Background and purpose: The aim of this study was to examine the prevalence of autoimmune antibodies (autoimmune hypophysitis, adrenalitis, thyropathy, pernicious anemia, celiac disease) and clinically relevant endocrine autoimmune disease (AIEK) in patients with type 1 diabetes in the course of 1 year.
Patients and methods: Antibody screening was performed in 139 diabetic patients (age 44 +/- 14 years; years since diagnosis 26 +/- 15 years; duration of diabetes 18 +/- 12 years; body mass index 26 +/- 4 kg/m(2); HbA(1c) 7.5% +/- 1.1% [normal range 4.4-5.9%]) who completed a routine clinic visit in 2003. Patients with pathologically increased antibody titers were further examined regarding the clinically relevant AIEKs. Reexamination was performed 1 year later.
Results: In 2003, 63% of diabetic patients showed at least one pathologically increased antibody titer (2004: 60%). In 32% of the patients, increased antibody titers were clinically inapparent. Apart from diabetes mellitus type 1, in 2003, 31% suffered from other AIEK requiring therapy (2004: +3.6%): 22.3% harbored two additional AIEKs (2004: +2.2%) and 8.6% even > or = 3 AIEKs (2004: +1.5%). The following pathologically increased antibody titers/prevalences of clinically relevant AIEKs were found (in comparison with 2004): increased antithyroid autoantibodies: 47.5% (-0.7%)/autoimmune thyroiditis 24.5% (+2.8%) and Graves' disease 4.3% (+0.7%), respectively; adrenal cortex autoantibodies 0.7% (+1.5%)/Addison's disease 1.4% (+/-0), gliadin peptide antibodies and IgA to tissue transglutaminase, respectively: 18.7% (-5.0%)/celiac disease 1.4% (+0.8%), parietal cell antibodies: 15.8% (+7.2%)/pernicious anemia 7.2% (+1.4%), hypophysitis 0.7% (+/-0), hypogonadism 0.7% (+/-0). All new AIEK manifestations in 2004 had had an at least tenfold increased antibody titer in 2003. Comparing patients with and without polyglandular autoimmune syndrome (PAS), no difference in age (43 +/- 14 vs. 46 +/- 13 years), duration of diabetes (17 +/- 13 vs. 18 +/- 12 years), and HbA1c (7.3% +/- 0.9% vs. 7.6% +/- 1.1%) could be found.
Conclusion: In this study, more than half of the patients with diabetes mellitus type 1 had at least one pathologically increased antibody titer apart from diabetes without clinical sign of an additional AIEK. 31% of patients with increased antibodies presented with symptoms of another AIEK (increase by 3.6% within 1 year). Patients with diabetes mellitus type 1 should be screened for other AIEKs. Thyropathy had the greatest prevalence and increased by 3.5% within 1 year's time.