Clinical practice guidelines for the management of hypothyroidism

Bone development in fetuses with intrauterine growth restriction caused by maternal endocrine-metabolic dysfunctions

Intrauterine growth restriction (IUGR) affects a large proportion of infants, particularly in underdeveloped countries. Among the main causes of IUGR, maternal endocrine-metabolic dysfunction is highlighted, either due to its high incidence or due to the severity of the immediate and mediated changes that these dysfunctions cause in the fetus and the mother. Although the effects of endocrine and metabolic disorders have been widely researched, there are still no reviews that bring together and summarize the effects of these conditions on bone development in cases of IUGR. Therefore, the present literature review was conducted with the aim of discussing bone changes observed in fetuses with IUGR caused by maternal endocrine-metabolic dysfunction. The main endocrine dysfunctions that occur with IUGR include maternal hyperthyroidism, hypothyroidism, and hypoparathyroidism. Diabetes mellitus, hypertensive disorders, and obesity are the most important maternal metabolic dysfunctions that compromise fetal growth. The bone changes reported in the fetus are, for the most part, due to damage to cell proliferation and differentiation, as well as failures in the synthesis and mineralization of the extracellular matrix, which results in shortening and fragility of the bones. Some maternal dysfunctions, such as hyperthyroidism, have been widely studied, whereas conditions such as hypoparathyroidism and gestational hypertensive disorders require further study regarding the mechanisms underlying the development of bone changes. Similarly, there is a gap in the literature regarding changes related to intramembranous ossification, as most published articles only describe changes in endochondral bone formation associated with IUGR. Furthermore, there is a need for more research aimed at elucidating the late postnatal changes that occur in the skeletons of individuals affected by IUGR and their possible relationships with adult diseases, such as osteoarthritis and osteoporosis.

Management of Subclinical Hypothyroidism: A Focus on Proven Health Effects in the 2023 Korean Thyroid Association Guidelines

Subclinical hypothyroidism (SCH) is characterized by elevated thyroid-stimulating hormone (TSH) and normal free thyroxine levels. The Korean Thyroid Association recently issued a guideline for managing SCH, which emphasizes Korean-specific TSH diagnostic criteria and highlights the health benefits of levothyroxine (LT4) treatment. A serum TSH level of 6.8 mIU/L is presented as the reference value for diagnosing SCH. SCH can be classified as mild (TSH 6.8 to 10.0 mIU/L) or severe (TSH >10.0 mIU/L), and patients can be categorized as adults (age <70 years) or elderly (age ≥70 years), depending on the health effects of LT4 treatment. An initial increase in serum TSH levels should be reassessed with a subsequent measurement, including a thyroid peroxidase antibody test, preferably 2 to 3 months after the initial assessment. While LT4 treatment is not generally recommended for mild SCH in adults, it is necessary for severe SCH in patients with underlying coronary artery disease or heart failure and it may be considered for those with concurrent dyslipidemia. Conversely, LT4 treatment is generally not recommended for elderly patients, regardless of SCH severity. For those SCH patients who are prescribed LT4 treatment, the dosage should be personalized, and serum TSH levels should be regularly monitored to maintain the optimal LT4 regimen.

Technical Validation of Ultrasound Assessment of the Thyroid Gland in Cattle

Little is known about thyroid diseases in ruminants, probably due to the lack of diagnosis techniques developed in this species. However, thyroid ultrasound (TU) is widely used in human and in companion animal's medicine. It is a cheap and non-invasive examination, which allows for the identification of thyroid structures or diffuse diseases. The aim of this study was to evaluate the accuracy of TU in five calves and five cows through inter- and intra-observer repeatability. The size of the thyroid gland was measured from three views: left sagittal, right sagittal and transverse; nine measurements per view. The intra-observer coefficient was calculated for each observer. For the inter-observer, the first observer was a board-certified imagist (European College of Veterinary Diagnostic Imaging diplomate), the second was a board-certified specialist in bovine and herd management (European College of Bovine Health Managementdiplomate) and the third was an in-trained veterinarian for the TU. They each scanned the thyroid gland successively, following the same method. The intra-observer variabilities for observers 1, 2 and 3 were 8.22%, 5.53%, 5.38%, and 7.18%, 8.65% and 6.36%, respectively, for calves and cows. The inter-observer variability for calves was 10.4% and for cows, 11.8%. This study confirms the feasibility of repeatable intra- and inter-observer TU-estimated measurements in cattle.

Thyroid disorders and their role in the pathogenesis of glaucoma

The literature analysis confirms the interrelationship of thyroid gland pathology and glaucoma. Patients with diffusetoxic goiter (DTG) and endemic goiter have an especially high risk of developing glaucoma, while those with autoimmune thyroiditis face a moderate risk. The prevalence of primary open angle glaucoma (POAG) in patients over 40 with endocrine ophthalmopathy is reliably associated with the male gender and the duration of the disease longer than 60 months. An increased risk of POAG is noted in men with hypothyroidism averagely aged 69. In most cases, ophthalmic hypertension that accompanies endocrine pathology does not need any topical hypotensive treatment. The main pathogenetically validated therapy of thyroid disorders results in a reduction of IOP level and an improvement of fluid outflow from the eye.

Approach to adult patients with primary hypothyroidism in some special situations: a position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM)

Primary hypothyroidism is a common disorder in clinical practice. The management of most cases of hypothyroidism is usually straightforward, but the best approach in some special situations may raise questions among physicians. This position statement was prepared by experts from the Brazilian Society of Endocrinology and Metabolism to guide the management of three special situations, namely, hypothyroidism in the elderly, subclinical hypothyroidism in patients with heart disease, and difficult-to-control hypothyroidism. The authors prepared the present statement after conducting a search on the databases MEDLINE/PubMed, LILACS, and SciELO and selecting articles with the best evidence quality addressing the selected situations. The statement presents information about the current approach to patients in these special situations.

Indications for ordering thyroid-stimulating hormone in noncritically ill adult inpatients-A Delphi consensus recommendation

BACKGROUND

Thyroid-stimulating hormone (TSH) is ordered commonly among inpatients, but the possibility of nonthyroidal illness syndrome challenges interpretation.

OBJECTIVE

Our objective was to obtain Canadian consensus on appropriate indications for ordering TSH in the first 48 h following presentation of a noncritically ill internal medicine patient.

DESIGN, SETTING AND PARTICIPANTS

Canadian endocrinologists with inpatient expertise were invited via snowball sampling to an online 3-round Delphi study. Main Outcome and Measures using a 6-point Likert scale, they rated 58 indications on appropriateness for measuring TSH in medical inpatients. These indications included clinical presentations, signs, and symptoms. Items that reached consensus and agreement (≥80% of participants selecting a rating of 5 or 6 on the Likert scale) were tabulated and dropped after each round. Qualitative analysis of comments identified additional contextual considerations as themes.

RESULTS

There were 45 participants (academic setting: 84%) representing 8 provinces (Ontario: 64%). Rounds 2 and 3 were completed by 42 and 33 participants, respectively. Nine indications reached consensus and agreement: presumed myxedema coma, presumed thyroid storm, atrial fibrillation/flutter, euvolemic hyponatremia, proptosis, adrenal insufficiency, hypothermia, thyroid medication noncompliance, and goiter. There was also agreement that two contextual considerations identified in thematic analysis, including a recent abnormal outpatient TSH, and the presence of other findings of thyroid dysfunction, would significantly change some mid-range responses.

CONCLUSIONS

Canadian experts agreed upon nine specific indications for ordering an inpatient TSH, with others requiring consideration of previous TSH measurement and clinical context.

Thyroid Dysfunction: An Alternate Plausibility in Perimenopausal Women!

Introduction

Perimenopause phase of a woman's life is featured by decline in the ovarian activity, predisposing her to several health consequences. The signs and symptoms of thyroid disorders simulate those of menopausal features which may go unnoticed and can cause untoward complications in these women.

Aims and Objective

The primary objective is to screen women of perimenopausal age for thyroid disorders. The secondary objective is to examine the variations in thyroid hormone levels in these women with advancing age.

Materials and Methods

One hundred and forty-eight apparently healthy women between the age group of 46 and 55 years were study subjects. They were divided into, Group I which constituted women between 46 and 50 years and Group II consisted of women between 51 and 55 years. Thyroid profile comprising serum thyroid-stimulating hormone (TSH), serum total triiodothyronine (T3), and serum total thyroxine (T4) were estimated for all the women recruited in the study.

