The enigma of persistent symptoms in hypothyroid patients treated with levothyroxine: A narrative review

Medically not yet explained symptoms in hypothyroidism

Persistent symptoms are common in the general population and even more so in people with hypothyroidism. When symptoms are unexplained and brought to medical attention, they can be referred to as medically not yet explained symptoms (MNYES), a term preferred to other descriptors by patients, care-givers and experts. MNYES might be neglected by endocrinologists or misattributed to hypothyroidism. Awareness of MNYES could open up more effective and less harmful interventions for patients who present to endocrinologists with unexplained symptoms than costly over-investigations and over-treatment with thyroid hormones (such as levothyroxine and liothyronine). The role of the endocrinologist is to recognize and acknowledge that MNYES could be underlying a patient's presentation, to communicate effectively with the patient and others involved in the patient's care, to apply a 'two-track approach' in management by paying equal attention to physical and psychosocial contributors, and to collaborate with other relevant health professionals. Categorization of patients into levels of risk for symptom deterioration helps in selecting suitable therapies. Effective management of MNYES demands time, training, expertise and resources.

Association of Non-High-Density Lipoprotein Cholesterol With Cardiometabolic Risk Factors in Patients With Hypothyroidism

INTRODUCTION

Non-high-density lipoprotein cholesterol (non-HDL-C) levels can increase the cardiometabolic risk factors in patients with hypothyroidism, but the findings across studies have not been consistently conclusive. The aim of this study was to find the association between non-HDL-C and cardiometabolic risk factors in patients with hypothyroidism.

MATERIAL AND METHODS

In this case-control study, a total of 120 subjects among which 60 diagnosed hypothyroidism patients and 60 age-matched healthy controls were enrolled, aged 30-65 years. Body mass index (BMI), waist circumference (WC), and systolic and diastolic blood pressures (SBP and DBP) were measured. Thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), fasting blood sugar (FBS), total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) were estimated. Low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and non-HDL-C were calculated. A p-value of <0.05 was considered statistically significant.

RESULTS

Mean of BMI, WC, FBS, TSH, TC, TG, non-HDL-C, LDL-C, VLDL-C, SBP, and DBP were significantly elevated in cases compared to controls (p<0.001). However, the mean of T3, T4, and HDL-C were significantly reduced in cases compared to controls (p<0.001). Non-HDL-C has shown a significant positive correlation with age (r=0.345, p<0.01), TC (r=0.451, p<0.01), TG (r=0.269, p<0.05), LDL-C (r=0.402, p<0.01), and VLDL-C (r=0.269, p<0.05) among cases. However, non-HDL-C has shown a significant negative correlation with HDL-C (r=-0.330, p<0.05) among cases. Non-HDL-C significantly predicted cardiometabolic risk in patients with hypothyroidism (F(13,46)=3.500, p<0.001).

CONCLUSION

Non-HDL-C has shown a significant association with age and lipid abnormalities in patients with hypothyroidism. Non-HDL-C significantly predicts cardiometabolic risk factors in patients with hypothyroidism.

Levothyroxine may not adequately prepare hypothyroid women for controlled ovarian hyperstimulation

BACKGROUND

Thyroid axis dysregulation during controlled ovarian hyperstimulation (COH) is more pronounced in hypothyroid-treated women. Whether or not this leads to compromised thyroid hormone levels within the ovarian follicular fluid is not known.

AIMS

To determine whether ovarian follicular thyroid hormone levels are compromised in adequately replaced hypothyroid women undergoing controlled ovarian hyperstimulation (COH), and/or influence cycle/pregnancy outcomes.

MATERIALS AND METHODS

Prospective cohort study involving 46 euthyroid (anti-thyroid peroxidase antibody negative) and 16 levothyroxine-replaced women with baseline thyroid-stimulating hormone (TSH) <2.5 mIU/L attending their first COH cycle. Follicular fluid TSH, free triiodothyronine (T3) and free thyroxine (T4) were recorded at oocyte pick-up. Serum levels were measured at: (i) baseline; (ii) human chorionic gonadotropin trigger day; and (iii) cycle conclusion. The number of mature oocytes retrieved, fertilisation, early pregnancy loss and live birth rates were compared.

RESULTS

Median serum TSH levels were similar at baseline (1.76 vs 1.24 mIU/L, P = 0.053), but free T3 levels were lower (4.5 vs 4.8 pmol/L, P = 0.029) in levothyroxine-replaced compared to euthyroid women, with serum TSH levels increasing across ovarian stimulation (P = 0.006) into pregnancy testing (P = 0.030). Follicular fluid free T3 levels were lower in levothyroxine-replaced women (median 4.3 vs 4.6 pmol/L, P = 0.032). Fertilisation rates were lower (52% vs 71%, P = 0.043) in women requiring levothyroxine replacement, but numbers of mature oocytes retrieved, early pregnancy loss and live births did not differ.

CONCLUSION

Adequately replaced hypothyroid women achieve lower ovarian follicular fluid free T3 levels and poorer fertilisation rates compared to euthyroid women undergoing COH. Optimising T3 levels may be pivotal in improving COH outcomes in hypothyroid women.

Use of thyroid hormones in hypothyroid and euthyroid patients: A survey of members of the Endocrine Society of Australia

OBJECTIVE

Hypothyroidism is a common endocrine condition usually managed with levothyroxine (LT4). However, controversy remains around the use of liothyronine (LT3). We aimed to investigate the practices of Australian endocrinologists when managing patients with hypothyroidism, their use of LT3 + LT4 combination therapy and use of thyroid hormones in euthyroid patients.

DESIGN AND PARTICIPANTS

Members of the Endocrine Society of Australia (ESA) were invited to participate in an online questionnaire.

MEASUREMENTS

We analysed questionnaires that had complete demographic data.

RESULTS

Eighty-seven questionnaires fulfilled the criteria. LT4 was used as first line treatment for hypothyroidism by all respondents. Only 45% reported that their patients were dispensed the brand of LT4 that they recommend. LT3 (alone or in combination) was prescribed by 44% in their clinical practice. Although 49% of respondents would consider LT3 + LT4 in patients with normal TSH who had ongoing symptoms of hypothyroidism, the inability of LT4 to restore normal physiology was ranked the least likely explanation for persistent symptoms and only 32% would consider it for themselves if they were diagnosed with hypothyroidism. The majority (55%), in accordance with evidence, would not prescribe thyroid hormone to euthyroid individuals but 39% would consider use in euthyroid female infertility with high levels of thyroid antibodies and 11% in euthyroid patients with a simple goitre growing over time. LT4 use in pregnancy was variable among members.

