To Treat or Not to Treat Subclinical Hypothyroidism, What Is the Evidence?

Long-term forecasting and evaluation of medicine consumption for the ATC class H with a focus on thyroid hormones in OECD countries using ARIMA models

Thyroid hormones are among the most prescribed medicines. In many countries, there are shortages combined with evidence of overuse and irrational prescribing. An analysis was conducted for ATC class H with a focus on thyroid hormones for OECD countries. This study aims to evaluate prescribing behaviours, forecast long-term developments and promote rational prescribing behaviour. The ARIMA(2,1,2) (autoregressive integrated moving average) model successfully predicted the future for 30 OECD countries and the non-OECD country Croatia until 2040. An upward trend is forecast for 18 countries, including Austria (+ 5.7%), Chile (+ 220.0%), Czechia (+ 52.8%), Denmark (+ 15.6%), Estonia (+ 87.8%), Greece (+ 238.7%), Hungary (+ 5.7%), Iceland (+ 18.6%), Italy (+ 42.9%), Latvia (+ 83.7%), Lithuania (+ 131.2%), Portugal (+ 106.7%), Slovakia (+ 182.1%), Slovenia (+ 57.4%), Spain (+ 162.8%), Turkey (+ 168.7%), the United Kingdom (+ 138.1%) and Croatia (+ 190.6%). A downward trend is forecast for 13 countries, including Australia (-3.4%), Belgium (-38.8%), Canada (-95.1%), Costa Rica (-79.5%), Finland (-14.7%), France (-100.0%), Germany (-16.4%), Israel (-21.6%), Korea (-100.0%), Luxembourg (-100.0%), the Netherlands (-35.9%), Norway (-23.6%) and Sweden (-43.6%). The reliability and accuracy of the forecasts varies, being influenced by data quality. While a downward trend is favoured, an upward trend is seen as problematic. Increasing trends predominate in Southern and Eastern Europe and Latin America, while decreasing trends predominate in Northern and Western Europe and the Asia-Pacific Region. Some external factors affect all countries, like an increasing prevalence of thyroid disease. There is evidence of cultural influences on prescribing behaviour. While there is evidence of inappropriate use in countries where prescriptions are predicted to increase, measures to restrict the use of thyroid hormones are more common in countries with a recently reported and predicted declining trend.

Thyroid disorders in patients with human immunodeficiency virus infection: a meta-analysis

BACKGROUND

Thyroid disorders have significant clinical sequelae, including impaired growth in children, metabolic abnormalities, and impaired cognitive function. However, available studies on burden of thyroid diseases in people with human immunodeficiency virus (HIV), particularly its prevalence and its interaction with HIV related factors (like CD4 count), are controversial. This review aimed to provide a comprehensive summary and analysis on the extent of thyroid dysfunctions in this population.

METHODS

Following Preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines, a comprehensive search was done through Medline/PubMed, Web of Science, Science Direct, and World Health Organization Virtual Health Library Regional Portal. Using Comprehensive Meta-Analysis Software version 3.3, we calculated the pooled prevalence and standardized mean difference (SMD) estimates with 95% confidence intervals (CIs).

RESULTS

A total of 30 studies met the eligibility criteria and were further included for the analyses. The most common types of thyroid dysfunction identified among HIV patients were subclinical hypothyroidism (7.7%), overt hypothyroidism (2.7%), sick euthyroid syndrome (2.47%), isolated low FT4 (1.80%), and overt hyperthyroidism (0.7%). Hypothyroidism among HIV patients was significantly associated with lower CD4 count (p < 0.001). The analysis revealed that only FT4 levels had significant differences between patients with HIV and healthy people (p = 0.013).

CONCLUSION

Individuals with HIV are at risk of developing variable manifestations of thyroid abnormalities. While being not abundant in the HIV population, monitoring of thyroid dysfunction is essential due to the potential for progression to overt hypothyroidism and associated adverse health outcomes.

Macro-Thyrotropin Syndrome: Prevalence and Clinical Profile of an Under-Recognised Rare Entity in Thyroidology

Introduction

Macro-thyrotropin syndrome (macro-TSH) is a rare condition characterised by the formation of a complex between thyroid-stimulating hormone (TSH) and an unknown component, resulting in elevated TSH levels that do not accurately reflect thyroid status. This study aimed to investigate the prevalence and clinical profile of macro-TSH among patients with subclinical hypothyroidism (SCH).

Methods

A total of 1500 patients were evaluated, with 135 exhibiting elevated TSH levels (>10 IU/mL) and normal free-thyroxine levels. Macro-TSH was diagnosed based on persistent elevated TSH levels despite serial dilutions and confirmed by less than 60% TSH recovery following polyethylene glycol (PEG) precipitation.

