BackgroundSome of the thyroid disorders (TD) and Myasthenia gravis (MG) are autoimmune related disease. The purpose of the study to evaluate the relationship of MG with all morphological and functional thyroid disorders.MethodsWe constructed a population-based cohort study during the period from January 2000-December 2002 by using reimbursement data from the Bureau National Health Insurance (NHI) system in Taiwan. Patients with TD and MG were identified by referring to the ICD-9-CM codes. (ICD-10-CM as reference) .The association of TD with MG occurred only in the same person within the study period. The Q value was used to measure the strength of disease-disease associations.ResultsWe obtained 520628 TD and 7965 MG records for analysis. Diffuse toxic goiter had highest association rate, followed by nontoxic nodular goiter, simple goiter, chronic lymphocytic thyroiditis, thyroid cancer, and toxic nodular goiter. Female and older patients had a higher rate than their male and younger counterparts, respectively. Functional abnormalities revealed higher incidence of thyrotoxicosis and hypothyroidism in both sexes. We also found the strongest association in men with chronic thyroiditis, diffuse toxic goiter, thyrotoxicosis, acquired hypothyroidism, thyroid cancer, and simple goiter. While an intermediate association was observed in female with diffuse toxic goiter, in a male with toxic and nontoxic nodular/multinodular goiters, in female with thyrotoxicosis, thyroid cancer and acquired hypothyroidism.ConclusionThis population based cohort study showed potential association of all types of TD with MG, and observed a higher association rate in female autoimmune TD whereas males showed a higher strength of association.

Graves disease (GD) and type 2 diabetes mellitus (T2DM) both impair liver function; we therefore explored the possibility of a relationship among diabetic control, thyroid function, and liver function. This retrospective, cross-sectional study compared serum liver function biomarkers of primary GD patients in a single center between 2016 and 2020, derived from clinical databases, and clarified the correlation of liver function in GD patients with or without T2DM. Furthermore, the diabetes mellitus group was divided into glycated hemoglobin A1C (HbA1C) <6.5% group and ≥6.5% group to further analyze the effect by disease control in patients. Statistical differences between groups were assessed using independent t tests to clarify the association of serum biomarkers between GD with T2DM. Pearson test was applied to assess within-group statistical correlation of serum biomarkers. The correlation of factors in each group was demonstrated by using the Kendall tau-b method and stepwise regression analysis. A total of 77 patients were included in the study. In the study population, glutamate pyruvate transaminase (GPT) was significantly correlated with thyroid-stimulating hormone, and HbA1C was significantly correlated with alkaline phosphatase (ALK-P), glutamate oxaloacetate transaminase (GOT), and GPT. An examination of GOT, GPT, free thyroxine (FT4), and HbA1C levels revealed a significant difference between the non-T2DM and T2DM groups. GPT also exhibited a significant correlation with triiodothyronine in the T2DM group. The T2DM group was further divided into groups: HbA1C <6.5% and ≥6.5%. The results demonstrated that ALK-P, GOT, GPT, and FT4 levels were significantly different between the groups. A significant correlation between ALK-P and thyroid-stimulating hormone and between GOT and FT4 was also identified in the HbA1C <6.5% group. Our single-center study revealed that diabetes affects liver function in patients with GD. For patients with T2DM, when liver function becomes impaired, thyroid function control deteriorates. GPT was correlated with triiodothyronine but not with FT4, which indicated the impairment of deiodination in the liver. This phenomenon was not observed in the non-T2DM population. The early detection of abnormal liver function in patients with GD and T2DM may help limit the development of comorbidities and improve disease management.