Subclinical Hypothyroidism Is Associated With Adverse Prognosis in Heart Failure Patients

Background

It is widely recognized that overt hyper- as well as hypothyroidism are potential causes of heart failure (HF). Additionally it has been recently reported that subclinical hypothyroidism (sub-hypo) is associated with atherosclerosis, development of HF, and cardiovascular death. We aimed to clarify the effect of sub-hypo on prognosis of HF, and underlying hemodynamics and exercise capacity.

Community-based study of the association of subclinical thyroid dysfunction with blood pressure

The relationship between subclinical thyroid dysfunction and blood pressure has been controversial and received unsufficient attention. Thus, we performed a cross-sectional study conducted among 6,992 inhabitants from six districts of Jiangsu Province to investigate the association of subclinical thyroid dysfunction with blood pressure in China. The data from 6,583 subjects (4,115 women and 2,468 men) were included and divided into three groups: euthyroidism (n = 5669, 86.11%), subclinical hyperthyroidism (n = 108, 1.65%), and subclinical hypothyroidism (n = 806, 12.24%). In the groups with subclinical hypothyroidism and hyperthyroidism, systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure were not significantly different from those in the groups with euthyroidism after being adjusted for age, sex, BMI, and smoking status (P > 0.05). More extensively, the SBP and DBP in the group of subclinical hypothyroidism with lower level of TSH (TSH 4.51–10.00 mIU/l, SCH₁) were significantly higher than those of participants with euthyroidism (P < 0.05). Multivariable logistic analysis revealed that subclinical hypothyroidism with lower TSH (TSH 4.51–10.00 mIU/l) was an independent risk factor for increased SBP (OR = 1.28, 95% CI 1.03–1.59, P = 0.028). Similar results could not be found between groups of euthyroid and subclinical hypothyroid with higher level of TSH (TSH > 10 mIU/l, SCH₂). Further subdivision of the euthyroid group on the basis of a TSH cut-off of 2.5 mIU/l, revealed still no significant difference in blood pressure after adjustment regardless of whether the TSH levels were in the lower reference (TSH 0.40–2.50 mIU/l, n = 4093) or in the upper reference ranges (TSH 2.51–4.50 mIU/l, n = 1576) (P > 0.05). We concluded that subclinical thyroid dysfunction was not associated with blood pressure. Neither subclinical hyperthyroidism nor subclinical hypothyroidism independently predicted increased blood pressure.     

Prognostic impact of subclinical thyroid dysfunction in heart failure

Background

Therapeutic and prognostic implications of subclinical thyroid dysfunction in patients with heart failure (HF) are unclear. We compared the prognostic impact of euthyroidism, subclinical thyroid dysfunction, and euthyroid sick syndrome (ESS) in systolic HF.

Methods

We included 1032 patients hospitalized for systolic HF (left ventricular ejection fraction [LVEF] ≤ 40%) who participated in a randomized trial assessing the effects of a HF disease management program. Patients with incomplete thyroid function tests or thyrotropic medication were excluded. In the remaining 758 subjects, the risk of all-cause death was estimated based on TSH only, or full thyroid function profile. Changes of thyroid function after six months were assessed in 451 subjects.

Results

Subclinical thyroid dysfunction was present in 103 patients at baseline (14%). No differences were found between groups regarding NYHA class (P = 0.29), and LVEF (P = 0.60). After a median follow-up of three years patients with ESS (n = 13) had a 3-fold age-adjusted increased risk of death compared to euthyroid patients (P = 0.001). However, neither subclinical hyperthyroidism (HR 1.18, 95%CI:0.82–1.70) nor hypothyroidism (HR 1.07, 95%CI:0.58–1.98) were associated with increased age-adjusted mortality risk. Subclinical thyroid dysfunction had normalized spontaneously at follow-up in 77% of patients. However, persistent subclinical thyroid dysfunction was also not associated with worse outcome.

Conclusions

In this large well-characterized HF cohort, subclinical thyroid dysfunction did not predict an increased mortality risk. Thus, in patients with moderate to severe HF, further diagnostic and therapeutic procedures for subclinical thyroid dysfunction appear dispensable. ESS was an infrequent but important indicator of a poor prognosis in HF.

