Predictive Effects of FT3/FT4 on Diabetic Kidney Disease: An Exploratory Study on Hospitalized Euthyroid Patients with T2DM in China

The Correlation Between Impaired Thyroid Hormone Sensitivity and Diabetic Nephropathy in Euthyroid Patients with Type 2 Diabetes Mellitus

Purpose

To investigate the association between impaired thyroid hormone sensitivity and diabetic nephropathy (DN) in euthyroid patients with type 2 diabetes mellitus (T2DM).

Methods

1305 euthyroid patients with T2DM who were hospitalized in the Endocrinology Department of the First Hospital of Lanzhou University between July 2021 and August 2023 were selected. Several indices, such as the parameters thyroid feedback quantile index (PTFQI), thyroid feedback quantile index (TFQI), thyroid stimulating hormone index (TSHI), serum-free triiodothyronine to free thyroxine (FT3/FT4) ratio, and thyrotropin thyroxine resistance index (TT4RI) to evaluate thyroid hormone sensitivity were used. The patients were subdivided into four groups (Q 1 to Q 4) based on the quartile levels of the five indices. The correlation between thyroid hormone sensitivity and DN was analyzed by binary logistic regression and restricted cubic spline (RCS) analysis.

Results

The levels of PTFQI, TFQI, and TSHI in the DN group were higher than those in the Non-DN group [0.04(-0.21, 0.31) vs -0.003(-0.27, 0.25), 0.05(-0.20, 0.30) vs 0.006(-0.26, 0.25), 2.54±0.52 vs 2.47±0.51, all P<0.05], while the FT3/FT4 levels were decreased in the DN group (0.40±0.07 vs 0.42±0.07, P<0.05). Multivariate logistic regression analysis showed that the increase in PTFQI and TFQI levels was positively correlated with DN [OR=1.518, 95% CI(1.074, 2.145) and OR=1.546, 95% CI(1.084, 2.204)]. RCS showed a linear dose-response relationship between PTFQI, TFQI, TSHI, FT3/FT4, TT4RI, and the tendency of DN (all P non-linear>0.05). As the levels of PTFQI, TFQI, and TSHI increased, and the FT3/FT4 levels decreased, the prevalence of DN and the urinary albumin-to-creatinine (UACR) level showed an upward trend (all Ptrend test <0.05), while the estimated glomerular filtration rate (eGFR) level showed a downward trend (all Ptrend test <0.05).

Conclusion

Among euthyroid patients with T2DM, impaired thyroid hormone sensitivity is associated with DN, as well as elevated UACR levels and decreased eGFR levels.

Association between FT4/FT3 ratio and microalbuminuria in euthyroid patients with type 2 diabetes mellitus

Aims Studies confirm that microalbuminuria (MAU) can not only predict diabetic kidney disease (DKD) but also indicate of systemic vascular endothelial injury. Thyroid hormones (TH) have been reported to be associated with various cardiovascular diseases and endothelial cell damage. Currently, few studies have reported the association between free thyroxine (FT4) to free triiodothyronine (FT3) ratio and MAU. The purpose of this study was to investigate the association between FT4/FT3 ratio and MAU in euthyroid patients with type 2 diabetes mellitus (T2DM). Methods This study enrolled a total of 1734 T2DM patients with euthyroid status. MAU was defined as 30 ≤ urinary albumin-to-creatinine ratio (UACR) < 300 mg/g. The participants were divided into MAU group and normal albuminuria group (NAU group). The relationship between FT4/FT3 ratio and MAU was analyzed. Results In this study, there were 367 patients with MAU. Compared with the NAU group, the MAU group had higher FT4/FT3 ratio (P < 0.001). In univariate analysis, the FT4/FT3 ratio was positively related to both UACR and MAU (both P < 0.001). In multivariate linear stepwise regression, the FT4/FT3 ratio is independently related to UACR (Standardized coefficients: 0.148, P < 0.001). In binary logistic regression analysis, the FT4/FT3 ratio emerges as an independent risk factor for MUA (odds ratio: 1.947, 95% confidence interval: 1.522-2.491). Conclusion The FT4/FT3 ratio was independently and positively correlated with MAU in euthyroid patients with T2DM.