Results

Subclinical hypothyroidism (SCH) and overt hypothyroidism (OH) were detected in 22 and 8 women who constituted 14.9% and 5.4%, respectively, of the total women populace. In Group I, it was noted that 17.1% and 1.8% of women were suffering from SCH and OH, respectively. In Group II, while 8.1% of the women had SCH, 16.2% of women had progressed to OH. TSH levels were significantly higher (P = 0.002) in women of Group II than in Group I, suggesting increase in TSH levels with advancing age.

Conclusion

Screening of perimenopausal women for thyroid disorders will assure timely detection and proper management which will aid in reducing the morbidity and associated complications.

Oxidative stress in Hashimoto's thyroiditis: possible adjuvant therapies to attenuate deleterious effects

A number of studies have shown that oxidative stress is related to the pathogenesis of several immunological diseases, such as Hashimoto's thyroiditis (HT), although there is no plausible mechanism to explain it. Thus, we aimed at hypothesizing and providing some possible mechanisms linking oxidative stress to autoimmunity aspects and its implications for HT, as well as adjuvant therapeutic proposals to mitigate the deleterious effects. Our hypothesis is that deficient eating habits, autoimmune regulator gene predisposing gene, dysbiosis and molecular mimicry, unfolded proteins and stress in the endoplasmic reticulum, and thymus involution appear to be the main potential factors leading to HT oxidative stress. Likewise, we show that the use of minerals selenium and zinc, vitamins D and C, as well as probiotics, can be interesting adjuvant therapies for the control of oxidative damage and poor prognosis of HT. Further clinical trials are needed to understand the real beneficial and side effects of these supplements.

Effect of Levothyroxine Supplementation on the Cardiac Morphology and Function in Patients With Subclinical Hypothyroidism: A Systematic Review and Meta-analysis

CONTEXT

The impact of abnormal thyroid hormone levels on the cardiovascular system has been explored for decades. Recent emerging evidence suggests that subclinical thyroid dysfunction, especially subclinical hypothyroidism (SCH), significantly affects cardiac indices.

OBJECTIVE

We aimed to determine whether levothyroxine (LT4), commonly used to treat hypothyroidism, affects cardiovascular indices in SCH patients.

METHODS

This is a systematic review and meta-analysis. We searched online databases for studies analyzing cardiac morphology and functional changes in SCH patients before and after LT4 supplementation. A total of 294 SCH patients participated and finished the follow-up. The standard mean difference and 95% CI were calculated in fixed or random-effects models. The clinical outcomes analyzed in this study included 18 indicators, mainly covering cardiac morphology, myocardial performance (including various indicators of systolic and diastolic function), mitral wave flow, and systemic vascular resistance.

RESULTS

A total of 11 studies met our search criteria. All studies explicitly mentioned that serum thyrotropin levels decreased to normal at follow-up. Our results suggest that the cardiac output (CO), left ventricular ejection fraction (LVEF), and the ratio of peak E velocity/peak A velocity were all significantly increased after LT4 supplementation compared with the baseline level. However, we found no clear evidence of significant morphological changes in the heart.

CONCLUSION

Judging from the obvious changes in the CO, LVEF, and E/A ratio, LT4 supplementation can effectively improve the cardiac systolic and diastolic dysfunction prevalent in SCH patients. This study provides evidence of the recommendation for LT4 supplementation in adult SCH patients.

Hypothyroidism

Hypothyroidism is the common clinical condition of thyroid hormone deficiency and, if left untreated, can lead to serious adverse health effects on multiple organ systems, with the cardiovascular system as the most robustly studied target. Overt primary hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) concentration in combination with free thyroxine (fT₄) concentration below the reference range. Subclinical hypothyroidism, commonly considered an early sign of thyroid failure, is defined by elevated TSH concentrations but fT₄ concentrations within the reference range. Hypothyroidism is classified as primary, central or peripheral based on pathology in the thyroid, the pituitary or hypothalamus, or peripheral tissue, respectively. Acquired primary hypothyroidism is the most prevalent form and can be caused by severe iodine deficiency but is more frequently caused by chronic autoimmune thyroiditis in iodine-replete areas. The onset of hypothyroidism is insidious in most cases and symptoms may present relatively late in the disease process. There is a large variation in clinical presentation and the presence of hypothyroid symptoms, especially in pregnancy and in children. Levothyroxine (LT4) is the mainstay of treatment and is one of the most commonly prescribed drugs worldwide. After normalization of TSH and fT₄ concentrations, a considerable proportion of patients treated with LT4 continue to have persistent complaints, compromising quality of life. Further research is needed regarding the appropriateness of currently applied reference ranges and treatment thresholds, particularly in pregnancy, and the potential benefit of LT4/liothyronine combination therapy for thyroid-related symptom relief, patient satisfaction and long-term adverse effects.

Management of primary hypothyroidism in adults: An analysis of the results of a survey in 546 primary care physicians

OBJECTIVE

To document current practices in the management of adult patients with hypothyroidism in the setting of primary healthcare.

METHODS

We designed a web-based survey to inquire information on real-life practices regarding management of hypothyroidism by primary care physicians in the region of Madrid (Spain).

RESULTS

In total, 546 out of 3897 (14%) physicians (aged 50.9±8.5 yr, 404 females) completed the survey. More than 90% of respondents requested serum thyrotropin measurement in subjects with symptoms of thyroid hypofunction, family history of thyroid disease and history of autoimmune disease. A thyroid ultrasound was requested to evaluate subclinical and overt hypothyroidism by 27.1% and 69.6% of respondents, respectively. Only 22.1% of respondents stated that they do not treat subclinical hypothyroidism with thyrotropin values less than 10mU/l. Most physicians use brand-name formulations of levothyroxine and advise patients on how to take the tablets. To start treatment, the gradual replacement rate was the option chosen by most of the respondents, even in young patients. The thyrotropin target preferred by most respondents was 0.5-5.0mU/l, especially in older patients. In patients with persistent symptoms, 61.4% search for the causes through complementary investigations. A longer professional practice time was not always accompanied by better adherence to guidelines and expert recommendations.

CONCLUSION

Our results reveal a proactive attitude in the diagnosis and of therapy by most of the respondents. However, we observed a tendency to perform unnecessary diagnostic tests and an excessive propensity to treat mild subclinical hypothyroidism.

Subcutaneous transplantation of human thyroid tissue into a pre-vascularized Cell Pouch™ device in a Mus musculus model: Evidence of viability and function for thyroid transplantation

This study aimed to investigate the survival and efficacy indicators of human thyroid tissue transplantation into a retrievable, prevascularized implanted Sernova Corp Cell Pouch™ (CP) device. Thyroid tissue from human donors was transplanted subcutaneously into the pre-implanted CP device or into the subcutaneous (SC) space alone as a control in a nude Mus musculus model. Transplanted M. musculus were monitored for human serum thyroglobulin (TG) levels for 3 months until the transplants were removed for histological assessment. Human thyroid tissue survived and continued to produce TG in transplanted nude M. musculus in the CP, with no adverse events. CP transplants exhibited more persistent and robust production of human TG than tissue placed in the SC space alone from 3 to 13 weeks post transplantation. Fresh thyroid transplants had better survival and function compared to cryopreserved transplants. Thyroid transplant viability correlated with TG levels at 3 months post-transplant (p = 0.03). Immunofluorescence staining of transplants for TG and TPO localized in thyroid follicles. Human thyroid tissue transplanted into the subcutaneously implanted pre-vascularized CP in nude M. musculus survived and continued to produce robust and persistent human TG and warrants further investigation as a treatment for postoperative hypothyroidism.

Case Report: Myxedema Coma Caused by Immunoglobulin A Vasculitis in a Patient With Severe Hypothyroidism

Myxedema coma is a critical disorder with high mortality rates. Disruption of the compensatory mechanism for severe and long-term hypothyroidism by various causes leads to critical conditions, including hypothermia, respiratory failure, circulatory failure, and central nervous system dysfunction. Infectious diseases, stroke, myocardial infarction, sedative drugs, and cold exposure are considered the main triggers for myxedema coma. A 59-year-old Japanese woman presented with bilateral painful purpura on her lower legs. She was diagnosed with coexisting immunoglobulin A (IgA) vasculitis and severe IgA vasculitis with nephritis and was consequently treated with intravenous methylprednisolone (125 mg/day). However, she rapidly developed multiple organ failure due to the exacerbation of severe hypothyroidism, i.e., myxedema. Her condition improved significantly following oral administration of prednisolone along with thyroxine. There was a delayed increase in the serum free triiodothyronine level, while the serum free thyroxine level was quickly restored to normal. Rapid deterioration of the patient’s condition after admission led us to diagnose her as having myxedema coma triggered by IgA vasculitis. Hence, clinicians should be aware of the risks of dynamic exacerbations in patients with hypothyroidism. Furthermore, our study suggested that combination therapy with thyroxine and liothyronine might prove effective for patients with myxedema coma, especially for those who require high-dose glucocorticoid administration.