CONCLUSIONS

Australian endocrinologists mostly follow international guidelines when prescribing thyroid hormone therapy and many prescribe combination LT3 and LT4 therapy, particularly for patients who remain symptomatic on LT4 monotherapy. Prescribing practices are largely similar to other countries who have completed similar questionnaires.

Metabolomic insights into the therapeutic mechanisms of costus (Saussurea costus (Falc.) Lipsch.) root extract in propylthiouracil-induced hypothyroidism rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Saussurea costus (Falc.) Lipschitz. is one of the most reputed medicinal plants as a traditional medicine in the Arab and Middle East regions in the treatment of thyroid disorders, however, more investigations are needed to fully understand its effectiveness and mechanism of action.

AIM OF THE STUDY

The primary objective of the study was to assess the impact of Saussurea costus (COST) on the metabolic profiles of propylthiouracil (PTU)-induced hypothyroidism in rats. This involves a comprehensive examination of serum metabolites using UPLC/QqQ-MS analysis aiming to identify differential metabolites, elucidate underlying mechanisms, and evaluate the potential pharmacological effect of COST in restoring metabolic homeostasis.

MATERIALS AND METHODS

Hypothyroidism was induced in female Sprague-Dawley rats by oral administration of propylthiouracil (PTU). UPLC/QqQ MS analysis of serum samples from normal, PTU, and PTU + COST rats was utilized for annotation of intrinsic metabolites with the aid of online Human metabolome database (HMDB) and extensive literature surfing. Multivariate statistical analyses, including orthogonal partial least squares discriminant analysis (OPLS-DA), discerned variations between the different groups. Serum levels of T3, T4 and TSH in addition to arachidonic acid (ARA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) levels in thyroid gland tissues; Phospholipase A2 group IIA (PLA2G2A), and lipoprotein lipase (LPL) in liver tissues were assessed by specific ELISA kits. Gene expression for key proteins of the primary evolved pathwayswere quantified by one-step qRT-PCR technique. Histopathological evaluation of thyroid gland tissue was performed by an investigator blinded to the experimental group using light microscope.

RESULTS

Distinct clustering in multivariate statistical analysis models indicated significant variations in serum chemical profiles among normal, disease, and treated groups. VIP values guided the selection of differential metabolites, revealing significant changes in metabolite concentrations. Subsequent to COST treatment, 43 differential intrinsic metabolites exhibited a notable tendency to revert towards normal levels. Annotated metabolites, such as lysophosphatidylcholine (LPC), L-acetylcarnitine, gamma-glutamylserine, and others, showed differential regulation in response to PTU and subsequent S. costus treatment. Notably, 21 metabolites were associated with polyunsaturated fatty acids (PUFAs) biosynthesis, arachidonic acid (ARA) metabolism, and glycerophospholipid metabolism exhibited significant changes on conducting metabolic pathway analysis.

CONCLUSIONS

COST improves PTU-induced hypothyroidism by regulating biosynthesis of PUFAs signified by n-3/n-6, ARA and glycerophospholipid metabolism. The study provides us a novel mechanism to explain the improvement of hypothyroidism and associated dyslipidemia by COST, depicts a metabolic profile of hypothyroidism, and gives us another point cut for further exploring the biomarkers and pathogenesis of hypothyroidism.

Hypothyroidism and Type D Personality: Results From E-MPATHY, a Cross-sectional International Online Patient Survey

CONTEXT

Between 10% and 15% of people with hypothyroidism experience persistent symptoms, despite achieving biochemical euthyroidism. The underlying causes are unclear. Type D personality (a vulnerability factor for general psychological distress) is associated with poor health status and symptom burden but has not been studied in people with hypothyroidism.

OBJECTIVE

To investigate type D personality in hypothyroidism and explore associations with other characteristics and patient-reported outcomes.

DESIGN

Multinational, cross-sectional survey.

SETTING

Online.

PARTICIPANTS

Individuals with self-reported, treated hypothyroidism.

INTERVENTION

Questionnaire.

MAIN OUTCOME MEASURES

Type D personality and associations with baseline characteristics, control of the symptoms of hypothyroidism by medication, satisfaction with care and treatment of hypothyroidism, impact of hypothyroidism on everyday living.

RESULTS

A total of 3915 responses were received, 3523 of which were valid. The prevalence of type D personality was 54.2%. Statistically significant associations were found between type D personality and several respondent characteristics (age, marital status, ethnicity, household income, comorbidities, type of treatment for hypothyroidism, most recent TSH level), anxiety, depression, somatization, poor control of the symptoms of hypothyroidism by medication, dissatisfaction with care and treatment of hypothyroidism, and a negative impact of hypothyroidism on everyday living).

DISCUSSION

Our study found a high prevalence of type D personality among people with hypothyroidism who responded to the survey. Type D personality may be an important determinant of dissatisfaction with treatment and care among people with hypothyroidism. Our findings require independent confirmation. Close collaboration between the disciplines of thyroidology and psychology is likely to be key in progressing our understanding in this area.

Patients' Persistent Symptoms, Clinician Demographics, and Geo-Economic Factors Are Associated with Choice of Therapy for Hypothyroidism by European Thyroid Specialists: The "THESIS" Collaboration

Background: Hypothyroidism is common, however, aspects of its treatment remain controversial. Our survey aimed at documenting treatment choices of European thyroid specialists and exploring how patients' persistent symptoms, clinician demographics, and geo-economic factors relate to treatment choices. Methods: Seventeen thousand two hundred forty-seven thyroid specialists from 28 countries were invited to participate in an online questionnaire survey. The survey included respondent demographic data and treatment choices for hypothyroid patients with persistent symptoms. Geo-economic data for each country were included in the analyses. Results: The response rate was 32.9% (6058 respondents out of 17,247 invitees). Levothyroxine (LT4) was the initial treatment preferred by the majority (98.3%). Persistent symptoms despite normal serum thyrotropin (TSH) while receiving LT4 treatment were reported to affect up to 10.0% of patients by 75.4% of respondents, while 28.4% reported an increasing such trend in the past 5 years. The principal explanations offered for patients' persistent symptoms were psychosocial factors (77.1%), comorbidities (69.2%), and unrealistic patient expectations (61.0%). Combination treatment with LT4+liothyronine (LT3) was chosen by 40.0% of respondents for patients who complained of persistent symptoms despite a normal TSH. This option was selected more frequently by female thyroid specialists, with high-volume practice, working in countries with high gross national income per capita. Conclusions: The perception of patients' dissatisfaction reported by physicians seems lower than that described by hypothyroid patients in previous surveys. LT4+LT3 treatment is used frequently by thyroid specialists in Europe for persistent hypothyroid-like symptoms even if they generally attribute such symptoms to nonendocrine causes and despite the evidence of nonsuperiority of the combined over the LT4 therapy. Pressure by dissatisfied patients on their physicians for LT3-containing treatments is a likely explanation. The association of the therapeutic choices with the clinician demographic characteristics and geo-economic factors in Europe is a novel information and requires further investigation.