Correlation between thyroid hormone sensitivity and diabetic peripheral neuropathy in euthyroid patients with type 2 diabetes mellitus

Previous studies have revealed that thyroid hormone (TH) levels are associated with the risk of diabetic peripheral neuropathy (DPN) in euthyroid patients with type 2 diabetes mellitus (T2DM). However, the relationship between TH sensitivity, a complementary method for assessing thyroid function, and DPN remains unclear. This study aimed to investigate the correlation between DPN and TH sensitivity in euthyroid patients with T2DM. Exactly 708 euthyroid adults with T2DM were retrospectively enrolled. The FT3/FT4 ratio was used to estimate peripheral TH sensitivity. Central TH sensitivity was assessed using the Thyrotroph T4 Resistance Index (TT4RI), Thyroid-Stimulating Hormone Index (TSHI), Thyroid Feedback Quantile-based Index (TFQI), and Parametric TFQI (PTFQI). DPN was assessed using neurologic symptoms, signs, and nerve conduction velocity tests. The relationship between DPN and TH sensitivity was examined using logistic regression analysis. We observed that an elevated FT3/FT4 ratio was associated with DPN (OR = 1.36, 95%CI: 1.13-1.63, p = 0.0012). For each standard deviation (SD) increase in the TT4RI, TSHI, TFQI, and PTFQI, the OR of DPN was 0.80 (95%CI: 0.68-0.94, p = 0.0078), 0.72 (95%CI: 0.60-0.86, p = 0.0002), 0.69 (95%CI: 0.58-0.83, p < 0.0001), and 0.69 (95%CI: 0.58-0.82, p < 0.0001), respectively. These results suggested that reduced central and peripheral TH sensitivity is associated with a decreased risk of developing DPN.

Prognostic implications of thyroid hormones in acute aortic dissection: mediating roles of renal function and coagulation

Background

Thyroid hormones significantly influence cardiovascular pathophysiology, yet their prognostic role in acute aortic dissection (AAD) remains inadequately explored. This study assesses the prognostic value of thyroid hormone levels in AAD, focusing on the mediating roles of renal function and coagulation.

Methods

We included 964 AAD patients in this retrospective cohort study. Utilizing logistic regression, restricted cubic splines, and causal mediation analysis, we investigated the association between thyroid hormones and in-hospital mortality and major adverse cardiovascular events (MACEs).

Results

In AAD patients overall, an increase of one standard deviation in FT4 levels was associated with a 31.9% increased risk of MACEs (OR 1.319; 95% CI 1.098-1.584) and a 36.1% increase in in-hospital mortality (OR 1.361; 95% CI 1.095-1.690). Conversely, a higher FT3/FT4 ratio was correlated with a 20.2% reduction in risk of MACEs (OR 0.798; 95% CI 0.637-0.999). This correlation was statistically significant predominantly in Type A AAD, while it did not hold statistical significance in Type B AAD. Key renal and coagulation biomarkers, including blood urea nitrogen, creatinine, cystatin C, prothrombin time ratio, prothrombin time, and prothrombin time international normalized ratio, were identified as significant mediators in the interplay between thyroid hormones and MACEs. The FT3/FT4 ratio exerted its prognostic influence primarily through the mediation of renal functions and coagulation, while FT4 levels predominantly impacted outcomes via a partial mediation effect on coagulation.

Conclusion

FT4 levels and the FT3/FT4 ratio are crucial prognostic biomarkers in AAD patients. Renal function and coagulation mediate the association between the thyroid hormones and MACEs.

Impaired Sensitivity to Thyroid Hormones is Associated with the Risk of Diabetic Nephropathy in Euthyroid Patients with Type 1 Diabetes Mellitus

Purpose

This study aims to investigate the relationship between thyroid and type 1 diabetic nephropathy (T1DN) in euthyroid populations, focusing on thyroid hormone sensitivity.

Methods

A cross-sectional study was conducted between January 2016 and December 2021, including 357 euthyroid patients with type 1 diabetes mellitus (T1DM). Parameters representing thyroid hormone sensitivity were assessed, including the thyroid feedback quantile-based index (TFQI), parameter thyroid feedback quantile index (PTFQI), thyroid stimulating hormone index (TSHI), thyrotropin thyroxine resistance index (TT4RI), and free triiodothyronine/free thyroxine (FT3/FT4). Logistic regression and restricted cubic spline regression were performed to detect the association between thyroid hormone sensitivity and the risk of T1DN.

Results

The study found a negative correlation between the risk of T1DN and FT3/FT4 in euthyroid T1DM patients (OR 0.71, 95% CI 0.51-0.97, P <0.01). PTFQI (P<0.05), TSHI (P<0.05), and TT4RI (P<0.01) showed an M-shaped nonlinear relationship with the risk of T1DN. Elevated risk of T1DN was associated with PTFQI, TSHI, and TT4RI values outside the range of zero, 2.3-3.88, and 27.56-32.19, respectively.

Conclusion

This study confirms the relationship between impaired thyroid hormone sensitivity and the risk of T1DN in euthyroid patients. It emphasizes the importance of evaluating thyroid hormone sensitivity in T1DM patients, even when their thyroid function appears normal, to promptly prevent the occurrence of T1DN.