (from 1.24 +/- 0.59 to 0.95 +/- 0.54 microg/L, P = .004; from 1.99 +/- 0.82 to 1.61 +/- 0.77 microg/L, P = .007), whereas no such difference was observed in the GADA-negative patients. We demonstrate that a significant proportion of Korean patients may be positive for GADA; this is consistent with studies of white subjects, although disagrees with previous reports on Korean subjects. By assessing the presence of GADA in Korean type 2 diabetic patients, we are able to predict their course of beta-cell function and identify in advance those who are likely to require insulin treatment.

Clinical phenotype and beta-cell autoimmunity in Italian patients with adult-onset diabetes

OBJECTIVE

To characterize the phenotype of a large population of Italian patients with adult onset (> or =40 years) diabetes who were attending outpatient clinics and who were screened for glutamic acid decarboxylase 65 autoantibodies (GADA), protein tyrosine phosphatase IA-2 (IA-2A) and IA-2beta/phogrin (IA-2betaA).

DESIGN AND METHODS

This was a cross-sectional study comprising a total of 881 patients, aged < or = 70 years, diagnosed with type 2 diabetes after the age of 40 years, and consecutively recruited in five clinics located in different geographic areas of Italy (Milan, Florence, Rome, Naples and Catania). Their mean disease duration was 8.1 (6.9; s.d.) years. GADA, IA-2A and IA-2betaA were measured with radiobinding assays with in vitro translated S-methionine-labelled glutamic acid decarboxylase 65 (GAD65) or IA-2 or IA-2beta. Anthropometric and clinical data were collected and compared amongst patients with or without autoantibodies.

RESULTS

Sixty-three (7.1%) patients had one or more autoantibodies, 58 (6.6%) had GADA, 22 (2.5%) had IA-2A, six (0.7%) had IA-2betaA and 19 (2.15%) had two or more autoantibodies. IA-2A or IA-2betaA, in the absence of GADA, were found in only five patients. Autoantibody-positive patients were more often female (63.5 vs 36.5%; P < 0.009), had higher glycated haemoglobin (Hb A1c) (P < 0.001), lower body mass index (BMI; P < 0.0005) and waist/hip ratio (WHR; P < 0.01); female gender being the main contributor to BMI and WHR. We did not observe any differences in age at diagnosis or duration of disease with respect to the presence or absence of islet autoantibodies. The proportion of patients on insulin therapy was higher in patients with two or more antibodies, compared with those with one antibody only, and no antibodies (P for trend < 0.001), and among patients with GADA, in those with higher antibody titre (73.9% in those with > 10 units vs 42.0% in those with < or = 10 units; P < 0.007).

CONCLUSIONS

Patients with adult onset diabetes characterized by autoimmunity to beta-cells showed a clinical phenotype with anthropometric features that differed from those classically observed in patients with type 2 diabetes. The number and titre of autoantibodies, which reflect the severity of autoimmunity and beta-cell impairment, amplified this difference. The usefulness of autoantibody screening in adult-onset diabetes is further emphasized by these findings.

Prevalência de sobrepeso e obesidade em pacientes com diabetes mellitus do tipo 2 no Brasil: estudo multicêntrico nacional