Clinical trial registration

URL: http://www.controlled-trials.com. Unique identifier: ISRCTN23325295.     

Thyroid dysfunction and anti-thyroid antibodies in systemic sclerosis patients

Aim of the workTo assess the frequency of thyroid dysfunction and thyroid auto-antibodies in systemic sclerosis (SSc) patients.Patients and methodsThis study included thirty-three SSc patients and 30 matching controls. Thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), anti thyroglobulin (ATG) and anti thyroid peroxidase autoantibodies (ATPO) were measured in the sera of patients and controls.ResultsThe mean age of the patients was 45.9 ± 13.05 years; 28 females and 5 males (F: M 5.6:1) and a disease duration of 4.58 ± 3.84 years. The FT3, FT4, TSH tended to be higher in patients (T3: 2.8 ± 0.66 pg/ml; T4: 1.5 ± 0.65 ng/ml; TSH: 1.9 ± 2.1 ul/ml) than in controls (p = 0.07, p = 0.21 and p = 0.24 respectively) while the ATG level in patients was 40 ± 21.3 IU/ml and ATPO 36.7 ± 88.2 IU/ml. Four patients had hypothyroidism (12 %); 3 (9 %) subclinical hypothyroidism (SCHT) and 1 (3 %) clinical hypothyroidism (CHT). ATG was positive in one patient and in 2 controls while ATPO was positive in two patients compared to one control. Both antibodies were positive in one patient. ATPO was associated with SCHT in one (3 %) and with overt hypothyroidism in another (3 %). The thyroid profile, ATG and ATPO were comparable between females and males (p = 0.34, p = 0.23, p = 0.96, p = 0.77 and p = 0.35 respectively) and all were similar between lcSSc and dcSSc except TSH (lower in dcSSc; p = 0.03). Muscle weakness was significantly higher among ATPO positive patients (p = 0.005) while thyroid dysfunction was significantly associated with arthralgia (p = 0.007).ConclusionThyroid dysfunction mainly hypothyroidism is more frequent among SSc patients.     

Growth hormone/insulin-like growth factor axis in patients with subclinical thyroid dysfunction

ObjectiveOur aim was to evaluate serum concentrations of GH, IGF-I, and insulin-like growth factor-binding protein-3 (IGFBP-3) in patients with subclinical thyroid dysfunction before and after normalization of thyroid function.Design and methodsThe study included 51 patients (mean age 42.2 ± 1.8 years) with subclinical hypothyroidism and 30 patients (mean age 44.3 ± 2.4 years) with subclinical hyperthyroidism. A group of 37 euthyroid healthy subjects were studied as controls. Serum concentrations of TSH, FT4, FT3, GH, insulin, IGF-I, and IGFBP-3 were measured in all patients before starting therapy and after normalization of thyroid function. The dosage of levothyroxine (LT4) and antithyroid drugs was adjusted in attempt to keep the serum-free thyroxine (FT4) and thyrotropin (TSH) concentrations within the normal range.Main outcomeBaseline growth hormone levels were similar with hypothyroid group and hyperthyroid group in relation to euthyroid control subjects. Fasting serum IGF-I levels were significantly lower in the subclinical hypothyroid group compared with the control group. On the other hand, IGF-I levels of subclinical hyperthyroid patients and control group were similar. After normalization of thyroid function tests, IGF-I concentrations were increased in subclinical hypothyroid subjects, but unchanged in subclinical hyperthyroid subjects. Patients with subclinical hyperthyroidism showed slightly lower mean serum IGFBP-3 concentrations than those found in control group, but the difference was not statistically significant. Serum GH and IGFBP-3 levels were unaltered by treatment.ConclusionsIn this study, it was shown that GH–IGF axis was not affected in patients with subclinical hyperthyroidism, while it was affected in patients with subclinical hypothyroidism. That is, investigation of the axis in subclinical hyperthyroidism would not bring any extra advantages, but LT4 replacement therapy could prevent abnormalities related to GH–IGF axis in patients with subclinical hypothyroidism.     

