Association of Thyroid-Stimulating Hormone Levels with Microvascular Complications in Type 2 Diabetes Patients

The effect of Central and peripheral thyroid resistance indices on diabetic retinopathy: a study of hospitalized euthyroid patients with T2DM in China

OBJECTIVE

This study aims to explore the correlation between central and peripheral thyroid resistance indices and diabetic retinopathy(DR) in patients with type 2 diabetes mellitus (T2DM), so as to provide a clinical basis for the prevention and treatment of diabetic retinopathy.

METHODS

This study retrospectively analyzed 1249 euthyroid patients with T2DM hospitalized in the Department of Endocrinology, Peking University International Hospital from January 2017 to June 2022, including 852 males and 397 females, with an average age of 54.73 ± 13.40 years. According to the degree of DR, the patients were divided into three groups including the no diabetic retinopathy (NDR) group, non-proliferative diabetic retinopathy (NPDR) group and proliferative diabetic retinopathy (PDR) group.

RESULTS

Free thymidine (FT4), thyroid stimulating hormone (TSH), thyroid feedback quantile index (TFQI), thyrotropin-T4 resistance index (TT4RI), thyroid stimulating hormone index (TSHI) and free triiodothyronine/free thyroxine (FT3/FT4) levels among the three groups were significantly different, with the NDR group having lowest TSH, TFQI, TT4QI, TSHI and the highest in the PDR group (all p < 0.05). Logistic regression showed that after adjusting for age, body mass index (BMI), sex, diabetes duration, blood pressure, blood lipid, HbA1c, lower level of FT4 was an independent risk factor for DR, high level of TSH, TFQI, TSHI and TT4RI were independent risk factors for DR. Central and peripheral thyroid sensitivity indices have predictive value for DR, the overall predictive accuracy of FT3/FT4 was 0.61 (95%CI 0.57, 0.65), the overall predictive accuracy of TFQI was 0.66(95%CI 0.63, 0.70), the overall predictive accuracy of TSHI was 0.66(95%CI 0.62, 0.68), the overall predictive accuracy of TT4RI was 0.63 (95%CI 0.59, 0.66).

CONCLUSION

The reduction of central and peripheral thyroid hormone sensitivity is an independent risk factor for DR. These results can help predict the risk of the occurrence and development of DR, which may provide a clinical basis for the prevention and treatment of DR in T2DM patients.

Assessment of the association between genetic factors regulating thyroid function and microvascular complications in diabetes: A two-sample Mendelian randomization study in the European population

BACKGROUND

Observational studies have identified a possible link between thyroid function and diabetic microangiopathy, specifically in diabetic kidney disease (DKD) and diabetic retinopathy (DR). However, it is unclear whether this association reflects a causal relationship.

OBJECTIVE

To assess the potential direct effect of thyroid characteristics on DKD and DR based on Mendelian randomization (MR).

METHODS

We conducted an MR study using genetic variants as an instrument associated with thyroid function to examine the causal effects on DKD and DR. The study included the analysis of 4 exposure factors associated with thyroid hormone regulation and 5 outcomes. Genomewide significant variants were used as instruments for standardized freethyroxine (FT4) and thyroid-stimulating hormone (TSH) levels within the reference range, standardized free triiodothyronine (FT3):FT4 ratio, and standardized thyroid peroxidase antibody (TPOAB) levels. The primary outcomes were DKD and DR events, and secondary outcomes were estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (ACR) in diabetes, and proliferative diabetic retinopathy (PDR). Satisfying the 3 MR core assumptions, the inverse-variance weighted technique was used as the primary analysis, and sensitivity analysis was performed using MR-Egger, weighted median, and MR pleiotropy residual sum and outlier techniques.

RESULTS

All outcome and exposure instruments were selected from publicly available GWAS data conducted in European populations. In inverse-variance weighted random-effects MR, gene-based TSH with in the reference range was associated with DKD (OR 1.44; 95%CI 1.04, 2.41; P = 0.033) and eGFR (β: -0.031; 95%CI: -0.063, -0.001; P = 0.047). Gene-based increased FT3:FT4 ratio, decreased FT4 with in the reference range were associated with increased ACR with inverse-variance weighted random-effects β of 0.178 (95%CI: 0.004, 0.353; P = 0.046) and -0.078 (95%CI: -0.142, -0.014; P = 0.017), respectively, and robust to tests of horizontal pleiotropy. However, all thyroid hormone instruments were not associated with DR and PDR at the genetic level.