Results

Finally, 115 were diagnosed with SCH, 15 with macro-TSH, and 1245 were categorised into non-thyroid groups. The prevalence of macro-TSH, SCH, and heterophilic antibodies interfering with immunoassay was 1.09%, 8.36%, and 0.36%, respectively. Among macro-TSH patients, 13.33% exhibited classical hypothyroid features, contrasting with the 52.0% observed in SCH patients. Female gender and a family history of hypothyroidism were associated with higher odds of having macro-TSH. Diabetes mellitus, clinical symptoms of hypothyroidism (except lethargy), higher TSH level, and post-PEG TSH recovery were significantly associated with SCH compared to macro-TSH. The mean TSH level was five times higher in macro-TSH compared to SCH.

Conclusion

Macro-TSH syndrome represents a distinct clinical entity within the spectrum of SCH, characterised by disproportionately high TSH levels. Recognising macro-TSH is crucial for accurate diagnosis and appropriate management of SCH.

Efficacy of Thyroid Hormone Replacement Therapy in Nasopharyngeal Carcinoma Patients with Radiation-Induced Subclinical Hypothyroidism

AIMS

Hypothyroidism is a common side effect of radiotherapy for nasopharyngeal carcinoma. However, the impact of thyroid hormone replacement therapy on patients with radiation-induced subclinical hypothyroidism has not been extensively explored. This study aimed to analyze the efficacy of thyroid hormone replacement therapy in nasopharyngeal carcinoma patients with subclinical hypothyroidism.

METHODS

Patients diagnosed with nasopharyngeal carcinoma who developed subclinical hypothyroidism after definitive radiotherapy between September 2019 and December 2020 were selected for inclusion in this study. Prior to thyroid hormone replacement therapy and after maintaining euthyroidism for 6-12 months through thyroid hormone replacement therapy, assessments using the SF36 Brief Health Status Scale and the Hypothyroidism-related Symptom Questionnaire were conducted via trained questionnaires. Lipid profiles were assessed at baseline and after 6-12 months of thyroid hormone replacement therapy. Statistical analyses were performed using matched samples T-test or Mann-Whitney U test.

RESULTS

The median follow-up period was 14.5 months. The median score of hypothyroid symptoms was 5.5 out of 19 points, with the most common symptoms being chills (65.0%), fatigue (50.0%), weight gain (45.0%), and limb numbness (40.0%). Thyroid hormone replacement therapy did not significantly improve the quality of life, hypothyroidism-related symptoms, or blood lipid profile in patients. However, there was an observed downward trend in serum cholesterol levels following treatment (P=0.052).

CONCLUSION

Thyroid hormone replacement therapy did not have a significant impact on alleviating hypothyroid symptoms, improving quality of life, or enhancing lipid profiles in patients with radiation-induced subclinical hypothyroidism. Nevertheless, a potential decrease in serum cholesterol levels was noted after thyroid hormone replacement therapy.

Analysis of factors influencing the dose of levothyroxine treatment in adequately controlled hypothyroid patients of different etiologies

Objective

The mainstay therapy of hypothyroidism is levothyroxine (LT4). In most cases lifelong treatment is warranted, therefore, choosing adequate doses are of paramount significance. The purpose of this study was to assess several factors that have been proposed to influence LT4 therapy including etiology of hypothyroidism, gender, age, bodyweight, BMI, concomitant drug use, disease severity and time since diagnosis in patients with stable, adequately controlled hypothyroidism.

Methods

In this cross-sectional study we analysed past medical history, anthropometric data and biochemical parameters reflecting thyroid function of patients with chronic hypothyroidism who were adequately treated (TSH levels in normal range) with LT4 for at least 6 months. Potential predictors of LT4 requirement were evaluated using uni- and multivariate linear modelling.

Results

191 individuals were enrolled in this study, who were divided into autoimmune (n = 147) and post-surgery (n = 44) groups. Mean age, time since diagnosis and LT4 dose (1.3 versus 1.1 mcg/kgBW) were significantly lower in the autoimmune group. In the post-surgery group age was the only significant (p = 0.016) predictor of LT4 dose. In the autoimmune group BMI (p = 0.001), time since diagnosis (p = 0.023), as well as their interaction (p = 0.012) turned out to be significant predictors of LT4 requirement.

Conclusions

Our results implicate the necessity of differentiating between etiologies of hypothyroidism when starting or changing thyroxine replacement therapy. Patient in both groups required significantly lower doses of LT4 replacement, than previous reports suggest, to maintain stable euthyroidism. Distinctly different factors predicted hormone requirement in the two study groups.

