Antepartum Care for Pregnant People with Overt Hypothyroidism, Subclinical Hypothyroidism, and Positive Thyroid Autoantibodies

Maternal thyroid hormones are critical for the growth and development of a healthy fetus. During pregnancy, maternal thyroid hormone production is increased to meet the demands of fetal growth. The purpose of this review is to provide clinicians with current evidence about possible adverse maternal and fetal effects of hypothyroidism in pregnancy, including the role of hypothyroidism in recurrent pregnancy loss. In addition, clinical presentation, evidence-based screening guidelines, and evidence-based treatments are discussed.

Effects of Antihypertensive Drugs on Thyroid Function in Type 2 Diabetes Patients With Euthyroidism

Objective: There is little literature about whether antihypertensive drugs would affect thyroid function in patients with euthyroid type 2 diabetes, which was significant in maintaining a proper balance of thyroid function. A retrospective cohort study was conducted to evaluate the influence of antihypertensive drugs on thyroid function in patients with type 2 diabetes with euthyroidism. Design and Methods: The study involved dividing 698 patients with antihypertensive monotherapy into five groups according to the antihypertensive drugs they were treated with. Antihypertensive drugs included in this study were β-blockers, angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), and calcium channel blockers (CCB). The clinical data and thyroid function level between or within groups were compared. Multiple logistic regression analysis was conducted to evaluate the association of antihypertensive drugs with thyroid function level. Results: Selective β₁- adrenergic receptor blockers treatment was related to thyroid-stimulating hormone (TSH), increasing in patients with diabetes and euthyroidism as shown by multiple logistic regression analysis. The association existed after adjustment for confounding factors. No significant influence on thyroid function was found among other antihypertensive drugs. Conclusion: These data show the TSH-lifting effect of selective β₁-adrenergic receptor blockers in patients with type 2 diabetes with euthyroidism.

High-Sensitive Detection and Quantitative Analysis of Thyroid-Stimulating Hormone Using Gold-Nanoshell-Based Lateral Flow Immunoassay Device

Au nanoparticles (AuNPs) have been used as signal reporters in colorimetric lateral flow immunoassays (LFAs) for decades. However, it remains a major challenge to significantly improve the detection sensitivity of traditional LFAs due to the low brightness of AuNPs. As an alternative approach, we overcome this problem by utilizing 150 nm gold nanoshells (AuNSs) that were engineered by coating low-density silica nanoparticles with a thin layer of gold. AuNSs are dark green, have 14 times larger surface area, and are approximately 35 times brighter compared to AuNPs. In this study, we used detection of thyroid-stimulating hormone (TSH) in a proof-of-concept assay. The limit of detection (LOD) with AuNS-based LFA was 0.16 µIU/mL, which is 26 times more sensitive than the conventional colorimetric LFA that utilizes AuNP as a label. The dynamic range of the calibration curve was 0.16−9.5 µIU/mL, making it possible to diagnose both hyperthyroidism (<0.5 µIU/mL) and hypothyroidism (>5 µIU/mL) using AuNS-based LFA. Thus, the developed device has a strong potential for early screening and diagnosis of diseases related to the thyroid hormone.

Assessing maternal thyroid function and its relationship to duration of the first stage of labor

INTRODUCTION

Maternal thyroid function plays a critical role in the normal labor process. Whether maternal thyroid function affects the duration of the first stage of labor is still unknown.

METHODS

Maternal serum levels of free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPOAb) were detected in 31,382 pregnant women. A multiple linear regression model was applied to investigate the effect of maternal thyroid function on the duration of the first stage of labor.

RESULTS

FT4 level in the second trimester and in the third trimester was found to be negatively associated with duration of the first stage of labor (β = -1.30 h, 95% CI: -2.28, -0.32, P < 0.01; β = -0.35 h, 95% CI: -0.61, -0.10, P < 0.01). TSH level in the third trimester was found to be positively associated with the duration of the first stage of labor (β = 0.12 h, 95% CI: 0.06, 0.18, P < 0.001). Per unit increase in TPOAb (IU/mL) in the second trimester and in the third trimester was significantly associated with prolonged first stage of labor (β = 0.08 h, 95% CI: 0.01, 0.14, P = 0.02; β = 0.09 h, 95% CI: 0.02, 0.15, P = 0.01). For pregnant women suffering from subclinical hypothyroidism combined without TPOAb, TSH level in the third trimester exhibited a significant positive association with the length of the first stage of labor (β = 2.44 h, 95% CI: 0.03, 4.84, P = 0.04).

CONCLUSIONS

These findings suggest that maternal FT4, TSH and TPOAb might be important predictors of the first stage of labor.

Utility of Repeat Testing for Congenital Hypothyroidism in Infants with Very Low Birth Weight

OBJECTIVE

To assess for possible missed hypothyroidism in infants of very low birth weight (VLBW) whose initial newborn screening (NBS) was within normal reference range.

STUDY DESIGN

We analyzed serum thyroid-stimulating hormone (TSH) obtained at 36 weeks of corrected gestational age or at hospital discharge if earlier (retest TSH) in infants with VLBW in the neonatal intensive care unit to determine the prevalence and factors associated with retest TSH ≥5 mU/L, a concentration requiring close follow-up for hypothyroidism. Utility of alternative cut-offs for NBS TSH also was assessed.

