Effect of growth hormone therapy on thyroid function in isolated growth hormone deficient and short small for gestational age children: a two-year study, including on assessment of the usefulness of the thyrotropin-releasing hormone (TRH) stimulation test.

Background The relationship between growth hormone (GH)-replacement therapy and the thyroid axis in GH-deficient (GHD) children remains controversial. Furthermore, there have been few reports regarding non-GHD children. We aimed to determine the effect of GH therapy on thyroid function in GHD and non-GHD children and to assess whether thyrotropin-releasing hormone (TRH) stimulation test is helpful for the identification of central hypothyroidism before GH therapy. Methods We retrospectively analyzed data from patients that started GH therapy between 2005 and 2015. The free thyroxine (FT4) and thyroid-stimulating hormone (TSH) concentrations were measured before and during 24 months of GH therapy. The participants were 149 children appropriate for gestational age with GHD (IGHD: isolated GHD) (group 1), 29 small for gestational age (SGA) children with GHD (group 2), and 25 short SGA children (group 3). Results In groups 1 and 2, but not in group 3, serum FT4 concentration transiently decreased. Two IGHD participants exhibited central hypothyroidism during GH therapy, and required levothyroxine (LT4) replacement. They showed either delayed and/or prolonged responses to TRH stimulation tests before start of GH therapy. Conclusions GH therapy had little pharmacological effect on thyroid function, similar changes in serum FT4 concentrations were not observed in participants with SGA but not GHD cases who were administered GH at a pharmacological dose. However, two IGHD participants showed central hypothyroidism and needed LT4 replacement therapy during GH therapy. TRH stimulation test before GH therapy could identify such patients and provoke careful follow-up evaluation of serum FT4 and TSH concentrations.

Color discrimination assessment in patients with hypothyroidism using the Farnsworth-Munsell 100 hue test.

There is evidence in the literature that hypofunction of the thyroid gland (hypothyroidism) affects color vision in rodents by influencing the production of the visual pigment opsin. The effect of hypothyroidism on color vision in humans has not been examined in any great detail. In this cross-sectional study we evaluated color discrimination using the Farnsworth-Munsell 100 hue test (FM-100 test) in 25 individuals with pre-treatment hypothyroidism (mean age ${38}\;{\pm }\;{9}.{2}\;\text{yr}$38±9.2yr), and a control euthyroid group, ${ n} ={26}$n=26 (mean age ${39.6}\;{\pm }\;{8}.{4}\;\text{yr}$39.6±8.4yr). There was no statistically significant difference in the total error score ($\surd{\text{TES}}$√TES) between the groups, but the hypothyroid group had a significantly greater partial error score ($\surd{\text{PES}}$√PES) along the blue-yellow (B-Y) axis compared to the red-green (R-G) axis. No statistically significant differences in B-Y and R-G PES were observed in the control group. This study shows that hypothyroidism affects color vision in humans, causing significant impairment in the B-Y color subsystem.

Understanding the most commonly billed diagnoses in primary care: Hypothyroidism.

ABSTRACT: This next article in the Most Commonly Billed Diagnoses series focuses on hypothyroidism and the significant role NPs play in identifying and managing patients with this condition and its associated comorbidities. Pathophysiology, systemic manifestations, screening, and treatment are discussed.

General Movement assessment and neurodevelopmental trajectory in extremely preterm infants with hypothyroxinaemia of prematurity (THOP).

