Prevalence and clinical significance of organ-specific autoantibodies in type I diabetes mellitus

As diabetes mellitus type 1 (DM1) is associated with other autoimmune diseases, clinical tools are needed to diagnose and predict the occurrence of other autoimmune diseases in DM1. We performed a systematic search of the literature on the prevalence, and the diagnostic and prognostic significance of organ-specific autoantibodies in DM1, focusing on the most prevalent autoimmune diseases in DM1: Hashimoto's disease, autoimmune gastric disease, Addison's disease and coeliac disease. We found 163 articles that fulfilled our selection criteria. We analysed and compared the prevalence of autoantibodies in DM1 and control populations, studied the relation between antibody prevalence and age, gender, race and DM1 duration and studied the relation between the presence of autoantibodies and organ dysfunction. Because of the large variation in population characteristics and study design, a uniform conclusion on the relation of these autoantibody prevalences with age, gender, race, DM1 duration and target organ failure cannot be drawn easily. In addition, most studies reviewed used a cross-sectional design. Therefore, few data on the predictive value of the organ-specific antibodies in DM1 populations are present in these studies. Obviously, prospective studies are needed to fill this gap in knowledge. Despite these restrictions, the general picture from the present review is that the prevalence of the organ-specific autoantibodies is significantly higher in DM1 than in control populations. Given the relevant risk for organ failure in DM1 patients with autoantibodies against thyroid, gastric, adrenal and intestinal antigens, we recommend checking these autoantibodies in these patients at least once, for instance at the diagnosis of DM1. For detailed advice on assessing the different organ autoantibodies and function we refer to the summaries in the results section.