Real Practice Assessment of Persistent Symptoms After Initiation of Levothyroxine

OBJECTIVE

Levothyroxine (LT4) is the standard treatment for hypothyroidism. However, certain patients experience persistent symptoms even after achieving euthyroid status with LT4 therapy. We aimed to determine the frequency of persistent or new symptoms in patients with hypothyroidism after initiating LT4.

METHODS

This retrospective study included patients with hypothyroidism who started on LT4 between January 2017 and December 2019 at Mayo Clinic in Rochester, Minnesota, USA. Five hundred patient charts were randomly selected for review. Patients with at least 1 documented follow-up encounter after LT4 initiation were evaluated for ≤3 follow-up visits regarding their biochemical status and symptoms.

RESULTS

We included 356 patients, a majority of whom were female (66.6%), white (92.3%), and obese (71.9%), with an average age of 59.5 years. At the baseline visit, approximately one-half of the patients (177/356, 47.7%) reported hypothyroid symptoms, with fatigue being the most common symptom. During the follow-up periods, we observed that 17.8% (28/157), 17.9% (19/106), and 19.3% (11/57) of patients had normal thyroid stimulating hormone (TSH) values but persistent symptoms, while 12.3% (19/156), 19.9% (16/107), and 8.9% (5/56) had normal TSH values but new symptoms. Overall, during each respective follow-up period, 26.7% (42/157), 27.3% (29/106), and 28% (16/57) of patients experienced persistent or new symptoms alongside normal TSH values, with fatigue being the most constant symptom.

CONCLUSION

Our findings indicate that approximately 1 in every 4 patients with hypothyroidism receiving LT4 therapy and achieving normal TSH levels experience persistent or new hypothyroid symptoms. The cause of these symptoms remains unclear, emphasizing the need for a better understanding of their underlying causes and the development of effective management strategies.

Emerging Therapies in Hypothyroidism

Levothyroxine (LT4) is effective for most patients with hypothyroidism. However, a minority of the patients remain symptomatic despite the normalization of serum thyrotropin levels. Randomized clinical trials including all types of patients with hypothyroidism revealed that combination levothyroxine and liothyronine (LT4+LT3) therapy is safe and is the preferred choice of patients versus LT4 alone. Many patients who do not fully benefit from LT4 experience improved quality of life and cognition after switching to LT4+LT3. For these patients, new slow-release LT3 formulations that provide stable serum T3 levels are being tested. In addition, progress in regenerative technology has led to the development of human thyroid organoids that restore euthyroidism after being transplanted into hypothyroid mice. Finally, there is a new understanding that, under certain conditions, T3 signaling may be compromised in a tissue-specific fashion while systemic thyroid function is preserved. This is seen, for example, in patients with metabolic (dysfunction)-associated fatty liver disease, for whom liver-selective T3-like molecules have been utilized successfully in clinical trials.

Designing a combined liothyronine (LT3), L- thyroxine (LT4) trial in symptomatic hypothyroid subjects on LT4 - the importance of patient selection, choice of LT3 and trial design

Approximately 10%-15% of subjects with hypothyroidism on L-thyroxine (LT4) alone have persistent symptoms affecting their quality of life (QoL). Although the cause is unclear, there is evidence that "tissue T3 lack" may be responsible. If so, combining liothyronine (LT3) with LT4 would be helpful. However, randomized controlled trials (RCT), have not established greater efficacy for the LT3 + LT4 combination in these subjects than for LT4 alone. While the trial design may have been responsible, the use of unphysiological, short-acting LT3 preparations and non-thyroid-specific patient-reported outcome measures (PROMs) may have contributed. We recommend attention to the following aspects of trial design for future RCTs of LT3 + LT4 compared to LT4 alone: (a) Subject selection-(i) measurable symptoms (disadvantages should be recognized); (ii) using a validated thyroid specific PROM such as ThyPRO39 or the Composite scale derived from it; (iii) those taking over 1.2 μg/day or 100 μg/day (for pragmatic reasons) of LT4 defining a population likely without intrinsic thyroid activity who depend on exogenous LT4; (iv) recruiting a preponderance of subjects with autoimmune thyroiditis increasing generalisability; and (v) those with a high symptom load with a greater response to combination therapy e.g. those with the deiodinase 2 polymorphism. (b) The use of physiological LT3 preparations producing pharmacokinetic similarities to T3 profiles in unaffected subjects: two long-acting LT3 preparations are currently available and must be tested in phase 2b/3 RCTs. (c) The superiority of a crossover design in limiting numbers and costs while maintaining statistical power and ensuring that all subjects experienced the investigative medication.

Use of Thyroid Hormones in Hypothyroid and Euthyroid Patients: A THESIS questionnaire survey of members of the Irish Endocrine Society

BACKGROUND

Replacement of thyroid hormones (TH) with Levothyroxine (LT4) is the treatment of choice for hypothyroidism, however, there are aspects of treatment where uncertainties exist and practice varies. Factors influencing initiation and choice of TH replacement may impact patient satisfaction, safety, and health care costs.

METHODS

The aim of the study was to examine the attitudes of Irish endocrinologists regarding the treatment of hypothyroid and euthyroid patients with TH. Members of the Irish Endocrine Society (IES) were invited to participate in an online survey.

RESULTS

Forty-eight invitations were sent, and 39 (81.3%) participants responded. All respondents favoured LT4 tablet therapy for treatment of hypothyroidism, but 20.5% prescribed combination therapy (LT4 and liothyronine), and 13% regularly used desiccated thyroid extract. A significant proportion (51%) might prescribe TH in euthyroid patients; 41% for thyroid auto-antibody positive women seeking pregnancy, 18% for goitre and 5% for unexplained fatigue. Many (38%) consider combination therapy in patients with persistent symptoms. Respondents reported seeing LT4 treated patients with persistent symptomatology more frequently and perceive psychosocial factors and comorbidities to be the most common reasons for such symptoms.

CONCLUSION

LT4 tablets are the treatment of choice for hypothyroidism in Ireland. Approximately a third of Irish endocrinologists either regularly use, or would consider, liothyronine for hypothyroid patients. A significant proportion would give TH to euthyroid individuals in specific circumstances. The prescription of TH amongst Irish endocrinologists was generally in keeping with recommended practice, and areas where practice deviated from guidance were typically where evidence was conflicting or insufficient.