OBJETIVO: Avaliar a prevalência de sobrepeso e obesidade em pacientes ambulatoriais com diabetes mellitus tipo 2 (DM2) em diferentes regiões do Brasil. PACIENTES E MÉTODOS: Avaliamos aleatoriamente 2.519 pacientes em 11 hospitais, 2 ambulatórios especializados e um posto de saúde em 10 cidades brasileiras. Consideramos sobrepeso um índice de massa corporal (IMC) > 25 e obesidade um IMC > 30 kg/m². O controle glicêmico (CG) foi avaliado pelo índice de CG [ICG= HbA1 e ou HbA1c do paciente/limite superior de normalidade do método x 100]. RESULTADOS: Os pacientes tinham idade de 58,8 ± 11,6 anos, tempo de diagnóstico clínico de DM de 9,0 ± 7,3 anos, IMC de 28,3 ± 5,2 kg/m², e 39% eram do sexo masculino. Do total da amostra, 265 pacientes (10,5%) não apresentavam avaliação do IMC. Os pacientes da região Nordeste apresentaram menor IMC em comparação com os das regiões Centro-Oeste, Sudeste e Sul, respectivamente (26,4 ± 4,7 vs. 27,9 ± 4,8 vs. 29,2 ± 5,1 vs. 29,4 ± 5,4 kg/m²; p< 0,001). Houve maior prevalência de obesidade na região Sudeste e Sul em comparação à região Nordeste (p< 0,001) e nos pacientes do sexo feminino, respectivamente (69 vs. 31%; p< 0,001). Os pacientes com peso normal apresentaram menor ICG. Aqueles em tratamento com associação de duas ou mais drogas orais e associação de insulina + droga oral apresentaram maior IMC do que aqueles em tratamento com dieta, hipoglicemiante oral e insulina; p< 0,001. O IMC não diferiu entre os pacientes assistidos ou não por especialistas. CONCLUSÕES: Da população estudada, 75% não estava na faixa de peso ideal, sendo que um terço tinha obesidade. Nossos dados indicam que o sobrepeso e a obesidade já atingem um percentual de pacientes com DM2 no Brasil semelhante ao relatado em estudos europeus, mas ainda menor do que o observado nos EUA. A prevalência de obesidade nos pacientes diabéticos foi três vezes maior do que a observada na população brasileira em geral de acordo com os dados do IBGE.

Latent autoimmune diabetes in adults (LADA) should be less latent

'Latent autoimmune diabetes in adults' (LADA) is the term coined to describe adults who have a slowly progressive form of autoimmune or type 1 diabetes that can be treated initially without insulin injections. The diagnosis of LADA is currently based on three clinical criteria: (1) adult age at onset of diabetes; (2) the presence of circulating islet autoantibodies, which distinguishes LADA from type 2 diabetes; and (3) insulin independence at diagnosis, which distinguishes LADA from classic type 1 diabetes. The prevalence of LADA in adults presenting with non-insulin-requiring diabetes is approximately 10%. Recognition of LADA expands the concept and prevalence of autoimmune diabetes, but LADA remains poorly understood at both a clinical and research level. In this perspective, we review the nomenclature, diagnostic criteria, genetics, pathology and therapy of LADA, to arrive at recommendations that might advance knowledge and management of this form of diabetes.

The clinical characteristics of latent autoimmune diabetes in adults and its relation with chronic complications in metabolically poor controlled Turkish patients with Type 2 diabetes mellitus

It has been reported that some patients with Type 2 diabetes mellitus (DM) have latent autoimmune diabetes in adults (LADA) and may show different clinical characteristics than those with Type 2 DM. We aimed to determine the ratio and clinical features of LADA in patients with diagnosed initially as Type 2 DM. We measured glutamic acid decarboxylase antibodies (GADA) in 54 patients, diagnosed clinically with Type 2 DM. Of 54 patients, 17 (31%) were GADA positive. GADA-positive patients had significantly earlier diabetes onset age (P<.001), lower BMI (P<.05), and lower serum C-peptide value (P<.001) than did those who were GADA negative. A higher proportion of the GADA-positive patients were receiving insulin therapy (P<.01). With respect to the duration of DM, familial history of DM, and the levels of blood pressures, fasting plasma glucose, and HbA1c, there was no difference between the two groups. Nephropathy and retinopathy were more frequent in GADA-positive than in GADA-negative patients. The prevalence of neuropathy was comparable between the two groups. GADA was negatively associated with BMI, C-peptide levels, and diabetes-onset age, but positively related to retinopathy, nephropathy, and insulin treatment. This study indicated that the important portion of the patients who were initially diagnosed as Type 2 DM may have LADA. In Type 2 diabetic patients who have lower BMI and diagnosis of diabetes in relatively younger age, the possibility of LADA should be taken into consideration. The higher prevalence of nephropathy and retinopathy in GADA-positive patients also suggests the importance of early diagnosis and strict metabolic control in these patients.

