Endocrine Abstracts

Backrgound: Coexistent gastrointestinal pathology might alter hydrocortisone (HCT) and levothyroxine (LT4) absorption and gut transit times.

Aims: To screen patients with autoimmune Addison disease for the presence of serological markers of autoimmune gastrointestinal disorders, to compare doses of HCT and LT4 in patients with positive autoantibodies to those of patients without signs of autoimmune gastroenteropathy.

Subjects and methods: Of 62 patients with autoimmune Addison disease were investigated. Autoantibodies against tissue transglutaminase (t-TGA) were measured by CLIA, autoantibodies against gastric parietal cells (PCA) were measured by an indirect immunofluorescence method.

Results: Mean daily doses of HCT and LT4 were higher in patients (n=13) with positive PCA and/or t-TGA – HCT 22.5±5.9 vs 19.0±2.9 mg (P>0.05), HCT_BW 0.37±0.08 vs 0.32±0.04 mg/kg (P<0.05), HCT_BSA 13.9±3.0 vs 11.8±1.3 mg/m² (P<0.05); LT4 103.8±21.4 vs 87.9±28.0 μg (P>0.05), LT4_BW 1.75±0.46 vs 1.47±0.55 μg (P>0.05), LT4_BSA 65.4±14.3 vs 54.7±16.9 μg/m² (P>0.05). Conlusions

Our results suggest for high prevalence of serological markers of autoimmune gastrointestinal disorders in APS. Already state of PCA- and/or t-TGA positivity may underly the requirement of higher HCT and LT4 doses. Measurement of serum PCA and t-TGA should be part of the routine autoantibody screening and the diagnostic work up in Addison or APS patients with unexplained high HCT or LT4 doses.