Health status, psychological symptoms, mood, and cognition in L-thyroxine-treated hypothyroid subjects

The Association Between Hypothyroidism and Cognitive Function Change in Women across the Menopause Transition: The Study of Women's Health Across the Nation

Background: Patients treated for hypothyroidism with levothyroxine (LT4) monotherapy may present with persistent hypothyroidism symptoms, including cognitive symptoms, despite having a normal thyroid stimulating hormone (TSH) level. It remains unclear whether LT4 monotherapy is sufficient to normalize cognitive function outcomes over time. Methods: This is a multisite longitudinal study of a diverse group of women during midlife representing 5 ethnic/racial groups from 7 enrollment sites across the United States in the Study of Women's Health Across the Nation. Women were screened for a history of thyroid disease and the use of LT4. The study consisted of two primary groups: women with LT4-treated hypothyroidism and control women without thyroid disease. Each participant completed up to 9 cognitive assessments over the study period testing processing speed, working memory, and episodic memory (immediate and delayed recall). Multivariable generalized linear mixed models of scores for each cognitive assessment were developed to determine the association between LT4-treated hypothyroidism and cognitive function trajectories. Covariates included sociodemographic, clinical characteristics, and menopausal status (pre/early peri, late peri, and surgical/post). Sensitivity analyses were conducted to assess the impact of abnormal TSH levels and practice effects (i.e., improvements in scoring after repeated testing). Results: Of the 2033 women who were included in the study, 227 (11.2%) met criteria for LT4-treated hypothyroidism. At baseline, both processing speed and working memory scores were higher in LT4-treated women (mean processing speed scores: 56.5 vs 54.4; p value = 0.006; mean working memory scores: 6.8 vs 6.4; p value = 0.018). However, when considering the effect of LT4-treated hypothyroidism over time, there were no significant differences in the rate of cognitive decline (in any measure) between the hypothyroidism and control groups with or without covariate adjustment. The results were similar when considering LT4-treated women with abnormal TSH levels or after minimizing practice effects. Conclusions: We observed no difference in cognitive decline between women with LT4-treated hypothyroidism and women without thyroid disease. For similar aged patients with cognitive complaints, if thyroid function testing is normal, clinicians should consider causes other than inadequate thyroid hormone treatment to explain these symptoms.

Disease Experience of Patients With Differentiated Thyroid Cancer at Different Phases Based on Timing It Right Framework: A Qualitative Longitudinal Study

BACKGROUND

As the incidence of differentiated thyroid cancer (DTC) continues to rise globally, it is important to gain insight into the disease experience of cancer patients at different phases of the disease. However, surveys addressing the longitudinal disease experience and specific needs of this population are lacking.

OBJECTIVE

The aim of this study was to explore the disease experience of people with DTC at key time points in their cancer trajectory so support can be rendered for "patient-centered" supportive care services.

METHODS

On the basis of the Timing It Right framework, a semistructured in-depth interview was conducted with 14 patients with DTC at 5 key phases from initial diagnosis to 6 months postoperatively, and data were analyzed using the Colaizzi 7-step analysis.

RESULTS

The themes of disease experience at different phases were as follows: (1) diagnostic phase: differences in acceptance; (2) perioperative phase: physical and mental distress; (3) discharge preparation phase: anxiety and helplessness, and gap of disease knowledge; (4) discharge adjustment phase: fear of recurrence and proactive health; and (5) discharge adaptation phase: multiple needs.

CONCLUSION

The experience, care needs, and nature of the needs of patients with DTC change dynamically with the different phases of the disease. Capturing the most appropriate time throughout the continuum of care to implement supportive care that patients need most will help to improve the continuity and precision of cancer care.

IMPLICATIONS FOR PRACTICE

Healthcare providers should provide a continuum of dynamic care by scientifically and systematically assessing the actual supportive care needs of patients with DTC according to their different phases of disease.

Are resting metabolic rate and clinical symptoms affected by variation of serum thyroid stimulating hormone levels within the normal range in healthy and women with hypothyroidism? A case-control study

BACKGROUND

It is unclear whether variation in thyroid stimulating hormone (TSH) levels within the reference range affect energy expenditure and clinical symptoms and even within the normal range of TSH levels, resting energy expenditure may alter. The aim of the present study was to determine whether treated hypothyroid subjects and healthy subjects with a low-normal TSH range (0.3-2.3 mIU/L) have better clinical outcomes and increased energy expenditure than those with a high-normal TSH range (2.3-4.3 mIU/L).

METHODS

This was a case-control study of 160 overweight/obese women with TSH levels across the reference range of 0.3-4.3 mU/l. Subjects were paired in four groups: healthy subjects with low-normal target TSH (n = 40), healthy subjects with high-normal target TSH (n = 40), subjects with treated hypothyroidism with low-normal target TSH (n = 40), and subjects with treated hypothyroidism with high-normal target TSH (n = 40). Resting energy expenditure (RMR), dietary intake, body composition, physical activity, and biochemical markers were assessed.

RESULTS

Subjects with low-normal (≤2.3 mU/L) and high-normal (>2.3 mU/L) TSH levels did not differ in terms of RMR, serum T3 levels, and clinical symptoms except fatigue (P = 0.013). However, serum fT4 levels were found to be significantly different between the study groups (P = 0.002). Serum fT4 concentration was the highest in subjects with treated hypothyroidism with low-normal target TSH.

CONCLUSION

Variation in serum TSH levels within the reference range did not significantly affect REE and clinical symptoms except fatigue in healthy and women with hypothyroidism.

Gene polymorphisms and thyroid hormone signaling: implication for the treatment of hypothyroidism

INTRODUCTION

Mutations and single nucleotide polymorphisms (SNPs) in the genes encoding the network of proteins involved in thyroid hormone signaling (TH) may have implications for the effectiveness of the treatment of hypothyroidism with LT4. It is conceivable that loss-of-function mutations or SNPs impair the ability of LT4 to be activated to T3, reach its targets, and ultimately resolve symptoms of hypothyroidism. Some of these patients do benefit from therapy containing LT4 and LT3.

METHODS

Here, we reviewed the PubMed and examined gene mutations and SNPs in the TH cellular transporters, deiodinases, and TH receptors, along with their impact on TH signaling, and potential clinical implications.

RESULTS

In some mechanisms, such as the Thr92Ala-DIO2 SNP, there is a compelling rationale for reduced T4 to T3 activation that limits the effectiveness of LT4 to restore euthyroidism. In other mechanisms, a potential case can be made but more studies with a larger number of individuals are needed.

DISCUSSION/CONCLUSION

Understanding the clinical impact of the genetic makeup of LT4-treated patients may help in the preemptive identification of those individuals that would benefit from therapy containing LT3.

Adequacy of thyroid hormone replacement for people with hypothyroidism in real-world settings: A systematic review and meta-analysis of observational studies

OBJECTIVE

Thyroid hormone under-replacement and over-replacement are associated with adverse health outcomes. This systematic review aimed to evaluate the extent of thyroid hormone replacement adequacy for patients with known hypothyroidism in real-word settings, excluding those receiving thyroid hormone suppressive therapy as thyroid cancer treatment.

DESIGN

Four electronic databases (Embase [Ovid], Medline [Ovid], PubMed and SCOPUS) were searched for published and unpublished observational studies until 12 December 2022. The results of the studies were meta-analysed to calculate pooled prevalence estimates for thyroid hormone supplementation adequacy, over-replacement and under-replacement. Quality assessment of studies was performed using the Joanna-Briggs appraisal tool for prevalence studies.

RESULTS

Seven studies with a total of 4230 patients were eligible for quantitative synthesis. The pooled prevalence estimates of adequate thyroid replacement, over-replacement and under-replacement were 0.55 (95% confidence interval [CI]: 0.49-0.60, p = .001), 0.20 (95% CI: 0.14-0.27, p = .001) and 0.24 (95% CI: 0.13-0.36, p = .001), respectively. Four studies subclassified hypothyroidism and hyperthyroidism into overt and subclinical. The pooled prevalence of overt and subclinical hyperthyroidism was 0.04 (95% CI: 0.00-0.11, p = .01) and 0.17 (95% CI: 0.09-0.27 p = .001), respectively. For overt and subclinical hypothyroidism, the pooled prevalence was 0.02 (95% CI: 0.01-0.03, p = .001) and 0.20 (95% CI: 0.12-0.29, p = .001), respectively.

CONCLUSIONS

On average, approximately half of patients with hypothyroidism are only treated to target euthyroidism. In real-world practice, a significant number of patients are over-treated or under-treated, leading to adverse healthcare outcomes. It is imperative that more effective thyroid monitoring strategies be implemented, with an emphasis on primary care thyroid function monitoring, to minimise inappropriate thyroid replacement treatments and optimise healthcare outcomes at a population level.