CONCLUSION

In diabetic patients, an elevated TSH within the reference range was linked to a greater risk of DKD and decreased eGFR. Similarly, decreased FT4 and an increased FT3:FT4 ratio within the reference range were associated with increased ACR in diabetic patients. However, gene-based thyroid hormones were not associated with DR, indicating a possible pathway involving the thyroid-islet-renal axis. However, larger population studies are needed to further validate this conclusion.

Serum Antithyroglobulin Antibody Levels Are Associated with Diabetic Retinopathy among Euthyroid Type 2 Diabetes Patients: A Hospital-Based, Retrospective Study

BACKGROUND

Previous studies have revealed that the variation of thyroid indicators may be associated with the risk of diabetic retinopathy (DR) among euthyroid type 2 diabetes (T2D) patients. But the specific conclusions are currently inconsistent.

METHODS

This is a hospital-based retrospective survey. We recruited 1,145 euthyroid T2D patients and checked the thyroid function and fundus photographs. The modified Airlie House classification system was used to categorize the stages of DR. The association between thyroid indicators and different stages of DR was analyzed.

RESULTS

We divided free triiodothyronine (FT3) into tertiles and found that the prevalence of mild nonproliferative DR (NPDR) was significantly higher in T2, compared with T1 (32.0% vs. 25.2%, p < 0.05). When FT3 was within the level of T2, FT3 could be an independent risk factor for mild NPDR (OR 1.426, 95% CI (1.031, 1.971), p < 0.05). In addition, the prevalence of severe NPDR and proliferative DR (PDR) was significantly higher in thyroglobulin antibody (TgAb) positive group (8.8% vs. 4.1%, p < 0.05) and vice versa (33.3% vs. 18.4%, p < 0.05). TgAb positivity was also an independent risk factor for severe NPDR and PDR (OR 2.212, 95% CI (1.244, 3.934), p < 0.05).

CONCLUSIONS

We hardly observed a significant change in DR risk with the elevation or reduction of serum TSH or thyroid hormone within the reference interval. Although the slightly elevated FT3 may be associated to mild NPDR, the extensibility of this result remains to be seen. For T2D patients with euthyroid function, there may be a significant correlation between serum TgAb positivity and severe NPDR and PDR.

Thyroid stimulating hormone aggravates diabetic retinopathy through the mitochondrial apoptotic pathway

Diabetic retinopathy (DR) is a common complication of diabetes mellitus. High glucose-induced mitochondrial apoptosis is involved in the loss of retinal pericytes (PCs), which is considered to be a predominant pathologic change of diabetic retinopathy (DR). A high thyroid stimulating hormone (TSH) serum level is associated with an increased prevalence of DR in diabetic patients. Here, we investigated whether TSH regulated glucose-induced PCs loss through TSH-receptor (TSHR)-dependent mitochondrial apoptosis. First, the serum TSH level was found to be an independent risk factor for DR in Type 2 diabetic study participants (odds ratio = 2.294; 95% confidence interval: 1.925-2.733; p ≤ 0.001). Second, human PCs were treated with different concentrations of glucose, with or without bovine TSH (b-TSH). Glucose induced mitochondrial apoptosis through various mechanisms, including through regulating the expression of apoptosis-related proteins and inducing mitochondrial dysfunction, which could be deteriorated by costimulation of glucose and b-TSH. Additionally, we detected functional TSHR in PCs; blocking TSHR significantly restricted TSH-induced apoptosis. Thus, the presence of functional TSHR in human retinal PCs may facilitate the effect of high TSH on high glucose-induced PCs loss through TSHR-dependent mitochondrial apoptosis.

Subclinical Hypothyroidism in Patients with Diabetic Retinopathy: Role of Vascular Endothelial Growth Factor

BACKGROUND

Considering the vital role of vascular endothelial growth factor (VEGF) in the development of diabetic retinopathy (DR) in one hand and the frequent association between subclinical hypothyroidism (SCH) and DR on the other hand.