BACKGROUND: Transient hypothyroxinaemia of prematurity (THOP) has been associated with neurodevelopmental deficits with a paucity of literature leading to variable practice. AIM: Evaluation of the relationship between free T4 (fT4) levels at 2 weeks after birth and early markers of neurodevelopmental outcome. STUDY DESIGN: A retrospective study of prospectively collected data from infants born <29 weeks' gestation, admitted to NICU between January 2012 and December 2014. The primary outcomes were the relationship between fT4 levels at 2 weeks, Prechtl General Movement Assessment (GMA) at 36 weeks and 3 months postterm age, and Bayley Scales of Infant Development (BSID-III) at 2 years postterm age. Secondary outcomes were survival free of disability and other neonatal morbidities. RESULTS: Of 122 infants, 101 infants had normal fT4 levels (No-THOP) and 21 had fT4 levels >1SD below the mean (THOP group). There was increased frequency of abnormal GMA in the No-THOP group compared with the THOP group at 36 weeks (abnormal writhing GMs: 43% vs 21%, p = 0.15) and 3 months corrected age (absent fidgety GMs: 7.6% vs 0%, p = 0.36), though not statistically significant. The neurodevelopmental outcome was worse in the No-THOP group compared with the THOP group with significantly lower mean cognitive and motor scores at 2 year of corrected age (90 ±â€¯13.8 vs 100 ±â€¯8.3, p = 0.01 and 91 ±â€¯15.2 vs 100 ±â€¯13.2, p = 0.04 respectively). CONCLUSIONS: This is the first report describing General Movements (GMs) in preterm infants with THOP. We found worse neurodevelopmental outcome in No-THOP infants reflected by significantly worse cognitive and motor outcomes at 2 years corrected age.

Hypothyroidism and related diseases: a methodological quality assessment of meta-analysis.

OBJECTIVES: There is an increasing prevalence of hypothyroidism and there is a growing body of meta-analyses (MAs) on the association between hypothyroidism and other diseases. However, the methodological quality of the MAs significantly varies. Thus, this study aimed to evaluate and summarise data on the methodological quality of MAs on the associations between hypothyroidism and other diseases using the Assessment of Multiple Systematic Reviews (AMSTAR) scale, providing suggestions for clinical decision-making processes. DESIGN: To assess the methodological quality of MAs using the AMSTAR scale. DATA SOURCES: A systematic literature search was performed in PubMed, EMBASE, the Cochrane Library, web of science and Chinese Biomedicine Literature Database. ELIGIBILITY CRITERIA: We included MAs that had assessed the association between hypothyroidism and other diseases in humans and that had full texts regardless of the publication status. No restriction applied on language or date. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently screened the titles and abstracts of all searched literature to acquire potentially eligible publications. The full texts of possible eligible publications were downloaded and assessed. Inconsistent comments were resolved through discussions with a third reviewer. RESULTS: 52 studies were included. The average AMSTAR score of the included articles was 8.6 (range: 5-10), and those of English and Chinese MAs were 8.8 and 7.0, respectively. A total of 52 MAs were evaluated, and 19 (36.5%) and 33 (63.5%) of these MAs were of moderate and high quality, respectively. None of the MAs were of low quality. Only two MAs had an a priori design. Items 3, 5 and 9 had the highest compliance (50/52, 96.2%), and aside from item 1, items 7 and 8 had the lowest compliance (33/52,63.5%). According to the results of these MAs, hypothyroidism was significantly associated with cardiovascular diseases, metabolic diseases, neuropsychiatric disorders, breast cancer and pregnancy outcome. CONCLUSIONS: The methodological quality of the included MAs on the association between hypothyroidism and other diseases was moderate to high. MAs with high qualities confirmed that hypothyroidism was significantly associated with cardiovascular diseases, metabolic syndrome, preterm birth and neonatal outcomes. Consideration of scientific quality when formulating conclusions should be made explicit and more attention should be paid to improving the methodological quality of MAs, and increasing their applicability for clinical decision-making.

Stability of thyroid function in older adults: the Birmingham Elderly Thyroid Study.