Subclinical hypothyroidism in older individuals

Subclinical hypothyroidism, which is defined as a thyroid-stimulating hormone concentration higher than the reference range (generally 4·5 mIU/L or higher) with normal free thyroxine concentrations, is frequently found in older individuals. International guidelines differ in recommendations for management of subclinical hypothyroidism in older individuals. We assessed published data during the past decade on the clinical significance and treatment of subclinical hypothyroidism in individuals aged 65 years and older. Meta-analyses, randomised clinical trials, and cohort studies are discussed in this narrative Review. Studies showed no significantly increased incidence in adverse cardiovascular, musculoskeletal, or cognitive outcomes in individuals aged 65 years or older when serum thyroid-stimulating hormone concentration was 4·5-7·0 mIU/L versus a euthyroid group. Moreover, in older individuals with subclinical hypothyroidism, symptoms of hypothyroidism and cardiac and bone parameters did not improve after levothyroxine treatment. These data suggest that treatment with levothyroxine should be considered for individuals aged 65 years or older with subclinical hypothyroidism when thyroid-stimulating hormone concentration is persistently 7 mIU/L or higher and to not initiate treatment with thyroid-stimulating hormone concentrations of less than 7 mIU/L. Levothyroxine doses should be personalised according to age, comorbidities, and life expectancy.

Lipid profile in mild subclinical hypothyroidism: systematic review and meta-analysis

INTRODUCTION

Only severe subclinical hypothyroidism (SSCH) with TSH above 10 mIU/L is considered a risk factor of hyperlipidemia and cardiovascular disease. The results of published papers on mild subclinical hypothyroidism (MSCH) with TSH below10 mIU/L are contradictory. The objective of the study was to conduct a systematic review and meta-analysis on lipid profiles in a population of patients with MSCH (TSH10> mIU/L and normal T3, T4) in comparison with euthyroid subjects.

EVIDENCE ACQUISITION

The electronic databases PubMed, CIANHL, Scopus, and Web of Science were searched systematically between August 20, 2018 and September 15, 2018, without limitation on the date of publication or the language. Titles, abstracts and articles were reviewed to identify papers that evaluated lipid profiles in patients with MSCH compared to euthyroid.

EVIDENCE SYNTHESIS

A systematic review of the studies and a meta-analysis using R software (version 3.6.1) were performed. Thirty-five case control and cohort studies were included in the meta-analysis. Total cholesterol (TC), low density lipoprotein (LDL), and triglycerides (TG) were significantly higher and high-density lipoprotein (HDL) was significantly lower in MSCH patients compared to euthyroid individuals. Mean differences (MD) [95% CI] were 12.75 [6.02, 19.48], 10.95 [6.37, 15.54], 19.27 [10.90, 27.64], and -1.81 [-3.38, -0.23], respectively. No significant difference was observed for very low-density lipoproteins (VLDL), apolipoprotein A1 (apoA1), or apolipoprotein B (apoB). The studies were of fair to good quality.

CONCLUSIONS

MSCH is associated with an increase in major atherogenic lipoproteins and should be viewed as a cardiovascular risk factor.

Choosing Wisely for Thyroid Conditions: Recommendations of the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism

OBJECTIVE

Choosing Wisely (CW) is an initiative that aims to advance the dialogue between physicians and patients about low-value health interventions. Given that thyroid conditions are frequent in clinical practice, we aimed to develop an evidence-based list of thyroid CW recommendations.

METHODS

The Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM) named a Task Force to conduct the initiative. The Task Force work was based on an electronic Delphi approach. The 10 recommendations that received the highest scores by the Task Force were submitted for voting by all SBEM associates. The 5 recommendations that received the highest scores by SBEM associates are presented herein.

RESULTS

The Task Force was composed of 14 thyroidologists from 10 tertiary-care, teaching-based Brazilian institutions. The brainstorming/ideation phase resulted in 69 recommendations. After the removal of duplicates and recommendations that did not adhere to the initiative's scope, 35 remained. Then the Task Force voted to attribute a grade (0 [lowest agreement] to 10 [highest agreement]) for each recommendation. The 10 recommendations that received the highest scores by the Task Force were submitted to all SBEM associates. A total of 683 associates voted electronically, attributing a grade (0 to 10) for each recommendation. The 5 recommendations that received the highest scores by the SBEM associates compose our final list.

CONCLUSION

A set of recommendations to avoid unnecessary medical tests, treatments, or procedures for thyroid conditions are offered with a transparent methodology. This initiative aims to foster productive interactions between physicians and patients, stimulating shared decision-making.

A practical contemporary approach to decision-making on subclinical hypothyroidism

Subclinical hypothyroidism (Shypo) is an increasingly frequent condition in common medical practice. Its diagnosis continues to pose a challenge since a series of non-thyroidal and temporary conditions can elevate serum TSH levels. In addition, the consequences of Shypo are still up for debate. Although detrimental cardiovascular effects have been consistently demonstrated in the young, they are less evident in older adults (65-79 years), and even more so in the oldest old (≥80 years). In the absence of evidence of any benefits of treating Shypo in patients' clinical manifestations and unfavorable outcomes, the most effective decision-making approach should include a thorough investigation of the patient's condition integrating all relevant clinical data, such as TSH levels, age, quality of life, comorbidities, cardiovascular risk, safety, and personal preferences. The decision-making process needs to take into account the risk of levothyroxine overtreatment and the resulting adverse consequences, such as reduction of bone mineral density, heart failure, and atrial fibrillation. Hence, current evidence suggests that individuals with TSH > 10 mU/L, who test positive for TPO Ab or are symptomatic may benefit from levothyroxine treatment. However, a more cautious and conservative approach is required in older (≥65 years of age), and oldest-old (≥80 years) patients, particularly those with frailty, in which the risk of treatment can outweigh potential benefits. The latter may benefit from a wait-and-see approach.

Management of primary hypothyroidism in adults: An analysis of the results of a survey in 546 primary care physicians

OBJECTIVE

To document current practices in the management of adult patients with hypothyroidism in the setting of primary healthcare.

METHODS

We designed a web-based survey to inquire information on real-life practices regarding management of hypothyroidism by primary care physicians in the region of Madrid (Spain).

RESULTS

In total, 546 out of 3897 (14%) physicians (aged 50.9±8.5 yr, 404 females) completed the survey. More than 90% of respondents requested serum thyrotropin measurement in subjects with symptoms of thyroid hypofunction, family history of thyroid disease and history of autoimmune disease. A thyroid ultrasound was requested to evaluate subclinical and overt hypothyroidism by 27.1% and 69.6% of respondents, respectively. Only 22.1% of respondents stated that they do not treat subclinical hypothyroidism with thyrotropin values less than 10mU/l. Most physicians use brand-name formulations of levothyroxine and advise patients on how to take the tablets. To start treatment, the gradual replacement rate was the option chosen by most of the respondents, even in young patients. The thyrotropin target preferred by most respondents was 0.5-5.0mU/l, especially in older patients. In patients with persistent symptoms, 61.4% search for the causes through complementary investigations. A longer professional practice time was not always accompanied by better adherence to guidelines and expert recommendations.

CONCLUSION

Our results reveal a proactive attitude in the diagnosis and of therapy by most of the respondents. However, we observed a tendency to perform unnecessary diagnostic tests and an excessive propensity to treat mild subclinical hypothyroidism.

Thyroid dysfunction in patients older than 75 years: an analysis of inadequacy of treatment and therapeutic control

PURPOSE

Suboptimal control of thyroid dysfunction may carry harmful health consequences, especially in older population. We aimed to estimate the inadequacy of thyroid dysfunction treatment and control in people aged 75 years and over.

METHODS

A cross-sectional analysis of all serum thyrotropin (TSH) determinations carried out by the Biochemistry laboratory of the Hospital Universitario Puerta de Hierro Majadahonda during 2019 was performed. All samples from outpatients over age 75 years were selected. In patients with serum TSH out of the range of reference (0.35-5.0 mU/l), we calculated the proportions of patients with inadequate control and inadequate treatment.

