Endocrine Abstracts

Introduction: Autoimmune diabetes mellitus patients, either with Latent Autoimmune Diabetes of Adults (LADA) form or with conventional (juvenile) autoimmune type 1 diabetes (T1D) form, exhibit a higher prevalence of Accompanying Autoimmune Diseases (AADs). The aim of this study was to investigate possible differences in AADs, Familial Autoimmune Diseases (FADs) and metabolic profile between patients with LADA and T1D and between patients with or without anti-GAD (Anti-Glutamic Acid Decarboxylase) antibody titers.

Methods: We Retrospectively investigated 160 adult patients with autoimmune diabetes mellitus (114 with T1D and 46 with LADA), mean±SD 40.36±15.89 years, 81(50.63%) males. Personal and familial medical history was recorded for AAD and FAD respectively. Antibody titers were measured for anti-GAD, IA2(islet tyrosine phosphatase 2), ICA(islet cell antibodies) and other organ specific antibodies. Basic biochemical and hormonal parameters were also evaluated.

Results: In overall sample there was a significant correlation between total number of AADs and FADs (rho=0.16, P=0.039). Patients in LADA group had a higher prevalence of AADs (73.9% vs 51.7%, OR=2.64, P=0.01), while the total number of AADs was associated with LADA (for 1 AAD OR=2.29, P=0.05, for 2 AADs OR=3.56, P=0.006). There was no association between LADA and FADs (43.5% vs 35.9%, P=0.23). Patients with LADA had a higher prevalence of autoimmune thyroiditis (58.6% vs 39.4%, OR=2.17, P=0.027) and gastric autoimmunity (43.4% vs 19.2%, OR=3.21, P=0.002), whereas all patients with celiac disease had T1D (0% vs 5.2%, P=0.041). Patients with LADA had a greater proportion of anti-GAD titers (83.7% vs 64.8%, OR=2.78, P=0.025), ICA titers (85.2% vs 62%, OR=3.54, P=0.018) and anti-pancreatic titers in general (95.3% vs 79.3%, OR=2.78, P=0.017). Anti-GAD titers were found in 134(83.75%) patients. Those patients had a higher prevalence of AADs (70.6% vs 41%, OR=3.43, P=0.0015), higher prevalence of autoimmune thyroiditis (55.7% vs 33.3%, OR=2.52, P=0.017) and gastric autoimmunity (35.7% vs 17.9%, OR=2.54, P=0.036). There was no association between anti-GAD and FADs (38.9% vs 43.5%, P=0.37). After controlling for the effect of LADA anti-GAD remained a significant predictor of AADs.

Conclusions: Patients with LADA have a higher prevalence of AADs. Even if diabetes mellitus phenotype of LADA patients is similar to that of conventional autoimmune type 1 diabetes, the underlying autoimmune pathophysiology may differ. LADA patients may be characterized by a stronger, generalized and multiple autoimmune disorder. Anti-GAD are also associated with a higher prevalence of AADs, thus possibly considered to be a marker of further self-autoimmunity.