Thyroid under siege: Unravelling the toxic impact of real-life metal mixture exposures in Wistar rats

This study explored the effect of a toxic metal(oid) mixture (cadmium, lead, arsenic, mercury, chromium, and nickel) on thyroid function in Wistar rats exposed for 28 or 90 days. Dose levels were determined based on prior human-biomonitoring investigation. The experiment included control (male/female rats, 28 and 90 days) and treated groups, reflecting the lower confidence limit of the Benchmark Dose (BMDL) for hormone levels (M1/F1, 28 and 90 days), median concentrations (M2/F2, 28 and 90 days), 95th percentile concentrations (M3/F3, 28 and 90 days) measured in a human study, and reference values for individual metals extracted from the literature (M4/F4, 28 days only). Blood and thyroid gland samples were collected at the experimental termination. Serum TSH, fT3, fT4, T3, and T4 levels were measured, and SPINA-GT and SPINA-GD parameters were calculated. In silico analysis, employing the Comparative Toxicogenomic Database and ToppGene Suite portal, aimed to reveal molecular mechanisms underlying the observed effects. Results showed greater sensitivity in the female rats, with significant effects observed at lower doses. Subacute exposure increased TSH, fT3, and T3 levels in females, while subchronic exposure in males decreased TSH and fT3 levels and increased fT4. Subacute exposure induced changes even at allegedly safe doses, emphasizing potential health risks. Histological abnormalities were observed in all the treated groups. In silico findings suggested that toxic metal exposure contributes to thyroid disorders via oxidative stress, disruption of micronutrients, interference with hormone synthesis, and gene expression dysregulation. These results indicate that seemingly safe doses in single-substance research can adversely affect thyroid structure and function when administered as a mixture. These findings highlight the complex impact of toxic metal exposure on thyroid health, emphasizing that adhering to accepted safety limits for single-substance research fails to account for adverse effects on thyroid structure and function upon exposures to metal mixtures.

Subclinical hypothyroidism in Wales from 2000 to 2021: A descriptive cohort study based on electronic health records

BACKGROUND

Subclinical hypothyroidism (SCH) is a biochemical thyroid disorder characterised by elevated levels of Thyroid Stimulating Hormone (TSH) together with normal levels of thyroid hormones. Evidence on the benefits of treatment is limited, resulting in persistent controversies relating to its clinical management.

AIM

This study describes the demographic and clinical characteristics of patients identified as having subclinical hypothyroidism in Wales between 2000 and 2021, the annual cumulative incidence during this period and the testing and treatment patterns associated with this disorder.

METHODS

We used linked electronic health records from SAIL Databank. Eligible patients were identified using a combination of diagnostic codes and Thyroid Function Test results. Descriptive analyses were then performed.

RESULTS

199,520 individuals (63.8% female) were identified as having SCH, 23.6% (n = 47,104) of whom received levothyroxine for treatment over the study period. The median study follow-up time was 5.75 person-years (IQR 2.65-9.65). Annual cumulative incidence was highest in 2012 at 502 cases per 100,000 people. 92.5% (n = 184,484) of the study population had TSH levels between the upper limit of normal and 10mIU/L on their first test. 61.9% (n = 5,071) of patients identified using Read v2 codes were in the treated group. 41.9% (n = 19,716) of treated patients had a history of a single abnormal test result before their first prescription.

CONCLUSION

In Wales, the number of incident cases of SCH has risen unevenly between 2000 and 2021. Most of the study population had mild SCH on their index test, but more than a third of the identified patients received levothyroxine after a single abnormal test result. Patients with clinically recorded diagnoses were more likely to be treated. Given the expectation of steadily increasing patient numbers, more evidence is required to support the clinical management of subclinical hypothyroidism.

Supplementation with selenium and coenzyme Q10 in an elderly Swedish population low in selenium - positive effects on thyroid hormones, cardiovascular mortality, and quality of life

BACKGROUND

Selenium-dependent deiodinases play a central role in thyroid hormone regulation and metabolism. In many European countries, insufficient selenium intake may consequently lead to adverse effects on thyroid function. In this randomised placebo-controlled double-blind study, we examined the effect of supplementation with selenium and coenzyme Q10 on thyroid hormonal status, cardiovascular (CV) mortality and health-related quality of life (Hr-QoL).

METHODS

Free T3, free T4, reverse T3, and TSH were determined in 414 individuals at baseline, and the effect of selenium yeast (200 µg/day) and coenzyme Q10 (200 mg/day) supplementation on hormone concentrations, CV mortality and Hr-QoL was evaluated after 48 months using Short Form 36 (SF-36). Pre-intervention plasma selenium was low, mean 67 µg/L, corresponding to an estimated intake of 35 µg/day. Changes in concentrations of thyroid hormones following the intervention were assessed using T-tests, repeated measures of variance, and ANCOVA analyses.

RESULTS

In the total population, the group with the lowest selenium concentration at baseline presented with significantly higher levels of TSH and lower levels of fT3 as compared to subjects with the highest selenium concentration. Supplementation with selenium and coenzyme Q10 for 4 years significantly increased fT3 and rT3, decreased fT4, and diminished the increase in TSH levels compared with placebo treatment (p = 0.03, all). In the placebo group, TSH and fT4 values above the median were associated with an increase in 10-year CV mortality, as compared with the mortality rate among those with TSH and fT4 below the median (p < 0.04, both), with no difference in mortality rate according to TSH and fT4 levels in the active intervention group. Similarly, TSH > median and fT3 < median were associated with a decline in mental Hr-QoL measures vs. TSH < and fT3 > median in the placebo group during 4 years of follow-up, but this was wiped out in the active group.