RESULTS

Of a total of 15,255 patients (mean (SD) age, 82.9 ± 6.1 years; 62.1% females), 13,796 had normal serum TSH (82.8 ± 6.1 years; 61.1% females), 398 low TSH (83.3 ± 6.7 years; 75.6% females), and 1061 high TSH (83.0 ± 4.0 years; 69.5% females). Inadequate control of thyroid function was found in 45.2% (95% CI 40.0-51.0) of patients with low TSH and in 6.93% (95% CI 5.40-8.85) of patients with high TSH. Furthermore, 39.7% (95% CI 34.1-45.6) of patients with low TSH and 27.5% (95% CI 24.5-30.6) of patients with high TSH were not adequately treated. Inadequacy of control was higher in women and patients over 82 years with elevated TSH. Inadequacy of therapy was higher in women.

CONCLUSIONS

Inadequacy in both treatment and control of thyroid dysfunction is found in a significant number of aged patients. Clinicians should strive to improve thyroid medication prescription and closely monitor older patients with thyroid dysfunction.

A Clinical Debate: Subclinical Hypothyroidism

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Multinational Survey of Treatment Practices of Clinicians Managing Subclinical Hypothyroidism in Older People in 2019

BACKGROUND

International societies have recommended that levothyroxine should not routinely be prescribed in older individuals for the management of mild subclinical hypothyroidism (SCH). However, it is unknown whether clinicians managing people with SCH are either aware of or adhere to these guidelines.

METHODS

A web-based survey of members of several international thyroid associations and general practitioners in North-East England was conducted. Respondents were presented with a vignette of an 80-year-old gentleman with mild persistent SCH experiencing tiredness. Multivariable logistic regression analyses were performed to evaluate predictors of awareness of guidelines and responses to treatment.

RESULTS

The survey response rate was 21.9% (565/2,583). Only 7.6% of clinicians were unaware of guidelines regarding management of SCH in older people. Twenty percent of clinicians stated that they would treat the older patient with mild SCH, whereas 13% were unsure. Clinicians from North America were more likely to treat the older person with mild SCH than clinicians from elsewhere (OR 2.24 [1.25-3.98]). Likewise, non-endocrinologists were also more likely than endocrinologists to treat the older person with mild SCH (OR 3.26 [1.45-6.47]).

CONCLUSION

The majority of clinicians are aware of guidelines regarding management of SCH in older individuals. However, a considerable proportion of clinicians would still treat an older person with non-specific symptoms and mild SCH. These guidelines need to be disseminated more widely and more research is required to understand barriers to adherence to international recommendations.

Benefits and Harms of a Prevention Program for Iodine Deficiency Disorders: Predictions of the Decision-Analytic EUthyroid Model

Background: Iodine deficiency is one of the most prevalent causes of intellectual disability and can lead to impaired thyroid function and other iodine deficiency disorders (IDDs). Despite progress made on eradicating iodine deficiency in the last decades in Europe, IDDs are still prevalent. Currently, evidence-based information on the benefit/harm balance of IDD prevention in Europe is lacking. We developed a decision-analytic model and conducted a public health decision analysis for the long-term net benefit of a mandatory IDD prevention program for the German population with moderate iodine deficiency, as a case example for a European country. Methods: We developed a decision-analytic Markov model simulating the incidence and consequences of IDDs in the absence or presence of a mandatory IDD prevention program (iodine fortification of salt) in an open population with current demographic characteristics in Germany and with moderate ID. We collected data on the prevalence, incidence, mortality, and quality of life from European studies for all health states of the model. Our primary net-benefit outcome was quality-adjusted life years (QALYs) predicted over a period of 120 years. In addition, we calculated incremental life years and disease events over time. We performed a systematic and comprehensive uncertainty assessment using multiple deterministic one-way sensitivity analyses. Results: In the base-case analysis, the IDD prevention program is more beneficial than no prevention, both in terms of QALYs and life years. Health gains predicted for the open cohort over a time horizon of 120 years for the German population (82.2 million inhabitants) were 33 million QALYs and 5 million life years. Nevertheless, prevention is not beneficial for all individuals since it causes additional hyperthyroidism (2.7 million additional cases). Results for QALY gains were stable in sensitivity analyses. Conclusions: IDD prevention via mandatory iodine fortification of salt increases quality-adjusted life expectancy in a European population with moderate ID, and is therefore beneficial on a population level. However, further ethical aspects should be considered before implementing a mandatory IDD prevention program. Costs for IDD prevention and treatment should be determined to evaluate the cost effectiveness of IDD prevention.

Treatment of subclinical hypothyroidism: assessing when treatment is likely to be beneficial

Introduction: Subclinical hypothyroidism (SCH) is a common condition diagnosed in up to 16% of the population. SCH is diagnosed when serum TSH is high and circulating thyroid hormones are within the reference range. SCH is considered to be a mild form of thyroid failure by some due to the log-linear relationship between TSH and thyroid hormones. Nevertheless, it is unclear whether the treatment of SCH with thyroid hormones is beneficial, and hence, it is not surprising that expert opinions and recommendations from societies differ in their opinions on how best to manage SCH.Areas covered: This article reviews the currently available evidence pertaining to SCH and provides recommendations as to when treatment of SCH should be considered. An electronic search of PubMed from 1970 to 2019 was performed and systematically reviewed studies assessing the effects of treatment in SCH. The main areas that are considered are the effects of treatment on symptoms and quality of life, and important clinical consequences including psychocognitive outcomes and cardiovascular events.Expert opinion: Treatment of SCH with thyroid hormones is debated and the current literature in this area lacks clarity. We provide an evidence-based recommendation for when treatment of SCH with thyroid hormones should be considered.

The economic impact of prevention, monitoring and treatment strategies for iodine deficiency disorders in Germany

OBJECTIVE

More than 30% of the German population suffers from mild to moderate iodine deficiency causing goiter and other iodine deficiency disorders (IDDs). The economic burden of iodine deficiency is still unclear. We aimed to assess costs for prevention, monitoring and treatment of IDDs in Germany.

DESIGN

We performed a comprehensive cost analysis.

METHODS

We assessed direct medical costs and direct non-medical costs for inpatient and outpatient care of IDDs and costs for productivity loss due to the absence of work in 2018. Additionally, we calculated total costs for an IDD prevention program comprising universal salt iodization (USI). We performed threshold analyses projecting how many cases of IDDs or related treatments would need to be avoided for USI to be cost-saving.

RESULTS

Annual average costs per case in the year of diagnosis were € 211 for goiter/thyroid nodules; € 308 for hyperthyroidism; and € 274 for hypothyroidism. Average one-time costs for thyroidectomy were € 4184 and € 3118 for radioiodine therapy. Average costs for one case of spontaneous abortion were € 916. Annual costs of intellectual disability were € 14,202. In the German population, total annual costs for USI would amount to 8 million Euro. To be cost-saving, USI would need to prevent, for example, 37,900 cases of goiter/thyroid nodules.

CONCLUSION

USI potentially saves costs, if a minimum amount of IDDs per year could be avoided. In order to recommend the implementation of USI, a full health-economic evaluation including a comprehensive benefit-harm assessment is needed.

Does oral salbutamol improve fatigue in multiple sclerosis? A pilot placebo-controlled study

BACKGROUND

Because MS-related fatigue could be associated with enhanced proinflammatory cytokine production, drugs with immunomodulatories properties, such as salbutamol, may represent an alternative treatment. We aimed to evaluate the effect of salbutamol on MS-related fatigue.

METHODS

Thirty patients with relapsing-remitting MS who were between 18 and 69 years old, and suffering from fatigue, were evaluated with the Fatigue Severity Scale (FSS) and the Brazilian version of the neurological fatigue index for multiple sclerosis (NFI/MS-BR). They received salbutamol 2 mg twice a day or a placebo in a pilot randomized, double-masked placebo-controlled trial. The primary outcome was the change in the FSS score at the end of 90 days. The secondary outcome was the efficacy, represented by changes in their scores on the NFI/MS-BR subdomains (in the same period) and the Expanded Disability Status Scale (EDSS) at the end of 90 days.

RESULTS

Thirty subjects were allocated to receive either salbutamol (14) or a placebo (16). There was no superiority of salbutamol over the placebo in the FSS outcome at 30 (p ==0.498), 60 (p = 0.854) and 90 (p = 0.240) days. There was no a significant decrease in the proportion of patients with severe or moderate fatigue in the salbutamol group at the end of the follow-up. The scores on the NFI/MS-BR and its subscales did not improve significantly with treatment. No significant difference was observed in the EDSS outcome (p = 0.313). No serious adverse events were found. An increase in heart rate was evident in the salbutamol group only in the first 30 days, but without statistical significance in relation to placebo (p = 0.077).