Protocol for a double-blinded randomised controlled trial to assess the effect of faecal microbiota transplantations on thyroid reserve in patients with subclinical autoimmune hypothyroidism in the Netherlands: the IMITHOT trial

BACKGROUND

Hashimoto's thyroiditis (HT) is a common endocrine autoimmune disease affecting roughly 5% of the general population and involves life-long treatment with levothyroxine, as no curative treatment yet exists. Over the past decade, the crosstalk between gut microbiota and the host immune system has been well-recognised, identifying the gut microbiome as an important factor in host health and disease, including susceptibility to autoimmune diseases. Previous observational studies yielded a link between disruption of the gut microbiome composition and HT. This is the first study that investigates the potential of restoring a disrupted gut microbiome with faecal microbiota transplantations (FMTs) to halt disease progression and dampen autoimmunity.

METHODS AND ANALYSIS

The IMITHOT trial is a randomised, double-blinded, placebo-controlled study evaluating either autologous or allogenic FMTs in medication-naïve patients with subclinical autoimmune hypothyroidism. In total, 34 patients will be enrolled to receive either three allogenic or autologous FMTs. FMT will be made of fresh stool and directly administered into the duodenum. Patients will be evaluated at baseline before the first FMT is administered and at 6, 12 and 24 months post-intervention to assess efficacy and adverse events. The primary outcome measure will be the net incremental increase (incremental area under the curve) on thyrotropin-stimulated free thyroxine and free triiodothyronine release at 6 and 12 months compared with baseline. Results will be disseminated via peer-reviewed journals and international conferences. The recruitment of the first patient and donor occurred on 18 December 2019.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the hospital Ethics Committee (Medical Ethics Committee) at Amsterdam University Medical Center. The trial's outcomes offer high-quality evidence that aids in unveiling distinct patterns within the gut microbiota potentially associated with improved thyroid function. Consequently, this may open avenues for the future clinical applications of microbial-targeted therapy in individuals at risk of developing overt HT.

TRIAL REGISTRATION NUMBER

NL7931.

Hypothyroidism and Somatization: Results from E-Mode Patient Self-Assessment of Thyroid Therapy, a Cross-Sectional, International Online Patient Survey

Background: Between 10% and 15% of hypothyroid patients experience persistent symptoms despite achieving biochemical euthyroidism. Unexplained persistent symptoms can be a sign of somatization. This is associated with distress and high health care resource use and can be classified as somatic symptom disorder (SSD). Prevalence rates for SSD differ depending on classification criteria and how they are ascertained, varying between 4% and 25%. As this has not been studied in hypothyroid patients before, the aim of this study was to document somatization in people with hypothyroidism and to explore associations with other patient characteristics and outcomes. Methods: Online, multinational cross-sectional survey of individuals with self-reported, treated hypothyroidism, which included the validated Patient Health Questionnaire-15 (PHQ-15) for assessment of somatization. Chi-squared tests with the Bonferroni correction were used to explore outcomes for respondents with a PHQ-15 score ≥10 (probable somatic symptom disorder [pSSD]) versus a PHQ-15 score <10 (absence of SSD). Results: A total of 3915 responses were received, 3516 of which contained the valid PHQ-15 data (89.8%). The median score was 11.3 (range 0-30 [confidence interval 10.9-11.3]). The prevalence of pSSD was 58.6%. Associations were found between pSSD and young age (p < 0.001), women (p < 0.001), not working (p < 0.001), having below average household income (p < 0.001), being treated with levothyroxine (LT4) (rather than combination of LT4 and L-triiodothyronine [LT3], LT3 alone, or desiccated thyroid extract) (p < 0.001), expression of the view that the thyroid medication taken did not control the symptoms of hypothyroidism well (p < 0.001), and with number of comorbidities (p < 0.001). pSSD was associated with respondent attribution of most PHQ-15 symptoms to the hypothyroidism or its treatment (p < 0.001), dissatisfaction with care and treatment of hypothyroidism (p < 0.001), a negative impact of hypothyroidism on daily living (p < 0.001), and with anxiety and low mood/depression (p < 0.001). Conclusions: This study demonstrates a high prevalence of pSSD among people with hypothyroidism and associations between pSSD and negative patient outcomes, including a tendency to attribute persistent symptoms to hypothyroidism or its treatment. SSD may be an important determinant of dissatisfaction with treatment and care among some hypothyroid patients.

Use of liothyronine (T3) in hypothyroidism: Joint British Thyroid Association/Society for endocrinology consensus statement

Persistent symptoms in patients treated for hypothyroidism are common. Despite more than 20 years of debate, the use of liothyronine for this indication remains controversial, as numerous randomised trials have failed to show a benefit of treatment regimens that combine liothyronine (T3) with levothyroxine over levothyroxine monotherapy. This consensus statement attempts to provide practical guidance to clinicians faced with patients who have persistent symptoms during thyroid hormone replacement therapy. It applies to non-pregnant adults and is focussed on care delivered within the UK National Health Service, although it may be relevant in other healthcare environments. The statement emphasises several key clinical practice points for patients dissatisfied with treatment for hypothyroidism. Firstly, it is important to establish a diagnosis of overt hypothyroidism; patients with persistent symptoms during thyroid hormone replacement but with no clear biochemical evidence of overt hypothyroidism should first have a trial without thyroid hormone replacement. In those with established overt hypothyroidism, levothyroxine doses should be optimised aiming for a TSH in the 0.3-2.0 mU/L range for 3 to 6 months before a therapeutic response can be assessed. In some patients, it may be acceptable to have serum TSH below reference range (e.g. 0.1-0.3 mU/L), but not fully suppressed in the long term. We suggest that for some patients with confirmed overt hypothyroidism and persistent symptoms who have had adequate treatment with levothyroxine and in whom other comorbidities have been excluded, a trial of liothyronine/levothyroxine combined therapy may be warranted. The decision to start treatment with liothyronine should be a shared decision between patient and clinician. However, individual clinicians should not feel obliged to start liothyronine or to continue liothyronine medication provided by other health care practitioners or accessed without medical advice, if they judge this not to be in the patient's best interest.

Treating subclinical hypothyroidism in individuals with or without mental health problems -A Delphi based expert consensus study in two countries

Background

Subclinical hypothyroidism (SCH) is a common endocrine problem with prevalence estimates between 4% and 20%. Symptoms are often non-specific but can substantially affect well-being leading to repeated medical consultations. The effect of thyroid hormone replacement therapy (THRT) in patients with SCH remains uncertain. Current guidelines, limited by the lack of high-quality evidence, have been controversial with limited adherence in clinical practice.

Methods

Three-round modified Delphi method to establish consensus regarding diagnosis and treatment of individuals with SCH with and without affective disorder or anxiety, conducted with clinicians from three specialties, general practice, endocrinology and psychiatry, and two countries, Sweden and the United Kingdom.

