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Thyroxine treatment in patients with symptoms of hypothyroidism but thyroid function tests within the reference range: randomised double blind placebo controlled crossover trial.

ABSTRACT: OBJECTIVES:To determine whether thyroxine treatment is effective in patients with symptoms of hypothyroidism but with thyroid function tests within the reference range, and to investigate the effect of thyroxine treatment on psychological and physical wellbeing in healthy participants. DESIGN:Randomised double blind placebo controlled crossover trial. SETTING:Outpatient clinic in a general hospital. PARTICIPANTS:25 patients with symptoms of hypothyroidism who had thyroid function tests within the reference range, and 19 controls. METHODS:PARTICIPANTS were given thyroxine 100 microgram or placebo to take once a day for 12 weeks. Washout period was six weeks. They were then given the other to take once a day for 12 weeks. All participants were assessed physiologically and psychologically at baseline and on completion of each phase. MAIN OUTCOME MEASURES:Thyroid function tests, measures of cognitive function and of psychological and physical wellbeing. RESULTS:22 patients and 19 healthy controls completed the study. At baseline, patients' scores on 9 out of 15 psychological measures were impaired when compared with controls. Patients showed a significantly greater response to placebo than controls in 3 out of 15 psychological measures. Healthy participants had significantly lower scores for vitality when taking thyroxine compared to placebo (mean (SD) 60 (17) v 73 (16), P<0.01). However, patients' scores from psychological tests when taking thyroxine were no different from those when taking placebo except for a poorer performance on one visual reproduction test when taking thyroxine. Serum concentrations of free thyroxine increased and those of thyroid stimulating hormone decreased in patients and controls while they were taking thyroxine, confirming compliance with treatment. Although serum concentrations of free triiodothyronine increased in patients and controls taking thyroxine, the difference between the response to placebo and to thyroxine was significant only in the controls. CONCLUSIONS:Thyroxine was no more effective than placebo in improving cognitive function and psychological wellbeing in patients with symptoms of hypothyroidism but thyroid function tests within the reference range. Thyroxine did not improve cognitive function and psychological wellbeing in healthy participants.

SUBMITTER: Pollock MA

PROVIDER: S-EPMC58535 | biostudies-literature | 2001 Oct

REPOSITORIES: biostudies-literature

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Thyroxine treatment in patients with symptoms of hypothyroidism but thyroid function tests within the reference range: randomised double blind placebo controlled crossover trial.

Pollock M A MA Sturrock A A Marshall K K Davidson K M KM Kelly C J CJ McMahon A D AD McLaren E H EH

BMJ (Clinical research ed.) 20011001 7318

<h4>Objectives</h4>To determine whether thyroxine treatment is effective in patients with symptoms of hypothyroidism but with thyroid function tests within the reference range, and to investigate the effect of thyroxine treatment on psychological and physical wellbeing in healthy participants.<h4>Design</h4>Randomised double blind placebo controlled crossover trial.<h4>Setting</h4>Outpatient clinic in a general hospital.<h4>Participants</h4>25 patients with symptoms of hypothyroidism who had thy ...[more]

PMID: 11668132

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Project description:ObjectiveTo estimate the effect of antenatal treatment of subclinical hypothyroidism on maternal depressive symptoms.MethodsWe conducted an ancillary study to a multicenter trial in women with singleton pregnancies diagnosed with subclinical hypothyroidism randomized to antenatal thyroxine therapy or placebo. Treatment was discontinued at the end of pregnancy. Women with overt thyroid disease, diabetes, autoimmune disease, and those diagnosed with depression were excluded. Participants were assessed for depressive symptoms using the Center for Epidemiological Studies-Depression scale (CES-D) before starting the study drug (between 11 and 20 weeks of gestation), between 32 and 38 weeks of gestation, and at 1 year postpartum. The primary outcome was maternal depressive symptoms score as assessed using the CES-D. Secondary outcome was the percentage of women who scored 16 or higher on the CES-D, as such a score is considered screen-positive for depression.ResultsTwo hundred forty-five (36.2% of parent trial) women with subclinical hypothyroidism were allocated to thyroxine (n=124) or placebo (n=121). Median CES-D scores and the proportion of participants with positive scores were similar at baseline between the two groups. Treatment with thyroxine was not associated with differences in CES-D scores (10 [5-15] vs 10 [5-17]; P=.46) or in odds of screening positive in the third trimester compared with placebo, even after adjusting for baseline scores (24.3% vs 30.1%, adjusted odds ratio 0.63, 95% CI 0.31-1.28, P=.20). At 1 year postpartum, CES-D scores were not different (6 [3-11] vs 6 [3-12]; P=.79), nor was the frequency of screen-positive CES-D scores in the treated compared with the placebo group (9.7% vs 15.8%; P=.19). Treatment with thyroxine during pregnancy was also not associated with differences in odds of screening positive at the postpartum visit compared with placebo even after adjusting for baseline scores. Sensitivity analysis including women who were diagnosed with depression by the postpartum visit did not change the results.ConclusionsThis study did not achieve its planned sample size, thus our conclusions may be limited, but in this cohort of pregnant women with subclinical hypothyroidism, antenatal thyroxine replacement did not improve maternal depressive symptoms.

