Treating primary hypothyroidism with weekly doses of levothyroxine: a randomized, single-blind, crossover study

Effects of timing and scheduling in levothyroxine adherence to hypothyroidism control: Meta-analysis with trial sequential analysis of Randomized Clinical Trials

PURPOSE

Treatment adherence for chronic conditions is a common clinical challenge. This systematic review aimed to assess the impact of scheduling and timing on levothyroxine adherence in patients with hypothyroidism.

METHODS

We searched multiple databases (PubMed, EMBASE, SCOPUS, Web Of Science, and CINAHL) using relevant terms related to hypothyroidism and medication adherence. Two independent reviewers conducted study selection, evaluation, and data extraction. The primary outcome was thyrotropin (TSH) levels, analyzed using inverse-variance meta-analysis. Trial sequential analysis (TSA) was conducted to assess the statistical reliability of the meta-analyses results.

RESULTS

Of the 706 articles initially found, 11 met the inclusion criteria: eight assessed evening administration and three evaluated weekly administration of levothyroxine. Comparison between evening and morning administration showed no significant difference in changes of TSH levels (dTSH 0.18; 95% confidence interval [95%CI] -0.29-0.65, P = 0.46). However, considering weekly administration of levothyroxine, TSH levels were higher in the experimental group (dTSH 1.14; 95%CI 0.80-1.14, P < 0.01), although the mean final TSH remained within the reference range in both groups. TSA indicated that the required information size was achieved for scheduling interventions.

CONCLUSION

Both daily timing and weekly administration of levothyroxine were effective in maintaining TSH levels within reference values. Individualized dosing regimens may be considered based on patient convenience and preference.

The effect of different levothyroxine administration regimens on thyroid hormone levels: a systematic review, pairwise, and network meta-analysis

INTRODUCTION

This systematic review aimed to compare the effect of alternative levothyroxine administration regimens on thyroid hormone levels and patient-reported outcomes (PROs) among adults with hypothyroidism.

METHODS

We searched PubMed, Embase, CENTRAL, CINAHL, LILACS, SciELO, Scopus, Web of Science, OpenGrey, ProQuest, ClinicalTrials.gov, and ICTRP from inception to May/2023 for randomized controlled trials (RCTs). We assessed the risk of bias with Cochrane Risk of Bias 2.0 tool. We analyzed TSH levels by pairwise and network meta-analyses (NMA). The FT4 levels and PROs were qualitatively assessed.

RESULTS

We included 14 RCTs (906 participants) comparing different regimens, as bedtime vs. before breakfast. A total of 12 RCTs were at high risk of bias. Seven RCTs were included in the TSH meta-analysis, where the mean difference (MD) and 95% confidence interval (CI) were as follows: bedtime vs before breakfast (4 RCTs) 0.69 (-1.67-3.04), I2 = 92%, very low certainty evidence; weekly dose vs before breakfast (2 RCTs) 1.68 (0.94-2.41), I2 = 0%, low certainty evidence; and at breakfast vs before breakfast (1 RCT) 0.65 (-1.11-2.41), very low certainty evidence. The NMA showed no evidence of differences in TSH level with different regimens.

CONCLUSION

The evidence is insufficient to determine the most effective levothyroxine administration regimen for hypothyroidism.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO - CRD42021279375.

Twice or thrice weekly levothyroxine provides similar rates of adherence and post-Ramadan euthyroidism compared to daily levothyroxine during Ramadan fasting

BACKGROUND

Having to take levothyroxine (L-T4) on a daily basis, on an empty stomach is burdensome and may impair adherence, especially during Ramadan fasting. A long half-life and autoregulation of thyroid hormone levels allows for twice or thrice weekly administration of L-T4. This study aims to establish twice or thrice weekly L-T4 dosing as a convenient and effective practice during Ramadan fasting.