High-intensity interval training ameliorates spatial and recognition memory impairments, reduces hippocampal TNF-alpha levels, and amyloid-beta peptide load in male hypothyroid rats

Thyroid hormones are critical for healthy brain functions at every stage of life. Hypothyroidism can cause severe cognitive dysfunction in patients who do not receive adequate treatment. Although thyroid hormone replacement alleviates cognitive decline in hypothyroid patients, there are studies showing that there is no complete recovery. The aim of this study was to investigate the effects of high-intensity interval training (HIIT) in hypothyroid rats on spatial and recognition memory, neuroinflammation, amyloid-beta load and compare these effects with T3 replacement. Hypothyroidism was induced and maintained by administration of 6-n-propyl-2-thiouracil (PTU) with their drinking water to 6-weeks-old male Sprague-Dawley rats for 7 weeks. The animals exercised in the treadmill according to the HIIT protocol for four weeks. T3 was injected intraperitoneally daily during the last two weeks of the study. All animals performed in the elevated plus maze test, Morris water maze test, novel object recognition test, and rotarod motor performance test in the last week of the study and then the animals were sacrificed. Amyloid beta (1-42) and TNFα levels were measured in the prefrontal cortex and hippocampus by ELISA. Anxiety-like behaviors did not significantly differ between groups. T3 replacement with or without HIIT increased motor performance in PTU-treated rats. HIIT and/or T3 replacement increased the exercise performance. HIIT and/or T3 replacement alleviated spatial and recognition memory impairments and normalized TNFα and amyloid-beta levels in the hippocampus in hypothyroid rats. In summary, regular physical exercise may have potential benefits in preserving cognitive functions in hypothyroid patients.

A Cross-Sectional Analysis of Cardiovascular and Bone Health Care Utilization During Treatment With Thyroid Hormone

CONTEXT

Combination therapy with levothyroxine and liothyronine (LT4 + LT3) and desiccated thyroid extract (DTE) make up >10% of new thyroid hormone (TH) prescriptions in the United States.

OBJECTIVE

To assess health care utilization related to cardiovascular disease (CVD) and bone health (BH) events (atrial fibrillation [AF], heart failure [HF], myocardial infarction [MI], stroke, and osteoporosis/fractures [FX]) in participants taking LT4+LT3 or DTE surveyed in the Medical Expenditure Panel Survey database.

MATERIALS AND METHODS

Multi-year cross-sectional analysis examining 5437 participants (≥18 years old) treated with LT4, LT4+LT3, or DTE between 2016 and 2020. Health care utilization was assessed through outpatient, emergency, and hospital visits for AF, HF, MI, stroke, FX, and a composite index. A weighted analysis provided national estimates of health care utilization parameters. Utilization was re-analyzed following propensity score-based matching to balance sociodemographic and clinical covariates between treatment groups. Additionally, provider type and specialty data were obtained from visits associated with TH prescriptions.

RESULTS

5106 participants were treated with LT4 monotherapy, 252 with DTE, and 79 with LT4 + LT3. Prevalence of combined outpatient CVD and BH-related care utilization was lower among DTE/LT4+LT3 vs LT4 users (3.5% vs 7.7%; P = .008). There were no differences in emergency/hospital events. After covariate balancing, CVD and BH-related care utilization was similar between groups in outpatient and emergency/hospital settings. LT3 and DTE made up 7.6% of all TH prescriptions. For visits associated with DTE prescriptions, nurse practitioners and alternative medicine professionals were more likely to be identified as the primary provider type.

CONCLUSION

No significant differences in CVD- and BH-related health care utilization were identified between LT4 and DTE/LT4+LT3 users after covariate balancing. Non-MD providers were more likely to prescribe DTE.

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.

GlycA as a Novel Biomarker of Systemic Inflammation in Hypothyroidism

Background: GlycA is a novel glycoprotein biomarker of systemic inflammation and cardiovascular risk. Our objective was to assess the levels of GlycA in individuals with hypothyroidism. We also explored whether levothyroxine (LT4)-treated patients had different levels of GlycA, with attention to thyrotropin (TSH) levels. Methods: We performed a cross-sectional analysis, using baseline data from the ELSA-Brasil cohort study. We included only participants with serum TSH and GlycA levels measurements, using magnetic resonance spectroscopy (n = 4745). We excluded individuals with endogenous hyperthyroidism and those using drugs impacting thyroid function. Participants not taking LT4 and whose serum TSH was 0.4-4.0 mIU/L were classified as euthyroid (EU) and those with elevated TSH as undiagnosed hypothyroidism (UH). For those on LT4 (n = 345), adequacy of treatment was defined as TSH within the reference range. Those with TSH <0.4 mIU/L were considered over-treated (OT), and those >4.0 mIU/L, under-treated (UT). Both (UT+OT) were considered inadequately treated (IT). Group comparisons were performed by Kruskal-Wallis, adjusted Chi-square, and the post hoc Dunn test. Additional subgroup analysis were performed in patients with circulating thyroperoxidase antibodies (TPO-Ab+). Respective multivariable analyses were performed to evaluate the relationship between thyroid-related variables and GlycA levels (Generalized Linear Model), as well as an abnormal GlycA (>400 μmol/L; Logistic Binary Regression). Results: The prevalence rate of UH was 9.8% (467/4745) and, among those on LT4, only 61.7% (213/345) were adequately treated (AT). GlycA levels were higher in IT in comparison to EU (429 vs. 410 μmol/L, p < 0.01) but did not differ between UH (413 μmol/L) and euthyroidism. However, the subgroup analysis of those TPO-Ab+ showed that not only those with IT, but also those with UH, had higher levels of GlycA in comparison to euthyroidism (423 and 424 vs. 402 μmol/L, p = 0.04). This association between higher levels of GlycA and IT was maintained even in multivariable analysis (odds ratio 1.53, confidence interval 1.03 to 2.31) Lower levels of GlycA were detected in AT (405 μmol/L,) compared with OT (432 μmol/L, 0.04) and UT (423 μmol/L, p = 0.02). Conclusions: Patients with IT, both OT and UT, had higher GlycA levels, which may be associated with low-grade systemic inflammation and, possibly, increased cardiovascular risk.

Are We Restoring Thyroid Hormone Signaling in Levothyroxine-Treated Patients With Residual Symptoms of Hypothyroidism?

INTRODUCTION

Levothyroxine (LT4) at doses that maintain the serum thyroid-stimulating hormone levels within the normal range constitutes the standard of care for the treatment of hypothyroidism. After a few months, this eliminates the signs and symptoms of overt hypothyroidism in the majority of patients, owing to the endogenous activation of thyroxine to triiodothyronine, the biologically active thyroid hormone. Still, a small percentage of the patients (10%-20%) exhibit residual symptoms, despite having normal serum thyroid-stimulating hormone levels. These symptoms include cognitive, mood, and metabolic deficits, with a significant impairment in psychological well-being and quality of life.

OBJECTIVE

To provide a summary of progress in the approach of patients with hypothyroidism that exhibit residual symptoms despite treatment.

METHODS

We reviewed the current literature and here we focused on the mechanisms leading to a deficiency of T3 in some LT4-treated patients, the role of residual thyroid tissue and the rationale for combination therapy with LT4 + liothyronine (LT3).

RESULTS

A score of clinical trials comparing therapy with LT4 versus LT4 + LT3 concluded that both are safe and equally effective (neither is superior); however, these trials failed to recruit a sufficiently large number of patients with residual symptoms. New clinical trials that considered LT4-treated symptomatic patients revealed that such patients benefit from and prefer therapy containing LT4 + LT3; desiccated thyroid extract has also been used with similar results. A practical approach to patients with residual symptoms and on initiation of combination therapy with LT4 + LT3 is provided.

CONCLUSION

A recent joint statement of the American, British, and European Thyroid Associations recommends that a trial with combination therapy be offered to patients with hypothyroidism that do not fully benefit from therapy with LT4.

The effect of thyroid hormone withdrawal performed to evaluate the success of I-131 ablation on quality of life and psychological symptoms in female patients with low-risk differentiated thyroid cancer

Aim: There is a need to evaluate the treatment response in patients who have undergone radioiodine treatment (RIT) for differentiated thyroid cancer. Diagnostic tests that are used for this purpose include radioiodine whole-body scan (WBS) and serum thyroglobulin (Tg) measurement, which are most accurate during thyroid-stimulating hormone (TSH) stimulation. However, temporary discontinuation of thyroid hormone therapy to increase TSH (withdrawal) may be associated with the morbidity of hypothyroidism. The study aimed to show the effects of thyroid hormone withdrawal (THW) on quality of life and psychological symptoms in female patients with low-risk, well-differentiated papillary thyroid cancer. Methods: We applied the short form-36 (SF-36) and Symptom Checklist-90-R (SCL-90-R) questionnaires to the patients in the euthyroid state who have referred a median of 9 months (6-13 months) after RIT to perform a dWBS and to evaluate stimulated Tg. We applied the same questionnaire again when thyroid-stimulating hormone (TSH) was > 30 μIU/mL 4 weeks after THW (hypothyroid state). Results: 52 patients were evaluated (median age 48 years, range 23-65 years). There was a statistically significant worsening in anxiety, psychosis, additional items, and general symptoms of the SCL-90-R questionnaire, physical functioning, role limitation due to physical health, energy/fatigue, emotional well-being, social function, and general health change in the SF-36 questionnaire. Conclusions: THW worsened the patients’ psychological symptoms and quality of life. To reduce the side effects of hypothyroidism, treatment response assessment with TSH stimulation should be used only in a selected group of patients with a higher risk of recurrence.