OBJECTIVE

The present study was proposed to explore the possible role of VEGF in the relation between SCH and DR, thus we investigated the relation between SCH and VEGF levels in patients with DR.

METHODS

Two hundred patients with DR were recruited in this study [100 patients with proliferative diabetic retinopathy (PDR) and 100 patients with non-proliferative diabetic retinopathy (NPDR)]. Patients with DR were divided into 2 groups according to thyroid function: patients with SCH or those with euthyroidism. Patients were subjected to careful history taking, and underwent clinical and ophthalmological examination. Fasting blood glucose, glycosylated hemoglobin, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), TSH, FT4, FT3, VEGF and thyroid volume were assessed Results: Among all the studied patients, 21.5% (43/200) had SCH. DR patients with SCH had higher age, diabetes duration, HbA1c, HOMA-IR and VEGF than those with euthyroidism. The frequency of PDR in patients with SCH was 72.1% (31/43) and 43.9% (69/157) in those with euthyroidism, whereas the frequency of NPDR in patients with SCH was 27.9 (12/43) and 56.1% (88/157) in those with euthyroidism (P < 0.003). In multivariate analysis, PDR, HOMA-IR and VEGF levels were the significant predictor variables of SCH.

CONCLUSIONS

Increased VEGF levels may be implicated in the relationship between SCH and DR.

The effect of coexisting autoimmune thyroiditis in children with Type 1 diabetes on optical coherence tomography results

OBJECTIVE

To assess the influence of thyroid hormones status and coexistence of autoimmune thyroiditis on optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) results in children with Type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

In the prospective, observational study (n = 175) we analyzed the impact of thyroid hormones on OCT results and the differences between the matched groups of children with T1D (n = 84; age = 13.14 ± 3.6; diabetes duration = 5.99 ± 3.3 years) and the children with T1D and autoimmune thyroiditis (AT) (n = 20; age = 13.94 ± 3.6; diabetes duration = 6.7 ± 4 years). We analyzed the following parameters: fovea avascular zone (FAZ), foveal thickness (FT), parafoveal thickness (PFT), ganglion cell complex (GCC), loss volume (global-GLV, focal-FLV), capillary vessel density: superficial (whole-wsVD, foveal-fsVD, parafoveal-psVD), and deep (whole-wdVD, foveal-fdVD, parafoveal-pdVD. The differences between the groups were tested by the unpaired t-Student test, Mann-Whitney U test as appropriate, whereas p level .05 was recognized as significant.

RESULTS

We detected the significant correlations between thyroid-stimulating hormone (TSH) level and PFT (r = -0.14; p < .05), psVD (r = -0.18; p < .005). The level of free triiodothyronine (FT3) was correlated with psVD (r = -0.14; p < .05). We found significant correlation between free thyroxine (FT4) and fsVD (r = -0.17; p < .01). In the studied T1D and AT groups there were statistical differences in FT (p < .005), PFT (p < .03), GCC (p < .01), and GLV (p < .003). We did not observe any significant differences in the FAZ area between the groups.

CONCLUSIONS

In our patients the co-occurrence of T1D and AT worsens the status of retinal parameters. Further studies are necessary to observe these relations and their potential influence on the occurrence of diabetic retinopathy (DR).

Thyroid and Eye: Where They Meet in Clinical Practice

OBJECTIVE

Thyroid Hormones (TH) are essential for normal growth, development and continued optimal function of most of the body organs including the eye. TH signaling plays a central role in the regulation of retinal development and maturation. Deficiency in TH during fetal and early postnatal development impairs growth of the eye and proliferation of all retinal cell types. The present article reviews the most important topics of the different derangements in thyroid function and structure and its relation with eye diseases.

METHODS

A literature search strategy was conducted for all English-language literature.

RESULTS

From a clinical practice viewpoint, it should be mentioned that both hypothyroidism and hyperthyroidism are accompanied by ocular diseases i.e. thyroid-associated ophthalmopathy, diabetic retinopathy and age-related macular degeneration. Although the orbit and globe are not common sites for metastatic thyroid cancers, orbital metastasis may be the primary clinical manifestation of thyroid carcinoma. Finally, some medications as amiodarone may be accompanied by both thyroid dysfunction and adverse ocular events.