Results

Sixty clinicians, 20 per specialty, were recruited. Fifty-three (88%) participants completed all three rounds. The participants reached consensus on five of the 26 practice statements that (a) repeated testing was required for the diagnosis of subclinical hypothyroidism, (b) antibody screening should usually occur, and (c and d) antibody screening would strengthen the indication for thyroid hormone replacement therapy in both individuals with or without affective disorder or anxiety. The participants disagreed with (e) a requirement of a TSH threshold ≥ 20 mIU/L for thyroid hormone replacement therapy start. Psychiatrists and GPs but not endocrinologists, agreed that there was a frequent discrepancy between laboratory results and clinical symptoms, and disagreed that testing for thyroid dysfunction was overused in patients presenting with depression or anxiety, or fatigue.

Conclusions

In many aspects, attitudes toward diagnosing and treating SCH remain diverse. The inability of our Delphi panel to achieve consensus on most items and the disagreement with a TSH ≥ 20 mIU/L threshold for treatment suggest that the concept of SCH may need rethinking with a better understanding of the hypothalamic-pituitary-thyroid physiology. Given that the scientific evidence is currently not conclusive, guidelines in this area should not be taken as definitive.

Use of thyroid hormones in hypothyroid and euthyroid patients: A THESIS questionnaire survey of UK endocrinologists

OBJECTIVE

Management of hypothyroidism is controversial because of medication cost pressures and scientific uncertainty on how to address treatment dissatisfaction experienced by some patients. The objective was to investigate the experience and preferences of UK endocrinologists in use of thyroid hormones.

DESIGN

Web-based survey.

PATIENTS

UK endocrinologists were invited to participate.

MEASUREMENTS

Responses to questionnaire.

RESULTS

The response rate was 21% (272/1295). While levothyroxine monotherapy is regarded as the treatment of choice for hypothyroidism, 51% of respondents stated that combined treatment with levothyroxine and liothyronine could be considered for levothyroxine-treated patients whose symptoms persist despite normalisation of serum thyroid stimulating hormone (TSH) concentration. However, only 40% are currently prescribing such treatment, and just 23% would consider taking it themselves. A small minority prescribe desiccated thyroid extract, and those most likely to do so are aged over 60 years. Most respondents stated that they have no influence over brand or formulation of levothyroxine dispensed to their patients and expect no major differences in efficacy between different formulations. A total of 9% would prescribe levothyroxine for euthyroid enlarging goitre, and 29% for euthyroid female infertility with high titre thyroid peroxidase antibodies, despite recent trials finding no benefit.

CONCLUSIONS

UK endocrine practice in management of hypothyroidism is broadly in line with international guidance. However, a minority of respondents would consider thyroid hormone supplementation in euthyroid individuals for female infertility, enlarging goitre, and other indications in which evidence of efficacy is lacking. Willingness to consider prescribing combined levothyroxine and liothyronine, for hypothyroid symptoms which persist despite normalised TSH, has increased in comparison to previous international surveys, despite inconsistent evidence of benefit.

Hypothyroidism: The difficulty in attributing symptoms to their underlying cause

Common symptoms of overt hypothyroidism are non-specific and include fatigue, lethargy, and dry skin. Although the diagnosis is considered to be straightforward, no single symptom can be used to identify patients with overt hypothyroidism, while many patients with subclinical hypothyroidism are asymptomatic. A large population-based study on the spectrum of symptoms in subclinical hypothyroidism showed similar rates of thyroid disease-related symptoms compared with euthyroid subjects, while the TSH concentration had no impact on symptom score. Together, these findings make it challenging to attribute symptoms to their underlying cause. This is also true in the case of unexplained persistent symptoms in levothyroxine-treated patients. Although generally considered a life-long replacement therapy, successful thyroid hormone discontinuation resulting in euthyroidism has been reported in approximately one third of patients. Thus, we overtreat patients with (subclinical) hypothyroidism, highlighting the importance of reliable diagnostic criteria. The diagnostic process, including the implementation of robust TSH and FT4 reference intervals, is especially challenging in specific situations including aging, pregnancy, non-thyroidal illness, and central hypothyroidism. There is a clear need for improved adherence to current guidelines from scientific societies and for willingness to manage symptoms without a clear pathological correlate, especially in the case of mild TSH elevations. This review will highlight recent literature on this topic and offers some practice points.

The Impact of Hypothyroidism on Satisfaction with Care and Treatment and Everyday Living: Results from E-Mode Patient Self-Assessment of Thyroid Therapy, a Cross-Sectional, International Online Patient Survey

Background: Hypothyroid patients often report dissatisfaction and poor quality of life. This survey explored the impact of hypothyroidism on patient satisfaction, everyday living, experiences with health care professionals, and influence of demographic and socioeconomic factors. Methods: Cross-sectional questionnaire survey targeting an international population of hypothyroid patients. Multilevel regression modeling was used for analyses. Results: The total number of responses was 3915 from 68 countries. Satisfaction with care and treatment was not associated with type of treatment for hypothyroidism. Having no confidence and trust in health care professionals was strongly associated with dissatisfaction (p < 0.001). Controlling for all other variables, significant differences were found among satisfaction rates between countries. A weak inverse relationship was found between satisfaction with care and treatment and impact on everyday living (p < 0.001). Respondents taking levothyroxine (LT4) alone were more likely to report a positive impact on everyday living (pooled odds ratio 2.376 [confidence interval: 0.941-5.997]) than respondents taking liothyronine-containing treatments. Conclusions: Low levels of satisfaction with care and treatment for hypothyroidism were strongly associated with lack of confidence and trust and negative experiences with health care professionals. Differences in responses between countries were noted, implying the potential influence of national health care systems, socioeconomic and cultural factors. Contrary to widespread anecdotes in social media, this large-scale survey shows no association between type of treatment for hypothyroidism and patient satisfaction, as well as better outcomes on everyday living associated with LT4, compared with liothyronine-containing treatments.

Use of thyroid hormone in hypothyroid patients and euthyroid subjects in Spain: A THESIS* questionnaire survey

BACKGROUND

Hypothyroidism is one of the leading conditions in endocrinology. Despite that fact, clinical indications for treatment still vary among Spanish specialists.

AIMS

To identify attitudes of Spanish specialists relating to the use of levothyroxine (LT4) and the management of hypothyroidism.

METHODS

The members of the Sociedad Española de Endocrinología y Nutrición (Spanish Society of Endocrinology and Nutrition) were invited to participate in a web-based survey. The survey, initially in English, was modified to reflect in accordance with the availability of thyroid hormone formulations in Spain.

