Clinical significance of hepatic function in Graves disease with type 2 diabetic mellitus: A single-center retrospective cross-sectional study in Taiwan

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.