CONCLUSION

Treatment with salbutamol does not improve fatigue in patients with relapsing-remitting MS.

Do Thyroid Diseases during Pregnancy and Lactation Affect the Nutritional Composition of Human Milk?

OBJECTIVE

 To identify whether the effects of thyroid disease during pregnancy and lactation affect the nutritional composition of human milk.

METHODS

 Systematic review of the scientific literature using the Medical Literature Analysis and Retrieval System Online/MedLine databases to evaluate the association of thyroid diseases during pregnancy and lactation with the nutritional composition of human milk. There was no delimitation by period or by language, and the searches were completed in March 2019. The following descriptors were applied: human milk AND thyroid AND composition, using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol for data search, selection, and extraction. The flowchart proposed for bibliographic search resulted in 12 articles and, of these, four were selected.

RESULTS

 The articles elected for this review were published between 1976 and 2018. Two studies found significant differences in the nutritional composition of mothers' milk with hypothyroidism or overweight compared with the milk of those without hypothyroidism. Studies have shown that the presence of the disease led to changes in the nutritional composition of human milk, especially a higher concentration of human milk fat.

CONCLUSION

 It is extremely important that these women have continuous nutritional follow-up to minimize the impact of these morbidities on the nutritional composition of human milk.

Liothyronine and Desiccated Thyroid Extract in the Treatment of Hypothyroidism

Background: The basis for the treatment of hypothyroidism with levothyroxine (LT4) is that humans activate T4 to triiodothyronine (T3). Thus, while normalizing serum thyrotropin (TSH), LT4 doses should also restore the body's reservoir of T3. However, there is evidence that T3 is not fully restored in LT4-treated patients. Summary: For patients who remain symptomatic on LT4 therapy, clinical guidelines recommend, on a trial basis, therapy with LT4+LT3. Reducing the LT4 dose by 25 mcg/day and adding 2.5-7.5 mcg liothyronine (LT3) once or twice a day is an appropriate starting point. Transient episodes of hypertriiodothyroninemia with these doses of LT4 and LT3 are unlikely to go above the reference range and have not been associated with adverse drug reactions. Trials following almost a 1000 patients for almost 1 year indicate that similar to LT4, therapy with LT4+LT3 can restore euthyroidism while maintaining a normal serum TSH. An observational study of 400 patients with a mean follow-up of ∼9 years did not indicate increased mortality or morbidity risk due to cardiovascular disease, atrial fibrillation, or fractures after adjusting for age when compared with patients taking only LT4. Desiccated thyroid extract (DTE) is a form of combination therapy in which the LT4/LT3 ratio is ∼4:1; the mean daily dose of DTE needed to normalize serum TSH contains ∼11 mcg T3, but some patients may require higher doses. The DTE remains outside formal FDA oversight, and consistency of T4 and T3 contents is monitored by the manufacturers only. Conclusions: Newly diagnosed hypothyroid patients should be treated with LT4. A trial of combination therapy with LT4+LT3 can be considered for those patients who have unambiguously not benefited from LT4.

Congenital hypothyroidism as a risk factor for hearing and parents' knowledge about its impact on hearing

Aim

To evaluate the hearing of children with congenital hypothyroidism (CH) and to analyze the knowledge that parents’ have on the possible auditory impacts of the disease.

Methods

A total of 263 parents/guardians were interviewed about aspects of CH and hearing. Audiological evaluation was performed on 80 participants, divided into two groups: with CH (n= 50) and without CH (n=30). Clinical and laboratory CH data were obtained from medical records, pure tone auditory thresholds and acoustic reflexes were analyzed. The auditory data was compared between groups. Student’s t-test and Chi-square were used for statistical analysis at a significance level of 5% (p ≤0.05).

Results

The majority (78%), of the parents were unaware that CH when not treated early is a potential risk to hearing. There was no correlation between socioeconomic class and level of information about CH and hearing (p>0,05; p=0.026). There was a statistically significant difference between the auditory tone thresholds of the groups and between the levels of intensity necessary for the triggering of the acoustic reflex. The group with CH presented the worst results (p≤0.05) and absence of acoustic reflex in a normal tympanometric condition.

Conclusions

Children with CH are more likely to develop damage to the auditory system involving retrocochlear structures when compared to healthy children, and that the disease may have been a risk factor for functional deficits without deteriorating hearing sensitivity. The possible impacts of CH on hearing, when not treated early, should be more publicized among the parents/guardians of this population.

Hypothyroidism

Hypothyroidism is a common condition in which the thyroid gland provides insufficient amounts of thyroid hormone for the needs of peripheral tissues. The most common cause in adults is chronic lymphocytic thyroiditis (Hashimoto thyroiditis), but there are many other causes. Because most of the clinical features of hypothyroidism are nonspecific, the diagnosis requires laboratory testing. Serum thyroid-stimulating hormone (TSH) measurement is the best diagnostic test; an elevated TSH level almost always signals primary hypothyroidism. Serum free thyroxine levels may be below the reference range (overt hypothyroidism) or within the reference range (subclinical hypothyroidism). All patients with overt hypothyroidism should be treated, but those with subclinical hypothyroidism do not always benefit from treatment, especially elderly patients and those with baseline TSH levels below 10 mU/L. Oral L-thyroxine is the treatment of choice because of its well-demonstrated efficacy, safety, and ease of use. Therapy goals are symptom relief and maintenance of serum TSH levels within the reference range. Myxedema coma is a life-threatening form of decompensated hypothyroidism that must be treated with aggressive L-thyroxine replacement and other supportive measures in the inpatient setting.

Hypothyroidism and isolated hypothyroxinemia in pregnancy, from physiology to the clinic

Many changes occur in the physiology of the maternal thyroid gland to maintain an adequate level of thyroid hormones (THs) at each stage of gestation during normal pregnancy, however, some factors can produce low levels of these hormones, which can alter the onset and progression of pregnancy. Deficiency of THs can be moderate or severe, and classified as overt or clinical hypothyroidism, subclinical hypothyroidism, and isolated hypothyroxinemia. Overt hypothyroidism has been reported in 0.3-1.9% and subclinical hypothyroidism in approximately 1.5-5% of pregnancies. With respect to isolated hypothyroxinemia, the frequency has been reported in approximately 1.3% of pregnant women, however it can be as high as 25.4%. Worldwide, iodine deficiency is the most common cause of hypothyroidism, however, in iodine-sufficient countries like the United States, the most common cause is autoimmune thyroiditis or Hashimoto's thyroiditis. The diagnosis and timely treatment of deficiency of THs (before or during the first weeks of gestation) can significantly reduce some of the related adverse effects, such as recurrent pregnancy loss, preterm delivery, gestational hypertension, and alterations in the offspring. However, so far there is no consensus on the reference levels of thyroid hormones during pregnancy to establish the diagnosis and there is no consensus on universal screening of women during first trimester of pregnancy to identify thyroid dysfunction, to give treatment and to reduce adverse perinatal events, so it is necessary to carry out specific studies for each population that provide information about it.

Association between Frozen Shoulder and Thyroid Diseases: Strengthening the Evidences

Objective  To clarify the association of thyroid disorders and primary frozen shoulder by comparing this group with controls without shoulder disease and with patients with rotator cuff tears.

Methods  We evaluated 166 patients who presented frozen shoulder with treatment in progress or already treated, which were compared with 129 patients with diagnosis of rotator cuff tears and 251 control subjects. All of the participants answered the questionnaire on the following variables: age, gender, body mass index (BMI), occupation, physical activity, presence of thyroid disorders and other comorbidities, smoking and use of alcohol.

Results  When comparing the frozen shoulder group with the control and rotator cuff groups, there is a specific association between the presence of thyroid disorders and frozen shoulder. By calculating relative risk, it is possible to state that an individual with thyropathy has 2.69 more chance of developing frozen shoulder. Also, there was an association with gender, since women with frozen shoulder exceeded significantly the risk.

Conclusions  Thyroid disorders, especially hypothyroidism and the presence of benign thyroid nodules, are risk factors significantly associated with frozen shoulder, rising the chances to 2.69 times of developing frozen shoulder.

This is the first study that uses, in addition to the control group, a second group with rotator cuff tears, so it was shown that there is a specific association of thyroid disorders and frozen shoulder, but not with shoulder disorders in general.