Does Subclinical Hypothyroidism Add Any Symptoms? Evidence from a Danish Population-Based Study

BackgroundFew studies have scrutinized the spectrum of symptoms in subclinical hypothyroidism.MethodsFrom 3 Danish Investigation on Iodine Intake and Thyroid Diseases (DanThyr) cross-sectional surveys performed in the period 1997 to 2005, a total of 8903 subjects participated in a comprehensive investigation including blood samples and questionnaires on previous diseases, smoking habits, alcohol intake, and education. From the 3 surveys we included patients with subclinical hypothyroidism (n = 376) and euthyroid controls (n = 7619). We explored to what extent patients with subclinical hypothyroidism reported 13 previously identified hypothyroidism-associated symptoms (tiredness, dry skin, mood lability, constipation, palpitations, restlessness, shortness of breath, wheezing, globus sensation, difficulty swallowing, hair loss, dizziness/vertigo, and anterior neck pain). In various uni- and multivariate regression models we searched for circumstances predicting why some patients have more complaints than others.ResultsSubclinically hypothyroid patients did not report higher hypothyroidism score [(median, interquartile range), 2 (0-4) vs 2 (0-4), P = .25] compared with euthyroid controls. Within the group of subclinical hypothyroid patients, comorbidity had the highest impact on symptoms (tiredness, shortness of breath, wheezing; all P < .001); TSH level had no impact on symptom score; and younger age was accompanied by higher mental burden (tiredness, P < .001; mood lability, P < .001; restlessness, P = .012), whereas shortness of breath was associated with high body mass index (P < .001) and smoking (P = .007).ConclusionPatients with a thyroid function test suggesting subclinical hypothyroidism do not experience thyroid disease-related symptoms more often than euthyroid subjects. In subclinical hypothyroidism, clinicians should focus on concomitant diseases rather than expecting symptomatic relief following levothyroxine substitution.     

Mortality rate of chronically ill geriatric patients with subnormal serum thyrotropin concentration: a 2-yr follow-up study

We investigated the natural course of subclinical thyroid dysfunctions in geriatric patients, especially regarding their association with mortality rate. Ninety-three randomly selected chronically ill geriatric patients 64–87 (median: 77) yr of age participated in the screening study with a 2-yr follow-up. Serum thyrotropin (thyroid-stimulating hormone [TSH]), free thyroxine, triiodothyronine, and antibodies against thyroid peroxidase were measured. During the follow-up, patients with suppressed TSH levels who were otherwise euthyroid (untreated) had a higher mortality rate than patients with normal TSH (5/8 vs 18/64; p<0.05). The initial clinical state of these two subgroups did not differ significantly. Two-thirds of patients with treated hyperthyroidism died. The mortality rate of patients with initially subnormal but not suppressed TSH level was average and did not differ statistically from either the euthyroid or the hyperthyroid groups. Only 1 of 13 euthyroid patients with positive thyroid antibody titers developed a subsequent subclinical hypothyroidism. Subclinical hyperthyroidism was found to be associated with a higher mortality rate in chronically ill geriatric patients, which justifies screening for thyroid dysfunction and treatment of subclinical hyperthyroidism. In addition, a subnormal but measurable TSH was not indicative regarding the future development of hyperthyroidism. Finally, during the 2-yr follow-up, antibody positivity in the euthyroid cases did not prove to be predictive for the subsequent development of hypothyroidism.     

The prognostic nutritional index might predict clinical outcomes in patients with idiopathic dilated cardiomyopathy

Background and aimsThe prognostic nutritional index (PNI) had been associated with adverse outcomes in numerous clinical conditions. However, its influence on idiopathic dilated cardiomyopathy (DCM) was not determined. This aim of this study was to determine the predictive ability of PNI in patients with idiopathic DCM.Methods and resultsA total of 1021 consecutive patients with idiopathic DCM were retrospectively included and divided into three groups based on admission PNI tertiles: <41.7 (n = 339), 41.7–47.3 (n = 342), >47.3 (n = 340). The association of PNI with in-hospital major adverse clinical events (MACEs) and death during follow-up was evaluated. In-hospital mortality (2.9% vs. 1.5% vs. 0.0%, respectively; p = 0.006) and MACEs (13.6% vs. 6.7% vs. 3.5%, respectively; p < 0.001) decreased from the lowest to the highest PNI tertile. The optimal cut-off value of PNI to predict in-hospital MACEs was 44.0 (area under the curve: 0.689; 95% confidence interval [CI]: 0.626–0.753; p < 0.001). Multivariate analysis showed that a PNI≤44.0 was an independent risk factor of in-hospital MACEs (odd ratio: 2.86; 95% CI: 1.64–4.98; p < 0.001) and all-cause mortality at a median follow-up of 27 months (hazard ratio: 1.67; 95% CI: 1.11–2.49; p = 0.013). In addition, patients with a PNI≤44.0 had a lower cumulative survival rate during follow-up (log-rank: 35.62; p < 0.001).ConclusionThe PNI was an independent risk factor for in-hospital MACEs and all-cause mortality at a median follow-up of 27 months in patients with idiopathic DCM; hence, it may be considered a tool for risk assessment.     