BACKGROUND: Thyroid function tests (TFTs) are among the most requested tests internationally. However, testing practice is inconsistent, and potentially suboptimal and overly costly. The natural history of thyroid function remains poorly understood. AIM: To establish the stability of thyroid function over time, and identify predictors of development of overt thyroid dysfunction. DESIGN AND SETTING: Longitudinal follow-up in 19 general practices in the UK. METHOD: A total of 2936 participants from the Birmingham Elderly Thyroid Study (BETS 1) with a baseline TFT result indicating euthyroid or subclinical state were re-tested after approximately 5 years. Change in thyroid-stimulating hormone (TSH), free thyroxine (FT4), and thyroid status between baseline and follow-up was determined. Predictors of progression to overt dysfunction were modelled. RESULTS: Participants contributed 12 919 person-years; 17 cases of overt thyroid dysfunction were identified, 13 having been classified at baseline as euthyroid and four as having subclinical thyroid dysfunction. Individuals with subclinical results at baseline were 10- and 16-fold more likely to develop overt hypothyroidism and hyperthyroidism, respectively, compared with euthyroid individuals. TSH and FT4 demonstrated significant stability over time, with 61% of participants having a repeat TSH concentration within 0.5 mIU/L of their original result. Predictors of overt hypothyroidism included new treatment with amiodarone (odds ratio [OR] 92.1), a new diagnosis of atrial fibrillation (OR 7.4), or renal disease (OR 4.8). CONCLUSION: High stability of thyroid function demonstrated over the 5-year interval period should discourage repeat testing, especially when a euthyroid result is in the recent clinical record. Reduced repeat TFTs in older individuals is possible without conferring risk, and could result in significant cost savings.

Effects of Altering Levothyroxine Dose on Energy Expenditure and Body Composition in Subjects Treated With LT4.

Background: It is unclear whether variations in thyroid status within or near the reference range affect energy expenditure, body mass, or body composition. Methods: 138 subjects treated with levothyroxine (LT4) for hypothyroidism with normal TSH levels underwent measurement of total, resting, and physical activity energy expenditure; thermic effect of food; substrate oxidation; dietary intake; and body composition. They were assigned to receive an unchanged, higher, or lower LT4 dose in randomized, double-blind fashion, targeting one of three TSH ranges (0.34 to 2.50, 2.51 to 5.60, or 5.61 to 12.0 mU/L). The doses were adjusted every 6 weeks to achieve target TSH levels. Baseline measures were reassessed at 6 months. Results: At study end, the mean LT4 doses and TSH levels were 1.50 ± 0.07, 1.32 ± 0.07, and 0.78 ± 0.08 µg/kg (P < 0.001) and 1.85 ± 0.25, 3.93 ± 0.38, and 9.49 ± 0.80 mU/L (P < 0.001), respectively, in the three arms. No substantial metabolic differences in outcome were found among the three arms, although direct correlations were observed between decreases in thyroid status and decreases in resting energy expenditure for all subjects. The subjects could not ascertain how their LT4 dose had been adjusted but the preferred LT4 dose they perceived to be higher (P < 0.001). Conclusions: Altering LT4 doses in subjects with hypothyroidism to vary TSH levels in and near the reference range did not have major effects on energy expenditure or body composition. Subjects treated with LT4 preferred the perceived higher LT4 doses despite a lack of objective effect. Our data do not support adjusting LT4 doses in patients with hypothyroidism to achieve potential improvements in weight or body composition.

Assessment of insulin like growth factor-1 and IGF binding protein-3 in healthy Indian girls from Delhi and their correlation with age, pubertal status, obesity and thyroid hormonal status.

BACKGROUND: Population specific data and influence of sub-clinical hypothyroidism on insulin like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3) in Indian children is lacking. This study was undertaken to evaluate serum IGF-1 and IGFBP-3 and their correlation with age, gender, pubertal status and thyroid functions. METHODS: A total of 840 apparently healthy school girls aged 6-18 years, were recruited for the study and underwent assessment of height, weight, body mass index, pubertal status and serum T3, T4, TSH, IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio. RESULTS: The mean serum levels of IGF-1, IGFBP-3 levels and IGF-1/IGFBP-3 molar ratio were 381.8±240.5 ng/mL, 4.19±2.08 µg/mL and 40.5±37.2%, respectively. The serum IGF-1 and IGF-1/IGFBP-3 molar ratio increased significantly (p<0.0001) at 11 years followed by a steady yet non-significant rise till 16 years of age. A similar pattern was observed for IGFBP-3 showing a steep rise at 12 years and peaking at 16 years. Likewise, serum levels of IGF-1 and molar ratio of IGF-1/IGFBP-3 increased significantly with pubertal maturation from stage 1 to 3 and were higher in overweight girls compared to normal weight and obese girls. The growth factors were no different in girls with or without subclinical hypothyroidism. CONCLUSIONS: There was no significant impact of age on IGF-1 and IGFBP-3 in pre-pubertal girls. A sudden marked increase at 11 years followed by a gradual rise in growth factors till 16 years is indicative of pubertal initiation and maturation. Subclinical hypothyroidism did not influence growth factors in girls.