Latent autoimmune diabetes of adulthood. Unique features that distinguish it from types 1 and 2

A number of patients with poor glycemic control receive the diagnosis of type 2 diabetes despite the fact that they do not exhibit some of the traditional characteristics of the disease, such as obesity. A more accurate diagnosis for many of these patients is latent autoimmune diabetes of adulthood (LADA). In this article, Dr Nabhan and coauthors describe features that LADA has in common with type 1 and type 2 diabetes, as well as those that distinguish LADA from these more widely recognized forms of diabetes. The authors also describe the pathogenesis of the disease, potential complications, and treatment options.

Prevalence of LADA and frequency of GAD antibodies in diabetic patients with end-stage renal disease and dialysis treatment in Austria

BACKGROUND

The prevalence of individuals with latent autoimmune diabetes in adults (LADA) among diabetic patients with end-stage renal disease is unknown. Furthermore, there are no references in the literature about the persistence of glutamic acid decarboxylase antibodies (GADA) in uraemic LADA patients. The aim of the study, therefore, was to evaluate the prevalence of LADA, classified according to special features, in diabetic patients undergoing dialysis therapy as well as to find out the frequency of GADA in these patients. In addition, we investigated vascular risk factors and the prevalence of vascular diseases in each type of diabetes.

METHODS

538 patients undergoing chronic dialysis therapy from 37 Austrian dialysis centres were analysed in the study. Patients were divided into three groups: patients with type 1 or type 2 diabetes and patients with LADA. The classification of the different types of diabetes was based on the guidelines of the German Diabetes Society. We measured GADA and estimated the baseline data with reference to body mass index (BMI), age at onset of diabetes and at initiating dialysis therapy, the actual values of haemoglobin (Hb) A1c and cholesterol and the prevalence of vascular diseases by using a structured questionnaire.

RESULTS

Type 1 diabetes was classified in 52 patients, type 2 diabetes in 434 and LADA in 52 (9.7%). The prevalence of positive GADA was 17.3% in the type 1 diabetic patients and 26.9% in the LADA patients. There was no positive GADA in the type 2 diabetic subjects. Age at the onset of diabetes and age at the start of dialysis were approximately the same in the LADA and the type 2 diabetic patients, while the age of the subjects with type 1 diabetes was significantly lower (P<0.001). BMI was significantly lower (25+/-3 vs 27+/-5 kg/m2) in the LADA patients than in the type 2 diabetic patients. The mean HbA1c value in the LADA patients was significantly higher than in the subjects with type 2 diabetes (P<0.01). Blood pressure (BP) was similar between LADA and type 1 or type 2 diabetes, though diastolic BP tended to be lower in the LADA patients than in the type 1 diabetics. The cholesterol levels were comparably high in each type of diabetes. In the LADA patients, the prevalence of retinopathy was lower than in the type 1 diabetics and the prevalence of stroke and angina pectoris was lower than in the type 2 diabetic patients, but the differences were not significant.

CONCLUSIONS

The prevalence of LADA in diabetic patients on maintenance dialysis was 9.7%. This value is comparable to the frequency of LADA at onset of diabetes. The frequency of persisting GAD autoantibodies was 27% in the LADA patients and 17% in the type 1 diabetic patients. BMI was significantly lower in the LADA patients than in the type 2 diabetic patients, while diastolic BP only tended to be lower in the LADA patients than in the type 1 diabetics. The prevalence of vascular diseases was not significantly different between LADA and types 1 or 2 diabetes. According to our data it can be assumed that only a few uraemic patients with LADA are suitable for simultaneous pancreas-kidney transplantation.