Brain Fog in Hypothyroidism: What Is It, How Is It Measured, and What Can Be Done About It

Background: Some levothyroxine (LT4)-treated hypothyroid patients report a constellation of persistent and distressing cognitive symptoms that has been termed brain fog. This narrative review focuses on attempts to define and measure hypothyroid-associated brain fog, summarize possible etiologies and contributing factors, present treatment options, and propose avenues for future research. Methods: Published literature was reviewed to summarize available information on patient-reported symptoms associated with brain fog in hypothyroidism, as well as objective evidence of impairment based on neurocognitive testing and functional imaging studies. Given the limited information specific for hypothyroid-associated brain fog, relevant data from other medical conditions associated with brain fog were also reviewed and incorporated into recommendations for clinical care and future research areas. Results: Hypothyroid-associated brain fog has not been well defined or quantitated, and the underlying pathophysiology is unclear. Symptoms vary among patients but commonly include fatigue, depressed mood, and cognitive difficulties in the areas of memory and executive function. Symptoms often predate the diagnosis of hypothyroidism, and the magnitude of cognitive impairment can range from mild to severe. Regardless of severity, these symptoms are associated with impaired quality of life and cause dissatisfaction with treatment, so often lead to requests for alternate therapies. Disease-specific and psychological factors impact the experience of brain fog in complex ways, including potential limitations in LT4 monotherapy, self-knowledge of a disease state, and expectations for therapeutic effects. Conclusions: Brain fog is a variable symptom complex in people with hypothyroidism, causing significant distress and diminished quality of life. In the absence of proven therapies, individualized treatment plans are recommended, which incorporate thyroid-specific, general medical, and psychosocial approaches. In particular, cognitive rehabilitation is an underutilized technique that is beneficial in other medical conditions associated with brain fog and could improve symptoms in hypothyroid people. The limitations in our current knowledge and questions presented throughout this review highlight a major need for clinical research in this understudied area. Future research should include attention to standardization of survey instruments to quantitate brain fog in hypothyroid people, as well as rigorously designed intervention studies.

Quality of life following lobectomy versus total thyroidectomy is significantly related to hypothyroidism

OBJECTIVE

The aim of the present study was to investigate the differences in quality of life (QOL) following complete or partial thyroidectomy and with regard to thyroid hormone replacement (LT4) therapy.

STUDY DESIGN

Patients who underwent thyroidectomy were asked to complete the validated thyroid-specific ThyPRO QOL questionnaire at least 6 months following surgery.

SETTING

Tertiary medical center.

METHODS

Thyroid specific QOL questionnaire analysis.

RESULTS

A total of 190 patients completed the ThyPRO questionnaire. Of them 89 patients had complete thyroidectomy and 101 patients had unilateral thyroid lobectomy. The total thyroidectomy group had significantly worse overall QOL self-assessment score than the lobectomy patients (p < 0.0001). Patients receiving LT4 therapy regardless of the extent of surgery, reported worse QOL compared to patients not receiving LT4.

CONCLUSIONS

Quality of life following thyroid surgery is significantly related to hypothyroidism and the requirement for LT4 therapy, rather to the extent of surgery. The best QOL was reported in patients treated with lobectomy who did not require LT4 therapy.

Brain Fog in Hypothyroidism: Understanding the Patient's Perspective

OBJECTIVE

Patient-centered studies have shown that several patients on thyroid hormone replacement therapy for hypothyroidism exhibit persistent symptoms, including "brain fog." Here, we aimed to determine which of these specific symptoms are associated with brain fog, identify patient-reported factors that modify these symptoms, and identify patient concerns related to brain fog not included in thyroid-specific questionnaires.

METHODS

A survey on brain fog symptoms adapted from thyroid-specific patient-reported outcome was distributed online. Textual data analysis was performed to identify common areas of concern from open-ended survey responses.

RESULTS

A total of 5170 participants reporting brain fog while being treated for hypothyroidism were included in the analysis. Of these, 2409 (46.6%) participants reported symptom onset prior to the diagnosis of hypothyroidism, and 4096 (79.2%) participants experienced brain fog symptoms frequently. Of the symptoms listed, participants associated fatigue and forgetfulness most frequently with brain fog. More rest was the most common factor provided for improving symptoms. The textual data analysis identified areas of concern that are not often included in thyroid-specific quality of life questionnaires, including a focus on the diagnosis of hypothyroidism, the types and doses of medications, and the patient-doctor relationship.

CONCLUSION

Brain fog in patients treated for hypothyroidism was associated most frequently with fatigue and cognitive symptoms. Several additional areas of patient concern were found to be associated with brain fog, which are not typically addressed in thyroid-specific questionnaires.

Change in Thyroid Hormone Metabolite Concentrations Across Different Thyroid States

Background: In contrast to the thyroid hormones (TH) 3,3',5-triiodothyronine (T3) and thyroxine (T4), current literature on thyroid hormone metabolite concentrations in the hypothyroid and hyperthyroid states is inconclusive. It is unknown how thyroidectomy affects thyroid hormone metabolite concentrations and if levothyroxine (LT4) replacement therapy after thyroidectomy restores thyroid hormone metabolite concentrations in those without a thyroid gland. The treatment of patients with differentiated thyroid cancer (DTC) covers the euthyroid, hypothyroid, and (subclinical) hyperthyroid states and therefore provides a unique model to answer this. Here, we prospectively studied nine TH and its metabolites (THM) across different thyroid states in a cohort of patients treated for DTC. Also, three potentially important determinants for THM concentrations were studied. Methods: We prospectively included patients aged 18 to 80 years who were scheduled for DTC treatment at the Erasmus MC. Peripheral blood samples were obtained before surgery (euthyroid, endogenous TH production), after surgery just before radioactive iodine therapy (hypothyroid), and six months later on LT4 therapy ([subclinically] hyperthyroid, exogenous T4 supplementation). Nine THMs were quantified in serum with an established liquid chromatography/tandem mass spectrometry method. Repeated measurement analysis was used to compare the three different thyroid states with each other for each THM, while linear regression was used to determine the association between THM concentrations and age, sex, and kidney function. Results: In total, 77 patients (mean age 49 years; 65% women) were eligible for the study. 3,5-diiodothyronine and 3,3',5-triiodothyroacetic acids were below the lower limit of detection. Compared with the euthyroid state, all THMs were significantly decreased in the hypothyroid state and significantly increased in the (subclinically) hyperthyroid state, with T3 concentrations remaining within the reference interval. Higher age was associated with higher 3-monoiodothyronine (3-T1) concentrations (p < 0.001). Women had higher L-thyronine concentrations than men (p = 0.003). A better kidney function was associated with lower 3-T1 concentrations (p < 0.001). Conclusions: All THMs decrease after a thyroidectomy and increase under thyrotropin (TSH)-suppressive LT4-therapy, suggesting that formation of thyroid hormone metabolites is dependent on peripheral extrathyroidal metabolism of T4. This is also reflected by T3 concentrations that remained within the reference interval in patients receiving TSH-suppressive LT4-therapy as T3 has some thyroidal origin.

Relatively Lower FT3 Levels Are Associated with Impaired Quality of Life in Levothyroxine-Treated Patients with Hashimoto Thyroiditis

OBJECTIVE

Patients with Hashimoto thyroiditis (HT) frequently have some complaints despite achieving euthyroidism after levothyroxine (LT4) treatment. This study aimed to investigate the relevant factors affecting the quality of life (QoL) in euthyroid HT patients after LT4 treatment.

METHODS

In this case-control study, 133 participants with HT were included. They were divided into two groups: 64 euthyroid HT subjects (control group) and 69 HT patients were rendered euthyroid by LT4 treatment (well-controlled group). QoL was measured with the Thyroid-Related Patient-Reported Outcome (ThyPRO-39) questionnaire.

RESULTS

Both study groups were well matched with respect to gender, age, BMI, euthyroidism, and thyroid antibodies (TPOAb and TGAb). Compared with the control group, the well-controlled group had lower FT3 (P < 0.01) levels. Of note, QoL was impaired on all scales in the well-controlled group. Moreover, ThyPRO-39 scores among the well-controlled group were significantly higher (worse) than the control group in all scales. Regarding the composite scale, its score was related to FT3 (r = -0.176, P=0.043) but not to FT4 and TSH levels. Further logistic regression analysis revealed FT3 was significantly associated with elevated composite QoL [0.128 (0.029-0.577), P < 0.01] after adjustment of potential confounders.

CONCLUSION

Relatively lower FT3 concentrations, even within the normal reference range, were related to impaired QoL in HT patients treated with LT4. This finding supports the great value of FT3 in clinical decision-making on dose adequacy.

Evaluating health outcomes in the treatment of hypothyroidism

Clinical hypothyroidism is defined by the inadequate production of thyroid hormone from the thyroid gland to maintain normal organ system functions. For nearly all patients with clinical hypothyroidism, lifelong treatment with thyroid hormone replacement is required. The primary goal of treatment is to provide the appropriate daily dose of thyroid hormone to restore normal thyroid function for each individual patient. In current clinical practice, normalization of thyrotropin (TSH) level is the primary measure of effectiveness of treatment, however the use of a single biomarker to define adequate thyroid hormone replacement is being reevaluated. The assessment of clinical health outcomes and patient-reported outcomes (PROs), often within the context of intensity of treatment as defined by thyroid function tests (i.e., undertreatment, appropriate treatment, or overtreatment), may play a role in evaluating the effectiveness of treatment. The purpose of this narrative review is to summarize the prominent health outcomes literature in patients with treated hypothyroidism. To date, overall mortality, cardiovascular morbidity and mortality, bone health and cognitive function have been evaluated as endpoints in clinical outcomes studies in patients with treated hypothyroidism. More recent investigations have sought to establish the relationships between these end results and thyroid function during the treatment course. In addition to clinical event outcomes, patient-reported quality of life (QoL) has also been considered in the assessment of adequacy of hypothyroidism treatment. From a health care quality perspective, treatment of hypothyroidism should be evaluated not just on its effectiveness for the individual patients but also to the extent to which patients of different sociodemographic groups are treated equally. Ultimately, more research is needed to explore differences in health outcomes between different sociodemographic groups with hypothyroidism. Future prospective studies of treated hypothyroidism that integrate biochemical testing, PROs, and end result clinical outcomes could provide a more complete picture into the effectiveness of treatment of hypothyroidism.