CONCLUSIONS

Supplementation with selenium and coenzyme Q10 had a beneficial effect on thyroid hormones with respect to CV mortality and Hr-QoL outcomes. The initial deficient selenium status was associated with an impaired thyroid function and the changes in thyroid hormone levels can be explained by increased activity of deiodinases. We conclude that a substantial part of the elderly study population might suffer from suboptimal thyroidal function with adverse clinical implications due to selenium deficiency.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov and has the identifier NCT01443780. Since it was not mandatory to register at the time the study began, the study has been registered retrospectively.

Impact of metformin on hypothalamic-pituitary-thyroid axis activity in women with autoimmune and non-autoimmune subclinical hypothyroidism: a pilot study

BACKGROUND

Metformin reduces plasma TSH levels if these levels are elevated. No study has investigated whether the hormonal effects of metformin are impacted by thyroid autoimmunity. The current study aimed to compare the effect of metformin on hypothalamic-pituitary-thyroid axis activity between subjects with mild hypothyroidism of different origins.

METHODS

The study population consisted of two groups of women with prediabetes and mildly elevated TSH levels, matched by age, insulin sensitivity, TSH, and thyroid hormone levels. Group A included 26 women with autoimmune thyroiditis, while group B enrolled 26 individuals with hypothyroidism of non-autoimmune origin. Both groups were treated with metformin (2.55-3 g daily). Circulating levels of TSH, total and free thyroid hormones, glucose, insulin, prolactin, high-sensitivity C-reactive protein (hsCRP) and 25-hydroxyvitamin D, concentrations of thyroid antibodies, and structure parameters of thyroid homeostasis were assessed at baseline and 6 months later.

RESULTS

All patients completed the study. At baseline, both groups differed in concentrations of thyroid peroxidase antibodies, thyroglobulin antibodies, hsCRP, and 25-hydroxyvitamin D. The drug reduced TSH and Jostel's index, with no difference between the study groups. The improvement in insulin sensitivity, observed in both groups, was more pronounced in group B than in group A. In women with autoimmune hypothyroidism, the drug increased SPINA-GT and decreased hsCRP levels. The remaining markers did not change throughout the study.

CONCLUSIONS

The obtained results suggest that, despite differences in thyroid output, the impact of metformin on TSH levels is similar in hypothyroid women with and without thyroid autoimmunity.

Appropriateness of Levothyroxine Prescription: A Multicenter Retrospective Study

CONTEXT

Levothyroxine is one of the most prescribed medications in the United States.

OBJECTIVE

This study explores the appropriateness of levothyroxine prescriptions.

METHODS

A retrospective multicenter study was conducted on adult patients who were prescribed levothyroxine for the first time between 2017 and 2020 at three academic centers in the United States. We classified each case of levothyroxine initiation into one of three mutually exclusive categories: appropriate (clinically supported), indeterminate (clinically unclear), or nonevidence based (NEB, not clinically supported).

RESULTS

A total of 977 participants were included. The mean age was 55 years (SD 19), there was female (69%) and White race predominance (84%), and 44% had possible hypothyroid symptoms. Nearly half of the levothyroxine prescriptions were considered NEB (528, 54%), followed by appropriate (307, 31%) and indeterminate (118, 12%). The most common reason for NEB prescription was an index thyrotropin (TSH) value of less than 10 mIU/L without previous TSH or thyroxine values (131/528, 25%), for appropriate prescription, was overt hypothyroidism (163/307, 53%), and for an indeterminate prescription was a nonconfirmed subclinical hypothyroidism with TSH greater than or equal to 10 mIU/L (no confirmatory testing) (51/118, 43%). In multivariable analysis, being female (odds ratio [OR]: 1.3; 95% CI, 1.0-1.7) and prescription by a primary care provider (OR: 1.5; 95% CI, 1.2-2.0) were associated with NEB prescriptions.

CONCLUSION

There is a considerable proportion of NEB levothyroxine prescriptions. These results call for additional research to replicate these findings and to explore the perspective of those prescribing and receiving levothyroxine.

Hypothyroidism Predicts Fistula Development Following Salvage Oropharyngectomy

IMPORTANCE

Previous work demonstrated postoperative hypothyroidism adversely affects wound healing in salvage laryngectomy. Currently, no studies have evaluated the association between wound healing and hypothyroidism in patients undergoing salvage oropharyngectomy.