Project description:Thyroxine metabolism is an important topic of pathogenesis research and treatment schedule of subclinical hypothyroidism (SCH). L-Thyroxine replacement therapy (LRT) is usually recommended for severe SCH patients only. Our previous studies reported that disordered serum lipid of mild SCH people could also benefit from LRT. However, the benefits were different among individuals, as shown by the variations in drug dosage that required to maintain thyroid-stimulating hormone (TSH) stability. Alternative pathways, such as sulfation and glucuronidation of iodothyronine, may play a role in thyroid hormones metabolism in peripheral tissues aside from thyroid. Conjugated thyroxine can be hydrolyzed and reused in tissues including gastrointestinal tract, in which gut microbiota are one of the most attractive physiological components. On this site, the roles of gut microbiota in thyroidal metabolism should be valued. In this study, a cross-sectional study was performed by analyzing 16S rDNA of gut microbiota in mild SCH patients treated with L-thyroxine or not. Subjects were divided by serum lipid level, L-thyroxine treatment, or L-thyroxine dosage, respectively. Relationship between gut microbiome and serum profile, L-thyroxine treatment, and dose were discussed. Other metabolic disorders such as type 2 diabetes and hypertension were also taken into consideration. It turned out that microbiome varied among individuals divided by dose and the increment of L-thyroxine but not by serum lipid profile. Relative abundance of certain species that were associated with thyroxine metabolism were found varied among different L-thyroxine doses although in relatively low abundance. Moreover, serum cholesterol may perform relevance effects with L-thyroxine in shaping microbiome. Our findings suggested that the differences in L-thyroxine dosage required to maintain TSH level stability, as well as the SCH development, which was displayed by the increased L-thyroxine doses in subsequent follow-up, had relationship with gut microbial composition. The reason may due to the differences in thyroxine metabolic capacity in gut. In addition, the metabolic similarity of iodothyronines and bile acid in gut also provides possibilities for the correlation between host's thyroxine and cholesterol levels. This study was registered with ClinicalTrials.gov as number NCT01848171.

Project description:BACKGROUND:Atrial fibrillation (AF) is a highly prevalent disorder leading to heart failure, stroke, and death. Enhanced understanding of modifiable risk factors may yield opportunities for prevention. The risk of AF is increased in subclinical hyperthyroidism, but it is uncertain whether variations in thyroid function within the normal range or subclinical hypothyroidism are also associated with AF. METHODS:We conducted a systematic review and obtained individual participant data from prospective cohort studies that measured thyroid function at baseline and assessed incident AF. Studies were identified from MEDLINE and EMBASE databases from inception to July 27, 2016. The euthyroid state was defined as thyroid-stimulating hormone (TSH) 0.45 to 4.49 mIU/L, and subclinical hypothyroidism as TSH 4.5 to 19.9 mIU/L with free thyroxine (fT4) levels within reference range. The association of TSH levels in the euthyroid and subclinical hypothyroid range with incident AF was examined by using Cox proportional hazards models. In euthyroid participants, we additionally examined the association between fT4 levels and incident AF. RESULTS:Of 30?085 participants from 11 cohorts (278?955 person-years of follow-up), 1958 (6.5%) had subclinical hypothyroidism and 2574 individuals (8.6%) developed AF during follow-up. TSH at baseline was not significantly associated with incident AF in euthyroid participants or those with subclinical hypothyroidism. Higher fT4 levels at baseline in euthyroid individuals were associated with increased AF risk in age- and sex-adjusted analyses (hazard ratio, 1.45; 95% confidence interval, 1.26-1.66, for the highest quartile versus the lowest quartile of fT4; P for trend ?0.001 across quartiles). Estimates did not substantially differ after further adjustment for preexisting cardiovascular disease. CONCLUSIONS:In euthyroid individuals, higher circulating fT4 levels, but not TSH levels, are associated with increased risk of incident AF.

Dataset Information

Thyroxine treatment in patients with symptoms of hypothyroidism but thyroid function tests within the reference range: randomised double blind placebo controlled crossover trial.

Publications

Thyroxine treatment in patients with symptoms of hypothyroidism but thyroid function tests within the reference range: randomised double blind placebo controlled crossover trial.

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