RESULTS

A total of 505 of 1956 (25.8%) members (66% female) completed the survey; 97.4% declared that LT4 is the first-line therapy for hypothyroidism. The indications for LT4 therapy in euthyroidism were infertility in thyroid antibody-positive women (48.5%) and simple goitre (21.2%). However, 44.2% of specialists reported that there was no indication for LT4 therapy in such patients. Only a minority of respondents (2.6%) considered combining LT4 with liothyronine as the treatment of choice from inception, whereas 49% stated that it should never be used.

CONCLUSIONS

The standard of treatment of hypothyroidism in Spain is almost exclusively with LT4 tablets. Availability of other formulations of LT4 or combination therapy for hypothyroidism management remains to be explored, especially in patients with persistent symptoms. Notably, non-evidence-based use of LT4 is widely practiced in Spain for euthyroid women with autoimmune thyroiditis and fertility issues.

Role of Levothyroxine/Liothyronine Combinations in Treating Hypothyroidism

Diverse causes potentially underlie decreased quality of life in biochemically euthyroid patients treated for hypothyroidism with levothyroxine. Once these contributing factors are addressed, if symptoms persist, there may be benefit to personalized use of combination therapy adding liothyronine. This approach should be carefully monitored: avoiding overtreatment and ensuring that therapy is only continued if it improves patient-reported quality of life. Most randomized clinical trials have not shown benefits, perhaps because of not targeting the most symptomatic patients. Sustained-release liothyronine preparations may soon be available for optimally designed studies assessing whether combination therapy provides superior therapy for hypothyroidism in select patients.

Use of thyroid hormones in hypothyroid and euthyroid patients: a 2020 THESIS questionnaire survey of members of the Czech Society of Endocrinology

BACKGROUND

Inconsistencies in the management of hypothyroidism have been reported among endocrinologists in different European countries. Aim of this study was to explore Czech endocrinologists' use of thyroid hormones in hypothyroid and euthyroid patients.

METHODS

We used a web-based survey containing 32 questions regarding the use of thyroid hormones. Four-hundred thirty-two members of the Czech Society of Endocrinology received an e-mail invitation to participate in the survey.

RESULTS

We received and analysed 157 responses (112 females and 45 males) from the 432 members (36.3%). According to 99.4% of the respondents, levothyroxine (LT4) is the primary drug of choice for the treatment of hypothyroidism. Liothyronine (LT3) was used in clinical practice by 29.9% of responders. According to 90.5% of respondents, thyroid hormones may be indicated in biochemically euthyroid patients. Female physicians prescribe thyroid hormones in euthyroid infertile women with high antibody levels more frequently than male physicians (P = 0.003). Most Czech endocrinologists (76.4%) consider combined therapy with LT4 and LT3 in various clinical scenarios, but only 1 of 29 hypothyroid physicians (3.5%) would recommend it to their patients, and only 4 out of 128 respondents (3.1%) would consider LT3 or desiccated thyroid for themselves, if diagnosed with hypothyroidism.

CONCLUSION

LT4 is the primary thyroid hormone used in the Czech Republic for treatment of hypothyroidism. At variance with thyroid guideline recommendations, Czech endocrinologists are quite liberal when prescribing thyroid hormones to euthyroid patients and in the use of LT4/LT3 combination treatment for hypothyroid patients with persisting symptoms.

Enhanced Well-Being Associated with Thyrotoxicosis: A Neglected Effect of Thyroid Hormones?

CONTEXT

Thyrotoxicosis may be associated with a better sense of well-being than in the euthyroid state, though this is not widely recognised.

EVIDENCE ACQUISITION

A comprehensive literature search in PubMed and Google Scholar, was performed to identify studies investigating factors influencing well-being, mood, and psychological features associated with elevated thyroid hormones.

RESULTS

Enhanced well-being associated with thyrotoxicosis has been described, although the evidence is observational and anecdotal.

CONCLUSIONS

Enhanced well-being associated with thyrotoxicosis is probably experienced in a minority of patients and may explain why some seek overtreatment with thyroid hormones and report significant improvement on larger than physiological thyroid hormone replacement regimens. It may also explain why some patients with hyperthyroidism (usually due to Graves' disease) are reluctant to adhere to anti-thyroid medication.

Primary hypothyroidism and quality of life

In the 1970s, treatment with thyroid extract was superseded by levothyroxine, a synthetic L form of tetraiodothyronine. Since then, no major innovation has emerged for the treatment of hypothyroidism. The biochemical definition of subclinical hypothyroidism is a matter of debate. Indiscriminate screening for hypothyroidism has led to overdiagnosis and treatment initiation at lower serum levels of thyroid-stimulating hormone (TSH) than previously. Adverse health effects have been documented in individuals with hypothyroidism or hyperthyroidism, and these adverse effects can affect health-related quality of life (QOL). Levothyroxine substitution improves, but does not always normalize, QOL, especially for individuals with mild hypothyroidism. However, neither studies combining levothyroxine and liothyronine (the synthetic form of tri-iodothyronine) nor the use of desiccated thyroid extract have shown robust improvements in patient satisfaction. Future studies should focus not only on a better understanding of an individual's TSH set point (the innate narrow physiological range of serum concentration of TSH in an individual, before the onset of hypothyroidism) and alternative thyroid hormone combinations and formulations, but also on autoimmunity and comorbidities unrelated to hypothyroidism as drivers of patient dissatisfaction. Attention to the long-term health consequences of hypothyroidism, beyond QOL, and the risks of overtreatment is imperative.

Optimal Thyroid Hormone Replacement

Hypothyroidism is a common endocrinopathy, and levothyroxine is frequently prescribed. Despite the basic tenets of initiating and adjusting levothyroxine being agreed on, there are many nuances and complexities to consistently maintaining euthyroidism. Understanding the impact of patient weight and residual thyroid function on initial levothyroxine dosage and consideration of age, comorbidities, thyrotropin goal, life stage, and quality of life as levothyroxine is adjusted can be challenging and continually evolving. Because levothyroxine is a lifelong medication, it is important to avoid risks from periods of overtreatment or undertreatment. For the subset of patients not restored to baseline health with levothyroxine, causes arising from all aspects of the patient's life (coexistent medical conditions, stressors, lifestyle, psychosocial factors) should be broadly considered. If such factors do not appear to be contributing, and biochemical euthyroidism has been successfully maintained, there may be benefit to a trial of combination therapy with levothyroxine and liothyronine. This is not supported by the majority of randomized clinical trials, but may be supported by other studies providing lower-quality evidence and by animal studies. Given this discrepancy, it is important that any trial of combination therapy be continued only as long as a patient benefit is being enjoyed. Monitoring for adverse effects, particularly in older or frail individuals, is necessary and combination therapy should not be used during pregnancy. A sustained-release liothyronine preparation has completed phase 1 testing and may soon be available for better designed and powered studies assessing whether combination therapy provides superior therapy for hypothyroidism.