OBJECTIVE

The primary objective was studying hypothyroidism and other factors associated with oropharyngocutaneous fistula development and fistula requiring reoperation within 30 days after salvage oropharyngectomy.

DESIGN

Retrospective cohort study.

SETTING

Tertiary academic center.

PARTICIPANTS

All patients who underwent salvage oropharyngectomy for recurrent or second primary oropharyngeal squamous cell carcinoma between 2001 and 2017 after radiation or chemoradiation. Patients with no preoperative thyroid-stimulating hormone (TSH) values were excluded.

EXPOSURES

Salvage oropharyngectomy for recurrent or second primary oropharyngeal squamous cell carcinoma.

MAIN OUTCOMES MEASURES

The principle explanatory variable was postoperative hypothyroidism, defined as TSH greater than 5.5 mIU/L. Univariate, bivariate, and binary logistical regression multivariate analysis was performed.

RESULTS

Fifty-three patients met inclusion criteria, 37.7% of patients developed hypothyroidism, 18.9% developed a fistula, and 9.4% required an operation to manage the fistula. Postoperative fistula rate was 35% among hypothyroid patients, which was significantly greater than among euthyroid patients (9.1%; P = .03). A fistula requiring reoperation occurred in 20% of hypothyroid patients compared with that of euthyroid patients (3%; P = .061). In a multivariate analysis, postoperative hypothyroid patients were at a 9.5-fold increased risk of developing a fistula [95% confidence interval (CI) 1.6-57.0, P = .013]. Additionally, postoperative hypothyroid patients were at 13.6-fold increased risk for development of a fistula requiring reoperation (95% CI 1.2-160.5, P = .038).

CONCLUSIONS AND RELEVANCE

Postoperative hypothyroidism in patients who underwent salvage oropharyngectomy can predict fistula development and fistula requiring operative management. This study supports the treatment of hypothyroidism after surgery to reduce wound complications.

Analysis of Subclinical Thyroid Dysfunction and Metabolic Abnormality in 28568 Healthy People

We analyzed the detection rates of metabolic syndrome (MetS) and subclinical thyroid dysfunction, including subclinical hyperthyroidism (SCHyper) and subclinical hypothyroidism (SCH), in healthy people, as well as their relationship. Clinical data were collected from 28,568 healthy individuals who underwent physical examinations. The detection rates of SCHyper, SCH, and MetS, as well as in different genders and ages, were analyzed. The detection rate of SCHyper and SCH in females was significantly higher than that in males (P < 0.001), but that of MetS in males was significantly higher than that in females (P < 0.001). In each age group, the detection rate of SCH in females was higher than that in males (P < 0.001). The detection rate of SCH was significantly different in different age groups (P < 0.001). The detection rates of hyperlipidemia (P < 0.001), obesity (P = 0.004), hypertension (P = 0.009), and hyperglycemia (P < 0.001) in the female SCH group were significantly higher than those in the normal group. The detection rates of hyperlipidemia (P = 0.006), obesity (P = 0.04), and hypertension (P = 0.04) in the male SCH group were higher than those in the normal group. The males with SCHyper were more prone to hyperlipidemia (P = 0.02) and obesity (P = 0.03). In addition, the female SCHyper group was not significantly different from the normal group (P > 0.05). Conclusively, the detection rate of SCHyper and SCH in females is higher than that in males, which increases with age. Attention should be paid to subclinical thyroid dysfunction in elderly people, especially females. Early individualized screening and early intervention should be carried out for people with abnormal metabolism.

The effect of low dose thyroid replacement therapy in patients with episodic migraine and subclinical hypothyroidism: A randomised placebo-controlled trial

INTRODUCTION

Migraine is a common headache syndrome associated with various other comorbidities. Thyroid replacement in migraine patients with hypothyroidism improves headaches; however, thyroid hormone replacement in subclinical hypothyroidism is debatable, and its efficacy is not known.

OBJECTIVE AND METHODOLOGY

This prospective, single-centre, quasi-randomised interventional study was conducted on patients visiting the General Medicine and Neurology outpatient department at a tertiary centre to look at the efficacy of thyroxine in subclinical hypothyroidism.

RESULTS

We assessed 87 patients for analysis; no patients were lost to follow-up. There was a decrease in all parameters evaluated (headache frequency, severity, duration, MIDAS score, MIDAS grade) at three months of follow-up in the treatment group compared to placebo group. There was a significant decrease in headache frequency and severity in the levothyroxine group compared to the placebo group at three months of follow-up. Also, the follow-up MIDAS score (mean ± SD: 6.30 ± 2.455 scores vs. 8.45 ± 5.757 scores) was significantly decreased by treatment at three months follow-up.

CONCLUSION

Treatment of subclinical hypothyroidism effectively reduces migraine headaches, and it is logical to check thyroid function status in patients presenting with migraine headaches. However, a larger randomised controlled trial is required to prove the efficacy of levothyroxine in migraine with subclinical hypothyroidism.