METHODS

The study included 2 groups; twice or thrice weekly (TTW) group included patients assigned to take L-T4 twice or thrice a week, and standard daily dosing (SDT) group included patients assigned to take L-T4 daily. Patients freely chose between three L-T4 regimens: before Iftar, before Suhor, or before the next fast. Thyroid status was assessed before and within 6 weeks after Ramadan. Only euthyroid patients were included.

RESULTS

TTW group included 57 patients, while SDT group included 91 patients. Pre-Ramadan TSH in TTW group (1.80 ± 0.88 µIU/L) was higher compared to SDT group (1.39 ± 0.72 µIU/L) [P = 0.003]. Similar adherence rates were observed in both groups, 96.5% in TTW group versus 89% in SDT group, [P = 0.13]. similar rates of post-Ramadan euthyroidism were also found in both groups, 91.2% in TTW group versus 94.5% in SDT group, [P = 0.509]. TTW group preferred regimen 1 (64.9%) significantly more than SDT group (35.2%) [P = 0.001].

CONCLUSION

Twice or thrice weekly levothyroxine results in similarly high rates of adherence (96.5%) and post-Ramadan euthyroidism (91.2%) compared to daily levothyroxine during Ramadan fasting.

Assessing the cardiovascular effects of levothyroxine use in an ageing United Kingdom population (ACEL-UK) protocol: a cohort and target trial emulation study

BACKGROUND

Subclinical hypothyroidism is diagnosed when serum thyroid stimulating hormone levels are higher whilst free thyroxine levels remain within their respective reference ranges. These reference ranges are uniformly applied in all adults, despite serum thyroid stimulating hormone levels naturally increasing with age. Research has found that mildly elevated thyroid stimulating hormone levels may be associated with some benefits in ageing patients, including reduced mortality and better cardiorespiratory fitness. Levothyroxine is typically prescribed to patients with hypothyroidism, but no conclusive evidence exists on whether levothyroxine therapy is beneficial or detrimental in older subclinical hypothyroid patients. Despite this, prescriptions for levothyroxine are increasing year-on-year. This study aims to determine if receiving levothyroxine affects the cardiovascular and bone health outcomes of subclinical patients in primary care aged 50 years and over.

METHODS

This project includes a retrospective cohort analysis and a target trial emulation study using electronic patient records collected between 2006 and 2021 and recorded in The Health Improvement Network database. The primary outcome of this study is to compare the cardiovascular outcomes of subclinical hypothyroid patients aged over 50 years treated with levothyroxine compared to those untreated. Secondary outcomes are bone health and all-cause mortality outcomes. Descriptive and inferential statistics will both be employed to analyse the data. Secondary analysis will explore confounding factors, including age, sex, smoking status, body mass index, co-morbidities, and levothyroxine dosage.

DISCUSSION

There needs to be a greater understanding of the potential risks of the current treatment for older patients with subclinical hypothyroidism in a primary care setting. We will investigate the clinical importance of this issue and whether older subclinical hypothyroid patients have poorer outcomes when treated. Clarifying this concern may help address the healthcare resource implications of ageing patients being misclassified as having mild hypothyroidism, as these patients are more likely to repeat their blood tests. This could reduce prescription wastage and improve patient outcomes and quality of life in the ageing population.

TRIAL REGISTRATION

Not applicable.

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

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

A Novel Levothyroxine Solution Results in Similar Bioavailability Whether Taken 30 or Just 15 Minutes Before a High-Fat High-Calorie Meal