Thyroid Nodules in Severely Obese Patients: Frequency and Risk of Malignancy on Ultrasonography

Background: We aimed to compare the thyroid ultrasonographic findings of severely obese versus nonobese individuals, and the frequency, characteristics, and risk of malignancy in detected nodules.Design: Case-control study including 67 adults with severe obesity (body mass index [BMI] ≥ 35 kg/m²) and 67 nonobese controls (BMI < 30 kg/m²). The participants underwent ultrasound evaluation of the thyroid and cervical subcutaneous tissue. The risk of malignancy in detected nodules was determined using the American Thyroid Association (ATA) 2015 and the Thyroid Imaging Reporting and Data System (TI-RADS) classifications. Fine-needle aspiration biopsy (FNAB) was performed in nodules for which the procedure was recommended according to the ATA-2015 or TI-RADS criteria, and the cytological evaluation followed the Bethesda classification.Results: The mean BMI values in the case and control groups were 47.0 ± 6.1 kg/m² and 22.8 ± 2.7 kg/m², respectively. There were no differences between groups regarding sex, age, total T3, and antiperoxidase (antiTPO) antibody positivity. When compared with controls, severely obese individuals showed a greater frequency of parenchymal hypoechogenicity (p = 0.042), cervical subcutaneous tissue thickness (p < 0.001), overall frequency of thyroid nodules (p = 0.038), and frequency of multiple nodules (p = 0.013). No significant differences were observed in terms of risk of nodular malignancy according to both the ATA-2015 and TI-RADS classifications in severely obese compared with nonobese individuals.Conclusions: Severely obese individuals (versus nonobese controls) presented increased parenchymal hypoechogenicity and frequency of thyroid nodules on ultrasonographic evaluation. However, no significant differences were observed in terms of risk of nodular malignancy between both groups according to the ATA-2015 and TI-RADS criteria. Thus, ultrasonographic thyroid screening of severely obese individuals is not justified.

Levothyroxine for the Treatment of Subclinical Hypothyroidism and Cardiovascular Disease

Subclinical hypothyroidism is a biochemical condition defined by elevated serum thyroid-stimulating hormone levels in the setting of normal levels of the peripheral thyroid hormones, thyroxine and triiodothyronine. Thyroid hormones act on the heart through various mechanisms and subclinical hypothyroidism has been associated with risk factors for cardiovascular disease, such as hypertension and dyslipidemia. In addition, evidence from multiple studies supports an association between subclinical hypothyroidism and cardiovascular disease. However, the use of levothyroxine in subclinical hypothyroidism to reduce cardiovascular disease risk is not clearly beneficial. Treatment with levothyroxine may only provide benefit in certain subgroups, such as patients who are younger or at higher risk of cardiovascular disease. At present, most of the international societal guidelines advise that treatment decisions should be individualized based on patient age, degree of serum thyroid-stimulating hormone (TSH) elevation, symptoms, cardiovascular disease (CVD) risk, and other co-morbidities. Further study in this area is recommended.

Contribuições da vitamina D no tratamento de sintomas depressivos e fatores de risco cardiovascular: protocolo de estudo para um ensaio clínico randomizado, duplo-cego e controlado por placebo

ABSTRATO

FUNDO: A depressão é uma das principais causas de incapacidade crônica em todo o mundo e um importante fator de risco cardiovascular, aumentando o risco relativo de doença arterial coronariana, bem como as taxas de morbimortalidade cardiovascular. Concomitantemente à alta prevalência de depressão, houve uma redução na exposição à luz solar com o aumento da urbanização e do uso de protetores solares, o que levou a uma redução nos níveis séricos de 25-hidroxivitamina D. Portanto, este artigo descreve uma protocolo para um ensaio clínico com o objetivo de avaliar os efeitos da suplementação de vitamina D na depressão e fatores de risco cardiovascular para contribuir com evidências sobre a influência potencial da suplementação na regulação do humor. MéTODOS: Este estudo de protocolo foi orientado pelos itens de protocolo padrão: recomendações para ensaios intervencionistas. Um ensaio clínico randomizado, controlado por placebo, duplo-cego será realizado envolvendo 224 adultos (faixa etária de 18 a 60 anos) com depressão que estão tomando antidepressivos e não têm histórico de suplementação de vitamina D, comorbidades psiquiátricas, doença renal crônica, hipercalcemia, ou neoplasia. Os participantes serão recrutados nos ambulatórios psiquiátricos de duas universidades do nordeste do Brasil. Os participantes elegíveis que fornecerem consentimento por escrito serão designados aleatoriamente para o grupo de intervenção (n = 112; suplementação de vitamina D 50.000 UI por semana durante 6 meses) ou para o grupo controle (n = 112; placebo tomado semanalmente por 6 meses). Medidas para monitorar sintomas depressivos, exames clínicos e exames laboratoriais para avaliar fatores de risco cardiovascular e níveis séricos de vitamina D serão realizadas antes e após o período de intervenção. DISCUSSãO: Até onde sabemos, este será o primeiro ensaio clínico com o objetivo de testar a eficácia da suplementação de vitamina D na redução do risco cardiovascular e como um adjuvante à terapia da depressão por um período prolongado (6 meses). Os resultados contribuirão para a compreensão dos efeitos terapêuticos da suplementação de vitamina D no tratamento da depressão e podem ajudar a orientar políticas públicas direcionadas à suplementação de vitamina para a redução do risco cardiovascular.

REGISTRO DE TESTE

Registro Brasileiro de Ensaios Clínicos, RBR-6yj8sj/ Número Universal de Ensaios (UTN) U1111-1217-9237 . Registrado em 23 de julho de 2018.

Thyroid hormone therapy for hypothyroidism

The purpose of this article will be to review the basics of thyroid hormone therapy, including various thyroid hormone formulations, the institution and monitoring of thyroid hormone therapy, adverse effects of overtreatment, the management of patients with persistent symptoms despite normal thyroid function tests, and potential new innovations in thyroid hormone therapy. The conclusions support the necessity to personalize thyroid hormone replacement therapy in hypothyroid patients.

Hypothyroidism in Context: Where We've Been and Where We're Going

Hypothyroidism affects up to 5% of the general population, with a further estimated 5% being undiagnosed. Over 99% of affected patients suffer from primary hypothyroidism. Worldwide, environmental iodine deficiency is the most common cause of all thyroid disorders, including hypothyroidism, but in areas of iodine sufficiency, Hashimoto’s disease (chronic autoimmune thyroiditis) is the most common cause of thyroid failure. Hypothyroidism is diagnosed biochemically, being overt primary hypothyroidism defined as serum thyroid-stimulating hormone (TSH) concentrations above and thyroxine concentrations below the normal reference range. Symptoms of hypothyroidism are non-specific and include mild to moderate weight gain, fatigue, poor concentration, depression, and menstrual irregularities, while the consequences of untreated or under-treated hypothyroidism include cardiovascular disease and increased mortality. Levothyroxine has long been the main tool for treating hypothyroidism and is one of the world’s most widely prescribed medicines. In adults with overt hypothyroidism, levothyroxine is usually prescribed at a starting dose of 1.6 µg/kg/day, which is then titrated to achieve optimal TSH levels (0.4–4.0 mIU/L), according to the therapeutic target. We here summarise the history of levothyroxine and discuss future issues regarding the optimal treatment of hypothyroidism. Because nearly one-third of patients with treated hypothyroidism still exhibit symptoms, it is important that levothyroxine is used more appropriately to achieve maximum benefit for patients. In order to ensure this, further research should include more accurate assessments of the true prevalence of hypothyroidism in the community, optimisation of the levothyroxine substitution dose, proper duration of treatment, and identification of patients who may benefit from combination therapy with levothyroxine plus levotriiodothyronine.

Funding: Merck.

Plain Language Summary: Plain language summary available for this article.

Hypothyroidism is one of the most common diseases worldwide, and levothyroxine is the usual medication prescribed to manage it. Hypothyroidism occurs when the thyroid gland, located in the neck, does not produce enough thyroid hormone for the body’s requirements. This can result in heart disease, infertility, and poor brain development in children. People with hypothyroidism may have changes in body weight, and feel tired, weak or unhappy, all of which can reduce their quality of life. In underdeveloped parts of the world, the main reason why people develop hypothyroidism is that they not getting enough iodine from food. Thus, many countries try to increase iodine intake by adding iodine to salt. In areas of the world where people ingest enough iodine, the most common cause of hypothyroidism is Hashimoto’s disease. This is an autoimmune disease in which the person’s immune system produces cells and antibodies that attack the thyroid gland. Most people with hypothyroidism will need to take levothyroxine for a long time, perhaps even for the rest of their lives. Levothyroxine replaces the person’s levels of thyroid hormone and makes them feel better, but the dose often needs to be adjusted for the best effect. In addition, many people with hypothyroidism do not know they have it. Research is ongoing to ensure that more people with hypothyroidism are diagnosed and are given effective treatment, and to work out the best way to use levothyroxine so that patients get the best results.