CONCLUSION

Thyroid disorders and eye diseases are interrelated through several mechanisms thus, awareness of this relation has a great impact on early diagnosis and treatment.

Prevalence and Predictors of Thyroid Dysfunction Among Type 2 Diabetic Patients: A Case-Control Study

Background

Type 2 diabetes mellitus (T2DM) and thyroid disorders are common endocrine disorders. This case–control study aims to determine the prevalence and predictors of thyroid disorders in T2DM patients.

Methods

A total of 998 T2DM patients attending a tertiary hospital were included and underwent investigations for thyroid function: thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3); and glycated hemoglobin (HbA1c). They were compared with 343 non-diabetic subjects as controls.

Results

A total of 1341 participants were included in the study. The mean age ± SD was 60.14 ± 12.21, and 47.9% were females. Among T2DM patients, 140 (14%) were known to have thyroid disorders; and as a direct result of screening, 126 (12.6%) new cases of thyroid disorder were diagnosed. Thus, the overall prevalence of thyroid disorders was found to be 26.7% in T2DM patients which significantly higher than the controls (13.7%), (p˂0.001). Subclinical hypothyroidism was the most common one. Using logistic regression, after adjusting for age, gender, obesity, smoking, anemia, presence of goiter, disease duration, and poorly controlled, the risk factors for thyroid dysfunction among T2DM patients were an age of ≥50 years with an adjusted OR of 3.895 (95% CI 2.151–7.052, p<0.001); female gender (OR 1.757, 95% CI 1.123–2.747, p=0.013); goiter (OR 2.904, 95% CI 1.118–7.547, p=0.029), and HbA1c>7% (OR 2.553, 95% CI 1.472–4.429, p=0.001). However, there were no significant associations between thyroid disorders and complications or duration of diabetes (p>0.050).

Conclusion

A high prevalence of thyroid disorders was reported in T2DM patients. Therefore, we suggest that diabetic patients should be routinely screened for thyroid dysfunction. Old age, female gender, goiter, and poorly controlled diabetes found to be risk factors for thyroid dysfunction among T2DM patients. Consequently, appropriate management and control of diabetes may lower the risk of thyroid dysfunction and vice versa.

Does autoimmune hypothyroidism increase the risk of neurovascular complications in type 1 diabetes?

BACKGROUND

Type 1 diabetes (T1DM) often coexists with other autoimmune diseases, most commonly with hypothyroidism. To date, the influence of coexisting autoimmune hypothyroidism (AHT) on the course of chronic neurovascular complications of autoimmune diabetes has not been established. The aim of the study was to assess the relationship between AHT and the occurrence of chronic T1DM complications.

METHODS

The study group comprised 332 European Caucasian participants with T1DM [165 (49.7%) men]. AHT was recognized in subclinical and overt hypothyroidism and confirmed by the presence of anti-thyroid autoantibodies: anti-peroxidase (ATPO) and/or anti-thyroglobulin (ATg) and ultrasonography (hypoechogenicity, parenchymal heterogeneity, lymph nodes assessment).

RESULTS

In the analyzed group, 48.5% of patients were diagnosed with at least one neurovascular complication. At the time of enrollment, 16.3% of participants were diagnosed with AHT. Patients with AHT, compared to those without AHT, were characterized by a higher prevalence of neurovascular complications (64.8 vs. 45.3%; P = 0.009) and retinopathy (55.6 vs. 38.9%; P = 0.02). There were significant differences between groups with and without neurovascular complications, with regard to classic risk factors for chronic diabetes complications: age, T1DM duration, SBP, DBP, HbA_1c, TG, eGFR and hypertension prevalence. In the multivariate logistic regression analysis, AHT was an independent predictor of neurovascular complications after adjusting for age, DBP, HbA_1c and TG (odds ratio, 2.40; 95% confidence interval, 1.17-4.92; P = 0.02).

CONCLUSIONS

AHT coexisting with T1DM was associated with a higher incidence of neurovascular complications.