Background: Levothyroxine (LT4) sodium is a standard treatment for hypothyroidism. Its absorption and bioavailability when taken as a tablet have been shown to be significantly decreased with concomitant food ingestion. Therefore, LT4 formulations are recommended to be taken on an empty stomach, at least 30, ideally 60, minutes before breakfast, potentially affecting adherence to therapy. A novel LT4 solution (Tirosint^®-SOL) has been shown to result in a faster absorption process than tablets or soft-gel capsule formulations. The objective of this trial was to evaluate the bioavailability of this preparation taken 15 minutes before a high-fat high-calorie meal in comparison with the minimally recommended 30-minute interval. Methods: Thirty-six (33 completers, 24 males and 9 females) healthy volunteers participating in the randomized study took 600 mcg of LT4 oral solution, single doses after a 10-hour fast, 15 or 30 minutes before a high-fat, high-calorie, FDA-approved standardized meal in a controlled research setting. We measured serum total thyroxine using Liquid Chromatography with Tandem Mass Spectrometry at baseline and multiple time points up to 72 hours after LT4 administration. The predefined equivalence boundaries for the extent of exposure reflected by the area under the curve (AUC) were 80-125%. The washout period was at least 35 days. Results: The geometric mean ratios and confidence intervals (CIs) for the baseline-adjusted extent of exposure represented by AUCs truncated at both 48 and 72 hours after dosing (AUC_0-48: 90% [90% CI 86-94]; and AUC_0-72: 92% [90% CI 87-97]) were within the prespecified equivalence boundaries. The baseline-adjusted peak concentration was also clinically similar (C_max: 85% [90% CI 80-90]). The median t_max was 1.5 hours in each group. The rate of adverse events was similar between groups. Conclusions: We observed no significant difference in the pharmacokinetic properties of a novel LT4 solution administered 15 and 30 minutes before a high-fat high-calorie meal in normal subjects. Further research is needed to evaluate (a) the differences in overall bioavailability at other time points (including immediately premeal) and (b) the real-world effectiveness of this preparation in newly proposed administration conditions to optimize treatment outcomes in hypothyroid patients.

Factors influencing the levothyroxine dose in the hormone replacement therapy of primary hypothyroidism in adults

Levothyroxine (LT4) is a safe, effective means of hormone replacement therapy for hypothyroidism. Here, we review the pharmaceutical, pathophysiological and behavioural factors influencing the absorption, distribution, metabolism and excretion of LT4. Any factor that alters the state of the epithelium in the stomach or small intestine will reduce and/or slow absorption of LT4; these include ulcerative colitis, coeliac disease, bariatric surgery, Helicobacter pylori infection, food intolerance, gastritis, mineral supplements, dietary fibre, resins, and various drugs. Once in the circulation, LT4 is almost fully bound to plasma proteins. Although free T4 (FT4) and liothyronine concentrations are extensively buffered, it is possible that drug- or disorder-induced changes in plasma proteins levels can modify free hormone levels. The data on the clinical significance of genetic variants in deiodinase genes are contradictory, and wide-scale genotyping of hypothyroid patients is not currently justified. We developed a decision tree for the physician faced with an abnormally high thyroid-stimulating hormone (TSH) level in a patient reporting adequate compliance with the recommended LT4 dose. The physician should review medications, the medical history and the serum FT4 level and check for acute adrenal insufficiency, heterophilic anti-TSH antibodies, antibodies against gastric and intestinal components (gastric parietal cells, endomysium, and tissue transglutaminase 2), and Helicobacter pylori infection. The next step is an LT4 pharmacodynamic absorption test; poor LT4 absorption should prompt a consultation with a gastroenterologist and (depending on the findings) an increase in the LT4 dose level. An in-depth etiological investigation can reveal visceral disorders and, especially, digestive tract disorders.

Twice or Thrice Weekly versus Daily Thyroxine in Hypothyroid Fasting Ramadan: A Pilot Study

CONTEXT

Hypothyroid patients require to take levothyroxine (L-T4) on an empty stomach, 60 min before next meal which is difficult to achieve while fasting Ramadan, on a daily basis. This pilot study aimed to assess the effect of twice or thrice weekly versus standard daily L-T4 dosing during Ramadan on adherence, post-Ramadan TSH, and thyroid status.