Does Hormone Supplementation With Levothyroxine Improve Hypothyroid Impaired Cognitive Dysfunction?

Hypothyroidism is a widespread condition in the United States, affecting approximately 5% of the adult population. Although the clinical use of levothyroxine is well understood, its effect on preventing dementia is not well established. While the exact role of thyroid hormones in the adult brain is unknown, it is apparent that poor thyroid function can lead to mood swings, cognitive impairment, and other psychiatric symptoms. Most studies demonstrate an association between thyroid health and cognition, specifically slow processing of information, decreased effectiveness of executive functions, and lack of learning. This study aims to review the effect of levothyroxine on dementia. We searched electronic databases such as PubMed, Google Scholar, Science Direct, Cochrane, gray literature, and the references of included articles to find relevant articles. Two investigators independently identified eligible studies, screened title/abstract, and extracted data. We identified a total of 319 citations through a database search with six studies (case-control, longitudinal, cross-sectional, randomized controlled trials) meeting the inclusion criteria. Studies with moderate to low risk of bias were evaluated using their respective quality check tools. Five of six studies showed a positive impact of levothyroxine (LT-4) on dementia. According to these studies, the plausible rationale behind the reversal of memory with LT-4 treatment is restoring thyroid-stimulating hormone (TSH), thyroxine (T4) levels, and gamma-aminobutyric acid (GABA) concentrations. People with abnormal thyroid function should be screened for cognitive dysfunction using specific neurocognitive tests and start treatment with LT-4 regardless of symptom presentation. Multi-dose randomized placebo-controlled intervention studies are recommended to assess the effect of LT-4 on lowering the risk of dementia in hypothyroid patients.

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.

Impact of Permanent Post-thyroidectomy Hypoparathyroidism on Self-evaluation of Quality of Life and Voice: Results from the National QoL-hypopara Study

OBJECTIVE

To compare the quality of life (mental health) and voice in patients with or without permanent hypoparathyroidism after total thyroidectomy.

SUMMARY BACKGROUND DATA

Permanent hypoparathyroidism is an underestimated complication of thyroid surgery owing to suppression of parathormone secretion. Few studies have evaluated the consequences of hypoparathyroidism on quality of life and none has studied its effects on voice.

METHODS

The QoL-hypopara study (ClinicalTrial.gov NCT04053647) was a national observational study. Adult thyroidectomized patients were included between January and June 2020. A Serum parathormone level <15pg/mL more than 6 months after surgery defined permanent hypoparathyroidism. Patients answered the MOS-36-item short-form health (SF-36), the Voice Handicap Index (VHI) surveys, and a list of questions regarding their symptoms.

RESULTS

141 patients were included, 45 with permanent hypoparathyroidism. The median period between thyroid surgery and the questionnaire was 6 [Q1-Q3 4-11] and 4 [4-5] years in hypoparathyroid patients and controls respectively. Hypoparathyroid patients presented a reduced median mental score ratio (SF-36) (0.88 [Q1-Q3 0.63-1.01] versus 1.04 [0.82-1.13], P=0.003) and a lower voice quality (incidence rate ratio for total VHI 1.83-fold higher, P<0.001). In multivariable analysis, hypoparathyroidism (-0.17 [95%CI -0.28--0.07], P=0.002), but not age, female sex, thyroid cancer, or abnormal TSH level, was associated with the reduced mental score ratio. Myalgia, joint pain, paresthesia, tetany, anxiety attack and exhaustion were the most common symptoms among hypoparathyroid patients (>50%).

CONCLUSIONS

Hypoparathyroid patients present significantly impaired quality of life, lower voice quality and frequent symptoms. These results reinforce the importance of preventing this complication.

What Is the Quality of Life in Patients Treated with Levothyroxine for Hypothyroidism and How Are We Measuring It? A Critical, Narrative Review

Thyroid hormone replacement therapy (THRT, generally using oral levothyroxine (LT4)) is a safe, effective means of treating hypothyroidism. However, a proportion of LT4-treated patients with biochemically normal thyroid function tests complain of persistent symptoms that impact their health-related quality of life (QoL). The objectives of this critical, narrative review of the literature were to identify studies of QoL in LT4-treated patients with hypothyroidism, examine the instruments used to measure QoL, determine whether normal QoL is restored by THRT, and identify factors associated with QoL. The PubMed database was searched from 1 January 2000 to 31 December 2020. A total of 809 publications were screened, 129 full-text articles were retrieved, and 58 were analyzed. The studies of overt hypothyroidism evidenced an improvement in psychological and emotional well-being after three to six months of THRT with LT4, although contrasting results were found for patients with subclinical hypothyroidism. Combination treatment with LT4 and liothyronine was not generally associated with better QoL. In hypothyroidism, QoL appears to be influenced by a number of physiological, behavioral, cognitive and/or lifestyle factors that are not strictly related to thyroid hormone levels.

A survey of the young person's experience of Graves' disease and its management

OBJECTIVE

A suboptimal quality of life (QoL) has been reported in patients with Graves' disease treated in adult life, but long-term QoL in those treated in childhood and adolescence is unclear. We wanted to understand how Graves' disease and its management impact on the physical, psychological and social well-being of young people and their longer-term QoL.

DESIGN, PATIENTS AND MEASUREMENTS

Two questionnaires were used to assess QoL and patient experience of Graves' disease; PedsQL™ Generic Core Scales and a Graves' disease questionnaire devised for this project. The anonymized questionnaires were sent to young people (<30 years) diagnosed with Graves' disease in childhood and adolescence and managed at a tertiary paediatric endocrine unit in the North of England. Respondent QoL scores were compared with a healthy UK cohort.

RESULTS

Questionnaires were sent to 51 young people, and 26 responded (51%). Graves' patients reported a lower total QoL score compared with the healthy cohort (p = .003). This was particularly apparent in the psychosocial domain (p = .0016). No patient regretted having definitive treatment (surgery/radioiodine), and all said they would recommend it to others. Half of those who had received definitive treatment still did not feel recovered. There was no difference in the long-term QoL in those who did/did not receive definitive treatment (p = .40).

CONCLUSIONS

This study highlights short- and long-term impacts on the QoL and general well-being of young people with Graves' disease. There were no regrets regarding the choice of definitive treatment. This information will help inform the counselling of patients and their families.

The Role of Illness-Related Beliefs in Depressive, Anxiety, and Anger Symptoms: An On-line Survey in Women With Hypothyroidism

Hypothyroidism may affect 3-8.5% of the population and is a growing global health problem. Objective: The aim of the current study was to assess the relationships between cognitive representations of this illness and the severity of symptoms of depression, anxiety, and anger in women who suffer from hypothyroidism. Methods: The study used a cross-sectional design with on-line recruitment and measurements. A total of 354 women took part in the study and completed the following questionnaires: a 5-point self-rating scale that measures the three major symptoms of hypothyroidism, the Illness-Related Beliefs Questionnaire, the Hospital Anxiety and Depression Scale-Modified (HADS-M), and a clinical and sociodemographic data questionnaire. Results: The study found a relationship between the severity of emotional distress symptoms and illness-related beliefs. These beliefs were correlated with depressive symptoms, anxiety, and anger regardless of age, education, hormone levels or time since the diagnosis. In addition, the results of regression analyses, both hierarchical and stepwise, indicated that beliefs about the disease explained relatively high levels of the outcome variables (about 30% of the variance of depressive and anxiety symptoms and 16% of anger) as measured by HADS-M. Conclusions: Psychological factors seem to play an important role in the development of symptoms of depression, anxiety, and anger in patients with hypothyroidism. Psychosocial interventions targeting personal beliefs about the nature of the disease and its social aspects may be an effective way to reduce emotional distress symptoms.

Health-Related Quality of Life in Levothyroxine-Treated Hypothyroid Women and Women without Hypothyroidism: A Case-Control Study

The use of levothyroxine is not always related to the elimination of the symptoms of hypothyroidism. The aim of this study is to compare the health-related quality of life (HRQOL) of a group of hypothyroid women under levothyroxine treatment with that of a group of non-hypothyroid women. Methodology: A case–control study was performed. We used convenience sampling. The case group consisted of 152 levothyroxine-treated hypothyroid women; the control group consisted of 238 women without hypothyroidism disorders. All of the participants were euthyroid according to the clinical practice guidelines. We used as instruments the Short Form-12 questionnaire (SF-12v1) and a sociodemographic questionnaire. Results: Hypothyroid women scored significantly lower in HRQOL in SF-12v1 mental and physical components than the control group (mental component summary: 41.23 ± 12.12 vs. 46.45 ± 10.22, p < 0.001; physical component summary: 49.64 ± 10.16 vs. 54.75 ± 5.76, p < 0.001). body mass index (BMI) and age showed an influence on the physical component (p < 0.001 in both variables). Adjusted for age and BMI, hypothyroidism was still related to worse scores (p < 0.001). Conclusion: Despite being euthyroid, women with hypothyroidism showed a poorer quality of life than women without hypothyroidism. Health professionals need to assess the HRQOL of women with hypothyroidism. Further research on HRQOL and hypothyroidism is needed.

