BACKGROUND
Although the majority of diabetes mellitus (DM) patients diagnosed as adults have non-autoimmune forms of the disease, islet autoimmunity is encountered in some patients initially thought to have type 2 DM. The phenotype of DM patients with glutamic acid decarboxylase (GAD) antibodies is different from that of patients with GAD antibody-negative type 2 DM, with features such as relative leanness and hyperglycemia which may influence the development of complications. We sought to compare the prevalence of chronic complications in patients with and without the GAD antibody. METHODS: We recruited 427 patients (M: 218, F: 209) that were clinically diagnosed with type 2 DM after the age of 35 years. We measured GAD antibody and assessed the factors associated with chronic microvascular and macrovascular complications. RESULTS: Of these patients, 26 were GAD antibody-positive. The patients with GAD antibody had lower systolic blood pressure, higher high-density lipoprotein cholesterol value, and lower level of fasting and stimulated C-peptide than patients without GAD antibody (P < 0.05). Also, the patients with GAD antibody had lower prevalence of retinopathy compared with the patients without GAD antibody (19.2 vs. 47.9%; P < 0.05). The prevalence of nephropathy, peripheral neuropathy and cardiovascular autonomic neuropathy did not differ between the groups. In addition, the prevalence of coronary heart disease, cerebrovascular disease and peripheral arterial disease did not differ between the two groups. CONCLUSION: This study suggests that diabetic patients with GAD antibody have a lower risk for the development of retinopathy compared with patients without GAD antibody.