Use of thyroid hormones in hypothyroid and euthyroid patients: a THESIS* survey of Belgian specialists *THESIS: treatment of hypothyroidism in Europe by specialists: an international survey

Background

Hypothyroidism is a topic that continues to provoke debate and controversy with regards to specific indications, type of thyroid hormone substitution and efficacy. We investigated the use of thyroid hormones in clinical practice in Belgium, a country where currently only levothyroxine (LT4) tablet formulations are available.

Method

Members of the Belgian Endocrine Society were invited to respond to an online questionnaire. Results were compared with those from other THESIS surveys.

Results

Eighty (50%) of the invited 160 individuals, completed the questionnaire. LT4 was the first treatment of choice for all respondents. As secondary choice, some also prescribed liothyronine (LT3) and LT4 + LT3 combinations (2 and 7 respondents, respectively). Besides hypothyroidism, 34 and 50% of respondents used thyroid hormones for infertile euthyroid TPOAb positive women and the treatment of a growing non-toxic goiter, respectively. Had alternative formulations of LT4 to tablets been available (soft gel or liquid L-T4), 2 out of 80 (2.5%) participants would consider them for patients achieving biochemical euthyroidism but remaining symptomatic. This proportion was higher in case of unexplained poor biochemical control of hypothyroidism (13.5%) and in patients with celiac disease or malabsorption or interfering drugs (10%). In symptomatic euthyroid patients, 20% of respondents would try combined LT4 + LT3 treatment. Psychosocial factors were highlighted as the main contributors to persistent symptoms.

Conclusions

LT4 tablets is the preferred treatment for hypothyroidism in Belgium. A minority of the respondents would try combined LT4 + LT3 in symptomatic but biochemically euthyroid patients. Thyroid hormones are prescribed for euthyroid infertile women with thyroid autoimmunity and patients with non-toxic goiter, a tendency noted in other European countries, despite current evidence of lack of benefit.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13044-022-00121-9.

Use of thyroid hormones in hypothyroid and euthyroid patients: a 2020 THESIS questionnaire survey of members of the Hellenic Endocrine Society

PURPOSE

To investigate current practices of specialists in the use of thyroid hormone preparations in Greece as part of an ongoing international survey, namely THESIS-Treatment of Hypothyroidism in Europe by Specialists: an International Survey.

METHODS

An electronic link leading to an anonymized questionnaire was sent to all (n = 837) members of the Hellenic Endocrine Society.

RESULTS

In total, 501 respondents participated in the survey, though only part of the questionnaire was filled in by some participants. A total of 88.2% were endocrinologists and 57.9% worked in private practice. Levothyroxine (LT4) was the first-line choice (98.6%) for the treatment of hypothyroid patients. In total, 70.2% preferred LT4 soft-gel capsules for patients reporting intolerance to various foods. Soft-gel capsules were the preferred LT4 formulation for patients on generic LT4 and with unexplained poor biochemical control of hypothyroidism (66.3%) or inability to take LT4 fasted and separate from food/drink (68.3%). It was found that 48.4% would never use combined LT4 + LT3. However, 25% would use combination therapy for a short period in patients recovering from protracted hypothyroidism or in patients with normal serum TSH but persistent symptoms. Concerning euthyroid individuals, 31.9% considered treatment with thyroid hormones in infertile females with positive thyroid antibodies and 24.4% in patients with growing goiter. Selenium or iodine supplementation was used occasionally, mostly in patients with coexisting autoimmune thyroiditis.

CONCLUSIONS

LT4 tablets are the treatment of choice for hypothyroidism in Greece. Several conditions may lead to various other practices, some of which deviate from current evidence-based guidelines and need more scrutiny.

Treating hypothyroidism is not always easy: When to treat subclinical hypothyroidism, TSH goals in the elderly, and alternatives to levothyroxine monotherapy

The majority of patients with hypothyroidism feel better when levothyroxine treatment restores thyroid-stimulating hormone (TSH) concentrations to normal. Increasingly, a significant minority of patients remain symptomatic and are dissatisfied with their treatment. Overzealous treatment of symptomatic patients with subclinical hypothyroidism may contribute to dissatisfaction among hypothyroidism patients, as potential hypothyroid symptoms in patients with minimal hypothyroidism rarely respond to treatment. Thyroid hormone prescriptions have increased by 30% in the United States in the last decade. The diagnosis of subclinical hypothyroidism should be confirmed by repeat thyroid function tests ideally obtained at least 2 months later, as 62% of elevated TSH levels may revert to normal spontaneously. Generally, treatment is not necessary unless the TSH exceeds 7.0-10 mIU/L. In double-blinded randomized controlled trials, treatment does not improve symptoms or cognitive function if the TSH is less than 10 mIU/L. While cardiovascular events may be reduced in patients under age 65 with subclinical hypothyroidism who are treated with levothyroxine, treatment may be harmful in elderly patients with subclinical hypothyroidism. TSH goals are age dependent, with a 97.5 percentile (upper limit of normal) of 3.6 mIU/L for patients under age 40, and 7.5 mIU/L for patients over age 80. In some hypothyroid patients who are dissatisfied with treatment, especially those with a polymorphism in type 2 deiodinase, combined treatment with levothyroxine and liothyronine may be preferred.

Practical Guidelines for Diagnosing and Treating Thyroid Disease Based on the WOMED Metabolic Model of Disease Focusing on Glycolysis and Coenzyme Q10 Deficiency—A Clinical Alternative to the 2021 Retired Clinical Practice Guidelines of the Endocrine Society

This review aims to provide a functional, metabolic view of the pathogenesis of benign thyroid disease. Here, we summarize the features of our previous publications on the “WOMED model of benign thyroid disease”. As of 2021, the current state of art indicates that the basic alteration in benign thyroid disease is a metabolic switch to glycolysis, which can be recognized using 3D-power Doppler ultrasound. A specific perfusion pattern showing enlarged vessels can be found using this technology. This switch originates from an altered function of Complex I due to acquired coenzyme Q₁₀ deficiency, which leads to a glycolytic state of metabolism together with increased angiogenesis. Implementing a combined supplementation strategy that includes magnesium, selenium, and CoQ₁₀, the morphological and perfusion changes of the thyroid can be reverted, i.e., the metabolic state returns to oxidative phosphorylation. Normalization of iron levels when ferritin is lower than 50 ng/mL is also imperative. We propose that a modern investigation of probable thyroid disease requires the use of 3D-power Doppler sonography to recognize the true metabolic situation of the gland. Blood levels of magnesium, selenium, CoQ₁₀, and ferritin should be monitored. Thyroid function tests are complementary so that hypo- or hyperthyroidism can be recognized. Single TSH determinations do not reflect the glycolytic state.