METHODS AND MATERIALS

The study included 2 groups; group 1 included 11 patients assigned to take L-T4 twice or thrice a week, and group 2 included 113 patients assigned to take L-T4 daily. Patients chose between three L-T4 regimens: regimen 1 - 60 min before Iftar; regimen 2 - 60 min before Suhor, on empty stomach for 3-4 h; regimen 3 - before the next fast, on empty stomach for 3-4 h. Thyroid status was assessed before and within 6 weeks after Ramadan. Only euthyroid patients were included.

RESULTS

No significant differences between the two groups regarding adherence, post-Ramadan TSH, or post-Ramadan thyroid status. 90.9% in group 1 and 88.5% in group 2 were adherent [p = 1.000]. Post-Ramadan TSH in group 1 was 1.9 ± 1.5 mIU/L, in group 2 was 2 ± 1.6 mIU/L [p = 0.809]. 81.8% in group 1 and 82.3% in group 2 were euthyroid post-Ramadan [p = 0.209].

CONCLUSIONS

In this pilot study, taking L-T4 twice or thrice weekly during Ramadan achieved similar adherence and metabolic control to standard daily L-T4, making it an easier option for hypothyroid patients wishing to fast Ramadan.

Weekly Versus Daily Levothyroxine Tablet Replacement in Adults with Hypothyroidism: A Meta-Analysis

Objectives

Daily levothyroxine is the treatment of choice and standard of care in hypothyroidism, sufficient to restore thyroid stimulating hormone (TSH) to normal range. For many patients, daily lifelong therapy is required, making adherence a major issue. In such cases, weekly replacement may be a suitable alternative to improve adherence. In this study, we aimed to determine the efficacy and safety of weekly levothyroxine replacement among adults with hypothyroidism.

Methodology

Electronic databases were searched. Two reviewers (HCC and RBL) independently screened the abstracts, reviewed full-text papers, critically appraised the quality of included studies using PRISMA guidelines. Meta-analysis was performed using the random-effects model. The primary outcome is the difference in serum TSH levels between weekly and daily administration, while secondary outcomes included adverse events and symptoms of hypothyroidism.

Results

The primary outcome is the difference in serum TSH levels between weekly and daily administration. Secondary outcomes included adverse events and clinical symptoms. The study included two randomized trials (n=109) in the primary analysis. The difference in TSH levels was 1.78 mIU/mL higher [(95% confidence interval (CI): 1.28 to 2.28, p<0.00001] at 6 weeks and 1.22 mIU/mL higher (95% CI: 0.76 to 1.67, p<0.00001) at 12 weeks for the weekly regimen. There was no significant heterogeneity between the two groups. There was no significant difference in hypothyroid symptoms and adverse events before and after levothyroxine treatment within each group.

Conclusions

Weekly levothyroxine resulted in less suppression and higher mean serum TSH levels, while still remaining within the normal reference range. It may be a suitable alternative for non-adherent patients. However, larger randomized trials with longer duration of follow-up are needed to firmly establish its role.

Subcutaneous administration of levothyroxine: a novel approach to refractory hypothyroidism - A review and a case report

Treatment-refractory hypothyroidism is a common clinical finding. Substantial causes include poor compliance and intake failure as well as gastrointestinal diseases, such as inflammatory bowel disease and short bowel syndromes. Increasing oral dosage of levothyroxine (LT4) is not always effective. Therefore, alternative routes of administration are necessary. In this report, we evaluate alternative treatment modalities for refractory hypothyroidism and present a 28-year-old woman with intestinal drug malabsorption successfully treated by subcutaneous LT4 administration. In this patient, a parenteral form of LT4, 500 μg/5 ml, was administered subcutaneously in a split dosage regimen. Blood hormone levels returned to normal within a few days and remained stable over an 8-month follow-up period.

Efficacy and Safety of Once Weekly Thyroxine as Compared to Daily Thyroxine in Managing Primary Hypothyroidism: A Systematic Review and Meta-Analysis

AIMS

No meta-analysis is available which has holistically analyzed efficacy and safety of once weekly thyroxine (OWT) vs. standard daily therapy (SDT) with regards to managing primary hypothyroidism. We undertook this meta-analysis to address this knowledge gap.

