scholarly journals A convenient diagnostic tool for discriminating adult-onset glutamic acid decarboxylase antibody-positive autoimmune diabetes from type 2 diabetes: a retrospective study

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8610
Author(s):  
Hon-Ke Sia ◽  
Shih-Te Tu ◽  
Pei-Yung Liao ◽  
Kuan-Han Lin ◽  
Chew-Teng Kor ◽  
...  

Background The glutamic acid decarboxylase antibody (GADA) test, commonly used to diagnose autoimmune diabetes, is not cost-effective in areas of low prevalence. The aim of this study was to develop a convenient tool to discriminate adult-onset GADA-positive autoimmune diabetes from type 2 diabetes (T2DM) in patients with newly diagnosed diabetes. Methods This retrospective cross-sectional study, conducted at Changhua Christian Hospital in Taiwan, collected electronic medical record data from January 2009 to December 2018. Patients were divided into a case group (GADA+, n = 152) and a reference group (T2DM, n = 358). Variables that differed significantly between the groups were subjected to receiver operator characteristic analysis to establish cutoff values. Discriminant function analysis was then employed to discriminate the two groups. Results At the onset of diabetes, the GADA+ group was younger, with lower body mass index (BMI), higher hemoglobin A1c (HbA1c), higher high-density lipoprotein cholesterol (HDL-C), and lower total cholesterol and triglycerides (TG). Five major factors were identified to form the linear discriminant functions: BMI, age at onset, TG, HDL-C, and HbA1c. BMI < 23 kg/m2 was the most important factor, followed by TG < 98 mg/dL, HDL-C ≥ 46 mg/dL, age at onset < 30 years, and HbA1c ≥ 8.6%. The overall accuracy of the linear discriminant functions was 87.1%, with 84.2% sensitivity and 88.3% specificity. Conclusions Routine tests in diabetes care were used to establish a convenient, low-cost tool that may assist in the early identification of adult-onset GAD+ autoimmune diabetes in clinical practice.

2019 ◽  
Vol 15 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Elin Pettersen Sørgjerd

Autoantibodies against Glutamic Acid Decarboxylase (GADA), insulinoma antigen-2 (IA- 2A), insulin (IAA) and the most recently Zinc Transporter 8 (ZnT8A) are one of the most reliable biomarkers for autoimmune diabetes in both children and adults. They are today the only biomarkers that can distinguish Latent Autoimmune Diabetes in Adults (LADA) from phenotypically type 2 diabetes. As the frequency of autoantibodies at diagnosis in childhood type 1 diabetes depends on age, GADA is by far the most common in adult onset autoimmune diabetes, especially LADA. Being multiple autoantibody positive have also shown to be more common in childhood diabetes compared to adult onset diabetes, and multiple autoantibody positivity have a high predictive value of childhood type 1 diabetes. Autoantibodies have shown inconsistent results to predict diabetes in adults. Levels of autoantibodies are reported to cause heterogeneity in LADA. Reports indicate that individuals with high levels of autoantibodies have a more type 1 diabetes like phenotype and individuals with low levels of autoantibody positivity have a more type 2 diabetes like phenotype. It is also well known that autoantibody levels can fluctuate and transient autoantibody positivity in adult onset autoimmune diabetes have been reported to affect the phenotype.


Author(s):  
E Rapti ◽  
S Karras ◽  
M Grammatiki ◽  
A Mousiolis ◽  
X Tsekmekidou ◽  
...  

Summary Latent autoimmune diabetes in adults (LADA) is a relatively new type of diabetes with a clinical phenotype of type 2 diabetes (T2D) and an immunological milieu characterized by high titers of islet autoantibodies, resembling the immunological profile of type 1 diabetes (T1D). Herein, we report a case of a young male, diagnosed with LADA based on both clinical presentation and positive anti-glutamic acid decarboxylase antibodies (GAD-abs), which were normalized after combined treatment with a dipeptidyl peptidase-4 inhibitor (DPP-4) (sitagliptin) and cholecalciferol. Learning points Anti-glutamic acid decarboxylase antibodies (GAD-abs) titers in young patients being previously diagnosed as type 2 diabetes (T2D) may help establish the diagnosis of latent autoimmune diabetes in adults (LADA). Sitagliptin administration in patients with LADA might prolong the insulin-free period. Vitamin D administration in patients with LADA might have a protective effect on the progression of the disease.


2006 ◽  
Vol 154 (3) ◽  
pp. 441-447 ◽  
Author(s):  
S Genovese ◽  
E Bazzigaluppi ◽  
D Gonçalves ◽  
A Ciucci ◽  
M G Cavallo ◽  
...  

Objective: To characterize the phenotype of a large population of Italian patients with adult onset (≥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-2β/phogrin (IA-2βA). Design and methods: This was a cross-sectional study comprising a total of 881 patients, aged ≤ 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-2βA were measured with radiobinding assays with in vitro translated S-methionine-labelled glutamic acid decarboxylase 65 (GAD65) or IA-2 or IA-2β. 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-2βA and 19 (2.15%) had two or more autoantibodies. IA-2A or IA-2βA, 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 ≤ 10 units; P < 0.007). Conclusions: Patients with adult onset diabetes characterized by autoimmunity to β-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 β-cell impairment, amplified this difference. The usefulness of autoantibody screening in adult-onset diabetes is further emphasized by these findings.


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