Temporal Pole Responds to Subtle Changes in Local Thyroid Hormone Signaling

To study thyroid hormone (TH) signaling in the human brain, we analyzed published microarray data sets of the temporal pole (Brodmann area 38) of 19 deceased donors. An index of TH signaling built on the expression of 19 well known TH-responsive genes in mouse brains (T3S+) varied from 0.92 to 1.1. After Factor analysis, T3S+ correlated independently with the expression of TH transporters (MCT8, LAT2), TH receptor (TR) beta and TR coregulators (CARM1, MED1, KAT2B, SRC2, SRC3, NCOR2a). Unexpectedly, no correlation was found between T3S+ vs DIO2, DIO3, SRC1, or TRα. An unbiased systematic analysis of the entire transcriptome identified a set of 1649 genes (set #1) with strong positive correlation with T3S+ (r > 0.75). Factor analysis of set #1 identified 2 sets of genes that correlated independently with T3S+, sets #2 (329 genes) and #3 (191 genes). When processed through the Molecular Signatures Data Base (MSigDB), both sets #2 and #3 were enriched with Gene Ontology (GO)-sets related to synaptic transmission and metabolic processes. Ranking individual human brain donors according to their T3S+ led us to identify 1262 genes (set #4) with >1.3-fold higher expression in the top half. The analysis of the overlapped genes between sets #1 and #4 resulted in 769 genes (set #5), which have a very similar MSigDB signature as sets #2 and #3. In conclusion, gene expression in the human temporal pole can be assessed through T3S+ and fluctuates with subtle variations in local TH signaling.

Individualized Therapy for Hypothyroidism: Is T4 Enough for Everyone?

CONTEXT

It is well recognized that some hypothyroid patients on levothyroxine (LT4) remain symptomatic, but why patients are susceptible to this condition, why symptoms persist, and what is the role of combination therapy with LT4 and liothyronine (LT3), are questions that remain unclear. Here we explore evidence of abnormal thyroid hormone (TH) metabolism in LT4-treated patients, and offer a rationale for why some patients perceive LT4 therapy as a failure.

EVIDENCE ACQUISITION

This review is based on a collection of primary and review literature gathered from a PubMed search of "hypothyroidism," "levothyroxine," "liothyronine," and "desiccated thyroid extract," among other keywords. PubMed searches were supplemented by Google Scholar and the authors' prior knowledge of the subject.

EVIDENCE SYNTHESIS

In most LT4-treated patients, normalization of serum thyrotropin levels results in decreased serum T3/T4 ratio, with relatively lower serum T3 levels; in at least 15% of the cases, serum T3 levels are below normal. These changes can lead to a reduction in TH action, which would explain the slower rate of metabolism and elevated serum cholesterol levels. A small percentage of patients might also experience persistent symptoms of hypothyroidism, with impaired cognition and tiredness. We propose that such patients carry a key clinical factor, for example, specific genetic and/or immunologic makeup, that is well compensated while the thyroid function is normal but might become apparent when compounded with relatively lower serum T3 levels.

CONCLUSIONS

After excluding other explanations, physicians should openly discuss and consider therapy with LT4 and LT3 with those hypothyroid patients who have persistent symptoms or metabolic abnormalities despite normalization of serum thyrotropin level. New clinical trials focused on symptomatic patients, genetic makeup, and comorbidities, with the statistical power to identify differences between monotherapy and combination therapy, are needed.

The effects of the combination of Cyperus rotundus, Crocus sativus, Piper nigrum, and Boswellia serrata on learning and memory deficit and oxidative damage in brain tissue of hypothyroid rats

In the present study, the impact of a combination of four memory-enhancer herbs on cognitive impairment and brain tissue oxidative damage due to hypothyroidism was evaluated. Propylthiouracil (PTU; 0.05%) was administrated in drinking water. Rats were treated with a combination of four herbal products (Cyperus rotundus, Crocus sativus, Piper nigrum, and Boswellia serrata) mixed with honey at two doses (640 and 1,280 mg/kg) or donepezil (0.5 mg/kg), for 6 weeks. Memory performance on the Morris water maze (MWM) and avoidance behavior in passive avoidance was impaired by hypothyroidism, and brain tissue oxidative damage occurred. Herbal combination and donepezil significantly improved memory impairment, reduced malondialdehyde concentration, and nitric oxide metabolites while increased the thiol contents and catalase and superoxide dismutase enzymes activity in the brain. Our findings suggest that the mixture of herbal products improves learning and memory deficits caused by hypothyroidism, probably by reducing the brain tissue oxidative damage. PRACTICAL APPLICATIONS: Learning and memory impairment is a common feature of thyroid hormones deficiency. Several studies are showing that hypothyroidism in juvenile and mature rats induces significant cognitive impairment. Likewise, in humans, a close relationship between thyroid hormone deficiency and cognitive impairment has been reported. We used a mixture of herbal products, including Cyperus rotundus, Crocus sativus, Piper nigrum, and Boswellia serrata, to treat hypothyroidism-induced memory impairment. All these herbs are widely used as a food additive across the world. In Iranian traditional medicine, this herbal combination traditionally used to treat cognitive impairments. Numerous studies have indicated that these herbs show neuroprotective and memory-enhancing properties. Our finding indicated that a traditionally used herbal combination could potentially use as a treatment of cognitive impairment induced by thyroid hormone deficiency.

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.

Resting Energy Expenditure in Obese Women with Primary Hypothyroidism and Appropriate Levothyroxine Replacement Therapy

CONTEXT

Growing evidence suggests that appropriate levothyroxine (LT4) replacement therapy may not correct the full set of metabolic defects afflicting individuals with hypothyroidism.

OBJECTIVE

To assess whether obese subjects with primary hypothyroidism are characterized by alterations of the resting energy expenditure (REE).

DESIGN

Retrospective analysis of a set of data about obese women attending the outpatients service of a single obesity center from January 2013 to July 2019.

PATIENTS

A total of 649 nondiabetic women with body mass index (BMI) > 30 kg/m2 and thyrotropin (TSH) level 0.4-4.0 mU/L were segregated into 2 groups: patients with primary hypothyroidism taking LT4 therapy (n = 85) and patients with normal thyroid function (n = 564).

MAIN OUTCOMES

REE and body composition assessed using indirect calorimetry and bioimpedance.

RESULTS

REE was reduced in women with hypothyroidism in LT4 therapy when compared with controls (28.59 ± 3.26 vs 29.91 ± 3.59 kcal/kg fat-free mass (FFM)/day), including when adjusted for age, BMI, body composition, and level of physical activity (P = 0.008). This metabolic difference was attenuated only when adjustment for homeostatic model assessment of insulin resistance (HOMA-IR) was performed.

CONCLUSIONS

This study demonstrated that obese hypothyroid women in LT4 therapy, with normal serum TSH level compared with euthyroid controls, are characterized by reduced REE, in line with the hypothesis that standard LT4 replacement therapy may not fully correct metabolic alterations related to hypothyroidism. We are not able to exclude that this feature may be influenced by the modulation of insulin sensitivity at the liver site, induced by LT4 oral administration.

Graves' disease: developments in first-line antithyroid drugs in the young

Introduction: First-line treatment for most young people with Graves' disease (GD) will include the administration of a thionamide antithyroid medication (ATD); Carbimazole (CBZ), Methimazole (MMZ), or rarely, propylthiouracil (PTU). GD is a challenge for families and clinicians because the likelihood of remission following a course of ATD is lower in young people when compared to adults, yet the risk of adverse events is higher. An overall consensus regarding the optimal ATD treatment regimen is lacking; how ATD are prescribed, for how long and how the associated risk of adverse events is managed varies between clinicians, units and nations. This partly reflects clinician and family uncertainty regarding outcomes.Areas covered: This review will focus on some of the key articles published in the field of thionamide ATD in children. It will highlight key issues that need to be discussed with families as well as addressing the approach and controversies in the treatment of GD. This article does not reflect a formal systematic review of the literature.Expert opinion: New strategies in areas such as immunomodulation may see the development of new antithyroid drug treatments that, either in isolation or in combination with thionamide therapy, may increase the likelihood of long-term remission.

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

OBJECTIVE

levothyroxine prescriptions have increased remarkably during the last decade, and it is most likely to be prescribed in subclinical hypothyroidism. The aim of this review was to present data on when levothyroxine treatment should be initiated, and the effects of treatment in subclinical hypothyroidism on symptoms such as weight, quality of life, vitality, cognition, and cardiovascular disease. We also discuss evidence for different thyroid-hormone medications. In addition, the option to withhold medication when there is uncertain diagnosis or lack of clinical improvement is discussed.