METHODS

Electronic databases were searched for clinical trials involving hypothyroid patients receiving OWT in intervention arm, and SDT in control arm. Primary outcome was to evaluate changes in serum thyroid stimulating hormone. Secondary outcomes were to evaluate alterations in total tetra-iodothyronine (TT4), total tri-iodothyronine (TT3), free T4 (FT4), free T3 (FT4), heart rate (HR), cardiac function, symptomatology, and adverse events.

RESULTS

From initially screened 159 studies, data from four trials involving 294 patients were analyzed. Patients of OWT had significantly higher thyroid stimulating hormone (TSH) [mean difference (MD) +1.85 mU/L (95% confidence interval, CI: 0.95-2.75); P < 0.01; I ² = 63%], comparable TT4 [MD -0.87 mcg/dl (95% CI: -2.98-1.24); P = 0.42; I ² = 65%], and significantly lower TT3 [MD -15.7 ng/dl (95% CI: -29.9-1.51); P = 0.03; I ² = 90%], following 6-weeks therapy. TT4 [MD 3.05 mcg/dl (95% CI: 1.44-4.66); P < 0.01], and FT4 [MD 0.56 ng/dl (95% CI: 0.04-1.08); P = 0.03; I ² = 66%] were significantly higher 2 h after thyroxine intake, in people on OWT compared to SDT. TT4 levels were significantly higher 4 h after thyroxine intake in OWT as compared to SDT [MD 0.70 ng/dl (95% CI: 0.52-0.88); P < 0.01]. Following 4-8 h of intake of thyroxine, isovolumetric contraction time [MD 3.62 ms (95% CI: 1.93-5.31); P < 0.01; I ² = 0%] and aortic ejection time/pre-ejection period ratio [MD 0.01 (95% CI: 0.00-0.02); P = 0.02; I ² = 0%], were significantly higher in people on OWT as compared to SDT.

CONCLUSION

OWT is associated with less efficient control of hypothyroidism at 6 weeks and may be associated with supraphysiologic elevation of thyroid hormone levels along with transient echocardiographic changes in some patients following 2-4 h of thyroxine intake.

Efficacy and Safety of Once-Weekly Thyroxine for Thyroxine-Resistant Hypothyroidism

Context

Noncompliance with thyroxine therapy is the most common cause of poor control of hypothyroidism. An open-label prospective study to compare once-weekly thyroxine (OWT) with standard daily thyroxine (SDT) was undertaken.

Design

Patients taking thyroxine doses of >3 μg/kg/d, with or without normalization of TSH, were included and administered directly observed OWT or nonobserved SDT according to patient preference based on their weight for 6 weeks. Furthermore, patients on OWT were advised to continue the same at home without supervision.

Results

Twenty six of 34 patients on OWT and 7 of 18 patients on SDT achieved a TSH <10 μIU/mL (P < 0.05), and 2 patients from the SDT arm were lost to follow-up. During home treatment, 15 of 25 at 12 weeks and 19 of 23 contactable patients at a median follow-up of 25 months maintained TSH below target. Thyroxine absorption test was unable to predict normalization of TSH at 6 weeks of OWT therapy. No adverse events were seen with OWT-treated patients over the 12-week follow-up period. OWT has significantly higher efficacy (OR = 5.1) than SDT for patients with thyroxine-resistant hypothyroidism and is not associated with side effects.

Conclusion

OWT benefits a majority of patients in the long-term treatment of thyroxine-resistant hypothyroidism, in the real-world setting.

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.

The Effect of Daily versus Weekly Levothyroxine Replacement on Thyroid Function Test in Hypothyroid Patients at a Tertiary Care Centre in Haryana

OBJECTIVE

We compare the effect of daily versus weekly levothyroxine (LT4) replacement on thyroid function test (TFT) in hypothyroid patients at a tertiary care centre in Haryana.