Hyperthyroidism, Hypothyroidism, and Cause-Specific Mortality in a Large Cohort of Women.

BACKGROUND: The prevalence of hyperthyroidism and hypothyroidism is 0.5-4% in iodine-replete communities, but it is 5-10 times higher in women than in men. Those conditions are associated with a broad range of metabolic disorders and cardiovascular diseases. Biological evidence of a role of thyroid hormones in carcinogenesis also exists. However, the association between thyroid dysfunction and cardiovascular disease or cancer mortality risk remains controversial. In a large cohort of women, the associations of hyperthyroidism and hypothyroidism with cause-specific mortality were evaluated after nearly 30 years of follow-up. METHODS: The prospective study included 75,076 women aged 20-89 years who were certified as radiologic technologists in the United States in 1926-1982, completed baseline questionnaires in 1983-1998 from which medical history was ascertained, and reported no malignant disease or benign thyroid disease except thyroid dysfunction. A passive follow-up of this cohort was performed through the Social Security Administration database and the National Death Index-Plus. Cause-specific mortality risks were compared according to self-reported thyroid status, with proportional hazards models adjusted for baseline year and age, race/ethnicity, body mass index, family history of breast cancer, and life-style and reproductive factors. RESULTS: During a median follow-up of 28 years, 2609 cancer, 1789 cardiovascular or cerebrovascular, and 2442 other non-cancer deaths were recorded. Women with hyperthyroidism had an elevated risk of breast cancer mortality after 60 years of age (hazard ratio [HR] = 2.04 [confidence interval (CI) 1.16-3.60], 13 cases in hyperthyroid women) compared to women without thyroid disease. Hypothyroid women had increased mortality risks for diabetes mellitus (HR = 1.58 [CI 1.03-2.41], 27 cases in hypothyroid women), cardiovascular disease (HR = 1.20 [CI 1.01-1.42], 179 cases), and cerebrovascular disease (HR = 1.45 [CI 1.01-2.08], 35 cases, when restricting the follow-up to ≥10 years after baseline). Other causes of death were not associated with hyperthyroidism or hypothyroidism, though there was a suggestion of an elevated risk of ovarian cancer mortality in hyperthyroid women based on very few cases. CONCLUSION: The excess mortality risks observed in a large, prospective 30-year follow-up of patients with thyroid dysfunction require confirmation, and, if replicated, further investigation will be needed because of the clinical implications.

Monitoring Thyroid Function in Patients on Levothyroxine. Assessment of Conformity to National Guidance and Variability in Practice.

With demand for endocrine tests steadily increasing year-on-year, we examined thyroid function test (TFT) frequencies in patients on levothyroxine replacement therapy to assess the effect of initial TFT results and request source on TFT re-testing interval. All TFTs performed by the Clinical Biochemistry Departments at the Salford Royal Hospital (2009-2012; 288 263 requests from 139 793 patients) and University Hospital of North Midlands (2011-2014; 579 156 requests from 193 035 patients) were extracted from the laboratory computer systems. Of these, 54 894 tests were on 13 297 patients confirmed to be on levothyroxine therapy in the test cohort (Salford) and 67 298 requests on 11 971 patients in the confirmatory cohort (North Midlands). In the test cohort, median TFT re-testing interval in the total group was 19.1 weeks (IQR 9.1-37.7 weeks), with clearly defined peaks in TFT re-testing evident at 6 and 12 months and a prominent broad peak at 1-3 months. Median re-test interval was much lower than recommended (52 weeks) for those with normal TFTs at 31.3 weeks (30.6 weeks for the confirmatory cohort). Where thyroid-stimulating hormone (TSH) was elevated and free thyroxine (fT4) was below the reference range, re-test interval was much longer than is recommended (8 weeks) at 13.4-17.6 weeks (7.1-23.4 weeks in the confirmatory cohort), as was the interval when TSH was below and fT4 was above the normal range, at 16.7-25.6 weeks (27.5-31.9 weeks in the confirmatory cohort). Our findings show that the majority of TFT requests are requested outside recommended intervals and within-practice variability is high. A new approach to ensuring optimum monitoring frequency is required. Direct requesting from the clinical laboratory may provide one such solution.

Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition.

BACKGROUND: Thyrotropin (TSH)-suppressive doses of levothyroxine (LT4) have adverse effects on bone and cardiac function, but it is unclear whether metabolic function is also affected. The objective of this study was to determine whether women receiving TSH-suppressive LT4 doses have alterations in energy expenditure or body composition. METHODS: This study was a cross-sectional comparison between three groups of women: 26 women receiving chronic TSH-suppressive LT4 doses, 80 women receiving chronic replacement LT4 doses, and 16 untreated euthyroid control women. Subjects underwent measurements of resting energy expenditure (REE), substrate oxidation, and thermic effect of food by indirect calorimetry; physical activity energy expenditure by accelerometer; caloric intake by 24-hour diet recall; and body composition by dual X-ray absorptiometry. RESULTS: REE per kilogram lean body mass in the LT4 euthyroid women was 6% lower than that of the LT4-suppressed group, and 4% lower than that of the healthy control group (p = 0.04). Free triiodothyronine (fT3) levels were directly correlated with REE, and were 10% lower in the LT4 euthyroid women compared with the other two groups (p = 0.007). The groups of subjects did not differ in other measures of energy expenditure, caloric intake, or body composition. CONCLUSIONS: LT4 suppression therapy does not adversely affect energy expenditure or body composition in women. However, LT4 replacement therapy is associated with a lower REE, despite TSH levels within the reference range. This may be due to lower fT3 levels, suggesting relative tissue hypothyroidism may contribute to impaired energy expenditure in LT4 therapy.

Impact of thyroid status and age on comprehensive geriatric assessment.

This study aimed to evaluate the prevalence of thyroid dysfunction in elderly subjects attending an outpatient clinic at a tertiary hospital and to assess whether subclinical hypothyroidism (SCH) or aging affected activities of daily living (ADLs), instrumental activities of daily living (IADLs), cognitive status, or depressive symptoms. This crosssectional study included 411 patients recruited in the outpatient geriatric setting. 48 subjects reported levothyroxine use and were evaluated separately. After excluding subjects with diseases or drugs which could influence thyroid status, the 284 subjects remaining were classified as having euthyroidism (n = 235, 82.8 %), subclinical hypothyroidism (n = 43, 15.1 %), subclinical hyperthyroidism (n = 4, 1.4 %), or overt hyperthyroidism (n = 2, 0.7 %). ADLs and IADLs were assessed using the Katz Index (ranging from 0 [independence] to 6 [dependence in all activities]) and Health Assessment Questionnaire (ranging from 0 to 3 [severely disabled]), respectively. Cognition was assessed using the mini mental state depressive symptoms that were assessed using the Geriatric depression scale or cornell scale for depression in dementia. SCH did not reduce performance in ADLs or IADLs in elderly subjects as a whole, but was an independent protective factor against dependence in ADLs (OR = 0.196 [0.045-0.853]; p = 0.003) and IADLs (OR = 0.060 [0.010-0.361]; p = 0.002) in subjects aged ≥85 years. Very old subjects with SCH showed better performance in ADLs than did those with euthyroidism (Katz Index: 0.9 ± 1.6 [median: 0.5] vs. 1.7 ± 1.7 [1.0], p = 0.024; HAQ: 1.2 ± 0.8 [0.9] vs. 1.8 ± 1.0 [1.9], p = 0.015). This putative protective effect of SCH was not found in subjects aged <85 years. The number of falls, number of medications used, depressive symptoms, and cognitive impairment did not differ among thyroid status groups, regardless of age. In conclusion, SCH does not have impact functional performance in the elderly population as a whole, but was associated with better functional status in subjects aged ≥85 years.

Assessment of the elasticity properties of the ascending aorta in patients with subclinical hypothyroidism by tissue Doppler imaging.

