Clinical characteristics of patients with the initial diagnosis of NIDDM with positivity for antibodies to glutamic acid decarboxylase

The prevalence and characteristics of latent autoimmune diabetes in adults (LADA) and its relation with chronic complications in a clinical department of a university hospital in Korea

Few studies were performed to evaluate the prevalence of latent autoimmune diabetes in adults (LADA) and the difference of chronic complications between LADA, T1DM, and T2DM in Korean. The aim of this study is to establish the prevalence of LADA in a diabetic clinic of Soonchunhyang University hospital and to compare the phenotypic characteristics according to DM classification based on positivity of glutamic acid decarboxylase antibodies (GADA). Also, another important point concerns the occurrence of diabetes chronic microvascular complications in LADA. 323 patients who were checked GADA among diabetic patients admitted at Soonchunhyang University hospital were recruited. Twenty-eight patients (8.7%) were identified as positive for GADA. 11.5% (n = 37) were diagnosed with T1DM and 5.3% (n = 17) were diagnosed with LADA. GADA titer showed significant negative correlation with age of onset, total cholesterol (TC), triglyceride (TG), fasting C-peptide, stimulated C-peptide, BMI, and positive correlation with HbA1C and HDL-C. Compared with those that tested negative for GADA, patients with GADA positive had lower values of onset age, BMI, TC, TG, LDL-C, fasting, and stimulated C-peptide levels and higher values of HbA1C. A significant gradual increase of values was observed for the onset age, BMI, SBP, DBP, fasting, and stimulated C-peptide across the T1DM, LADA, and T2DM subgroups. Concerning the chronic complications there was no difference in prevalence of retinopathy, neuropathy and nephropathy between three groups. Of LADA patients, 12 patients were receiving insulin treatment and mean time to insulin initiation was about 37 months. In conclusion, because our study suggests LADA subgroups in Korea appear to have a faster decline in C-peptide levels, it is worth detecting the patients with LADA early and effort to preserve beta cell function. Furthermore, our results showed that the prevalence of microvascular complication was comparable between the subgroups.

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.

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.

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.

Latent autoimmune diabetes in adults

Latent autoimmune diabetes in adults (LADA) is a special form of diabetes that is clinically similar to type 2 diabetes but with positivity for pancreatic autoantibodies. The frequency of LADA patients among all patients diagnosed as type 2 varies between 6-50% in various populations. The frequency is higher in younger age groups. It is clear, however, that the frequency of autoimmune diabetes among adults is underestimated. Clinical features such as age and severity of symptoms are of no help in identifying these patients. Body mass index and C peptide levels in the general population increase with age, and these parameters are of limited use in identifying LADA patients. Determination of autoantibodies is necessary in order to correctly classify the type of diabetes. Among antibodies, GADA is the most frequently occurring autoantibody, followed by ICA. The natural course of these patients shows that C peptide will decrease with time in parallel with the curve for C peptide in classical type 1 diabetic patients. Most of the LADA patients will require insulin within three years. Our recommendation is that all patients be tested for pancreatic islet autoantibodies at diagnosis of diabetes to enable correct diagnosis and to avoid future failure of hypoglycemic agents and risk of complications due to hyperglycemia. It is still unclear whether early treatment with insulin is beneficial for the remaining beta cells.

Diabetic autoimmune markers in children and adolescents with type 2 diabetes

BACKGROUND

There is an increase in the incidence of type 2 diabetes in children and adolescents. Absence of known diabetes autoimmune markers is sometimes required to confirm the diagnosis.

OBJECTIVE

To identify clinical and autoimmune characteristics of type 2 diabetes in a pediatric population.

METHOD

We report an analysis of 48 children and adolescents with type 2 diabetes, compared with 39 randomly selected children with type 1 diabetes, diagnosed and followed at the Loma Linda University Pediatric Diabetes Center. Ethnic, familial, seasonal, and autoimmune marker characteristics are outlined. To determine the reliability of antibody testing in confirming the type of diabetes at diagnosis, we studied the incidence of positive islet cell antibodies (ICAs), glutamic acid decarboxylase antibodies (GADs), and insulin autoantibodies (IAAs) at diagnosis in both groups. ICA512, GADs, and IAAs were measured by radioimmunoassay.