RESULTS

A total of 398 infants, median gestational age 29 (range 22-36) weeks, birth weight 1138 (470-1498) g, were included in this study. Retest TSH was obtained at 49.5 (12-137) days after birth. Median retest TSH was 3.1 (0.5-27.9) mU/L. Seventy-three (18.3%) of the cohort had retest TSH ≥5 mU/L. Adjusting NBS cut-off to ≥15 or ≥10 mU/L identified <50% of infants with TSH ≥5 mU/L, resulting in 6% false positives and >70% false negatives. Multiple regression modeling indicated that 35% of variance in retest TSH value was explained by NBS TSH concentration, birth weight, and gestational age, all P < .01.

CONCLUSIONS

Retesting for hypothyroidism at 36 weeks of corrected gestational age in infants with VLBL and normal NBS could identify infants who require ongoing surveillance until thyroid function has been definitively ascertained. Adjusting NBS TSH cutoffs is not a valid option for identifying potential hypothyroidism in infants with VLBW because of lack of sensitivity and unacceptable false-positive and false-negative rates.

Reference intervals for thyroid-stimulating hormone, free thyroxine, free triiodothyronine, and total triiodothyronine in the Lebanese adult population

BACKGROUND

For a better assessment of thyroid function, each laboratory should establish its own reference intervals (RI). In Lebanon, no previous study has been conducted to establish the reference values for thyroid function tests.

METHODS

This cross-sectional study included 301 volunteers aged between 18 and 65 years (65.8% women, 34.2% men), free from any thyroid pathology and any condition that could affect thyroid function tests. The reference intervals of thyroid-stimulating hormone (TSH), free T4 (FT4), free T3 (FT3), and total T3 (TT3) were measured on the Roche Cobas e411 machine. 39 subjects tested positive for thyroid peroxidase antibodies (TPOAb) and/or thyroglobulin antibodies (TGAb), were excluded from the study.

RESULTS

There was an increase in the 2.5^th percentile for the TSH compared to the value provided by the manufacturer (from 0.27 to 0.53 mlU/L) as well as a decrease in the 97.5^th percentile for the FT4, TT3, and FT3 (respectively, from 22 to 19.78 pmol/L for FT4, from 3.1 to 2.71 nmol/L for TT3, and from 6.80 to 6.10 pmol/L for FT3). Higher TT3 and FT3 values were noted in men compared to women (respectively, p = 0.068 and p < 0.0001). An age decrease in FT4 and FT3 was also observed (respectively, p = 0.045 and p < 0.0001).

CONCLUSION

The established RI of thyroid function tests for the Lebanese population were significantly different from the values recommended by the manufacturer (Roche Diagnostics). Changing our RI values will allow a more accurate diagnosis of thyroid dysfunction.

[Restriction of breastfeeding in the early postnatal period leads to metabolic and endocrine disorders in eighteen-month-old male rats.]

Breastfeeding deficiency in the early postnatal period can lead to metabolic and hormonal disorders in adulthood. However, there are no studies on the effect of starvation in early ontogeny on metabolic and hormonal parameters in aging animals. The effect of such starvation on the functions of the endocrine system has not been practically studied. The aim of this work was to study how interruption of lactation in lactating female rats (19-21 days of postnatal development of rat pups) affects metabolic parameters, glucose tolerance, insulin sensitivity, and hormonal status of the gonadal and thyroid axes in their offspring, 18-month-old male rats. Inhibition of lactation was induced by treating female rats with bromocriptine (10 mg/kg/day). It has been shown that aging male rats with partial deprivation of breastfeeding have characteristic signs of the metabolic syndrome, such as the increased body weight and adipose tissue, impaired glucose tolerance, insulin resistance, and hyperleptinemia. They have reduced levels of testosterone and thyroid hormones, increased levels of thyroid-stimulating hormone, reduced steroidogenic response to gonadoliberin and a decrease in thyroliberin stimulating effect on thyroxine levels. Thus, short-term deprivation of breastfeeding caused by bromocriptine-induced inhibition of lactation in lactating females leads to the development of metabolic syndrome and hormonal dysregulation of the reproductive and thyroid systems in 18-month-old male rats.

Correlation of thyroid-related hormones with vascular complications in type 2 diabetes patients with euthyroid

BACKGROUND

This study aimed to evaluate the relationship between thyroid-related hormones and vascular complications in type 2 diabetes mellitus (T2DM) patients with euthyroidism.

METHODS

We enrolled 849 patients with T2DM after screening out the ineligible. Multivariate logistic regression was used to analyze the relationship between fT3, fT4, the fT3/fT4 ratio, thyroid-stimulating hormone, and diabetic vascular complications. Spearman correlation analysis was used to determine the correlation between thyroid-related hormones and vascular complications.

RESULTS

In this cross-sectional study of T2DM, 538 patients with carotid atherosclerosis (CA) and 299 patients with diabetic peripheral neuropathy (DPN). The prevalence of DPN was negatively correlated with fT3 and the fT3/fT4 ratio but positively correlated with fT4 (all P<0.01). At the same time, the odds ratio for DPN decreased with increasing fT3 (T1: reference; T2: OR: 0.689, 95%CI: 0.477, 0.993; T3: OR: 0.426, 95% CI: 0.286, 0.633, all P<0.05) and fT3/fT4 ratio (T1: reference; T2: OR: 0.528, 95% CI: 0.365, 0.763; T3: OR: 0.413, 95% CI: 0.278, 0.613, all P<0.001). In terms of sensitivity and specificity, fT4 was found to be 39.5% and 71.4% accurate, respectively, with a 95% CI of 0.531-0.611.