Phenotypic characteristics of GAD antibody-positive recently diagnosed patients with type 2 diabetes in North America and Europe

A number of patients with type 2 diabetes are GAD antibody positive. A Diabetes Outcome Progression Trial (ADOPT) is a randomized, double-blind clinical trial in recently diagnosed drug-naive patients with type 2 diabetes that allows for the evaluation of GAD positivity in the context of anthropometric and biochemical characteristics. Of the 4,134 subjects enrolled in ADOPT for whom GAD status was obtained, 174 (4.2%) were GAD positive, with the prevalence of GAD antibodies being similar in North America (4.7%) and Europe (3.7%). Although BMI and age were similar, GAD-positive patients had a lower fasting insulin level, compatible with them being more insulin sensitive. The lower fasting insulin concentration was accompanied by a decreased early insulin response to oral glucose. However, when this insulin response was corrected for the degree of insulin sensitivity, GAD-positive and -negative patients had similar beta-cell function. Consistent with the difference in insulin sensitivity, GAD-positive patients had higher HDL cholesterol and lower triglyceride levels. In the GAD-positive individuals, the prevalence of the metabolic syndrome as defined by NCEP ATP III (National Cholesterol Education Program Adult Treatment Panel III) was also lower (74.1 vs. 83.7%, P = 0.0009). These phenotypic differences may underlie a potential difference in the natural history of hyperglycemia and its clinical outcomes.

C-peptide is the appropriate outcome measure for type 1 diabetes clinical trials to preserve beta-cell function: report of an ADA workshop, 21-22 October 2001

The underlying cause of type 1 diabetes, loss of beta-cell function, has become the therapeutic target for a number of interventions in patients with type 1 diabetes. Even though insulin therapies continue to improve, it remains difficult to achieve normal glycemic control in type 1 diabetes, especially long term. The associated risks of hypoglycemia and end-organ diabetic complications remain. Retention of beta-cell function in patients with type 1 diabetes is known to result in improved glycemic control and reduced hypoglycemia, retinopathy, and nephropathy. To facilitate the development of therapies aimed at altering the type 1 diabetes disease process, an American Diabetes Association workshop was convened to identify appropriate efficacy outcome measures in type 1 diabetes clinical trials. The following consensus emerged: While measurements of immune responses to islet cells are important in elucidating pathogenesis, none of these measures have directly correlated with the decline in endogenous insulin secretion. HbA(1c) is a highly valuable clinical measure of glycemic control, but it is an insensitive measure of beta-cell function, particularly with the currently accepted standard of near-normal glycemic control. Rates of severe hypoglycemia and diabetic complications ultimately will be improved by therapies that are effective at preserving beta-cell function but as primary outcomes require inordinately large and protracted trials. Endogenous insulin secretion is assessed best by measurement of C-peptide, which is cosecreted with insulin in a one-to-one molar ratio but unlike insulin experiences little first pass clearance by the liver. Measurement of C-peptide under standardized conditions provides a sensitive, well accepted, and clinically validated assessment of beta-cell function. C-peptide measurement is the most suitable primary outcome for clinical trials of therapies aimed at preserving or improving endogenous insulin secretion in type 1 diabetes patients. Available data demonstrate that even relatively modest treatment effects on C-peptide will result in clinically meaningful benefits. The development of therapies for addressing this important unmet clinical need will be facilitated by trials that are carefully designed with beta-cell function as determined by C-peptide measurement as the primary efficacy outcome.