RESULTS

The cohort with type 2 diabetes had a similar gender distribution as the group with type 1 diabetes but a significantly higher age at diagnosis. Ethnic background was significantly different between the 2 groups, predominantly Hispanic in type 2 and white in type 1. Body mass index was significantly higher in type 2 diabetes (mean = 31.24 kg/m(2)). Among the patients with type 2 diabetes, 33% presented in diabetic ketoacidosis, random blood glucose at diagnosis ranged from 11.4 to 22.25 mmol/L (228-445 mg/dL), fasting C-peptide levels ranged from 0.89 to 2.7 nmol/L (2.7-8.2 ng/mL; normal: <1.36 nmol/L), and hemoglobin A(1C) was 10.8 +/- 3.5% (normal: <6.6%). None of these parameters was significantly different from the type 1 diabetes group. Although the incidence of diabetes antibody markers was significantly lower in type 2 versus type 1 diabetes, 8.1% of patients with type 2 diabetes had positive ICAs, 30.3% had positive GADs, and 34.8% had positive IAAs without ever being treated with insulin. In the type 2 diabetes group, none of the Hispanic patients had ICAs. However, there was no significant correlation between any of the diabetes antibodies and obesity, presence of acanthosis nigricans, or family history of diabetes. The frequency of thyroid antibodies was not significantly different from the group with type 1 diabetes. Daily insulin requirements 1 year after diagnosis were significantly lower in type 2 diabetes, ranging from 0 to 1.2 U/kg with a mean of 0.33.

CONCLUSION

Absence of diabetes autoimmune markers is not a prerequisite for the diagnosis of type 2 diabetes in children and adolescents.

All-cause mortality in the Canterbury (New Zealand) insulin-treated Diabetic Registry population

OBJECTIVE

To establish all-cause death rates and life expectancies of and risk factors for mortality in insulin-treated diabetic individuals living in Canterbury, New Zealand.

RESEARCH DESIGN AND METHODS

Insulin-treated diabetic subjects (n = 1,008) on the Canterbury Diabetes Registry were tracked over 9 years, and their vital status was determined. Death rates were standardized using direct and indirect methods. Cox proportional hazard regression was used to model the effects of demographic and clinical covariates on survival time.

RESULTS

At study entry, age ranged from 2.9 to 92.7 years, with mean 48.7 +/- 20.4 years; age at diagnosis was 0.2-88.9 years, mean 34.5 +/- 20.0 years; and duration of diabetes was 0.1-58.5 years, mean 14.0 +/- 10.6 years. There were 303 deaths in 7,372 person-years of follow-up with a standardized mortality ratio (SMR) of 2.6 (95% CI 2.4-3.0). Relative mortality was greatest for those aged 30-39 years (SMR 9.2 [4.8-16.2]). The death rate for the diabetic cohort standardized against the Segi world standard population was 16.2 per 1,000. Attained age, sex, and clinical subtype were significant predictors of mortality The SMR for subjects with type 1 diabetes and age at onset <30 years was 3.7 (CI 2.7-5.0), 2.2 (1.8-2.6) for those with onset > or =30 years, and 3.1 (2.5-3.7) for subjects suspected of having latent autoimmune diabetes in adulthood or insulin-treated type 2 diabetes. Life expectancy was reduced for both sexes at all ages.

CONCLUSIONS

Mortality rates for insulin-treated diabetic individuals remain high, resulting in shortened life spans relative to the general population. Marked differences in mortality exist between clinical groups of subjects. Further research is needed to improve diabetes classification and to clarify differences in health outcomes.

Autoantibodies to IA-2 in insulin-dependent diabetes mellitus. Measurements with a new immunoprecipitation assay

An immunoprecipitation assay for autoantibodies (Abs) to the human islet cell antigen IA-2 has been developed using 125I-labelled recombinant IA-2 expressed in E. coli. With this assay IA-2 Abs were detected in 103/217 (47%) of IDDM patients of different ages and with different disease duration. IA-2 Ab prevalence was higher in younger patients (at the age of 15 years or below) with the recent onset IDDM (64/113; 57%) compared to patients above the age of 15 years (11/25; 44%). One of 40 (2.5%) Graves' disease patients and five of 204 (2.5%) of NIDDM patients were also positive. IA-2 Abs were not detected in sera from patients with Hashimoto's thyroiditis (n=32), myasthenia gravis (n=20) or systemic lupus erythematosus (n=10). IA-2 Ab measurements based on 125I-labelled IA-2 showed a good correlation with the results of an immunoprecipitation assay based on 35S-labelled IA-2 produced in the in vitro transcription/translation system (r=0.78; n=113; p<0.001). Out of 217 IDDM sera which were tested for IA-2 Abs, 140 (65%) were positive for Abs to glutamic acid decarboxylase (GAD) and 166 (76%) were positive for Abs to IA-2 and/or Abs to GAD. In addition, Abs to IA-2, to GAD and to insulin were analysed in sera from recent onset IDDM patients who had not been treated with insulin (n=117). In all, 76/117 (65%) of these sera were positive for GAD Abs, 66/117 (56%) for IA-2 Abs, 45/117 (38%) for insulin Abs. However, 98/117 (84%) were positive for at least one of the three Abs confirming earlier observations on the complementarity of Ab testing in IDDM. Overall, the IA-2 Ab assay based on 125I-labelled recombinant IA-2 showed good sensitivity, precision and specificity which, combined with an easy and convenient protocol, makes it attractive for routine use.