CONCLUSIONS

We found a negative correlation between fT3 and fT3/fT4 ratio and the number of individuals with DPN, and a positive correlation between fT4 and the prevalence of DPN.

High-TSH Subclinical Hypothyroidism Is Associated With Postoperative Mortality in Acute Type A Aortic Dissection

BACKGROUND

Subclinical hypothyroidism can negatively affect the cardiovascular system and increase the risk of mortality, especially for individuals with thyroid-stimulating hormone (TSH) levels above 10 mU/L. We investigated the relationship between high-TSH subclinical hypothyroidism and postoperative mortality in acute type A aortic dissection (ATAAD) patients.

METHOD

We enrolled 146 patients with ATAAD who underwent aortic surgery in Beijing Anzhen Hospital from July 2016 to November 2018. Thyroid hormone levels were obtained before surgery, and participants were divided into a ≥10mU/L TSH level group and a <10mU/L level group. Cox proportional hazard regression and subgroup analysis were conducted to examine the association of preoperative high-TSH subclinical hypothyroidism with postoperative mortality.

RESULT

Participants with preoperative high-TSH (≥10mU/L) subclinical hypothyroidism tended to have longer hospitalization stays after surgery [16.0 (IQR 11.0-21.0) days vs 12.5 (IQR 8.0-16.0) days, P=0.001]. During the first 30 days after operation, 15 of 146 patients died (10.3%); during a median of 3.16 (IQR 1.76-4.56) years of follow-up, 24 patients died (16.4%). Cox proportional hazard regression showed that preoperative high-TSH subclinical hypothyroidism was independently associated with 30-day mortality (HR=6.2, 95% CI, 1.7-22.0, P=0.005) and postoperative mortality after adjusting for age, sex, BMI, hypertension, ejection fraction, diabetes and history of PCI (HR=3.4, 95% CI, 1.4-8.0, P=0.005).

CONCLUSION

This study showed that preoperative high-TSH subclinical hypothyroidism was an independent predictor of postoperative mortality in ATAAD patients who underwent aortic surgery.

Tea consumption affects the absorption of levothyroxine

Levothyroxine (LT4) is a convenient treatment for hypothyroidism. Coffee, however, prevents the body from efficaciously absorbing LT4. It is unknown whether the intake of tea interferes with LT4 absorption. Thirty-seven hypothyroidism patients with the following types of consumption were recruited: 1) only tea, 2) tea and coffee, and 3) only coffee. The concentrations of thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) were recorded before and 3 months after changing the consumption. The patients had reductions in the concentration of TSH to varying degrees after 3 months (p < 0.001 or p < 0.05). The natural logarithms of the differences between the concentrations of TSH before and after the change in the consumption (Δln-TSH) of tea and coffee, only coffee, and only tea were 1.94, 2.00, and 2.18, respectively. Long-term consumption of tea, like coffee, interfered with the absorption of LT4. We believe that avoiding tea when taking LT4 will reduce malabsorption.

Combination of Stimulated Thyroglobulin and Antithyroglobulin Antibody Predicts the Efficacy and Prognosis of 131I Therapy in Patients With Differentiated Thyroid Cancer Following Total Thyroidectomy: A Retrospective Study

BACKGROUND AND PURPOSE

This study aimed to analyze the diagnostic ability of the combination of stimulated thyroglobulin (sTg) and antithyroglobulin antibody (TgAb) in predicting the efficacy and prognosis of radioactive iodine (¹³¹I) therapy (RAIT) in patients with differentiated thyroid carcinomas (DTCs) after total thyroidectomy (TT).

METHODS

This retrospective study comprised 409 DTC patients who underwent ¹³¹I treatment following TT in the First Affiliated Hospital of Zhengzhou University from January 2019 to August 2020, and they were followed up to November 2021. Patients were divided into the successful ablation and the unsuccessful ablation group based on the classification of the efficacy of RAIT in the 2015 American Thyroid Association guidelines. The clinical characteristics and the efficacy of the initial RAIT were evaluated. The cutoffs of preablation sTg, sTg/thyroid-stimulating hormone (TSH) ratio, and sTg×TgAb product were calculated to predict the efficacy of RAIT. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors for unsuccessful ablation. Kaplan-Meier curves were used to estimate the prognostic value of sTg×TgAb product affecting progression-free survival (PFS).

RESULTS

The cohort consisted of 222 cases in the successful ablation group and 187 cases in the unsuccessful ablation group. Between the two groups, preablation sTg, sTg/TSH ratio, and sTg×TgAb product were significantly higher in the unsuccessful ablation group. The area under the curve (AUC) of the sTg×TgAb product was the highest among the above three factors. The cutoffs for the worse therapeutic effect of the initial RAIT in sTg, sTg/TSH ratio, and sTg×TgAb were >2.99 ng/ml, >0.029 mg/IU, and >34.18, respectively. STg >2.99 ng/ml and sTg×TgAb product >34.18 were independent risk factors for unsuccessful ablation. Patients with sTg×TgAb product >34.18 had shorter PFS than that of patients with sTg×TgAb product ≤34.18. In separate analyses of TgAb-negative and TgAb-positive subgroups, higher sTg×TgAb was both associated with a lower success rate of RAIT and a shorter PFS.