METHODS

a literature search in PubMed on the term "treatment of subclinical hypothyroidism" in combination with "quality of life", "weight", "cognition", and "cerebrovascular disease".

RESULTS

current research supports that levothyroxine should be initiated in patients with a thyroid stimulating hormone (TSH) >10 mIU/L. Treatment for hypothyroidism is becoming more frequent. Symptoms related to vitality, weight, and quality of life in subclinical disease often persist with levothyroxine treatment, and other causes should be explored. Patients with cardiovascular-risk factors may benefit from treatment, especially younger patients. Caution is necessary when treating elderly subjects with levothyroxine.

CONCLUSION

lifelong treatment with levothyroxine should normally only be considered in manifest hypothyroidism. However, in subclinical hypothyroidism with a TSH >10 mIU/L, therapy is indicated. In milder subclinical forms, a wait-and-see strategy is advocated to see if normalization occurs. Subgroups with cardiovascular risk and subclinical hypothyroidism may benefit from levothyroxine therapy.

Endocrine and Metabolic Disorders in Survivors of Childhood Cancers and Health-Related Quality of Life and Physical Activity

CONTEXT

Childhood cancer survivors experience chronic health conditions that impact health-related quality of life (HRQOL) and participation in optimal physical activity.

OBJECTIVE

The study aimed to determine independent effects of endocrine and metabolic disorders on HRQOL and physical activity.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort with longitudinal follow-up of survivors of childhood cancer enrolled in the North American Childhood Cancer Survivor Study.

MAIN OUTCOME MEASURES

Medical Outcomes Short Form-36 estimated HRQOL, and participation in physical activity was dichotomized as meeting or not meeting recommendations from the Centers for Disease Control and Prevention. Log binomial regression evaluated the association of each endocrine/metabolic disorder with HRQOL scales and physical activity.

RESULTS

Of 7287 survivors, with a median age of 32 years (range, 18 to 54 years) at their last follow-up survey, 4884 (67%) reported one or more endocrine/metabolic disorders. Survivors with either disorder were significantly more likely to be male, older, have received radiation treatment, and have experienced other chronic health conditions. After controlling for covariates, survivors with any endocrine/metabolic disorder were more likely to report poor physical function risk ratio (RR, 1.25; 95% CI, 1.05 to 1.48), increased bodily pain (RR, 1.27; 95% CI, 1.12 to 1.44), poor general health (RR, 1.49; 95% CI, 1.32 to 1.68), and lower vitality (RR, 1.21; 95% CI, 1.09 to 1.34) compared with survivors without. The likelihood of meeting recommended physical activity was lower among survivors with growth disorders (RR, 0.90; 95% CI, 0.83 to 0.97), osteoporosis (RR, 0.87; 95% CI, 0.76 to 0.99), and overweight/obesity (RR, 0.92; 95% CI, 0.88 to 0.96).

CONCLUSION

Endocrine and metabolic disorders are independently associated with poor HRQOL and suboptimal physical activity among childhood cancer survivors.

Experimentally induced subclinical hypothyroidism causes decreased functional connectivity of the cuneus: A resting state fMRI study

OBJECTIVE

The aim of this study was to experimentally evaluate the effects of subclinical mild hypothyroidism on brain network connectivity as determined by resting state fMRI (rsfMRI) which serves as a proxy for global changes in brain function.

METHODS

Fifteen otherwise healthy patients with complete hypothyroidism under stable, long term levothyroxine substitution volunteered for the study. They reduced their pretest levothyroxine dosage by 30% for 52-56 days. Basally and after partial levothyroxine withdrawal, rsfMRI along with a neuropsychological analysis was performed. RsfMRI was subjected to graph-theory-based analysis to investigate whole-brain intrinsic functional connectivity.

RESULTS

The desired subclinical hypothyroidism was achieved in all subjects. This was associated with a significant decrease in resting-state functional connectivity specifically in the cuneus (0.05 FWE corrected at cluster level) which was mainly caused by a weaker functional connectivity to the cerebellum and regions of the default mode network, i.e. the medial prefrontal cortex, the precuneus and the bilateral angular gyri. The decrease in cuneus connectivity was correlated to the increase in TSH serum levels. A working memory task showed a slightly longer reaction time and less accuracy after partial levothyroxine withdrawal.

CONCLUSION

Even short-term partial levothyroxine partial withdrawal leads to deficits in working memory tasks and to a weaker integration of the cuneus within the default mode network.

Partial withdrawal of levothyroxine treated disease leads to brain activations and effects on performance in a working memory task: A pilot study

Hypothyroidism is associated with memory impairments. The present study aimed to evaluate the effects of partial withdrawal of levothyroxine on working memory tasks and brain function. Fifteen subjects under long-term levothyroxine substitution as a result of complete hypothyroidism participated in the present study. Functional magnetic resonance imaging (MRI) was performed using a working memory task (n-back task) and neuropsychological tests were performed before and 52-54 days after the induction of subclinical hypothyroidism by reducing the pretest levothyroxine dosage by 30%. Reaction time of subjects under partial levothyroxine withdrawal was significantly longer and less accurate with respect to solving the working memory tasks. Functional MRI revealed significant activation changes after medication withdrawal in the cerebellum, insula, parietal, frontal, temporal and occipital lobes, lingual gyrus, and the cuneus. Partial withdrawal of levothyroxine may lead to deficits in a working memory task and to an activation of brain areas associated with working memory ability.

Hypothyroidism in the older population

BACKGROUND

Both overt hypothyroidism as well as minor elevations of serum thyrotropin (TSH) levels associated with thyroid hormones within their respective reference ranges (termed subclinical hypothyroidism) are relatively common in older individuals. There is growing evidence that treatment of subclinical hypothyroidism may not be beneficial, particularly in an older person. These findings are relevant at a time when treatment with thyroid hormones is increasing and more than 10-15% of people aged over 80 years are prescribed levothyroxine replacement therapy.

MAIN BODY

The prevalence of hypothyroidism increases with age. However, the reference range for TSH also rises with age, as the population distribution of TSH concentration progressively rises with age. Furthermore, there is evidence to suggest that minor TSH elevations are not associated with important outcomes such as impaired quality of life, symptoms, cognition, cardiovascular events and mortality in older individuals. There is also evidence that treatment of mild subclinical hypothyroidism may not benefit quality of life and/or symptoms in older people. It is unknown whether treatment targets should be reset depending on the age of the patient. It is likely that some older patients with non-specific symptoms and incidental mild subclinical hypothyroidism may be treated with thyroid hormones and could potentially be harmed as a result. This article reviews the current literature pertaining to hypothyroidism with a special emphasis on the older individual and assesses the risk/benefit impact of contemporary management on outcomes in this age group.

CONCLUSIONS

Current evidence suggests that threshold for treating mild subclinical hypothyroidism in older people should be high. It is reasonable to aim for a higher TSH target in treated older hypothyroid patients as their thyroid hormone requirements may be lower. In addition, age-appropriate TSH reference ranges should be considered in the diagnostic pathway of identifying individuals at risk of developing hypothyroidism. Appropriately designed and powered randomised controlled trials are required to confirm risk/benefit of treatment of subclinical hypothyroidism in older people. Until the results of such RCTs are available to guide clinical management international guidelines should be followed that advocate a conservative policy in the management of mild subclinical hypothyroidism in older individuals.

Subclinical Hypothyroidism and Depression: A Systematic Review and Meta-Analysis

Background: Thyroid function is closely associated with neuropsychological functions, including mental state and cognitive functions. Although thyroid function is routinely examined in persons with depressive symptom, the association between subclinical hypothyroidism (SCH) and depression remains inconclusive. Objective: This systematic review and meta-analysis aimed to evaluate the risk of depression in persons with SCH. Methods: The PubMed, Embase, and Web of Science databases were searched up to August 2018. The primary outcome was the prevalence of depression, as evaluated by various types of self-reported depression scales. Odds ratios (ORs) were calculated to compare the risk of depression between persons with SCH and those with euthyroidism. Results: Twenty-one studies were included in the systematic review, with a total of 103,375 subjects from 7 studies being pooled for the meta-analysis to evaluate the risk of depression. The meta-analysis showed that persons with SCH had a significantly elevated risk of depression than persons with euthyroidism (OR = 1.78, 95% confidence interval [CI]: 1.11-2.86, P = 0.02). No publication bias was found, as indicated by Egger's test (t = -0.49, P = 0.647) and Begg's test (z = -0.15, P = 0.881). In addition, the funnel plot showed a symmetric distribution. Conclusions: This meta-analysis demonstrated that SCH was positively associated with the risk of depression, especially in persons above 50 years of age, suggesting it is necessary to pay close attention to depressive symptoms in persons with SCH.

Effects of Long-Term Combination LT4 and LT3 Therapy for Improving Hypothyroidism and Overall Quality of Life

Guidelines from the American Thyroid Association and the American Association of Clinical Endocrinologists suggest monitoring thyroid-stimulating hormone and serum-free thyroxine to make clinical decisions for starting and monitoring therapy with their mainstay treatment of levothyroxine monotherapy. Although this monotherapy provides adequate control of symptoms for the majority of the population, a strong subset of the population continues to complain of hypothyroidism despite normal thyroid-stimulating hormone and serum-free thyroxine levels. Combination levothyroxine and liothyronine therapy to improve symptoms of hypothyroidism has been a topic of interest for several decades, but the data have been mixed. This study provides insight into the effects of combination therapy because there is no reported retrospective or prospective study in the literature.

