Latent autoimmune diabetes in adults with low-titer GAD antibodies: similar disease progression with type 2 diabetes: a nationwide, multicenter prospective study (LADA China Study 3)

• Published in: Diabetes care Vol. 38; no. 1; p. 16
• Main Authors: Liu, Lingjiao, Li, Xia, Xiang, Yufei, Huang, Gan, Lin, Jian, Yang, Lin, Zhao, Yunjuan, Yang, Zhifang, Hou, Can, Li, Yijun, Liu, Jie, Zhu, Dalong, Leslie, R David, Wang, Xiangbing, Zhou, Zhiguang
• Format: Journal Article
• Language: English
• Published: United States American Diabetes Association 01.01.2015
• Subjects: Adult; Autoantibodies - blood; Autoantibodies - immunology; Autoimmune diseases; Autoimmune Diseases - immunology; Autoimmunity - immunology; C-Peptide - blood; C-Peptide - metabolism; China; Diabetes; Diabetes Mellitus, Type 2 - immunology; Disease Progression; Fasting; Female; Follow-Up Studies; Genotype & phenotype; Glucose Intolerance - immunology; Glutamate Decarboxylase - immunology; Glycated Hemoglobin A - metabolism; Glycosylation; Hemoglobin; Humans; Insulin-Secreting Cells - metabolism; Male; Middle Aged; Peptides; Polyclonal antibodies; Prospective Studies; China
• ISSN: 0149-5992; 1935-5548; 1935-5548
• DOI: 10.2337/dc14-1770

This study investigated the relationship between GAD autoantibody (GADA) titers and changing of β-cell function in patients with latent autoimmune diabetes in adults (LADA). This 3-year prospective study enrolled 95 subjects from 15 Chinese cities including 25 high-titer (GADA ≥180 units/mL) LADA patients, 42 low-titer (GADA <180 units/mL) LADA patients, and 28 type 2 diabetic patients, the latter two groups as controls of similar age, sex, and BMI. Clinical characteristics were determined annually, including glycosylated hemoglobin (HbA1c), fasting C-peptide (FCP), and 2-h postprandial C-peptide (PCP). Despite similar initial FCP and PCP, FCP and PCP both decreased more in subjects with high GADA titer (FCP from mean 0.49 nmol/L at entry to 0.13 nmol/L at the third year; P < 0.05) than with low GADA titer (FCP from mean 0.48 to 0.38 nmol/L) and type 2 diabetes (FCP from mean 0.47 to 0.36 nmol/L); the latter two groups being similar. After 3 years, residual β-cell function (FCP >0.2 nmol/L) was detected in only 42% with an initial high GADA titer compared with 90% with a low GADA titer and 97% with type 2 diabetes (P < 0.01 for both). GADA positivity at the third year persisted more in subjects with initially high GADA (92%) than with low GADA (26%) titers (P < 0.01). In selected LADA patients, initial GADA titers identified subjects with different degrees of persistent autoimmunity and disease progression. LADA patients with a low GADA titer had metabolic phenotypes and loss of β-cell function similar to type 2 diabetic patients.