CONCLUSION

STg×TgAb product predicted the efficacy and prognosis of ¹³¹I therapy for both TgAb-negative and TgAb-positive DTC patients before the initial ¹³¹I treatment following TT. Thus, it can be used as a clinical reference indicator for the surveillance of DTC patients.

A patient with an ectopic sphenoid bone TSH secretory adenoma: Case report and review of the literature

Ectopic thyroid-stimulating hormone (TSH)oma located outside the sella turcica is exceedingly rare and can be associated with significant diagnostic delay. The clinical presentation depends on the anatomical location and size of the ectopic tumor and the degree of thyrotoxicosis. A 71-year-old woman presented with goiter and thyrotoxicosis. Initial investigations revealed elevated free thyroxine (fT4) and tri-iodothyronine (fT3) with inappropriately high-normal TSH. Assay interference was unlikely, pituitary magnetic resonance imaging (MRI) scan was reported as "normal," and germline sequencing was negative for thyroid hormone receptor ß pathogenic variants. One year later, total thyroidectomy for enlarging symptomatic goiter and suspicious nodule revealed multifocal microscopic papillary thyroid carcinoma. Six years later, she presented to an ear, nose, and throat surgeon with nasal congestion, and a sphenoid bone mass was discovered on nasoendoscopy and imaging. Ectopic TSHoma was confirmed on surgical resection, and a review of the initial pituitary MRI scan revealed the mass which had initially been missed. This is the first reported case of an ectopic TSHoma located in the sphenoid bone. Ectopic TSHoma should be considered in patients with inappropriate TSH secretion when more common differentials are excluded including thyroid hormone resistance or pituitary TSHoma.

Association of thyroid-stimulating hormone and lipid levels with suicide attempts among adolescents with major depressive disorder in China

OBJECTIVES

Evidence suggested that thyroid-stimulating hormone (TSH) and lipid levels were associated with major depressive disorder (MDD). However, its role in suicide attempts in adolescents with MDD was unclear. This investigation was to probe into the relationship between TSH, lipid levels, and attempted suicide in adolescents with MDD.

METHODS

A total of 179 adolescents with MDD were included from January 2021 to January 2022. Socio-demographic data and clinical data were obtained through self-made questionnaires. TSH and lipid levels were analyzed by a recognized laboratory. The Epidemiological Studies Depression Scale (CES-D) was used to assess the severity of depression. Questions about whether there was a behavior of suicide attempts were completed through conversation interviews.

RESULTS

Results showed that the CES-D total score, TSH, and low-density lipoprotein cholesterol (LDL-C) of suicide attempters were significantly higher than those of non-suicide attempters. Ordinary family relationships were more likely to attempt suicide than good family relationships. The CES-D total score, ordinary family relationships, TSH and LDL-C were still significant in binary logistic regression, with an adjusted odds ratio (OR) of 1.04, 3.42, 5.14, and 1.76, respectively. The area under the receiver operating characteristic (ROC) curve showed that the area under the ROC curve (AUC) ranged from 0.60 to 0.74.

CONCLUSION

Suicide attempts are common among adolescents with MDD and were associated with CES-D total score, ordinary family relationships, TSH, and LDL-C. Given the association between suicide attempts and TSH and LDL-C, the dynamic changes in TSH and LDL-C levels should be detected regularly.

Comparison of thyroid-stimulating hormone levels in adolescents with schizophrenia, bipolar disorder, unipolar depression, conduct disorders, and hyperkinetic disorders

The aim of this study was to retrospectively compare values of thyroid-stimulating hormone (TSH) in adolescent patients diagnosed with schizophrenia, bipolar disorder, unipolar depression (UNI-DEP), conduct disorders (CD), and hyperkinetic disorders.The research involved 1122 patients (718 women, 64%); aged 12 to 18 hospitalized in the Department of Adolescent Psychiatry, Medical University of Lodz. We analyzed TSH levels in the whole study population and compared it between the above-mentioned subgroups of diagnoses.Mean serum TSH concentration in the studied population (n = 1122) was 2.06 μIU/mL. The values of percentiles were as follows: 2.5th - 0.53 μIU/mL, 10th - 0.89 μIU/mL, 25th - 1.31 μIU/mL, 50th - 1.9 μIU/mL, 75th - 2.6 μIU/mL, 90th - 3.43 μIU/mL, 97.5th - 4.72 μIU/mL. TSH values were negatively correlated with patients' age (P = .00001). Patients with bipolar depression had higher TSH levels than patients with CD (P = .002). Also, when male and female groups were examined separately we found that female patients with UNI-DEP and bipolar disorder had higher TSH levels than female patients with CD (P = .001; P = .001).Our results confirm that there may be a higher prevalence of thyroid dysfunctions in bipolar and UNI-DEP subgroups among adolescents and that it is worthy to consider some kind of interventions regarding thyroid function in depressed individuals.