Supplemental digital content is available in the text.

Objectives

Hypothyroidism results in decreased mood and neurocognition, weight gain, fatigue, and many other undesirable symptoms. The American Association of Clinical Endocrinologists, the American Thyroid Association (ATA), and The Endocrine Society recommend levothyroxine (LT4) monotherapy as the treatment for hypothyroidism; however, after years of monotherapy, some patients continue to experience impaired quality of life. Combination LT4 and synthetic liothyronine (LT3) therapy or the use of desiccated thyroid extract (DTE), has not been suggested for this indication based on short-duration studies with no significant benefits. Our first observational study examined the role of combination therapy for 6 years in improving quality of life in a subset of a hypothyroid population without adverse effects and cardiac mortality.

Methods

An observational retrospective study examining patients prescribed thyroid replacements with serum triiodothyronine (FT3), LT4 with LT3 (synthetic therapy) or DTE (natural therapy), compared with LT4 alone in the United States from 2010 to 2016. Thyroid-stimulating hormone (TSH), serum thyroxine (FT4), and FT3 levels were documented for each patient in addition to any admissions of myxedema coma, thyrotoxicosis, or cardiovascular complications, such as arrhythmias, atrial fibrillation, and mortality. At the conclusion of the study, a cross-sectional interview assessed quality of life for each combination therapy through the Medical Outcomes Study Short Form-20 questionnaire.

Results

Compared with patients taking only LT4, 89.47% using synthetic therapy had therapeutic TSH (P < 0.05). Similarly, 96.49% using natural therapy had therapeutic TSH (P < 0.05). Less than 5% of patients had supratherapeutic FT3. None of the patients who had abnormally low TSH or elevated FT3 or FT4 levels had hospitalizations for arrhythmias or thyrotoxicosis. On the Medical Outcomes Study Short Form-20 questionnaire, >92% answered feeling “excellent, very good, or good” when questioned about their health while undergoing thyroid replacement compared with levothyroxine alone.

Conclusions

This is the only retrospective study reported to use long-term (mean 27 months) thyroid replacements with combination therapy and to compare between the two forms of therapy: synthetic and natural. For patients undergoing either therapy, we did not identify additional risks of atrial fibrillation, cardiovascular disease, or mortality in patients of all ages with hypothyroidism.

Cognitive functioning and quality of life in patients with Hashimoto thyroiditis on long-term levothyroxine replacement

OBJECTIVE

Intrinsic imperfections of thyroid hormone replacement therapy may affect long-term general well-being. In patients with Hashimoto thyroiditis (HT), cognitive functioning may be affected via altered thyroid hormones action as well as by the autoimmune process. The aim of this study was to evaluate cognitive function and quality of life (QoL) in patients on long-term levothyroxine replacement for HT in relation to thyroid function tests and TPO (thyroid-peroxidase) antibody (TPOAb) status.

DESIGN

Retrospective cross-sectional study.

PATIENTS AND MEASUREMENTS

One-hundred-and thirty patients with HT on long-term levothyroxine replacement and 111 euthyroid control subjects. Both groups were divided into two age subgroups, 20-49 years (N = 59 vs N = 79) and > 50 years (N = 71 vs N = 32). Evaluation included biochemical and neuropsychological tests, evaluating attention, global cognitive status, verbal and working memory, executive function, depression and anxiety, and quality of life. We used ANOVA and partial correlations to test for significant associations.

RESULTS

FT4 (free-thyroxine), FT3 (free-triiodothyronine) levels and FT3/FT4 ratio were not different between patients and controls. Mean TSH (thyroid-stimulating hormone) was normal in all subjects but significantly higher in the patients (20-49 yrs:3.64 ± 2.74 vs 1.93 ± 1.10, >50 yrs:3.93 ± 2.84 vs 1.91 ± 0.90). Antibodies (TgAb,TPOAb) were higher in patients. Global cognitive function (MMSE-Mini mental state examination), conceptual tracking (TMT-Trail Making Test:A/B), verbal divergent thinking (like Phonemic fluency test), and anxiety and depression scores were significantly worse in patients vs controls. QoL was impaired in patients. there was a significant negative correlation between antibodies (TPOAb, TgAb) and quality in life (total SF36 score).

CONCLUSION

Patients on long-term levothyroxine replacement show persistent impairments in both cognitive functioning and general well-being.

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.

Current evidence for the treatment of hypothyroidism with levothyroxine/levotriiodothyronine combination therapy versus levothyroxine monotherapy

OBJECTIVE

Hypothyroidism is relatively common, occurring in approximately 5% of the general US population aged ≥12 years. Levothyroxine (LT4) monotherapy is the standard of care. Approximately, 5%-10% of patients who normalise thyroid-stimulating hormone levels with LT4 monotherapy may have persistent symptoms that patients and clinicians may attribute to hypothyroidism. A long-standing debate in the literature is whether addition of levotriiodothyronine (LT3) to LT4 will ameliorate lingering symptoms. Here, we explore the evidence for and against LT4/LT3 combination therapy as the optimal approach to treat euthyroid patients with persistent complaints.

METHODS

Recent literature indexed on PubMed was searched in March 2017 using the terms "hypothyroid" or "hypothyroidism" and "triiodothyronine combination" or "T3 combination." Relevant non-review articles published in English during the past 10 years were included and supplemented with articles already known to the authors.

FINDINGS

Current clinical evidence is not sufficiently strong to support LT4/LT3 combination therapy in patients with hypothyroidism. Polymorphisms in deiodinase genes that encode the enzymes that convert T4 to T3 in the periphery may provide potential mechanisms underlying unsatisfactory treatment results with LT4 monotherapy. However, results of studies on the effect of LT4/LT3 therapy on clinical symptoms and thyroid-responsive genes have thus far not been conclusive.

CONCLUSIONS

Persistent symptoms in patients who are biochemically euthyroid with LT4 monotherapy may be caused by several other conditions unrelated to thyroid function, and their cause should be aggressively investigated by the clinician.

Thyroid Status, Quality of Life, and Mental Health in Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

In the general population, there is increasing recognition of the effect of thyroid function on patient-centered outcomes, including health-related quality of life and depression. Although hypothyroidism is highly prevalent in hemodialysis patients, it is unknown whether thyroid status is a risk factor for impaired health-related quality of life or mental health in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the association of thyroid status, defined by serum thyrotropin, with health-related quality of life and depressive symptoms over time in a prospective cohort of 450 patients on hemodialysis from 17 outpatient dialysis facilities from May of 2013 to May of 2015 who underwent protocolized thyrotropin testing, Short-Form 36 surveys, and Beck Depression Inventory-II questionnaires every 6 months. We examined the association of baseline and time-dependent thyrotropin categorized as tertiles and continuous variables with eight Short-Form 36 domains and Beck Depression Inventory-II scores using expanded case mix plus laboratory adjusted linear mixed effects models.

RESULTS

In categorical analyses, the highest baseline thyrotropin tertile was associated with a five-point lower Short-Form 36 domain score for energy/fatigue (P=0.04); the highest time-dependent tertile was associated with a five-point lower physical function score (P=0.03; reference: lowest tertile). In continuous analyses, higher baseline serum thyrotropin levels (+Δ1 mIU/L) were associated with lower role limitations due to physical health (β=-1.3; P=0.04), energy/fatigue (β=-0.8; P=0.03), and pain scores (β=-1.4; P=0.002), equivalent to five-, three-, and five-point lower scores, respectively, for every 1-SD higher thyrotropin. Higher time-dependent thyrotropin levels were associated with lower role limitations due to physical health scores (β=-1.0; P=0.03), equivalent to a three-point decline for every 1-SD higher thyrotropin. Baseline and time-dependent thyrotropin were not associated with Beck Depression Inventory-II scores.

CONCLUSIONS

In patients on hemodialysis, higher serum thyrotropin levels are associated with impaired health-related quality of life across energy/fatigue, physical function, and pain domains. Studies are needed to determine if thyroid-modulating therapy improves the health-related quality of life of hemodialysis patients with thyroid dysfunction.

Concurrent administration of thyroxine and donepezil induces plastic changes in the prefrontal cortex of adult hypothyroid rats

The aim of the present study was to observe the effects of the concurrent administration of thyroxine (T4) and an acetylcholinesterase (AChE) inhibitor, donepezil (DON), on the hypothyroidism-induced ultrastructural changes of the prefrontal cortex (PFC) in adult rats. The acetylcholine (ACh) content and AChE activity was assessed, as well as the expressions of synaptotagmin-1 (syt-1) and SNAP-25 were analyzed in the rats. Adding 0.05% propylthiouracil to rats' drinking water induced a hypothyroid rat model. The animals were treated with T4 and DON administered separately or in combination from the fifth week. Transmission electron microscope analysis revealed that hypothyroidism induced marked ultrastructural changes, including the neurons, the synapses and the myelin sheath in the PFC. T4 or DON treatment improved the morphologic features of the PFC, and the performance of the T4 combined DON group was the closest to the control group. Moreover, hypothyroidism significantly decreased the content of ACh (29.8%) and activity of AChE (27.8%), which were restored to control values by T4 administration. In addition, DON treatment restored ACh content to normal. At the protein level, hypothyroidism increased the levels of syt-1 and SNAP-25 in the PFC, both of which were not restored to control values following T4 administration, while concurrent administration of T4 and DON was able to induce this effect. These results suggested that adult-onset hypothyroidism induce morphological, biochemical and molecular alterations in the PFC, combined administration of T4 and DON induce plastic changes in the PFC, different from that of the standard T4 therapy, and that the DON treatment may facilitate the recovery of synaptic protein impairments induced by hypothyroidism.

