Association between sensitivity to thyroid hormone indices and chronic kidney disease in US adults from NHANES...

Thyroid function disorders are prevalent among individuals with chronic kidney disease (CKD). However, the relationship between thyroid hormone sensitivity and CKD remains poorly understood. Our study aims to explore the association between the thyroid hormone sensitivity index and CKD in the U.S. adults.

A total of 5,454 adults (aged ≥20 years) from NHANES (2007-2012) were included. We extracted thyroid hormones and other indicators, and calculated the thyroid-stimulating hormone index (TSHI), thyroid feedback quantile-based index (TFQI), thyrotropin-thyroxine resistance index (TT4RI), and the FT3/FT4 ratio for peripheral sensitivity. Linear and logistic regression models were employed to evaluate the association between thyroid hormone sensitivity indices and CKD.

Participants with CKD exhibited elevated levels of TSHI, TFQI, and TT4RI, along with lower FT3/FT4 ratios, compared to those without CKD. After adjusting for multiple covariates, FT3/FT4 was negatively associated with the risk of CKD (OR = 0.83, 95% CI: 0.72-0.96, p = .02). Both TSHI and TT4RI demonstrated U-shaped associations with CKD, indicating a significant nonlinear correlation. Stratified analysis revealed a decreasing trend in CKD risk with increasing FT3/FT4 levels among female participants and those with diabetes. For TSHI, a nonlinear U-shaped association with CKD was identified in participants with diabetes, hypertension, and hyperlipidemia.

FT3/FT4 levels were strongly associated with CKD risk, highlighting the complex interplay between the thyroid system and CKD. The observed U-shaped associations of TSHI and TT4RI with CKD offer novel insights for the evaluation and potential management of chronic kidney disease.