The Role of Thyroid Hormones in the Differential Diagnosis of Tuberculous and Parapneumonic Pleural Effusions

BACKGROUND

The differential diagnosis of tuberculous pleural effusion (TPE) and parapneumonic pleural effusion (PPE) is challenging due to similar clinical manifestations and body fluid biochemical profiles. Thyroid hormone levels change in response to lymphocyte proliferation in the peripheral blood of patients with mycobacterial infections such as tuberculosis; therefore, this study aimed to investigate the utility of assessing thyroid hormone levels to aid in the differential diagnosis of TPE and PPE.

METHODS

We measured free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) levels in the pleural effusions of 59 newly admitted patients (32 and 27 with TPE and PPE, respectively). Hormone levels were assessed using an electrochemiluminescence technique, and the diagnostic parameters for tuberculosis were evaluated. Differences in hormone levels between patients with TPE and PPE were assessed by t-tests, and their diagnostic value for a differential diagnosis was evaluated by receiver operating characteristic curve analyses.

RESULTS

FT3 and FT4 levels in patients with TPE were significantly higher than those in patients with PPE (p < 0.01 and p < 0.05, respectively), whereas TSH expression did not significantly differ between the two groups (p > 0.05). FT3 and FT4 levels showed no correlation with sex or history of smoking, although FT3 levels decreased with age. The highest sensitivity was observed for the quantification of FT3 levels (84.38%).

CONCLUSIONS

Increased FT3 and FT4 levels could potentially be used for the differential diagnosis of TPE and PPE.

Postpartum Thyroid Dysfunction in Women With Known and Newly Diagnosed Hypothyroidism in Early Pregnancy

Background

Hypothyroidism in the first trimester of pregnancy (T1) has great adverse effects on mothers and foetuses. However, few studies have investigated the influence on postpartum thyroid dysfunction. This study aimed to evaluate their long-term effect on postpartum thyroid function within one year after delivery.

Methods

In total, 151 women were recruited from 1496 participants and were classified as newly diagnosed subclinical hypothyroidism (SCH) in T1 (ND-SCH, n=50), previously known SCH before pregnancy (PK-SCH, n=51) and previously known overt hypothyroidism (PK-OH, n=50). Their thyroid functions were dynamically monitored from pre-conception to one-year postpartum.

Results

During pregnancy, the first thyroid functions' test time in T1 were 5-8 gestational weeks. After delivery, the prevalence of postpartum thyroiditis (PPT) was comparable in women with previously known and newly diagnosed hypothyroidism [ND-SCH 62.0% vs PK-SCH 64.7% vs PK-OH 64.0%, P=0.96]. For the ND-SCH group, PPT was significantly related with thyroid-stimulating hormone (TSH) >4.0 mU/L occurring at <8 gestational weeks [OR=8.06, 95% CI, 2.08-31.29] and TSH levels outside 1.0-2.5 mU/L near childbirth [OR=3.73, 95% CI, 1.04-13.41]. For patients with known hypothyroidism before pregnancy (PK-SCH and PK-OH), TSH>2.5 mU/L in T1 [OR=3.55, 95% CI, 1.43-8.81] and TPOAb≥300 μIU/mL [OR=6.58, 95% CI, 2.05-21.12] were associated with PPT. Regardless of whether SCH was diagnosed before pregnancy or in T1, the levothyroxine (LT4) treatment was discontinued at delivery. More than 50% of the patients had to face the hypothyroidism phase of postpartum and restarted LT4 treatment in the first-year follow-up. The logistic regression analysis revealed that TSH elevation occurring at <8 gestational weeks [OR=2.48, 95% CI, 1.09-5.6], TSH levels outside 1.0-2.5 mU/L near childbirth [OR=3.42, 95% CI, 1.45-8.05], and TPOAb≥300 μIU/mL [OR=6.59, 95% CI, 1.79-24.30] were the risk factors.

Conclusion

TSH elevation at <8 gestational weeks was associated with PPT after delivery in women with known and newly diagnosed hypothyroidism. Especially for SCH patients who stopped LT4 treatment at delivery, unsatisfactory TSH level at <8 gestational weeks and near childbirth, TPOAb≥300 μIU/mL were the risk factors for LT4 retreatment in one-year postpartum.

Association of Thyroid-Stimulating Hormone (TSH) Levels With the Prognosis of Patients Undergoing Heart Transplantation: A Retrospective Study

Purpose: To investigate the impact of TSH levels using a more stringent cutoff of subclinical hypothyroidism (i.e., TSH > 2.5 mIU/L) on the short-term complications and long-term prognosis in patients who underwent heart transplantation (HTx). Methods: This is a retrospective study of consecutive patients with end-stage heart failure (HF) who underwent HTx. They were divided into three groups: thyroid-stimulating hormone (TSH) ≤ 2.50 mIU/L (L-TSH), 2.50 < TSH ≤ 4.91 mIU/L (M-TSH), and TSH > 4.91 mIU/L (H-TSH). The outcomes are all-cause death and cardiogenic death. Results: There are 63 (70%) males and 27 (30%) females. Nine (10%) patients died within 1 month after surgery, including five cardiogenic deaths. By 1 year, a total of 19 patients total were dead. The survival rate in the M-TSH group was significantly higher than that of the L-TSH group (P = 0.017). After adjusted by variables of sex, age, BMI, diabetes history, hypertension history, the multivariable Cox analysis showed that body mass index (HR = 0.804, 95%CI: 0.680-0.951, P = 0.011), and L-TSH (HR = 8.757, 95%CI: 1.786-42.948, P = 0.007 vs. M-TSH), and H-TSH (HR = 6.427, 95%CI: 1.137-36.327, P = 0.035 vs. M-TSH) were independently associated with all-cause death. The multivariable Cox analysis showed that body mass index (HR = 0.703, 95%CI: 0.564-0.878, P = 0.002), and L-TSH (HR = 17.717, 95%CI: 1.907-164.607, P = 0.011 vs. M-TSH) were independently associated with cardiogenic death. Conclusion: For patients with end-stage HF undergoing HTx, low and high baseline TSH levels are independently associated with 1-year all-cause death and low baseline TSH levels with cardiogenic death.