Association between Normal Thyroid Hormones and Diabetic Retinopathy in Patients with Type 2 Diabetes

The relationship between normal thyroid function and type 2 diabetes mellitus (T2DM) has been a particular focus for concern. The present study determined the relationship between thyroid hormone levels and the prevalence of diabetic retinopathy (DR) in T2DM patients. A cross-sectional study (n = 633) was performed in Xi'an, Shaanxi Province, China. Subjects were evaluated for anthropometric measurements, thyroid function, and diabetic retinopathy. Logistic regression models were used to assess the relationships between thyroid hormones and DR. Of 633 patients, 243 (38.4%) patients suffered from DR. The prevalence of DR showed a significantly decreasing trend across the quartiles based on free triiodothyronine (FT3) (FT3 quartile 1 group [FT3-Q1] <4.35 pmol/L, FT3 quartile 2 group [FT3-Q2] 4.35–4.70 pmol/L, FT3 quartile 3 group [FT3-Q3] 4.70–5.08 pmol/L, and FT3 quartile 4 group [FT3-Q4] ≥5.08 pmol/L) (56.7%, 42.5%, 33.1%, 23.8%, P < 0.001). In comparison with all participants categorized in FT3-Q1, the multivariable adjusted odds ratios (95% confidence interval) of DR in FT3-Q2, FT3-Q3, and FT3-Q4 were 0.587 (0.340–1.012), 0.458 (0.258–0.813), and 0.368 (0.201–0.673), (P = 0.055, P = 0.008, P = 0.001), respectively. FT3 levels within the normal range are negatively associated with DR in euthyroid patients with type 2 diabetes. Further studies should be aimed at clarifying the relationship between thyroid hormones and T2DM.

The longitudinal effect of subclinical hypothyroidism on urine microalbumin-to-urine creatinine ratio in patients with type 2 diabetes mellitus

BACKGROUND

In patients with diabetes mellitus, the urinary microalbumin-to-urine creatinine ratio (UACR) can not only predict the occurrence of diabetic nephropathy but also can be a risk factor for cardiovascular disease and renal function damage. Current studies on subclinical hypothyroidism (SCH) and UACR are mainly cross-sectional studies, and the results suggest that SCH is an independent risk factor for UACR. To further explore the longitudinal effect of SCH on UACR, we carried out this study.

METHODS

This was a retrospective cohort study including 46 patients with type 2 diabetes mellitus and SCH in the Department of Endocrinology, The Affiliated Huai'an Hospital of Xuzhou Medical University from January 2013 to April 2018. At the same time, 96 patients with type 2 diabetes mellitus and euthyroid were chosen according to 1:2 approximately matched with age, sex and duration of diabetes mellitus. Univariate analysis, stratified analysis, and multiple linear regression analysis were used to investigate the effect of SCH on ΔUACR(ΔUACR = UACR after 1 year - baseline UACR) in patients with type 2 diabetes mellitus.

RESULTS

There was no significant difference between the baseline UACR, (p > 0.05). However, the ΔUACR was significantly higher in SCH group than euthyroid group, as shown by univariate analysis, stratified analysis and multiple linear regression analysis (β:-1.071, 95% CI: - 1.713--0.428), and the difference was statistically significant (all p < 0.05).

CONCLUSION

SCH is associated with an increased UACR in type 2 diabetes mellitus patients. It is necessary to screen for thyroid function in type 2 diabetes mellitus and increase the follow-up frequency of UACR in patients with SCH.

Prevalence of thyroid dysfunction in older Chinese patients with type 2 diabetes-A multicenter cross-sectional observational study across China