MATERIALS AND METHODS

This was a randomised crossover study in which 100 hypothyroid patients on a stable LT4 dose were divided into 2 groups of 50 each. In group I, patients were given daily therapy for 6 weeks and then shifted to weekly therapy for the next 6 weeks. In group II, patients were given LT4 once a week for 6 weeks and then switched to daily therapy for the next 6 weeks. TFT, quality of life (QOL), and hyperthyroidism symptom scale (HSS) score of patients were compared in each group at 0, 6, and 12 weeks.

RESULTS

TFT remained within the normal range, but TSH increased (group I, daily 2.8 ± 1.4 mIU/L, weekly 3.9 ± 1.1 mIU/L, p = 0.001; group II, weekly 4.6 ± 1.1 mIU/L, daily 2.7 ± 1.2 mIU/L, p = <0.001) and T3/T4 decreased with weekly therapy as compared to daily therapy. No significant difference in HSS score was found between daily and weekly administration of LT4. With weekly therapy, QOL showed improvement in bodily pain, vitality, mental health, and social functioning.

CONCLUSION

Once-weekly LT4 administration is a reasonable alternative for patients, especially for those who have issues with compliance.

Out-of-Reference Range Thyroid-Stimulating Hormone Levels in Levothyroxine-Treated Primary Hypothyroid Patients: A Multicenter Observational Study

OBJECTIVE

Although levothyroxine (LT4) replacement therapy for hypothyroidism has been established as safe, inexpensive and effective, many studies from different countries reported out-of-reference range thyroid-stimulating hormone (TSH) values for the hypothyroid patients under LT4 treatment. The aim of this study was to determine TSH levels of primary hypothyroid patients under LT4 treatment and to assess self-reported compliance with daily LT4 intake in tertiary care centers in Turkey.

DESIGN

In this cross-sectional, observational study, adult patients with primary hypothyroidism, receiving LT4 treatment for at least 6 months, were included. The patients were from 12 tertiary care centers in 9 cities of Turkey. TSH and free T4 levels were recorded from patient files and self-reported compliance with daily LT4 intake was assessed by interviewing the subjects at the last visit.

RESULTS

A total of 1,755 subjects (46 ± 13 years; F/M: 89.9/10.1%) with primary hypothyroidism were enrolled. Of the hypothyroid subjects, 44.8% had out-of-reference range serum TSH levels. TSH values were over the reference range (TSH > 4 mIU/L) in 26.2% and were under the reference range (TSH < 0.5 mIU/L) in 18.6% of the patients. Total duration of LT4 treatment was 5.9 ± 4.7 years and mean dose was 1.2 ± 0.6 μg/kg/day. Non-compliant patients (31.1%) had higher TSH levels (6.9 ± 16 vs 3.8 ± 0.9 mIU/L, P = 0.01) compared to compliant patients.

CONCLUSION

The results of this study revealed that nearly half of the hypothyroid patients had out-of-reference range serum TSH values, despite under LT4 treatment. Compliance with LT4 treatment seems to be one of the major determinants to reach the target TSH levels in hypothyroid patients.

Thyroxine replacement: a clinical endocrinologist's viewpoint

BACKGROUND

Hypothyroidism affects 2-5% of the general population. Patients with uncorrected disease suffer significant morbidity and have an increased risk of cardiovascular disease and neurocognitive impairment. Levothyroxine, the treatment of choice, is inexpensive, easy to administer and in most cases restores well-being while normalizing thyroid function. However, 30-50% of individuals on levothyroxine are either over-treated or under-treated and others remain dissatisfied with treatment despite achieving thyroid hormone concentrations within the laboratory reference interval.

METHODS

This review is based on a systematic search of the literature for controlled trials, systematic reviews, guideline papers and cohort studies addressing best practice in thyroid hormone replacement.