OBJECTIVE: We aimed to investigate whether aortic elastic properties were affected in subclinical hypothyroidism (SCH) by using tissue Doppler imaging (TDI). SUBJECTS AND METHODS: Forty-three patients with newly diagnosed SCH and forty-eight healthy controls were included to the study. Systolic and diastolic diameters of the ascending aorta were measured by M-mode transthoracic echocardiography, and the upper wall velocities of ascending aorta and mitral annulus velocities were measured by TDI. Aortic stiffness index (ASI) and aortic distensibility were computed using the formulas accepted in literature. RESULTS: The clinical and demographic features of both groups were comparable. Aortic distensibility was significantly lower, and ASI was significantly higher in SCH patients than in controls. Systolic aortic upper wall velocity (Sao) was also significantly lower in SCH patients. Early (Eao) and late diastolic aortic upper wall (Aao) velocities did not differ between the two groups. Mitral annulus (Sm, Em, and Am) velocities were also similar between the groups. Sao was negatively correlated with ASI, and positively correlated with aortic distensibility. TSH level was positively correlated with ASI, total cholesterol and low-density lipoprotein-cholesterol, and negatively correlated with aortic distensibility and Sao. CONCLUSIONS: In this study, our results showed that SCH is associated with impaired elasticity of the ascending aorta. Elastic properties of the ascending aorta can be directly evaluated by the reproducibly measurement of the upper wall movements of the ascending aorta by TDI in SCH patients.

Assessment of the elasticity properties of the ascending aorta in patients with subclinical hypothyroidism by tissue Doppler imaging / Avaliação das propriedades de elasticidade da aorta ascendente por Doppler tecidual em pacientes com hipotireoidismo subclínico

OBJECTIVE: We aimed to investigate whether aortic elastic properties were affected in subclinical hypothyroidism (SCH) by using tissue Doppler imaging (TDI). SUBJECTS AND METHODS: Forty-three patients with newly diagnosed SCH and forty-eight healthy controls were included to the study. Systolic and diastolic diameters of the ascending aorta were measured by M-mode transthoracic echocardiography, and the upper wall velocities of ascending aorta and mitral annulus velocities were measured by TDI. Aortic stiffness index (ASI) and aortic distensibility were computed using the formulas accepted in literature. RESULTS: The clinical and demographic features of both groups were comparable. Aortic distensibility was significantly lower, and ASI was significantly higher in SCH patients than in controls. Systolic aortic upper wall velocity (Sao) was also significantly lower in SCH patients. Early (Eao) and late diastolic aortic upper wall (Aao) velocities did not differ between the two groups. Mitral annulus (Sm, Em, and Am) velocities were also similar between the groups. Sao was negatively correlated with ASI, and positively correlated with aortic distensibility. TSH level was positively correlated with ASI, total cholesterol and low-density lipoprotein-cholesterol, and negatively correlated with aortic distensibility and Sao. CONCLUSIONS: In this study, our results showed that SCH is associated with impaired elasticity of the ascending aorta. Elastic properties of the ascending aorta can be directly evaluated by the reproducibly measurement of the upper wall movements of the ascending aorta by TDI in SCH patients.

OBJETIVO: Nosso objetivo foi investigar se as propriedades elásticas da aorta são afetadas no hipotireoidismo subclínico (HSC), utilizando o Doppler tecidual (UDT). SUJEITOS E MÉTODOS: Quarenta e três pacientes com diagnóstico recente de HSC e 48 indivíduos saudáveis ​​foram incluídos no estudo. Os diâmetros sistólico e diastólico da aorta foram medidos por ecocardiografia transtorácica modo M e as velocidades de fluxo da parede superior da aorta ascendente e de fluxo transvalvar mitral foram medidas por UDT. O índice de rigidez da aorta (IRA) e a distensibilidade aórtica foram calculados usando fórmulas aceitas na literatura. RESULTADOS: As características clínicas e demográficas dos dois grupos foram comparáveis. A distensibilidade aórtica foi significativamente menor e IRA significativamente maior nos pacientes com HSC do que nos controles. A velocidade de fluxo sistólico na parede aórtica superior (Sao) foi significantemente menor em pacientes com HSC. A velocidade de fluxo diastólico inicial (Eao) e tardio (Aao) na parede aórtica superior e as velocidades de fluxo transvalvar (Sm, Em e Am) não diferiram entre os dois grupos. Sao foi negativamente correlacionada com IRA e positivamente correlacionada com a distensibilidade aórtica. O nível de TSH foi positivamente correlacionado com IRA, colesterol total e lipoproteína de baixa densidade-colesterol e negativamente correlacionado com a distensibilidade aórtica e Sao. CONCLUSÕES: Os resultados do presente estudo demonstraram que o HSC é associado com elasticidade deficiente da aorta ascendente. Propriedades elásticas da aorta ascendente podem ser diretamente avaliadas por medições reprodutíveis dos movimentos da parede superior da aorta por UDT em pacientes com HSC.