Type 2 diabetes [T2D] and thyroid dysfunction [TD] often co-occur, have overlapping pathologies, and their risk increases with age. Since 1995, universal salt iodization has been implemented in China to prevent disorders caused by iodine deficiency. However, after two decades of implementation of universal salt iodization, the prevalence of TD in elderly Chinese patients with T2D is not well described and may have been underestimated. We conducted a questionnaire-based survey across 24 endocrinology centers in China between December 2015 and July 2016. Demographic and clinical data from 1677 patients with T2D were obtained and analyzed to examine the prevalence of TD along with T2D in these patients. We assessed TD prevalence according to the four TD subtypes [subclinical hypothyroidism, clinical hypothyroidism, subclinical hyperthyroidism, and clinical hyperthyroidism], TD history, gender, and age. The diagnosis rates were calculated for TD and also for the TD subtype. The number of patients reaching treatment goals for T2D [hemoglobin A1c <7%] and TD [normal free thyroxine and thyroid-stimulating hormone [TSH]] and the incidences of complications and comorbidities were recorded. Among the enrolled patients with T2D [N = 1677], TD was diagnosed in 23.79% [399/1677] out of which 61% (245/399) were previously diagnosed and 38.59% (154/399) were newly diagnosed cases. Subclinical hypothyroidism, clinical hypothyroidism, subclinical hyperthyroidism, and clinical hyperthyroidism were reported in 4.89%, 9.3%, 1.13%, and 3.16% of the total population, respectively. Among patients previously diagnosed with TD, the incidence in women [166/795; 20.88%] was higher than in men [79/882; 8.96%]. The treatment goals for TD and T2D were attained in 39.6% [97/245] and 34.41% [577/1677] of the cases, respectively. Diabetic complications and comorbidities were reported in 99.7% of patients, with peripheral neuropathy being the most common [43.46%] followed by cataract [24.73%]. We had found that the incidences of dyslipidemia, elevated LDL levels, and osteoporosis were significantly higher in patients with TD than those without TD. TD is underdiagnosed in elderly Chinese patients with T2D.

Thyroid stimulating hormone and free triiodothyronine are valuable predictors for diabetic nephropathy in patient with type 2 diabetes mellitus

Background

Diabetes seriously threatens human health, and diabetic nephropathy (DN) is one of the serious diabetic complications. Therefore, it is valuable to predict the occurrence of DN early. This study aims to evaluate the predicting significance of thyroid hormones for DN.

Methods

A total of 301 type 2 diabetes mellitus (T2DM) patients were enrolled. Thyroid hormones before treatment were measured, and the risk factors and their predicting significance for T2DM and DN were assessed.

Results

The results indicated that there was no statistical difference in any investigated variable between controls and patients without complications (P>0.05). However, patients with DN exhibited lower levels of triiodothyronine (T3) and free triiodothyronine (FT3), but higher levels of thyroid stimulating hormone (TSH) than T2DM patients without complications (P<0.001). Multivariate analysis did not demonstrate any thyroid hormone as the independent risk factor for T2DM without complications, but revealed increased TSH and decreased T3 and FT3 as the independent risk factors for patients with DN [odds ratio (OR): 2.087, 95% CI: 1.525-3.303; 1.335, 95% CI: 1.101-1.621; 7.414, 95% CI: 4.319-13.986; P<0.001, respectively]. The area under receiver operating characteristic (ROC) curve of TSH, FT3 and T3 was 0.850 (95% CI: 0.776-0.923), 0.824 (95% CI: 0.751-0.897), and 0.620 (95% CI: 0.515-0.725) for DN prediction. Based on their cutoff values of 1.85 mIU/L, 2.31 ng/L, and 0.61 µg/L, the sensitivity was 82%, 78%, and 64%, and the specificity was 77%, 79%, and 85%, respectively.

Conclusions

Our findings suggest that TSH and FT3 are useful predictors for DN in patients with T2DM.

Higher free triiodothyronine concentration is associated with lower prevalence of microangiopathic complications and better metabolic control in adult euthyroid people with type 1 diabetes

PURPOSE

Type 1 diabetes mellitus (T1DM) is a disorder of insulin deficiency but with a wide range of hormones simultaneously disturbed. The study was performed to explore relation of free triiodothyronine (FT3) with metabolic control and occurrence of microangiopathic complications.

METHODS

A total of 266 adult T1DM participants [56% men; 32 (interquartile range, IQR: 25-39) years and disease duration 13 (IQR: 8-19) years] in euthyroid state with negative history for hypothyroidism were included to the study. Participants were screened for thyroid-stimulating hormone (TSH), free thyroxine (FT4) and FT3. Moreover, microangiopathic complications (retinopathy, diabetic kidney disease, peripheral and autonomic neuropathy), markers of metabolic control such as glycated hemoglobin (HbA_1c) were evaluated.