RESULTS

Recent decades have seen improvements in patient management strategies driven by a better appreciation of levothyroxine pharmacokinetics. However, aspects of therapy such as the optimal timing of medication, strategies to overcome treatment non-adherence and target thyroid stimulating hormone concentrations in pregnancy and in patients with differentiated thyroid cancer remain challenging. Furthermore, there is now a substantial body of literature on common genetic variations in the deiodinases and thyroid hormone transporters and their role in the local regulation of thyroid hormone delivery. The benefits of combination therapy with liothyronine and levothyroxine are uncertain, and while it is theoretically probable that subsets of genetically predisposed individuals will benefit from combination therapy the existing evidence is as yet limited.

CONCLUSION

Despite the availability of thyroid hormone replacement for more than a century, there are still substantial challenges in practice and opportunities to improve treatment outcomes.

Thyroid Hormone Replacement in Patients Following Thyroidectomy for Thyroid Cancer

Thyroid hormone replacement therapy in patients following thyroidectomy for thyroid cancer, although a potentially straightforward clinical problem, can present the clinician and patient with a variety of challenges. Most often the problems are related to the dose and preparation of thyroid hormone (TH) to use. Some patients feel less well following thyroidectomy and/or radioiodine ablation than they did before their diagnosis. We present evidence that levothyroxine (L-T4) is the preparation of choice, and keeping the thyroid-stimulating hormone (TSH) between detectable and 0.1 mU/L should be the standard of care in most cases. In unusual circumstances, when the patient remains clinically hypothyroid despite a suppressed TSH, we acknowledge there may be as yet unidentified factors influencing the body's response to TH, and individualized therapy may be necessary in such patients.

Prostate stem cell antigen gene TT genotype and development of intestinal metaplasia in Helicobacter pylori infection

OBJECTIVES

Gastric cancer is etiologically related to interactions between Helicobacter pylori (H. pylori) infection, environmental and host factors. Gastric carcinoma is associated with a cascade of increasing atrophic gastric mucosal damage. Prostate stem cell antigen (PSCA) polymorphisms have been associated with an increased risk of gastric cancer. We aimed to examine the interaction between PSCA polymorphisms and H. pylori in the progression of H. pylori-related gastritis.

METHODS

The genotypes (TT, TC and CC) of PSCA single nucleotide polymorphism rs2294008 among H. pylori infected and uninfected Bhutanese were compared with the severity of H. pylori-related gastritis [neutrophils, monocytes, atrophy scores, H. pylori density, and the presence and extent of intestinal metaplasia (IM)] using the updated Sydney system.

RESULTS

Biopsies from 339 participants were included. The proportion of biopsies with IM was significantly (P < 0.05) greater in those with the TT genotype than in either those with the CT or CC genotype. Although no significant differences were found in inflammation or H. pylori density scores, the scores for IM at both gastric corpus and antrum among participants infected by H. pylori with the TT genotype was significantly (P < 0.05) greater than in the C allele carriers.

CONCLUSION

PSCA TT genotype is associated with a more than a threefold increase in the prevalence and the extent of gastric mucosal IM compared to C allele carriers among H. pylori-infected Bhutanese.

Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement

BACKGROUND

A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment.

METHODS

Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related mechanistic and bench research literature reviews, performed by our team of translational scientists. Ethics reviews were provided, when relevant, by a bioethicist. The responses to questions were formatted, when possible, in the form of a formal clinical recommendation statement. When responses were not suitable for a formal clinical recommendation, a summary response statement without a formal clinical recommendation was developed. For clinical recommendations, the supporting evidence was appraised, and the strength of each clinical recommendation was assessed, using the American College of Physicians system. The final document was organized so that each topic is introduced with a question, followed by a formal clinical recommendation. Stakeholder input was received at a national meeting, with some subsequent refinement of the clinical questions addressed in the document. Consensus was achieved for all recommendations by the task force.