Real-life practice of thyroid hormone use in hypothyroid and euthyroid patients: a detailed view from the THESIS* questionnaire survey in France

AIM

To describe practices of French physicians regarding thyroid hormone therapy, focusing on available LT4 formulations.

MATERIAL AND METHODS

Members of the French Endocrine Society (FES) and affiliated societies (the Endocrine Tumor Group, French College of Teachers of Endocrinology, Diabetes and Metabolic Diseases and the Union of Endocrinology, Diabetology, Metabolic Diseases and Nutrition Specialists) were invited to participate in an online survey.

RESULTS

534 of the 2,094 persons contacted (25.5%) completed the survey and were included in the analysis. The vast majority (99.4%) reported that levothyroxine (LT4) is the treatment of choice for hypothyroidism. 7.1% and 14.2% of respondents respectively considered liothyronine (LT3) or a combination of LT4 and LT3 for the treatment of hypothyroidism, mainly when symptoms persisted despite achieving normal TSH concentrations with LT4 therapy. For 44% of respondents, thyroid hormone treatment is never indicated in euthyroid patients, while the remainder would consider treating euthyroid patients with a goiter growing over time (40.2%) and/or euthyroid women with positive anti-TPO antibodies and infertility (31.7%). LT4 tablets were the preferred LT4 formulation. A significant proportion of FES members expected no major clinical differences upon changing to formulations such as soft-gel capsules or liquid solutions, even in specific scenarios such as poor biochemical control or suspicion of malabsorption.

CONCLUSION

The treatment of choice for hypothyroidism in France is LT4. LT3-based therapy is considered by some physicians in case of persistent symptoms of hypothyroidism despite normal TSH level. A significant proportion of respondents (66.0%) would consider treating euthyroid patients, contrary to the present state of knowledge. These outdated practices should be addressed by professional bodies such as the FES.

T4+T3 Combination Therapy: An Unsolved Problem of Increasing Magnitude and Complexity

Thyroxine (T4)+triiodothyronine (T3) combination therapy can be considered in case of persistent symptoms despite normal serum thyroid stimulating hormone in levothyroxine (LT4)-treated hypothyroid patients. Combination therapy has gained popularity in the last two decades, especially in countries with a relatively high gross domestic product. The prevalence of persistent symptoms has also increased; most frequent are complaints about energy levels and fatigue (80% to 90%), weight management (70% to 75%), memory (60% to 80%), and mood (40% to 50%). Pathophysiological explanations for persistent problems are unrealistic patient expectations, comorbidities, somatic symptoms, related disorders (Diagnostic and Statistical Manual of Mental Disorders [DSM-5]), autoimmune neuroinflammation, and low tissue T3. There is fair circumstantial evidence for the latter cause (tissue and specifically brain T3 content is normalized by T4+T3, not by T4 alone), but the other causes are viewed as more relevant in current practice. This might be related to the 'hype' that has emerged surrounding T4+T3 therapy. Although more and better-designed trials are needed to validate the efficacy of T4+T3 combination, the management of persistent symptoms should also be directed towards alternative causes. Improving the doctor-patient relationship and including more and better information is crucial. For example, dissatisfaction with the outcomes of T4 treatment for subclinical hypothyroidism can be anticipated as recent trials have demonstrated that LT4 is hardly effective in improving symptoms associated with subclinical hypothyroidism.

Use of thyroid hormone in hypothyroid patients and euthyroid subjects in Spain: A THESIS* questionnaire survey

BACKGROUND

Hypothyroidism is one of the leading conditions in endocrinology. Despite that fact, clinical indications for treatment still vary among Spanish specialists.

AIMS

To identify attitudes of Spanish specialists relating to the use of levothyroxine (LT4) and the management of hypothyroidism.

METHODS

The members of the Sociedad Española de Endocrinología y Nutrición (Spanish Society of Endocrinology and Nutrition) were invited to participate in a web-based survey. The survey, initially in English, was modified to reflect in accordance with the availability of thyroid hormone formulations in Spain.

RESULTS

A total of 505 of 1956 (25.8%) members (66% female) completed the survey; 97.4% declared that LT4 is the first-line therapy for hypothyroidism. The indications for LT4 therapy in euthyroidism were infertility in thyroid antibody-positive women (48.5%) and simple goitre (21.2%). However, 44.2% of specialists reported that there was no indication for LT4 therapy in such patients. Only a minority of respondents (2.6%) considered combining LT4 with liothyronine as the treatment of choice from inception, whereas 49% stated that it should never be used.

CONCLUSIONS

The standard of treatment of hypothyroidism in Spain is almost exclusively with LT4 tablets. Availability of other formulations of LT4 or combination therapy for hypothyroidism management remains to be explored, especially in patients with persistent symptoms. Notably, non-evidence-based use of LT4 is widely practiced in Spain for euthyroid women with autoimmune thyroiditis and fertility issues.

Use of Thyroid Hormones in Hypothyroid and Euthyroid Patients: A 2020 THESIS Questionnaire Survey of Members of the Swedish Endocrine Society

BACKGROUND

The standard treatment of hypothyroidism is levothyroxine (LT-4). However, there are several controversies regarding treatment of hypothyroid patients.

AIM

To investigate the Swedish endocrinologists' use of thyroid hormones in hypothyroid and euthyroid individuals.

METHODS

Physician members of the Swedish Endocrine Society (SEF) were invited by e-mail to participate in an online survey investigating this topic.

RESULTS

Out of the eligible 411 members, 116 (28.2%) responded. The majority (98.9%) stated that L-T4 is the treatment of choice. However, around 50% also prescribed liothyronine (L-T3) or a combination of L-T4+L-T3 in their practice. Combination therapy was mostly (78.5%) used in patients with persistent hypothyroid symptoms despite biochemical euthyroidism on L-T4 treatment. Most respondents prescribed L-T4 tablets and did not expect any major changes with alternative formulations such as soft-gel capsules or liquid formulations in situations influencing the bioavailability of L-T4. In euthyroid patients, 49.5% replied that treatment with thyroid hormones was never indicated, while 47.3% would consider L-T4 for euthyroid infertile women with high thyroid peroxidase (TPO) antibody levels.

CONCLUSION

The treatment of choice for hypothyroidism in Sweden is L-T4 tablets. Combination therapy with L-T4+L-T3 tablets was considered for patients with persistent symptoms despite biochemical euthyroidism. Soft-gel capsules and liquid solutions of L-T4 were infrequently prescribed. Swedish endocrinologists' deviation from endocrine society guidelines merits further study.