妊娠早期合并亚临床型甲状腺功能异常的超声表现

目的 探讨妊娠早期甲状腺血清学异常患者甲状腺超声表现特点.方法 选择2018年1月-2019年1月在深圳市龙岗区人民医院就诊的53例孕妇进行甲状腺超声检查.入组孕妇在孕早期检测血清促甲状腺激素(TSH)、血清游离甲状腺素(FT4)、甲状腺过氧化物酶抗体(TPoAb)水平并首次发现甲状腺功能或血清TPoAb 抗体水平异常.比较血清TPoAb≥45 IU/mL和血清TPoAb<45 IU/mL孕妇甲状腺回声异常发生率及腺体血流增多发生率差异.结果 53例孕妇当中其中有41例为亚临床型甲状腺功能亢进,5例为亚临床型甲状腺功能减低,7例为单纯TPoAb水平的增高.41例亚临床型甲状腺功能亢进孕妇中,35例不伴有TPoAb 水平升高的孕妇甲状腺超声表现未见明确异常,而其余有TPoAb水平升高的6例孕妇当中有2例孕妇(33.3%)甲状腺实质回声有弥漫性的改变;5例亚临床型甲状腺功能减低的孕妇当中,其中3例不伴有TPoAb水平升高的孕妇甲状腺实质回声出现弥漫性的改变,而2例伴有TPoAb水平升高的孕妇中1例(50.0%)出现甲状腺实质回声弥漫性改变;7例单纯TPoAb 水平升高的孕妇中,其中4例孕妇(57.1%)甲状腺实质回声出现弥漫性改变.在所有血清TPoAb水平升高的15例孕妇中,10例孕妇血清TPoAb≥45 IU/mL,5例孕妇血清TPoAb<45 IU/mL.血清TPoAb≥45 IU/mL的孕妇甲状腺回声异常发生率高于血清TPoAb<45 IU/mL的孕妇(7/10 vs 0/5);血清TPoAb≥45 IU/mL的孕妇甲状腺血流增多发生率高于血清TPoAb<45 I U/m L的孕妇(4/1 0 vs 1/5).结论 妊娠期具有甲状腺血清学检测指标异常的患者当中,可以出现不同的超声影像学表现,但超声影像学表现与血清学检测结果 并不完全一致.     

Thyroid dysfunction and its association with microvascular complications in patients with type 2 diabetes mellitus in south India

Background and aimsTo study the prevalence of thyroid disorders and their association with microvascular complications among adult type 2 diabetes mellitus (T2DM) patients from south-coastal Andhra Pradesh, IndiaMethodsThis cross-sectional study included 500 subjects with T2DM and was conducted in a tertiary health care center from south-coastal Andhra Pradesh. Participants previously diagnosed with thyroid disorders were excluded from the study.ResultsThyroid dysfunction was observed in 98 (19.6%) subjects of which subclinical hypothyroidism (n = 66, 13.2%) was the most common. Subclinical hypothyroidism (SCH) was more frequent in obese patients (16.2% vs 7.6%, p = 0.007) and metformin users (9.6% vs 18.7%, p = 0.0044). Diabetic retinopathy (27.3% vs 8.9%, p = 0.001) was significantly more frequent in SCH patients than euthyroid T2DM patients.ConclusionAmong T2DM patients from south-coastal Andhra Pradesh the prevalence of thyroid dysfunction, especially that of SCH was high; SCH was more frequent among obese and nonmetformin users and was associated was associated with increased risk of diabetic retinopathy.     