Diabetes autoimune em adultos: características clínicas e autoanticorpos

Avaliamos a prevalência dos anticorpos anti-insulina (IAA), anti-decarboxilase do ácido glutâmico (anti-GAD), anti-ilhota de Langerhans (ICA) e as características clínicas e metabólicas de 66 pacientes com diabetes mellitus (DM) de início na idade adulta (47,2±11,6 anos) e duração do DM de 14,3±8,4 anos. RESULTADOS: ICA foi positivo em 10 casos (10 a 640U JDF), três deles também positivos para anti-GAD (15,6 a 113,5U/ml) e um deles para IAA (naqueles sem terapia insulínica). 15,2% dos pacientes tinham um ou mais autoanticorpos, com maior prevalência para ICA. Os pacientes com e sem autoanticorpos não diferiram quanto à apresentação clínica do DM ou à prevalência de complicações. Apenas os níveis de colesterol foram menores no grupo anticorpo positivo (205,2±49,6 vs. 247,1±61,3mg/dl; p<0,05). CONCLUSÃO: 15,2% dos pacientes com DM de início na idade adulta tinham um ou mais autoanticorpos, com maior prevalência para ICA. A determinação de autoanticorpos é necessária para o diagnóstico do DM autoimune.

Similar genetic features and different islet cell autoantibody pattern of latent autoimmune diabetes in adults (LADA) compared with adult-onset type 1 diabetes with rapid progression

OBJECTIVE

To compare the clinical parameters, C-peptide levels, pattern of islet cell-specific autoantibodies, and prevalence of predisposing genotypes in subjects with latent autoimmune diabetes in adults (LADA) and those with adult-onset type 1 diabetes with rapid progression.

RESEARCH DESIGN AND METHODS

We evaluated the clinical parameters, C-peptide levels, and islet cell-specific autoantibodies in 54 LADA, 57 adult-onset type 1 diabetic, and 190 type 2 diabetic patients. Islet cell autoantibodies were also compared between subgroups of newly diagnosed patients with LADA and those with newly diagnosed adult-onset and childhood-onset type 1 diabetes. The genetic study was performed in subjects with LADA and those with adult-onset type 1 diabetes in comparison with a control population.

RESULTS

There were no differences in the clinical parameters between LADA and adult-onset type 1 diabetes. Patients with LADA had lower BMI (P < 0.0001), waist-to-hip ratio (0.0029), total cholesterol (P = 0.001), and triglycerides (P = 0.001); higher HDL cholesterol levels (P < 0.0001); and lower prevalence of hypertension (P = 0.0028) compared with patients with type 2 diabetes. C-peptide levels were similar at onset (P = 0.403) but decreased less rapidly in LADA than in adult-onset type 1 diabetes (P = 0.0253). Single-autoantibody positivity was more often seen in LADA than in type 1 diabetes (P = 0.0001). The prevalence of predisposing HLA-DQB1*0302, -DR4, -DR3, and -DR3/DR4 genotypes and the DR4-DQB1*0302 haplotype were increased in both LADA and adult-onset type 1 diabetic subjects compared with the control population. There were no differences in the frequencies of these risk alleles and haplotypes between the two patient groups.

CONCLUSIONS

Subjects with LADA had clinical characteristics similar to those with adult-onset type 1 diabetes with rapid progression. C-peptide levels did not differ at onset but decreased less rapidly in LADA. Patients with LADA rather had single islet cell-specific autoantibody positivity. The prevalence of HLA-DQB1*0302, -DR4, -DR3, and -DR3/DR4 risk alleles and the DR4-DQB1*0302 high-risk haplotype did not differ in the two forms of autoimmune diabetes.

Retinopathy in latent autoimmune diabetes of adults: the Fremantle Diabetes Study

AIMS

To determine the prevalence of retinopathy and its associations in patients diagnosed clinically with Type 2 diabetes and serum antibodies to glutamic acid decarboxylase (GADA) from a community-based sample.

METHODS

In a case-control design, 24 GADA-positive Type 2 patients from the Fremantle Diabetes Study (FDS) cohort were recruited and matched as closely as possible for age, sex and diabetes duration with 72 GADA-negative Type 2 patients from the FDS. Each patient had a detailed clinical and biochemical assessment including slit lamp biomicroscopy and colour fundus photography with Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) grading.