Impact of TPOAb-negative maternal subclinical hypothyroidism in early pregnancy on adverse pregnancy outcomes

PURPOSE

To investigate the effect of subclinical hypothyroidism on pregnancy outcomes of women early in their pregnancy with different thyroid-stimulating hormone levels and thyroid peroxidase antibody-negative status and to explore reasonable thyroid-stimulating hormone levels for subclinical hypothyroidism in early pregnancy.

METHODS

A total of 2378 women early in their pregnancy were studied retrospectively. The baseline characteristics were collected from medical records. Pregnancy outcomes were compared between the euthyroidism and subclinical hypothyroidism groups that were diagnosed by 2011 or 2017 American Thyroid Association guidelines. In addition, the effect of different maternal thyroid-stimulating hormone levels on adverse pregnancy outcomes was analyzed using binary logistic regression.

RESULTS

According to the 2011 American Thyroid Association diagnostic criteria of subclinical hypothyroidism, the prevalence of pregnancy outcomes was not significantly higher in the subclinical hypothyroidism group than in the euthyroidism group. However, pregnant women with subclinical hypothyroidism identified by the 2017 American Thyroid Association criteria had a higher risk of premature delivery (odds ratio = 3.93; 95% confidence interval = 1.22-12.64), gestational diabetes mellitus (odds ratio = 2.69; 95% confidence interval = 1.36-5.32), and gestational anemia (odds ratio = 3.28; 95% confidence interval = 1.60-6.75). Moreover, no differences in the prevalence of adverse pregnancy outcomes were observed between the mildly elevated thyroid-stimulating hormone group (2.5 < thyroid-stimulating hormone ⩽4.0 mIU/l) and the normal thyroid-stimulating hormone group (0.27 < thyroid-stimulating hormone ⩽2.5 mIU/l). The significantly elevated thyroid-stimulating hormone group (4.0 < thyroid-stimulating hormone < 10.0 mIU/l) had a higher prevalence of premature delivery, gestational diabetes mellitus, and gestational anemia than the normal thyroid-stimulating hormone group, even after controlling for potential confounding factors.

CONCLUSION

A mildly elevated thyroid-stimulating hormone level or maternal subclinical hypothyroidism diagnosed by 2011 American Thyroid Association guidelines during early pregnancy in thyroid peroxidase antibody-negative women was not associated with adverse pregnancy outcomes. However, maternal subclinical hypothyroidism identified by the 2017 American Thyroid Association guidelines increased the risks of several adverse pregnancy outcomes in women untreated with levothyroxine. The 2017 American Thyroid Association guidelines could be more reasonable for the diagnosis of subclinical hypothyroidism in southern China.

Obese patients with higher TSH levels had an obvious metabolic improvement after bariatric surgery

OBJECTIVE

Bariatric surgery has become the most effective treatment for morbid obesity. Increasing evidence showed that bariatric surgery can alleviate insulin resistance and influence thyroid function. This study aimed to investigate the relationship between changes in thyroid function and adipose tissue insulin resistance (adipo-IR) after bariatric surgery.

METHODS

A total of 287 non-diabetic participants with regular thyroid function were recruited and divided into the lean, overweight and obese groups. Among them, 50 morbidly obese patients submitted to bariatric surgery.

RESULTS

The obese group had a higher level of adipo-IR, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), FT3/free thyroxine (FT4) and metabolism disorders than the lean and overweight groups. BMI was correlated with TSH, FT3, FT3/FT4 and adipo-IR (r = 0.309, 0.315, 0.322 and 0.651, respectively, all P < 0.001). Adipo-IR was significantly correlated with TSH (r = 0.402, P < 0.001), FT3 (r = 0.309, P < 0.001), and FT3/FT4 (r = 0.228, P < 0.05). Bariatric surgery resulted in a sharp decline in BMI, adipo-IR, TSH, FT3 and FT3/FT4 levels, meanwhile, metabolic disorders improved. The decrease in BMI after bariatric surgery was significantly correlated with reductions in adipo-IR (r = 0.577, P < 0.001) and TSH (r = 0.401, P = 0.005). Interestingly, the fasting blood glucose, fasting insulin, adipo-IR and TSH in the higher TSH group decreased more remarkably than in the lower TSH group.

CONCLUSION

Obese individuals with higher TSH levels had an obvious metabolic improvement after bariatric surgery.

The Association between Thyroid-Stimulating Hormone and Long-Term Outcomes in Patients with ST Segment Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

Objective

Thyroid hormones are closely related to the cardiovascular system. Our study aimed to explore the impact of admission thyroid-stimulating hormone (TSH) levels on long-term outcomes in patients with acute ST segment elevation myocardial infarction (STEMI) by detailed stratifications of TSH.