Cohort study on radioactive iodine-induced hypothyroidism: implications for Graves' ophthalmopathy and optimal timing for thyroid hormone assessment.

BACKGROUND: Graves' ophthalmopathy (GO) develops or worsens in up to one-third of patients treated with radioactive iodine (RAI) for Graves' hyperthyroidism. We sought to identify the prevalence of development or worsening of GO in patients treated with RAI for Graves' hyperthyroidism and to identify the risk factors associated with that outcome. METHODS: We identified a retrospective cohort of consecutive patients treated with RAI at Mayo Clinic (Rochester, MN) between 2005 and 2006. We assessed their medical records for evidence of hypothyroidism and development or worsening of GO in the year after therapy. Hypothyroidism was defined as thyrotropin >3.0 mIU/L or free thyroxine <0.8 ng/dL. RESULTS: We identified 291 consecutive patients who received RAI therapy during the study period, with 195 out of 291 having complete follow-up data for a one-year period. GO was present in 46 out of 195 patients (23.6%) at baseline. After RAI treatment, GO developed or worsened in 25 out of 195 patients (12.8%) and it was associated with hypothyroidism at first follow-up (p=0.011) with an odds ratio (OR) of 3.3 [95% confidence interval (CI) 1.3-8.7]. More smokers than nonsmokers developed new or worse GO (17.7% vs. 11.8%), but that difference did not reach statistical significance (p=0.35). Preexisting GO (24% of patients) was associated with a higher risk for negative GO outcome compared with patients who had no GO at baseline (11%; p=0.021). Both development of hypothyroidism by the first visit after RAI therapy (OR 3.6) and preexistent GO (OR 2.8) remained significant in a multivariate analysis. Development of hypothyroidism was more likely in patients with longer duration to first follow-up (p<0.001). By 6-8 weeks after RAI treatment, the prevalence of hypothyroidism was ∼40%, while that of hyperthyroidism was only 20%. CONCLUSIONS: The presence of hypothyroidism at the first assessment of thyroid function after RAI administration is a strong predictor for adverse GO outcome. This risk is highest in patients with preexisting GO. We suggest that in order to prevent clinical hypothyroidism and the associated risk for GO, the optimal time for first measurement of fT4 is before 6 weeks after RAI therapy.

Evaluation of sleeping energy expenditure using the SenseWear Armband in patients with overt and subclinical hypothyroidism.

PURPOSE: The aim of the present study was to evaluate the average sleeping energy expenditure (EE) levels using the SenseWear Armband (SWA) in patients with overt and subclinical hypothyroidism. METHODS: Sixty patients with hypothyroidism and 30 healthy individuals were recruited for the study. Hypothyroid patients were divided into two groups: group 1 (n = 30) consisted of patients with overt hypothyroidism and group 2 (n = 30) consisted of patients with subclinical hypothyroidism. Lastly, group 3 (n = 30) consisted of healthy subjects. The average EE and metabolic equivalent of task (MET) values during sleep of all the hypothyroid participants were analyzed at baseline and at the end of the study. Data were also obtained from the healthy subjects at baseline. RESULTS: The average sleeping EE and METs values were not significantly different at baseline. Similarly, these values did not change significantly after achieving a euthyroid state via thyroid hormone replacement (both p > 0.05). CONCLUSIONS: Contrary to what has been previously reported , the average sleeping EE and METs values in all hypothyroid patients and healthy individuals were similar at baseline and did not change in the patients with overt and subclinical hypothyroidism after achievement of a euthyroid state.