RESULTS

The GADA-positive patients had a significantly higher HbA1c (median (interquartile range); 8.4 (7.3, 9.6)%) than those who were GADA-negative (7.2 (6.5, 8.1)%: P = 0.002). The overall prevalence of retinopathy amongst the 96 subjects was 26.0%. The majority (92%) of the retinopathy detected was mild and non-proliferative. GADA-positive patients had double the retinopathy prevalence of the GADA-negative group (41.7% vs. 20.8%; P = 0.044). In a logistic regression model, diabetes duration, HbA1c, systolic blood pressure and current smoking were each significantly and independently predictive of retinopathy (P < 0.025), but GADA status was not.

CONCLUSIONS

These data show that GADA-positive patients have an increased prevalence of retinopathy compared with GADA-negative controls with Type 2 diabetes from an urban Australian community. This increased prevalence is due mainly to relatively poor glycaemic control in the GADA-positive group.

Thiazolidinediones for the prevention of diabetes in the non-obese diabetic (NOD) mouse: implications for human type 1 diabetes

BACKGROUND

Thiazolidinediones (TZDs) are a recently introduced generation of drugs acting as receptor agonists to reduce insulin resistance and used currently in combination with other hypoglycaemic agents for the treatment of type 2 diabetes. In addition, TZDs possess anti-inflammatory properties that make them of interest for reducing the T-cell inflammation occurring in the islets in type 1 diabetes.

METHODS

The action of TZD treatment on diabetes incidence in the non-obese diabetic (NOD) mouse was studied by investigating the effect of rosiglitazone (RGL) (400 mg/kg body weight by gavage) from 3 weeks of age (soon after weaning) onwards and comparing its effect to that of troglitazone (TGL) given by the same route.

RESULTS

We found that RGL and TGL both significantly reduced diabetes incidence by >50% in the NOD mouse compared to litter-matched control NOD mice (p<0.05 and p<0.01, respectively). However, the withdrawal of TGL from the market due to hepatotoxicity led us to re-analyse our data for toxic liver effects. We found that TGL was more toxic to mice than RGL (causing ten deaths as compared with one death).

CONCLUSION

RGL reduces diabetes incidence in the NOD mouse model of type 1 diabetes. This may be an effect resulting from its action as on inhibitor of pro-inflammatory genes such as cytokines and metabolic proteases. Its use may be considered for trials designed to protect beta-cell function in humans, especially in patients with latent autoimmune diabetes of adults (LADA) and also for disease prevention.

Autoimmune diabetes not requiring insulin at diagnosis (latent autoimmune diabetes of the adult): definition, characterization, and potential prevention

Type 1 diabetes is caused by the immune-mediated destruction of islet insulin-secreting beta-cells. This chronic destructive process is associated with both cellular and humoral immune changes in the peripheral blood that can be detected months or even years before the onset of clinical diabetes. Throughout this prediabetic period, metabolic changes, including altered glucose tolerance and reduced insulin secretion, deteriorate at variable rates and eventually result in clinical diabetes. A fraction of individuals with humoral immunological changes have clinical diabetes that initially is not insulin-requiring. The onset of diabetes in these patients is usually in adult life, and because their diabetes is at least initially not insulin-requiring, they appear clinically to be affected by type 2 diabetes. Such patients probably have the same disease process as patients with type 1 diabetes in that they have similar HLA genetic susceptibility as well as autoantibodies to islet antigens, low insulin secretion, and a higher rate of progression to insulin dependency. These patients are defined as being affected by an autoimmune type of diabetes not requiring insulin at diagnosis, which is also named latent autoimmune diabetes of the adult (LADA). Special attention should be paid to diagnose such patients because therapy may influence the speed of progression toward insulin dependency, and in this respect, efforts should be made to protect residual C-peptide secretion. LADA can serve as a model for designing new strategies for prevention of type 1 diabetes but also as a target group for prevention in its own right.