Impaired central sensitivity to thyroid hormone is associated with decreased glycemic variability in patients with...

As abnormalities in thyroid hormones affect the metabolism of blood glucose, we aim to explore the relationship between central thyroid hormone sensitivity and glycemic variability in patients with type 2 diabetes (T2DM).

For hospitalized patients with T2DM, thyroid hormones (THs) were measured to calculate the Thyroid Feedback Quantile-based Index (TFQI), Thyrotropin Thyroxine Resistance Index (TT4RI) and TSH Index (TSHI). Coefficients of glycemic variation (CV) were monitored by continuous glucose monitoring systems (CGMs). Independent sample T-test indicated that there was no significant difference in central TH sensitivity between CV ≤ 36 % group and CV>36 % group. Smooth fitting curve and threshold effect analysis indicated that TSHI was negatively correlated with CV before the inflection point of TSHI = 2.428 (β = -2.547, P = 0.0478), while the negative correlation was strengthened after the inflection point (β = -7.512, P = 0.0003); TFQI was negatively correlated with CV before the inflection point of TFQI = 0.334 (β = -2.876, P = 0.0265), while the negative correlation was strengthened after the inflection point (β = -15.864, P < 0.0001). Interaction tests indicated that Sex, Age, BMI, INS-therapy, GLP-1RA-therapy and SGLT-2i-therapy had no differential impacts on the statistical results. Trend test results of multiple regression equations indicated that for per-quartile increase in TFQI, CV decreased by 1.375 correspondingly (β = -1.375,P < 0.00001), for per-SD increase in TFQI, CV decreased by 1.996 correspondingly (β = -1.996,P < 0.00001).

Impaired central sensitivity to THs is associated with reduced glycemic variability in patients with T2DM, which is speculated to be related with the self-regulation of blood glucose fluctuations in our body.