Impaired central sensitivity to thyroid hormone is associated with decreased glycemic variability in patients with type 2 diabetes.

BACKGROUND AND AIM: 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).

METHODS AND

RESULTS

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).

CONCLUSION

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.