Thyroid hormones and diabetic nephropathy: An essential relationship to recognize.

Although abnormal thyroid hormone metabolism is common in patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN), the relationship between thyroid hormones and DN is unclear and has been ignored during clinical practice. This study aimed to investigate the relationship between thyroid hormones and clinicopathologic changes in biopsy-proven DN patients. Clinical and pathological data for 146 biopsy-proven DN patients were collected. The patients were divided into four groups: euthyroid group, high-thyroid stimulating hormone (TSH) group (SCH), low-free triiodothyronine (FT3) group (with normal levels of TSH and FT4), and high-TSH + low-FT3 group (with normal levels of FT4). The clinicopathologic features among the four groups were investigated. We evaluated the risks of abnormal thyroid hormone levels on DN by logistic regression with multivariable adjustments for other risk factors. We also performed quarterback and eight-point analyses of TSH and FT3 levels to determine their influences on DN. The overt proteinuria (>5 g/24 h) (P = 0.008) and severity of glomerular lesions (P = 0.011) differed between euthyroid group and high-TSH group significantly. Moreover, the levels of estimated glomerular filtration rate (P =0.019), serum creatinine (P =0.014), and severity of glomerular lesions (P =0.003) differed between the euthyroid group and low-FT3 group significantly. There were also significant differences between high-TSH, low-FT3 and high-TSH + low-FT3 patients, respectively. Respective correlations between high-TSH, low-FT3 and renal clinicopathologic changes were found to be significant according to logistic regression analyses. Quarterback and eight-point analyses indicated that patients with TSH levels of 4.54-5.67 mU/L had the most severe renal clinicopathologic changes, and the severity of renal changes decreased with increased FT3 levels. Diabetic nephropathy patients with high-TSH and/or low-FT3 had more severe proteinuria, renal insufficiency, and glomerular lesions, suggesting that regulating thyroid hormones might have a renoprotective effect.

Han Q ，Zhang J ，Wang Y ，Li H ，Zhang R ，Guo R ，Li L ，Teng G ，Wang J ，Wang T ，Liu F ... -  《-》

[Correlation between thyroid hormones and renal function in severe pre-eclampsia patients with hypothyroidism].

Zhou J ，Li W ，Du J ，Qiao C ，Shang T ，Liu X ... -  《-》

Thyroid Parameters and Kidney Disorder in Type 2 Diabetes: Results from the METAL Study.

Diabetic kidney disease is one of the most common microvascular complications of diabetes mellitus. We aimed to analyze the association of thyroid parameters with kidney disorders, especially in euthyroid participants. The data were obtained from a cross-sectional study, the METAL study. Thyroid parameters, including thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), triiodothyronine (T3), thyroxin (T4), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb), of 4136 participants with type 2 diabetes were measured. Two structure parameters of thyroid homeostasis, including the sum activity of step-up deiodinases (SPINA-GD) and thyroid secretory capacity (SPINA-GT), and two pituitary thyrotropic function indices, including Jostel's TSH index (TSHI) and the thyrotroph thyroid hormone resistance index (TTSI), were also calculated. Kidney disorders were described according to the presence of reduced estimated glomerular filtration rate (eGFR) and/or higher urinary albumin to creatinine ratio (UACR). The prevalence of kidney disorders increased with decreasing FT3 or T3 and increasing FT4 or T4 quartile levels (all P < 0.05). After full adjustment, linear regression showed that UACR levels were negatively associated with FT3 and T3 (P < 0.001). In addition, eGFR was positively associated with FT3 and T3 and was negatively associated with TSH and FT4 levels and TgAb positivity (all P < 0.05). By using binary logistic regression, higher TSH and FT4 and lower FT3 and T3 were associated with kidney disorders (all P < 0.05). Similar results were seen in sensitivity analyses, which were performed in 3035 euthyroid diabetic participants; however, TSH was no longer related to them. The area under the receiver operating characteristic curve (AUROC) of lower FT3 for existing kidney disorder was greater than that for any other thyroid hormones (all P < 0.001). The cutoff value of FT3 for reduced eGFR was 4.39 pmol/L. Regarding thyroid homeostasis parameters, SPINA-GD was negatively associated with three statuses of kidney disorders, and TSHI and TTSI were positively associated with reduced eGFR (all P < 0.05). Among patients with type 2 diabetes, elevated TSH and FT4 (or T4), lower FT3 (or T3), TgAb positivity, lower SPINA-GD, and higher TSHI and TTSI were associated with kidney disorders. The lower FT3, even within the normal range (<4.38 pmol/L), may be the factor most related to reduced eGFR compared with other thyroid hormones in diabetic patients.

Chen Y ，Zhang W ，Wang N ，Wang Y ，Wang C ，Wan H ，Lu Y ... -  《-》

Glomerular filtration rate is associated with free triiodothyronine in euthyroid subjects: Comparison between various equations to estimate renal function and creatinine clearance.

Effects of variations in thyroid function within the euthyroid range on renal function are unclear. Cystatin C-based equations to estimate glomerular filtration rate (GFR) are currently advocated for mortality and renal risk prediction. However, the applicability of cystatin C-based equations is discouraged in patients with overt thyroid dysfunction, since serum cystatin C and creatinine levels are oppositely affected by thyroid dysfunction. Here, we compared relationships of thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) with various measures of kidney function in euthyroid subjects. Relationships of eGFR, based on creatinine (eGFRcrea), cystatin C (eGFRcysC), creatinine+cystatin C combined (eGFRcrea-cysC) and creatinine clearance (CrCl) with TSH, FT4 and FT3 were determined in 2180 euthyroid subjects (TSH, FT4 and FT3 all within the reference range; anti-thyroid peroxidase autoantibodies negative) who did not use thyroid hormones, anti-thyroid drugs, amiodarone or lithium carbonate. In multivariable models including TSH, FT3 and FT4 together, eGFRcrea, eGFRcysC and eGFRcrea-cysC and CrCl were all positively related to FT3 (P≤0.001), translating into a 2.61 to 2.83mL/min/1.73m2 increase in eGFR measures and a 3.92mL/min increase in CrCl per 1pmol/L increment in FT3. These relationships with FT3 remained taking account of relevant covariates. In euthyroid subjects renal function is associated with thyroid function status, especially by serum FT3, irrespective of the eGFR equation applied. In the euthyroid state, cystatin C-based eGFR equations are appropriate to assess the relationship of renal function with variation in thyroid function status.

Anderson JLC ，Gruppen EG ，van Tienhoven-Wind L ，Eisenga MF ，de Vries H ，Gansevoort RT ，Bakker SJL ，Dullaart RPF ... -  《-》

Correlation of serum thyrotropin and thyroid hormone levels with diabetic kidney disease: a cross-sectional study.

Gao J ，Liu J 《BMC Endocrine Disorders》