RESULTS

We reviewed the following therapeutic categories: (i) levothyroxine therapy, (ii) non-levothyroxine-based thyroid hormone therapies, and (iii) use of thyroid hormone analogs. The second category included thyroid extracts, synthetic combination therapy, triiodothyronine therapy, and compounded thyroid hormones.

CONCLUSIONS

We concluded that levothyroxine should remain the standard of care for treating hypothyroidism. We found no consistently strong evidence for the superiority of alternative preparations (e.g., levothyroxine-liothyronine combination therapy, or thyroid extract therapy, or others) over monotherapy with levothyroxine, in improving health outcomes. Some examples of future research needs include the development of superior biomarkers of euthyroidism to supplement thyrotropin measurements, mechanistic research on serum triiodothyronine levels (including effects of age and disease status, relationship with tissue concentrations, as well as potential therapeutic targeting), and long-term outcome clinical trials testing combination therapy or thyroid extracts (including subgroup effects). Additional research is also needed to develop thyroid hormone analogs with a favorable benefit to risk profile.

Daily versus alternate day thyroxine therapy to maintain euthyroidism in children with congenital hypothyroidism

BACKGROUND

Daily administration of thyroxine has proven efficacy in treatment of children with hypothyroidism. However, the possibility of treatment with longer dosing intervals that offers flexibility and choice in maintaining euthyroid state has not been tested in children.

OBJECTIVES

To study the efficacy of an alternate day regimen to maintain euthyroidism in children with congenital hypothyroidism.

PATIENTS AND METHODS

Forty patients given alternate day therapy, while 30 children continued on their daily regimen were followed up at monthly intervals for 3 months. Clinical and laboratory assessments were performed at each follow up visit.

RESULTS

The clinical and anthropometric parameters remained similar in both groups of patients during the study indicating a maintained euthyroid state clinically. The thyroid profiles also remained within normal limits suggesting biochemical euthyroidism status with alternate day therapy. However the baseline serum aminotransferase levels showed mild elevation in patients on alternate day regimen and the difference persisted during the follow up visits. Higher HDL and lower TC and LDL levels suggested some beneficial effect of alternate day schedule on lipid profiles.

CONCLUSIONS

In short-term, alternate day schedule can be effectively used to maintain clinical and biochemical euthyroid state in children with congenital hypothyroidism beyond 4 years of age.

Serum thyrotropin levels following levothyroxine administration at breakfast

BACKGROUND

Hypothyroidism is treated with oral levothyroxine. Some patients fail to attain adequate control because of poor compliance. Delaying breakfast to take levothyroxine on an empty stomach can decrease adherence to hypothyroidism treatment. The objective of this study was to evaluate whether administering levothyroxine with breakfast can maintain thyrotropin (TSH) levels in the therapeutic range, without major clinical changes.

METHODS

A prospective, randomized, open-label, crossover study was conducted to compare usual levothyroxine administration while in a fasting state with administration during breakfast. From September 2008 to April 2009, 45 patients with primary hypothyroidism who received levothyroxine were recruited. The patients completed 180 days of the protocol and were randomized to 90 days of each levothyroxine administration regimen (while fasting or with breakfast). Clinical and biochemical analyses were performed at baseline and on days 45, 90, 135, and 180. The primary outcome was TSH level.

RESULTS

Forty-two patients completed the protocol. The TSH level was higher for levothyroxine administration with breakfast than while fasting (2.89 vs. 1.9 mIU/L, p=0.028). Uncontrolled hypothyroidism (TSH ≥3.5 mIU/L) occurred regardless of the type of levothyroxine administration (p=0.26). No risk factors were identified for TSH elevation.

CONCLUSIONS

Levothyroxine administration with breakfast could be an alternative regimen for patients who have adherence difficulties due to the need for delaying intake, and is more likely to cause variability in the TSH level, meaning the patient should be followed more closely. For patients in whom a specific serum TSH goal is important, taking levothyroxine while fasting is recommended.