Subclinical Hypothyroidism: A Review

IMPORTANCE

Subclinical hypothyroidism, defined as an elevated serum thyrotropin (often referred to as thyroid-stimulating hormone, or TSH) level with normal levels of free thyroxine (FT4) affects up to 10% of the adult population.

OBSERVATIONS

Subclinical hypothyroidism is most often caused by autoimmune (Hashimoto) thyroiditis. However, serum thyrotropin levels rise as people without thyroid disease age; serum thyrotropin concentrations may surpass the upper limit of the traditional reference range of 4 to 5 mU/L among elderly patients. This phenomenon has likely led to an overestimation of the true prevalence of subclinical hypothyroidism in persons older than 70 years. In patients who have circulating thyroid peroxidase antibodies, there is a greater risk of progression from subclinical to overt hypothyroidism. Subclinical hypothyroidism may be associated with an increased risk of heart failure, coronary artery disease events, and mortality from coronary heart disease. In addition, middle-aged patients with subclinical hypothyroidism may have cognitive impairment, nonspecific symptoms such as fatigue, and altered mood. In the absence of large randomized trials showing benefit from levothyroxine therapy, the rationale for treatment is based on the potential for decreasing the risk of adverse cardiovascular events and the possibility of preventing progression to overt hypothyroidism. However, levothyroxine therapy may be associated with iatrogenic thyrotoxicosis, especially in elderly patients, and there is no evidence that it is beneficial in persons aged 65 years or older.

CONCLUSIONS AND RELEVANCE

Subclinical hypothyroidism is common and most individuals can be observed without treatment. Treatment might be indicated for patients with subclinical hypothyroidism and serum thyrotropin levels of 10 mU/L or higher or for young and middle-aged individuals with subclinical hypothyroidism and symptoms consistent with mild hypothyroidism.

Thyroid and Cardiovascular Disease: Research Agenda for Enhancing Knowledge, Prevention, and Treatment

Thyroid hormones have long been known to have a range of effects on the cardiovascular system. However, significant knowledge gaps exist concerning the precise molecular and biochemical mechanisms governing these effects and the optimal strategies for management of abnormalities in thyroid function in patients with and without preexisting cardiovascular disease. In September 2017, the National Heart, Lung, and Blood Institute convened a Working Group with the goal of developing priorities for future scientific research relating thyroid dysfunction to the progression of cardiovascular disease. The Working Group reviewed and discussed the roles of normal thyroid physiology, the consequences of thyroid dysfunction, and the effects of therapy in 3 cardiovascular areas: cardiac electrophysiology and arrhythmias, the vasculature and atherosclerosis, and the myocardium and heart failure. This report describes the current state of the field, outlines barriers and challenges to progress, and proposes research opportunities to advance the field, including strategies for leveraging novel approaches using omics and big data. The Working Group recommended research in 3 broad areas: (1) investigation into the fundamental biology relating thyroid dysfunction to the development of cardiovascular disease and into the identification of novel biomarkers of thyroid hormone action in cardiovascular tissues; (2) studies that define subgroups of patients with thyroid dysfunction amenable to specific preventive strategies and interventional therapies related to cardiovascular disease; and (3) clinical trials focused on improvement in cardiovascular performance and cardiovascular outcomes through treatment with thyroid hormone or thyromimetic drugs.

Thyroid and Cardiovascular Disease: Research Agenda for Enhancing Knowledge, Prevention, and Treatment

Thyroid hormones have long been known to have a range of effects on the cardiovascular system. However, significant knowledge gaps exist concerning the precise molecular and biochemical mechanisms governing these effects and the optimal strategies for management of abnormalities in thyroid function in patients with and without preexisting cardiovascular disease. In September 2017, The National Heart, Lung, and Blood Institute convened a Working Group with the goal of developing priorities for future scientific research relating thyroid dysfunction to the progression of cardiovascular disease. The Working Group reviewed and discussed the roles of normal thyroid physiology, the consequences of thyroid dysfunction, and the effects of therapy in three cardiovascular areas: cardiac electrophysiology and arrhythmias, the vasculature and atherosclerosis, and the myocardium and heart failure. This report describes the current state of the field, outlines barriers and challenges to progress, and proposes research opportunities to advance the field, including strategies for leveraging novel approaches using omics and big data. The Working Group recommended research in three broad areas: 1) investigation into the fundamental biology relating thyroid dysfunction to the development of cardiovascular disease and into the identification of novel biomarkers of thyroid hormone action in cardiovascular tissues; 2) studies that define subgroups of patients with thyroid dysfunction amenable to specific preventive strategies and interventional therapies related to cardiovascular disease; and 3) clinical trials focused on improvement in cardiovascular performance and cardiovascular outcomes through treatment with thyroid hormone or thyromimetic drugs.

CASE FINDING FOR HYPOTHYROIDISM SHOULD INCLUDE TYPE 2 DIABETES AND METABOLIC SYNDROME PATIENTS: A LATIN AMERICAN THYROID SOCIETY (LATS) POSITION STATEMENT

OBJECTIVE

Latin American Thyroid Society (LATS) Hypothyroidism Clinical Practice Guidelines recommend case finding of hypothyroid patients in multiple and different situations that agree with other Society guidelines. However, the detection of hypothyroidism in type 2 diabetes mellitus (T2DM) or metabolic syndrome (MetS) patients is not mentioned in particular. In the recent years, several basic and epidemiologic studies have appeared showing that a lower thyroid function and MetS/T2DM are associated. Hence, the aim of this review is to manifest the LATS position on the diagnosis of hypothyroidism in both MetS and T2DM patients.

METHODS

A search was made in PubMed using the following terms: "hypothyroidism" AND "diabetes" OR "metabolic syndrome." The most relevant studies describing the prevalence and complications due to hypothyroidism in both MetS and T2DM patients were selected.

RESULTS

The current document reviews new information from studies that have shown that the prevalence of hypothyroidism is higher in T2DM patients (odds ratio [OR], 3.45; 95% confidence interval [CI], 2.5 to 4.7) and that diabetic complications are more prevalent in subclinical hypothyroidism (ScH). The incidence of T2DM is 1.09-fold higher with each doubling of thyroid-stimulating hormone (TSH) mIU/L (95% CI, 1.06 to 1.12), and the incidence of prediabetes increases 15% (hazard ratio, 1.15; 95% CI, 1.04 to 1.26) in patients with TSH >5 mIU/L. Similarly, MetS is more prevalent in ScH compared to euthyroid individuals (OR, 1.31; 95% CI, 1.08 to 1.60).

CONCLUSION

Thyroid function is affected in MetS and T2DM, and hypothyroidism is more common in these patients. Diabetic complications are more frequent in ScH patients. Therefore, LATS now recommends aggressive case finding of hypothyroidism in both MetS and T2DM patients.

ABBREVIATIONS

CI = confidence interval; GLUT4 = glucose transporter 4; HOMA-IR = homeostatic model assessment for insulin resistance; HR = hazard ratio; LATS = Latin American Thyroid Society; MetS = metabolic syndrome; OR = odds ratio; ScH = subclinical hypothyroidism; T2DM = type 2 diabetes mellitus; T3 = triiodothyronine; T4 = thyroxine; TSH = thyroid-stimulating hormone.

Self-reported participation restrictions in normal hearing individuals in thyroid ontogeny: Evidence of subclinical changes

Purpose

To verify evidence of subclinical alterations through self-reported participation restrictions in normal hearing individuals and congenital hypothyroidism patients.

Methods

An analytical, quantitative, cross-sectional exploratory study with a 1:1 ratio, consisting of a convenience sample of 86 normal hearing individuals with (n = 42) and without (n = 44) congenital hypothyroidism diagnosis. All participants underwent tonal and speech audiometry, immitance and distortion product otoacoustic emissions. The researchers excluded people with hearing loss, genetic syndromes and metabolic diseases. The instrument used for evaluate of self-reported participation restrictions was the HHIE-adapted questionnaire, composed of 25 questions, 12 of which were social domain and 13 emotional domain. Student's t-test and chi-square test were used for statistical analysis at a significance level of 5%.

Results

There was a significant (p < 0.001) self-reported participation restrictions in CH (61.9%), with a greater relevance for the social domain (p = 0.002). There was a greater frequency of mild/moderate (40.5%) and higher prevalence of association with clinical factors and adherence to treatment.

Conclusion

The findings indicate that self-reported participation restrictions in normal hearing individuals with congenital hypothyroidism was more significant than in the non-exposed group, suggesting evidence of subclinical auditory abnormalities in this population.