[Hypothyroidism and aging: the search for protective factors]

Searching for aging key points is one of the main problems in geriatrics. More and more research in recent years has been devoted to the study of geroprotective mechanisms, the impact of various conditions and diseases on aging in general. Of particular importance is the determination of age-related involutive processes in the human body, whether they are part of normal aging or a condition that needs to be corrected to improve the functioning of organs and systems. An important mechanism of aging starts is a change in hormonal activity of endocrine glands, in particular in hormonal activity of thyroid. Frequency of hypothyroidism in advanced age explains relevance of the chosen topic. The aim of the review was to find out the role hypothyroidism in aging. The main task was to define, whether thyroid hormones decrease in older age was a protective factor or pathological process. A review of the literature over the past 10 years on subclinical treatment was carried out and we identified the most pressing issues associated with hypothyroidism and aging. We studied data on the relationship between hypothyroidism and major geriatric syndromes, with special attention paid to cognitive diseases and emotional disorders.

Preliminary observation of thyroid function changes in subclinical thyroid diseases

BACKGROUND

It is estimated that 1.95% and 5.55% of adults in China suffer from subclinical thyroid diseases, which is difficult to diagnose and treat.

OBJECTIVE

This study aimed to explore the development and prognosis of subclinical thyroid diseases to provide a reference from our single center experience.

METHODS

A total of 240 cases from April 2019 to August 2021 in the laboratory information system database of Huanghua Development Boai Hospital were retrospectively analyzed. Binary logistic regression was conducted to analyze odds ratio (OR) of subclinical thyroid disease types returning to a normal state.

RESULTS

Among the patients hypothyroidism Ia and hyperthyroidism Ia were the most common type with conversion to the normal state (P< 0.001). TSH level of patients with conversion to a normal state was significantly lower than that of those who developed to abnormal disease (P= 0.015). The OR values of hyperthyroidism Ia and hypothyroidism Ia that returned to a normal state compared with hyperthyroidism Ib were 2.659 (1.159 ∼ 6.096, P= 0.021) and 3.138 (1.1.278 ∼ 7.709, P= 0.013), respectively. The OR value of hypothyroidism Ib that returned to normal compared with hyperthyroidism Ib was 0.629 (0.131 ∼ 3.010, P= 0.561). Thyroid hormone levels, age, and gender at first diagnosis were not impact factor for prognosis of subclincal thyroid disease (P> 0.05).

CONCLUSION

Cases with grade hypothyroidism Ia and hyperthyroidism Ia are more likely to revert to normal state than other subclinical thyroid diseases. TSH reference range should be explored for diagnosis and treatment.

Evaluating Statin Tolerability in Historically Intolerant Patients After Correcting for Subclinical Hypothyroidism and Vitamin D Insufficiency

INTRODUCTION

Atherosclerotic cardiovascular disease (ASCVD) is the major cause of morbidity and mortality worldwide. Statins provide primary and secondary ASCVD prevention. Intolerance due to statin-associated myalgias reduces long-term adherence, thus muting potential benefits.

AIM

Our analysis sought to determine whether transition from a lipophilic statin to a water-soluble statin, or correction of subclinical hypothyroidism and/or vitamin D insufficiency/deficiency (metabolic abnormalities), improved statin tolerance.

METHODS

We performed a retrospective analysis of the data from patients referred to our lipid clinic because of statin intolerance. Patients intolerant to a lipophilic statin were switched to a water-soluble statin. Patients having vitamin D insufficiency/deficiency or subclinical hypothyroidism were re-challenged with a water-soluble statin (or lipophilic statin with minimal systemic exposure) after correction of the metabolic abnormality.

RESULTS

169 patients were statin intolerant. 86% (n = 145) were white and 48% (n = 81) were male. 82 of these patients had one or both metabolic abnormalities. The remaining patients (n = 87) had no metabolic abnormality, however, were unable to tolerate a lipophilic statin. 72% (n = 73) of eligible patients (n = 101), defined as those with a corrected metabolic abnormality or without a metabolic abnormality on a lipophilic statin, were able to tolerate a water-soluble statin or lipophilic statin with minimal systemic exposure. In addition, 75% (n = 127) of this total cohort met their LDL-C goal.

CONCLUSIONS

Our findings suggest that either correction of subclinical hypothyroidism and/or vitamin D insufficiency/deficiency or transition from a lipophilic statin to water-soluble statin (or lipophilic statin with minimal systemic exposure) improves statin tolerance.

Thyroid Diseases and Thyroid Asymptomatic Dysfunction in People Living With HIV

Thyroid diseases (TDs) and thyroid asymptomatic dysfunctions (TADs) are correlated with Human Immunodeficiency virus (HIV) infection and Acquired ImmunoDeficiency Syndrome (AIDS) as well as many endocrine dysfunctions and dysregulation of hormonal axes. To date, available studies on People Living With HIV (PLWH) affected by thyroid diseases and asymptomatic dysfunctions are few and rather controversial. The purpose of the present non-systematic literature review is to recap the current knowledge on the main features of thyroid dysfunctions and disorders in PLWH. Large cohort studies are needed for a better comprehension of the impact, evolution and treatment of thyroid pathologies in the HIV-infected population.

