Xia Li1, Gan Huang, Xiang Yan, Lin Yang, Zhi-guang Zhou. 1. Second Xiangya Hospital, Diabetes Center, Institute of Metabolism and Endocrinology, Central South University, Changsha 410011, China. hellolxwj@yahoo.com.cn
Abstract
OBJECTIVE: To investigate the relation between insulin resistance and glutamic acid decarboxylase antibody (GAD-Ab) titers in latent autoimmune diabetes in adults (LADA). METHODS: The patients with phenotypic type 2 diabetes were screened for GAD-Ab positivity, and the 141 positive patients were divided into two subgroups according to the GAD-Ab titer, namely the high-titer group (LADA-1 subtype) and low-titer group (LADA-2 subgroup). The clinical features and insulin resistance were compared between the two groups. Insulin resistance was calculated by HOMA 2 software, and GAD-Ab and C peptide were determined with radioligand and radioimmune assay, respectively. RESULTS: Compared with low-titer LADA patients, the patients with high titers had younger age of onset, lower BMI, higher HbA1c level, and worse fasting and postprandial C peptide levels. The insulin resistance index by HOMA 2 was significantly lower in LADA-1 group than in LADA-2 group (1.6-/+1.1 vs 2.1-/+1.1, P=0.001). The HOMA2-IR index showed a negative correlation to GAD-Ab titer. CONCLUSION: The degree of insulin resistance is correlated to GAD-Ab titers in LADA, and low titer patients have higher insulin resistance level.
OBJECTIVE: To investigate the relation between insulin resistance and glutamic acid decarboxylase antibody (GAD-Ab) titers in latent autoimmune diabetes in adults (LADA). METHODS: The patients with phenotypic type 2 diabetes were screened for GAD-Ab positivity, and the 141 positive patients were divided into two subgroups according to the GAD-Ab titer, namely the high-titer group (LADA-1 subtype) and low-titer group (LADA-2 subgroup). The clinical features and insulin resistance were compared between the two groups. Insulin resistance was calculated by HOMA 2 software, and GAD-Ab and C peptide were determined with radioligand and radioimmune assay, respectively. RESULTS: Compared with low-titer LADA patients, the patients with high titers had younger age of onset, lower BMI, higher HbA1c level, and worse fasting and postprandial C peptide levels. The insulin resistance index by HOMA 2 was significantly lower in LADA-1 group than in LADA-2 group (1.6-/+1.1 vs 2.1-/+1.1, P=0.001). The HOMA2-IR index showed a negative correlation to GAD-Ab titer. CONCLUSION: The degree of insulin resistance is correlated to GAD-Ab titers in LADA, and low titer patients have higher insulin resistance level.