RESULTS

A total of 114 (42.9%) people had diagnosed at least one microangiopathic complication. In multivariable linear regression higher HbA_1c was statistically significant independent predictor of lower FT3 (β = -0.25; p < 0.0001) after adjustment for sex, T1DM duration, HbA_1c, waist-to-hip ratio (WHR) (R² = 0.15, p < 0.0001). Higher FT3 was simultaneously a predictor of lower prevalence of microangiopathy in multivariate logistic regression analysis (odds ratio, 0.51; 95% confidence interval, 0.27-0.98; p = 0.04) after an adjustment for: age, hypertension, HbA_1c, WHR and total cholesterol (TC).

CONCLUSIONS

FT3 as tissue active hormone plays a clinically important role in T1DM people. The higher FT3 concentration is related to the lower prevalence of microangiopathy and better metabolic control of the disease in adult euthyroid people with T1DM.

Association between Thyroid Hormone Levels and Diabetic Kidney Disease in Euthyroid Patients with Type 2 Diabetes

The association between normal thyroid function and diabetic kidney disease (DKD) has gained increasing attention. The present study evaluated the relationship between normal thyroid hormone levels and DKD in type 2 diabetes mellitus (T2DM) patients. A total of 862 type 2 diabetes patients were enrolled in this cross-sectional study in Xi^’an, Shaanxi Province, China. The subjects were evaluated for anthropometric measurements, thyroid function and DKD. Of 862 patients, 246 (28.5%) suffered from DKD, and the prevalence of DKD did not differ between men and women. The prevalence of DKD showed a significantly decreasing trend across the quartiles based on free triiodothyronine (FT3) levels (41.1%, 30.6%, 23.8%, and 18.9%, P < 0.001). In comparison with all participants categorized in the first FT3 quartile group (FT3-Q1) (<4.380), the adjusted odds ratio of DKD in the second FT3 quartile group (FT3-Q2), the third FT3 quartile group (FT3-Q3), and the fourth FT3 quartile group (FT3-Q4) were 0.655(95%CI: 0.406–1.057), 0.493(95%CI: 0.299–0.813), 0.406(0.237–0.697) (P < 0.05). Also, similar results were observed in men. Conversely, none of the FT3 groups was associated with DKD in women. The present study showed that FT3 within normal range was negatively correlated with DKD in T2DM patients.

Relationship between Thyroid Function and Kidney Function in Patients with Type 2 Diabetes

PURPOSE

To determine if the TSH is related to estimated glomerular filtration rate (eGFR) in T2D patients without overt thyroid dysfunction.

METHODS

A cohort study of 5936 T2D patients was assessed for thyroid and kidney functions, in whom 248 with subclinical hyperthyroidism and 362 with subclinical hypothyroidism. Serum creatinine and 24-hour urine albumin excretion (UAE) were collected. Chronic kidney disease (CKD) was defined as eGFR < 60 ml/min/1.73 m².

RESULTS

Compared with euthyroid subjects, the patients with subclinical hypothyroidism had lower eGFR (82.7 ± 22.4 vs. 90.5 ± 22.4 ml/min/1.73 m², p < 0.01), higher UAE (114 ± 278 vs. 88 ± 229 mg/24 h, p < 0.05), and high incidence of CKD (16.0% vs. 10.1%, p < 0.05). The participants with a TSH level between 0.55 and 3.0 μIU/ml had a higher eGFR (91.4 ± 22.2 ml/min/1.73 m²) and a lower prevalence of CKD (9.5%) than those with higher TSH (3.01-4.78 μIU/ml, 85.6 ± 22.7 ml/min/1.73 m², p < 0.01 and 13.1%, p < 0.01). Linear logistic regression analysis showed that the eGFR was significantly negatively associated with TSH (OR: 0.519, 95% CI: 0.291-0.927, p < 0.05), after adjustment of confounders.

CONCLUSION

High TSH was independently associated with decreased eGFR in type 2 diabetes patients without overt thyroid dysfunction. Our findings indicate that doctors who treat T2D patients should routinely measure the thyroid function.