The continuum of care of anticancer treatment-induced hypothyroidism in patients with solid non thyroid tumors: time for an intimate collaboration between oncologists and endocrinologists

INTRODUCTION

Hypothyroidism is a common adverse event of various anticancer treatment modalities, constituting a notable paradigm of the integration of the endocrine perspective into precision oncology.

AREAS COVERED

The present narrative review provides a comprehensive and updated overview of anticancer treatment-induced hypothyroidism in patients with solid non-thyroid tumors. A study search was conducted on the following electronic databases: PubMed, Google Scholar, Scopus.com, ClinicalTrials.gov, and European Union Clinical Trials Register from 2011 until August 2021.

EXPERT OPINION

In patients with solid non-thyroid tumors, hypothyroidism is a common adverse event of radiotherapy, high dose interleukin 2 (HD IL-2), interferon alpha (IFN-α), bexarotene, immune checkpoint inhibitors (ICPi), and tyrosine kinase inhibitors (TKIs), while chemotherapy may induce hypothyroidism more often than initially considered. The path forward for the management of anticancer treatment-induced hypothyroidism in patients with solid non-thyroid tumors is an integrated approach grounded on 5 pillars: prevention, vigilance, diagnosis, treatment and monitoring. Current challenges concerning anticancer treatment-induced hypothyroidism await counteraction, namely awareness of the growing list of related anticancer treatments, identification of predictive factors, counteraction of diagnostic pitfalls, tuning of thyroid hormone replacement, and elucidation of its prognostic significance. Close collaboration of oncologists with endocrinologists will provide optimal patient care.

The Clinical Relevance of Hypothyroidism in Patients with Solid Non-Thyroid Cancer: A Tantalizing Conundrum

Hypothyroidism in patients with solid non-thyroid cancer is a tantalizing entity, integrating an intriguing thyroid hormones (THs)-cancer association with the complexity of hypothyroidism itself. The present narrative review provides a comprehensive overview of the clinical relevance of hypothyroidism in solid non-thyroid cancer. Hypothyroidism in patients with solid non-thyroid cancer is reminiscent of hypothyroidism in the general population, yet also poses distinct challenges due to the dual role of THs in cancer: promoting versus inhibitory. Close collaboration between oncologists and endocrinologists will enable the prompt and personalized diagnosis and treatment of hypothyroidism in patients with solid non-thyroid cancer. Clinical data indicate that hypothyroidism is a predictor of a decreased or increased risk of solid non-thyroid cancer and is a prognostic factor of favorable or unfavorable prognosis in solid non-thyroid cancer. However, the impact of hypothyroidism with respect to the risk and/or prognosis of solid non-thyroid cancer is not a consistent finding. To harness hypothyroidism, or THs replacement, as a personalized anticancer strategy for solid non-thyroid cancer, four prerequisites need to be fulfilled, namely: (i) deciphering the dual THs actions in cancer; (ii) identifying interventions in THs status and developing agents that block tumor-promoting THs actions and/or mimic anticancer THs actions; (iii) appropriate patient selection; and (iv) counteracting current methodological limitations.

Effect of Levothyroxine on Older Patients With Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis

BACKGROUND

Subclinical hypothyroidism (SCH) is usually treated with levothyroxine, but there is controversy as to whether SCH should be treated, especially for older patients. The aim of the systematic review and meta-analysis was to evaluate whether levothyroxine has a beneficial or harmful effect on older patients with SCH.

METHODS

Databases including PubMed, Embase, Cochrane Library, Web of Science, Wanfang, Weipu and China National Knowledge Infrastructure were searched from inception until December 21, 2021. Subjects must be diagnosed with SCH, and older than or equal to 60 years of age. Interventions should be thyroid hormone therapy (e.g. levothyroxine). The literature was independently screened by 2 researchers. Statistical analysis was performed using RevMan5.3 software.

RESULTS

A total of 13 articles were included. Meta-analysis results showed that in older SCH patients, levothyroxine can significantly reduce cholesterol (TC) (p < 0.00001), triglyceride (TG) (p < 0.00001), low-density lipoprotein cholesterol (LDL-C) (p = 0.03) and apolipoprotein B (ApoB) (p < 0.00001). In addition, levothyroxine had no significant effect on bone mineral density, fatigue, hypothyroidism symptoms, quality of life, BMI, cognitive function, depression, blood pressure, etc. in older SCH patients, and also did not significantly increase the incidence of adverse events.