Methods

Consecutive STEMI patients admitted to our hospital were divided into four groups: Group 1 (TSH <0.35 mIU/L), Group 2 (TSH 0.35–1.0 mIU/L), Group 3 (TSH 1.0–3.5 mIU/L), and Group 4 (TSH >3.5 mIU/L). The primary endpoint was all-cause mortality during follow-up, and the median follow-up was 2.5 years. Cox proportional hazard regression models were performed to identify the prognostic value of TSH.

Results

A total of 1186 patients were included. Group 4 was presented with higher systolic and diastolic blood pressure (all P < 0.001), and Group 1 had more patients complicated by heart failure (Killip class >I, P = 0.014). During follow-up, 138 deaths occurred. Patients in Group 4 had the worst long-term outcomes (P < 0.001). The cumulative survival in Group 4 was remarkably lower (Log rank P < 0.001), whereas the other three groups were comparable (Log rank P = 0.365). Through Cox regression analysis, only TSH >3.5 mIU/L was identified as an independent risk factor for long-term mortality after STEMI.

Conclusion

Only TSH elevation beyond the normal range was associated with worse long-term prognosis in STEMI patients, while high-normal TSH or reduced TSH did not alter long-term prognosis of STEMI patients. TSH >3.5 mIU/L was an independent risk factor for long-term mortality in STEMI.

Factors influencing the reference interval of thyroid-stimulating hormone in healthy adults: A systematic review and meta-analysis

BACKGROUND

Many studies have reported that the thyroid-stimulating hormone (TSH) reference interval is susceptible to external factors, such as age, sex, race, region and iodine intake. However, no meta-analysis has comprehensively explored the effect of these factors on the TSH reference interval.

METHODS

Articles published from January 1960 to January 2020 were searched in PubMed, Embase, Cochrane, Scopus, Medline English databases and CNKI, WanFang and CQVIP Chinese databases. In total, 19 studies were ultimately included. All data were analysed using Review Manager 5.3, STATA 16.0 software, GraphPad Prism 8.0 and Microsoft Excel 2010 to draw the TSH concentration curve.

RESULTS

The TSH reference interval was significantly influenced by sex and age. The mean of TSH concentration in females was 0.27 mIU/L higher than that in males. Reference interval of TSH is divided into 20-59 years old and >60 years old age groups in males, and 20-39 years old and >40 years old age groups in females. Regardless of sex, TSH concentrations all increase with age. In iodine-deficient areas, TSH reference intervals were generally lower than those in iodine-sufficient or iodine-excessive areas. The TSH reference interval in Asia and North American countries was generally higher than that in most European countries. In the subgroup analyses of sample size, region and assay methods and manufacturers, the between-group differences were significant.

CONCLUSION

The TSH reference interval was significantly influenced by sex, age, iodine intake, sample size, region, and assay methods and manufacturers, but other factors should not be ignored. Therefore, it is necessary for each laboratory to validate an appropriate TSH reference interval based on local conditions.

Genetic Polymorphisms of Pesticide-Metabolizing Enzymes and Transporters in Agricultural Workers and Thyroid Hormone Levels

PURPOSE

Chronic exposure to pesticides has been associated with thyroid dysfunction owing to their endocrine disruption ability. Genetic variations in genes encoding phase I and II enzymes and phase III transporters are partly responsible for individual responses to chemical pesticides. This study investigated the association between variations in genes involved in pesticide metabolism and altered thyroid hormone concentrations.

METHODS

We assessed thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) in organic agriculture workers (n = 216) and workers who used chemical pesticides (n = 229). A questionnaire was used to collect sociodemographic, pesticide exposure, and health status data. Blood samples were analyzed for TSH, FT3, and FT4. Genomic DNA was extracted and genotyped using the TaqMan real-time PCR genotyping assay and restriction fragment length polymorphism method for 15 metabolically related genes.

RESULTS

Significant differences in the TSH (1.58 vs 1.12 µIU/mL) and FT3 (0.34 vs 0.31 ng/dL) concentrations between the chemical and organic worker groups were observed. The frequencies of all single nucleotide polymorphisms were in Hardy-Weinberg equilibrium and were mostly consistent with Asian populations. The findings showed the association between SNPs of enzymes and transporters and TSH, FT3, and FT4. The odd ratio and adjusted odd ratio (with sex, age, smoking status, alcohol consumption and exposure parameters) for subclinical thyroid disease by the variant alleles CYP1A1 rs1048943, CYP2B6 rs2279343, CYP2C19 rs4244285, NAT2 rs1799931, and PON1 rs662 in the chemical workers compared with the organic workers were found (P values < 0.05).

CONCLUSION

This is the first study to assess gene-environment interactions in Thai agricultural workers by investigating disruptions of the hypothalamic-pituitary-thyroid axis. The investigated SNP profiles revealed several gene-thyroid hormone associations in which even low levels of pesticide exposure could disturb thyroid homeostasis. These findings provide a foundation for planning future studies investigating associations between complex diseases and occupational pesticide exposure.

C-reactive protein and thyroid-stimulating hormone levels as risk factors for hypothyroidism in patients with subacute thyroiditis

OBJECTIVE

This study was designed to explore the relationships between the clinical characteristics and outcomes of patients with subacute thyroiditis (SAT).