No Effect of the Thr92Ala Polymorphism of Deiodinase-2 on Thyroid Hormone Parameters, Health-Related Quality of Life, and Cognitive Functioning in a Large Population-Based Cohort Study

INTRODUCTION

The presence of the Thr92Ala polymorphism of deiodinase-2 (D2) has been thought to have several effects. It may influence its enzymatic function, is associated with increased expression of genes involved in oxidative stress in brain tissue, and may predict favorable response to combination levothyroxine (LT4) plus triiodothyronine (T3) therapy. It was hypothesized that homozygous carriers of the D2-92Ala allele have different thyroid hormone parameters, and reduced health-related quality of life (HRQoL) and cognitive functioning.

METHODS

In 12,625 participants from the LifeLines cohort study with genome-wide genetic data available, the effects of the Thr92Ala polymorphism (rs225014) were evaluated in the general population and in 364 people treated with thyroid hormone replacement therapy, the latter mainly because of primary hypothyroidism. In addition to evaluating anthropometric data, medication use, and existence of metabolic syndrome, HRQoL was assessed with the RAND 36-Item Health Survey, and the Ruff Figural Fluency Test was used as a sensitive test for executive functioning. Data on thyrotropin, free thyroxine (fT4), and free T3 (fT3) levels were available in a subset of 4479 participants.

RESULTS

The mean age (±standard deviation) was 53 ± 12 years and the body mass index was 27.0 ± 4.5 kg/m2 in the LT4 users compared with 48 ± 11 years and 26.2 ± 4.1 kg/m2 in participants from the general population. The Ala/Ala genotype of the D2-Thr92Ala polymorphism was present in 11.3% of LT4 users and in 10.7% of the general population. In total, 3742/4479 subjects with thyroid hormone data available had normal TSH (0.4-4.0 mIU/L), and 88% of LT4 users were females. LT4 users had higher fT4, lower fT3, and a lower fT3/fT4 ratio, and female patients had lower scores on the HRQoL domains of physical functioning, vitality, mental health, social functioning, bodily pain, and general health compared with those not using LT4 (p < 0.005). Executive functioning scores, as part of cognitive functioning, were comparable between female LT4 users and the general population. In both groups, the D2-Thr92Ala polymorphism was not associated with differences in TSH, fT4, fT3, the fT3/fT4 ratio, presence of metabolic syndrome or other comorbidities, use of medication, HRQoL, and cognitive functioning.

CONCLUSION

The Thr92Ala polymorphism of D2 was not associated with thyroid parameters, HRQoL, and cognitive functioning in the general population and in participants on thyroid hormone replacement therapy.

Effects of Dendropanax morbifera Léveille extract on hypothyroidism-induced oxidative stress in the rat hippocampus

In this experiment, we verified the effects of Dendropanax morbifera Léveille stem extract (DMS) on hypothyroidism-induced oxidative stress in the hippocampus of rats. Hypothyroidism was induced in rats by treating them with 0.03% 2-mercapto-1-methyl-imidazole dissolved in drinking water for 5 weeks. DMS (100 mg/kg) was also orally administered to the rats during the same period and the animals were sacrificed at 12 weeks of age. DMS administration tended to ameliorate these hypothyroidism-induced changes in serum triiodothyronine (T₃), thyroxine (T₄), and thyroid-stimulating hormone levels. DMS administration significantly reduced the hypothyroidism-induced increases in reactive oxygen species production as well as in lipid peroxidation in the hippocampus. In addition, DMS administration increased hippocampal Cu, Zn-superoxide dismutase (SOD1), catalase (CAT), and glutathione peroxidase (GPx) levels. These results suggest that DMS potentially ameliorates hypothyroidism-induced neuroendocrine phenotypes and oxidative stress in the hippocampus via the induction of antioxidant enzymes.

Treatment of hypothyroidism with levothyroxine plus liothyronine: a randomized, double-blind, crossover study

OBJECTIVE

To compare the effects of a unique fixed combination levothyroxine/liothyronine (LT4/LT3) therapy in patients with primary hypothyroidism.

SUBJECTS AND METHODS

This is a randomized, double-blind, crossover study. Adults with primary hypothyroidism (n = 32, age 42.6 ± 13.3, 30 females) on stable doses of LT4 for ≥ 6 months (125 or 150 μg/day) were randomized to continue LT4 treatment (G1) or to start LT4/LT3 therapy (75/15 μg/day; G2). After 8 weeks, participants switched treatments for 8 more weeks. Thyroid function, lipid profile, plasma glucose, body weight, electrocardiogram, vital signs, and quality of life (QoL) were evaluated at weeks 0, 8 and 16.

RESULTS

Free T4 levels were significantly lower while on LT4/LT3 (G1: 1.07 ± 0.29 vs. 1.65 ± 0.46; G2: 0.97 ± 0.26 vs. 1.63 ± 0.43 ng/dL; P < 0.001). TSH and T3 levels were not affected by type of therapy. More patients on LT4/LT3 had T3 levels above the upper limit (15% vs. 3%). The combination therapy led to an increase in heart rate, with no significant changes in electrocardiogram or arterial blood pressure. Lipid profile, body weight and QoL remained unchanged.

CONCLUSIONS

The combination therapy yielded significantly lower free T4 levels, with no changes in TSH or T3 levels. More patients on LT4/T3 had elevated T3 levels, with no significant alterations in the evaluated outcomes. No clear clinical benefit of the studied formulation could be observed. Future trials need to evaluate different formulations and the impact of the combined therapy in select populations with genetic polymorphisms.

Thyroid hormone and its metabolites in relation to quality of life in patients treated for differentiated thyroid cancer

BACKGROUND

Levothyroxine (LT4) is the standard of care in patients with hypothyroidism. Despite this replacement therapy, quality of life (QoL) remains impaired in a substantial amount of patients. The reasons for this are still a matter of debate. Suggested causes include lack of endogenous T3 secretion by the thyroid, changes in other thyroid hormone metabolites and interference by autoimmune processes.

OBJECTIVE

To investigate the association between thyroid function tests (TFTs) and QoL in patients with a history of differentiated thyroid cancer on LT4 monotherapy. These patients lack endogenous thyroidal T3 secretion in the absence of autoimmune disease.

MATERIALS AND METHODS

This is a cross-sectional study in 143 patients (69·2% female). Initial therapy consisted of total thyroidectomy followed by radioiodine ablation minimally one year before inclusion. We assessed health-related QoL (RAND-36), thyroid-specific QoL (ThyPRO) and fatigue with the Multidimensional Fatigue Inventory. Extensive TFTs were assessed, including 3,5-diiodo-L-thyronine (3,5-T2).

RESULTS

Mean age was 50·2 years and mean time since diagnosis was 8·4 years. Median TSH was 0·042 mU/l, total T4 145·0 nmol/l, free T4 25·6 pmol/l, total T3 1·93 nmol/l, reverse T3 0·53 nmol/l and 3,5-T2 0·86 nmol/l. Multiple linear regression analyses did not show any association between QoL and the different TFTs, including T4/T3 and 3,5-T2/T3 ratios reflecting peripheral metabolism.

CONCLUSION

We did not find any association between TFTs and QoL in athyreotic patients on LT4 monotherapy. Our data do not provide evidence that a slight increase in dose improves fatigue or well-being in hypothyroid patients on LT4 therapy.

Polymorphisms in the type I deiodinase gene and frontal function in recurrent depressive disorder

PURPOSE

Significant impairment of some psychological functions, including cognitive functioning, has been characteristically found in depressed patients. Memory disturbances may be related to the levels of thyroid hormones (TH) that are under the influence of different mechanisms and molecules, including deiodinase type 1(D1) - an important determinant of circulating triiodothyronine (T3). We investigated the relationship between two functionally known polymorphisms within the DIO1 gene, i.e. DIO1a-C/T and DIO1b-A/G, and cognitive functioning in patients diagnosed with recurrent depressive disorder (rDD). In the planned analysis we mainly concentrated on the frontal function: working memory, executive functions and verbal fluency.

MATERIALS AND METHODS

Genetic variants were genotyped in 128 patients using a method based on polymerase chain reaction (PCR). Cognitive functions were assessed by the Trail Making Test, the Stroop Test and the Verbal Fluency Test (VFT).

RESULTS

No significant associations were found between DIO1 polymorphisms and cognitive functioning in rDD. Only the CT and TT genotypes of the DIO1a variant were significantly related to verbal fluency. There were no significant differences between the distribution of the genotypes and demographic/medical variables.

CONCLUSIONS

Based on the study, the examined polymorphisms are not an important risk or protective factor for cognitive impairment in depressive patients. Functional variants within the DIO1 gene that affect triiodothyronine (T3) levels seem not to be associated with cognitive functions. Nevertheless, considering the fact that the DIO1 gene is related to the course and management of depression, further studies on a larger sample size might be suggested.