Evaluation and management of the child with hypothyroidism

BACKGROUND

Thyroid hormones are critical for early neurocognitive development as well as growth and development throughout childhood. Prompt recognition and treatment of hypothyroidism is, therefore, of utmost importance to optimize physical and neurodevelopmental outcomes.

DATA SOURCES

A PubMed search was completed in Clinical Queries using the key terms "hypothyroidism".

RESULTS

Hypothyroidism may be present at birth (congenital hypothyroidism) or develop later in life (acquired hypothyroidism). Thyroid dysgenesis and dyshormonogenesis account for approximately 85% and 15% of permanent cases of congenital primary hypothyroidism, respectively. More than 95% of infants with congenital hypothyroidism have few, if any, clinical manifestations of hypothyroidism. Newborn screening programs allow early detection of congenital hypothyroidism. In developed countries, Hashimoto thyroiditis is the most common cause of goiter and acquired hypothyroidism in children and adolescents. Globally, iodine deficiency associated with goiter is the most common cause of hypothyroidism. Central hypothyroidism is uncommon and may be associated with other congenital syndromes and deficiencies of other pituitary hormones. Familiarity of the clinical features would allow prompt diagnosis and institution of treatment.

CONCLUSIONS

To optimize neurocognitive outcome in infants with congenital hypothyroidism, treatment with levothyroxine should be started as soon as possible, preferably within the first 2 weeks of life. Children with acquired hypothyroidism should also be treated early to ensure normal growth and development as well as cognitive outcome. The target is to keep serum TSH < 5 mIU/L and to maintain serum free T4 or total T4 within the upper half of the age-specific reference range, with elimination of all symptoms and signs of hypothyroidism.

A Systematic Review and Meta-Analysis of Patient Preferences for Combination Thyroid Hormone Treatment for Hypothyroidism

Background: The standard of care in management of hypothyroidism is treatment with levothyroxine (L-T4). Sometimes patients are dissatisfied with L-T4 and the combination of levo-triiodothyronine (L-T3) with L-T4 is considered. Methods: We performed a systematic review and meta-analysis of blinded randomized controlled trials (RCTs), reporting how often hypothyroid patients prefer combination L-T3/L-T4 treatment to L-T4 alone. We also explored for explanatory factors for combination therapy preference in sensitivity analyses examining trial, patient, and disease characteristics. Potential dose-response relationships were explored using meta-regression analyses. We searched 9 electronic databases (from inception until February, 2019), supplemented with a hand-search. Two reviewers independently screened abstracts and citations and reviewed full-text papers, with consensus achieved on the included studies. Two reviewers independently critically appraised the quality of included studies and abstracted the data. Random effects meta-analyses were reported for the percentage of patients preferring combination L-T3/T-T4 therapy over L-T4 alone. A binomial distribution of choices (i.e., preference of combination therapy or no preference for combination therapy) was assumed. Results: We included 7 blinded RCTs including 348 hypothyroid individuals in the primary meta-analysis. The pooled prevalence rate for preference of combination therapy over L-T4 was 46.2% (95% confidence interval 40.2%, 52.4%) (p = 0.231 for the difference from chance). There was no significant statistical heterogeneity among study results (Q = 7.32, degrees of freedom = 6, p = 0.293, I ² = 18.0%). In sensitivity analyses, combination treatment preference was explained in part by treatment effects on TSH concentration, mood and symptoms, but not quality of life nor body weight. In a secondary dose-response meta-regression analyses, a statistically significant association of treatment preference was identified for total daily L-T3 dose, but not L-T3:L-T4 dose ratio. Conclusions: In conclusion, in RCTs in which patients and investigators were blinded to treatment allocation, approximately half of participants reported preferring combination L-T3 and L-T4 therapy compared to L-T4 alone; this finding was not distinguishable from chance. An observed potential positive L-T3 dose effect on treatment preference deserves further study, with careful consideration of thyroid biochemical indices and patient reported outcomes.

Vitamin D in Hashimoto's thyroiditis and its relationship with thyroid function and inflammatory status

Several studies have shown the correlation between vitamin D [25(OH)D] deficiency and thyroid autoimmunity and reducing of thyroid autoantibodies in patients with normal levels of vitamin D combining with thyroid hormone replacement. However, other authors not agree with this association. It is still unclear whether the low 25(OH)D levels are the result of HT disease or a part of its cause. We studied 88 patients with HT regarding vitamin D status and thyroid autoimmunity markers as well as the relationship with cytokines produced by Th1, Th2, and Th17 cells compared with a control group of 71 euthyroid healthy subjects. The present study demonstrated that vitamin D concentrations were similar in patients HT and the control group. The reduction of free T4 levels was a predictor of vitamin D insufficiency for Hashimoto's thyroiditis, but not for the control group. Lower concentrations of TNF-α was a predictor of lower levels of vitamin D. Differences in the association between HT and vitamin D insufficiency remain unresolved in the literature. The thyroid hormone status would play a role in the maintenance of vitamin D sufficiency, and its immunomodulatory role would influence the presence of autoimmune thyroid disease. The positive correlation between free T4 and vitamin D concentrations suggests that adequate levothyroxine replacement in HT would be an essential factor in maintaining vitamin D at sufficient levels.

Receptor for advanced glycation end products reveals a mechanism regulating thyroid hormone secretion through the SIRT1/Nrf2 pathway

Advanced glycation end products (AGEs) play a causative role in the complications involved with diabetes mellitus (DM). Nowadays, DM with hypothyroidism (DM-hypothyroidism) is indicative of an ascended tendency in the combined morbidity. In this study, we examine the role of the receptor (RAGE) played for AGEs in thyroid hormone (TH) secretion via the silent information regulator 1 (SIRT1)/nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2) pathway. Blood samples were collected from patients with type 2 DM (T2DM)-hypothyroidism and from patients with T2DM, followed by detection of serum AGEs level. The underlying regulatory mechanisms of RAGE were analyzed in association with the treatment of high glucose, siRNA against RAGE, AGE, SIRT1, or Nrf2 vector in normal immortalized thyroid Nthy-ori 3-1 cells. Serum of patients with T2DM-hypothyroidism indicated promoted levels of AGEs vs those with just T2DM. Both AGEs and high glucose triggered cellular damage, increased oxidative stress, as well as displayed a decreased survival rate along with TH secretion in the Nthy-ori 3-1 cells. Moreover, AGEs and high glucose also led to RAGE upregulation, both SIRT1 and NRF2 downregulation, and the decreased expression of TH secretion-related proteins in Nthy-ori 3-1 cells. Notably, these alternations induced by the AGEs can be reserved by silencing RAGE or upregulating either SIRT1 or Nrf2, indicating a mechanism of regulating TH secretion through the SIRT1/Nrf2 pathway. Collectively, our data proposed that AGEs and high glucose exerted a potent effect on cellular damage and TH deficiency in Nthy-ori 3-1 cells through the RAGE upregulation as well as SIRT1/Nrf2 pathway inactivation. This mechanism may underlie the occurrence of DM-hypothyroidism.

MANAGEMENT OF ENDOCRINE DISEASE: Pitfalls on the replacement therapy for primary and central hypothyroidism in adults

Hypothyroidism is one of the most common hormone deficiencies in adults. Most of the cases, particularly those of overt hypothyroidism, are easily diagnosed and managed, with excellent outcomes if treated adequately. However, minor alterations of thyroid function determine nonspecific manifestations. Primary hypothyroidism due to chronic autoimmune thyroiditis is largely the most common cause of thyroid hormone deficiency. Central hypothyroidism is a rare and heterogeneous disorder characterized by decreased thyroid hormone secretion by an otherwise normal thyroid gland, due to lack of TSH. The standard treatment of primary and central hypothyroidism is hormone replacement therapy with levothyroxine sodium (LT4). Treatment guidelines of hypothyroidism recommend monotherapy with LT4 due to its efficacy, long-term experience, favorable side effect profile, ease of administration, good intestinal absorption, long serum half-life and low cost. Despite being easily treatable with a daily dose of LT4, many patients remain hypothyroid due to malabsorption syndromes, autoimmune gastritis, pancreatic and liver disorders, drug interactions, polymorphisms in DIO2 (iodothyronine deiodinase 2), high fiber diet, and more frequently, non-compliance to LT4 therapy. Compliance to levothyroxine treatment in hypothyroidism is compromised by daily and fasting schedule. Many adult patients remain hypothyroid due to all the above mentioned and many attempts to improve levothyroxine therapy compliance and absorption have been made.