DESIGN

This is a single-center retrospective study.

PATIENTS

Eighty-nine patients with SAT who were hospitalized in the Sir Run Run Shaw Hospital in Zhejiang, China, from October 2014 to September 2020 were included.

METHODS

The Mann-Whitney U-test, chi-square test, and Cox regression analysis were conducted to identify the relationships between clinical characteristics and outcomes. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff levels of C-reactive protein (CRP) and thyroid-stimulating hormone (TSH).

RESULTS

The hypothyroidism and recurrence rates were 15.7 and 16.9%, respectively. CRP (≥72.0 mg/L), TSH (<0.02 mIU/L), and free triiodothyronine (fT3) (≥4.10 pg/mL) were associated with hypothyroidism. The cutoff level was 97.80 mg/L for CRP (area under the curve (AUC), 0.717, P = 0.014; sensitivity, 57.1%; specificity, 84.0%) and 0.10 mIU/L for TSH (AUC, 0.752, P = 0.004; sensitivity, 100%; specificity, 46.0%) by ROC curve analysis for hypothyroidism. The factors under study were not associated with recurrence.

CONCLUSION

CRP and TSH were risk factors for hypothyroidism in SAT. Thyroid functions should be monitored closely for the early detection of hypothyroidism, especially in patients with CRP levels of more than 97.80 mg/L and TSH levels of less than 0.10 mIU/L.

Percentile transformation and recalibration functions allow harmonization of thyroid-stimulating hormone (TSH) immunoassay results

Background The comparability of thyroid-stimulating hormone (TSH) results cannot be easily obtained using SI-traceable reference measurement procedures (RPMs) or reference materials, whilst harmonization is more feasible. The aim of this study was to identify and validate a new approach for the harmonization of TSH results. Methods Percentile normalization was applied to 125,419 TSH results, obtained from seven laboratories using three immunoassays (Access 3rd IS Thyrotropin, Beckman Coulter Diagnostics; Architect System, Abbott Diagnostics and Elecsys, Roche Diagnostics). Recalibration equations (RCAL) were derived by robust regressions using bootstrapped distribution. Two datasets, the first of 119 EQAs, the second of 610, 638 and 639 results from Access, Architect and Elecsys TSH results, respectively, were used to validate RCAL. A dataset of 142,821 TSH values was used to derive reference intervals (RIs) after applying RCAL. Results Access, Abbott and Elecsys TSH distributions were significantly different (p < 0.001). RCAL intercepts and slopes were -0.003 and 0.984 for Access, 0.032 and 1.041 for Architect, -0.031 and 1.003 for Elecsys, respectively. Validation using EQAs showed that before and after RCAL, the coefficients of variation (CVs) or among-assay results decreased from 10.72% to 8.16%. The second validation dataset was used to test RCALs. The median of between-assay differences ranged from -0.0053 to 0.1955 mIU/L of TSH. Elecsys recalibrated to Access (and vice-versa) showed non-significant difference. TSH RI after RCAL resulted in 0.37-5.11 mIU/L overall, 0.49-4.96 mIU/L for females and 0.40-4.92 mIU/L for males. A significant difference across age classes was identified. Conclusions Percentile normalization and robust regression are valuable tools for deriving RCALs and harmonizing TSH values.

A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism

BACKGROUND

Radioiodine (¹³¹ I) is the treatment of choice for hyperthyroidism in cats, but current ¹³¹ I-dosing protocols can induce iatrogenic hypothyroidism and expose azotemia.

OBJECTIVES

To develop a cat-specific algorithm to calculate the lowest ¹³¹ I dose to resolve hyperthyroidism, while minimizing risk of iatrogenic hypothyroidism and subsequent azotemia.

ANIMALS

One thousand and four hundred hyperthyroid cats treated with ¹³¹ I.

METHODS

Prospective case series (before-and-after study). All cats had serum concentrations of thyroxine (T₄ ), triiodothyronine (T₃ ), and thyroid-stimulating hormone (TSH) measured (off methimazole ≥1 week). Using thyroid scintigraphy, each cat's thyroid volume and percent uptake of ^99m Tc-pertechnatate (TcTU) were determined. An initial ¹³¹ I dose was calculated by averaging dose scores for T₄ /T₃ concentrations, thyroid volume, and TcTU; 80% of that composite dose was administered. Twenty-four hours later, percent ¹³¹ I uptake was measured, and additional ¹³¹ I administered, as needed, to deliver an adequate radiation dose to the thyroid tumor(s). Serum concentrations of T₄ , TSH, and creatinine were determined 6 to 12 months later.

RESULTS

The median calculated ¹³¹ I dose was 1.9 mCi (range, 1.0-10.6 mCi); 1380 cats required additional ¹³¹ I administration on day 2. Of the cats, 1047 (74.8%) became euthyroid, 57 (4.1%) became overtly hypothyroid, 240 (17.1%) became subclinically hypothyroid, and 56 (4%) remained hyperthyroid. More overtly (71.9%) and subclinically (39.6%) hypothyroid cats developed azotemia than euthyroid cats (14.2%; P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Our algorithm for calculating individual ¹³¹ I doses resulted in cure rates similar to historical treatment rates, despite much lower ¹³¹ I doses. This algorithm appears to lower prevalence of both ¹³¹ I-induced overt hypothyroidism and azotemia.