CONCLUSIONS

Among older SCH patients, levothyroxine treatment may reduce TC, TG, LDL-C, and ApoB.

High-dose radiation exposure and hypothyroidism: aetiology, prevention and replacement therapy

Without any doubt, high dose radiation exposure can induce hypothyroidism. However, there are open questions related to the mechanisms of its induction, corresponding dose thresholds and possible countermeasures. Therefore, this review addresses the aetiology, prevention and therapy of radiation induced hypothyroidism. External beam radiotherapy with several 10 Gy to the head and neck region and radioiodine therapy with several 100 Gy thyroid absorbed dose can destroy the thyroid gland and can induce autoantibodies against thyroid tissue. According to recent literature, clinical hypothyroidism is observed at threshold doses of ∼10 Gy after external beam radiotherapy and of ∼50 Gy after radioiodine therapy, children being more sensitive than adults. In children and adolescents exposed by the Chernobyl accident with mean thyroid absorbed doses of 500-800 mGy, subclinical hypothyroidism has been detected in 3%-6% of the cases with significant correlation to thyroid absorbed doses above 2.5 Gy. In case of nuclear emergencies, iodine thyroid blocking (ITB) is the method of choice to keep thyroid absorbed doses low. Large doses of stable iodine affect two different steps of internalization of radioiodine (transport and organification); perchlorate affecting the transport only may be an alternative to iodine. Administered before radioiodine incorporation, the effect of 100 mg iodide or more is still about 90% after 1 days, 80% after 2 days, and 50% or less after 3 days. If administered (too) late after exposure to radioiodine, the theoretically expected protective effect of ITB is about 50% after 6 h, 25% after 12 h, and about 6% after 24 h. In case of repeated or continuous exposure, repeated administration of 50 mg of iodide daily is indicated. If radiation-induced hypothyroidism cannot be avoided, thyroid hormone replacement therapy with individualized dosing and regular monitoring in order to maintain thyroid-stimulating hormone levels within the normal range ensures normal life expectancy.

Subclinical thyroid dysfunction and major depressive disorder

PURPOSE

This review attempts to investigate the link between subclinical thyroid dysfunction (SCH) and major depressive disorder (MDD). It has been speculated that SCH may be related to MDD through an autoimmune mechanism.

METHODS

A comprehensive literature search was conducted in the PubMed database for relevant research and review articles.

RESULTS

There appears to be an association between an autoimmune mechanism, possibly involving the thyroid gland, and depressive disorders, but the available evidence is so far inconclusive.

CONCLUSION

Lifetime prevalence of depression is significantly higher in patients with SCH, a finding reflecting a possible effect of SCH in lowering the threshold for the emergence of MDD. The relationship between SCH and MDD is, however, not clear, with large and well-designed studies investigating possible links between reference-range thyroid hormone levels and MDD having as yet found no relation between the two.

Subclinical Hypothyroidism: Prevalence, Health Impact, and Treatment Landscape

Subclinical hypothyroidism (sHypo) is defined as normal serum free thyroid hormone levels coexisting with elevated serum thyroid-stimulating hormone (TSH) levels. sHypo is a common condition observed in clinical practice with several unique features. Its diagnosis should be based on an understanding of geographic and demographic differences in biochemical criteria versus a global reference range for TSH that is based on the 95% confidence interval of a healthy population. During the differential diagnosis, it is important to remember that a considerable proportion of sHypo cases are transient and reversible in nature; the focus is better placed on persistent or progressive forms, which mainly result from chronic autoimmune thyroiditis. Despite significant evidence documenting the health impacts of sHypo, the effects of levothyroxine treatment (LT4-Tx) in patients with sHypo remains controversial, especially in patients with grade 1 sHypo and older adults. Existing evidence suggests that it is reasonable to refrain from immediate LT4-Tx in most patients if they are closely monitored, except in women who are pregnant or in progressive cases. Future research is needed to further characterize the risks and benefits of LT4-Tx in different patient cohorts.

Subclinical Hypothyroidism in Geriatric Population and Its Association With Heart Failure

Heart failure (HF) is one of the most common causes of hospitalization in the geriatric age group, above 65 years. It is associated with high morbidity, mortality, and bad prognosis. Subclinical hypothyroidism (SCH) is a common condition present in this age group that significantly affects the cardiovascular system. Thus, this review attempts to elaborate on the association between subclinical hypothyroidism and heart failure in terms of their prevalence, pathogenesis, prognosis, and possible management in a geriatric age group. Among the various published literature on this topic on PubMed, PubMed Central, and Google Scholar, 36 relevant studies were selected to correlate this association. We found that both SCH and HF can be present concurrently in this age group. Especially in the geriatric population with thyroid-stimulating hormone (TSH) higher than ten mIu/L, there is an increased incidence of heart failure and a worse prognosis with preexisting heart failure. However, randomized controlled trials will be needed to explore further whether treatment is warranted or not in this age group.