老年人甲状腺功能异常与心血管疾病

甲状腺功能异常与心血管疾病密切相关。老年人促甲状腺激素分布曲线向高水平方向偏移,因此,需应用年龄特异的参考范围判断甲状腺功能状态。近来,亚临床甲状腺疾病日益得到重视。研究表明亚临床甲状腺功能亢进（亚甲亢）可引起心脏结构和功能的改变,可引起房颤的发生率增加。而亚临床甲状腺功能减退（亚甲减）可能是心力衰竭、缺血性心脏病、全因死亡的一个潜在危险。异常甲状腺功能经纠正后,与甲亢和甲减相关的心血管疾病可得到缓解。基于老老年患者中亚临床甲减可能有保护作用,因此,亚临床甲状腺功能异常对心血管疾病的影响以及何种患者经过治疗可以获益,需要更多的循证医学的证据用以指导临床实践。     

Prevalence and predictors of hyperprolactinemia in subclinical hypothyroidism

Background and aimsHyperprolactinemia has been reported in 0–57% of primary hypothyroidism. Data on hyperprolactinemia in subclinical hypothyroidism (ScH) is scant and inconsistent. This study aimed to determine the prevalence and predictors of hyperprolactinemia in ScH.MethodsConsecutive patients diagnosed to have normal thyroid function, ScH or overt primary hypothyroidism underwent serum prolactin, gonadotropins, testosterone and estradiol estimation. Patients with pregnancy, pituitary adenomas, secondary hypothyroidism, hyperthyroidism, comorbid states and drug-induced hyperprolactinemia were excluded.ResultsFrom initially screened 4950 patients, hormonal data from 2848 individuals who fulfilled all criteria were analyzed. The occurrence of hyperprolactinemia (females:males) was highest in primary hypothyroidism (42.95%:39.53%) (n = 192), followed by ScH (35.65%:31.61%) (n = 770) and euthyroid individuals (2.32%:2.02%) (n = 1886) (P < 0.001). Hyperprolactinemia in ScH with TSH 5–7.5, 7.5–10 and > 10 mIU/L (females: males) was 25.56%:20.73%, 49.07%:50% and 61.43%:35.71% respectively (P < 0.001). Significant positive correlation between TSH and prolactin was noted in ScH and primary hypothyroidism. In females, testosterone was lowest in patients with primary hypothyroidism. In males, serum estradiol was significantly higher, and testosterone significantly lower in men with ScH and primary hypothyroidism. Regression analysis revealed serum TSH followed by free T₄, to be best predictors of serum prolactin in both sexes.ConclusionHyperprolactinemia is common in ScH, especially in those with TSH > 7.5 mIU/L. ROC analysis confirmed that TSH ≥ 7.51 mIU/L in females and ≥ 8.33 mIU/L in males had a sensitivity of ≈ 50% with a very high specificity of > 90% in detecting hyperprolactinemia. Prolactin screening may be warranted in ScH with TSH > 7.5mIU/L, and may form an indication for treating ScH.     

An Analysis of the Natural Course of Subclinical Hyperthyroidism

BackgroundOur aim was to evaluate the incidence rate of overt hyperthyroidism in a cohort of patients with subclinical hyperthyroidism and to assess the potential risk factors for the development of overt thyroid hyperfunction.MethodsWe performed a retrospective analysis in 75 patients (68 women, mean age 62.2 ± 14.2 years) with subclinical hyperthyroidism and different grades of serum thyrotropin (TSH) suppression. Incidence rate of overt hyperthyroidism and survival time, ie, time without requiring therapy for overt hyperthyroidism, were studied.ResultsThirty-four patients (45.3%) developed overt hyperthyroidism and 15 (20.0%) reverted to normal TSH values. The incidence rate of overt hyperthyroidism was 9.69 cases per 100 patient-year in the whole population and 4.12, 7.41, and 29.63 cases per 100 patient-year in subjects with initial TSH values of 0.30 to 0.49, 0.10 to 0.29, and <0.10 mU/L, respectively. Kaplan-Meier analysis of survival time curves showed that the development of overt thyroid hyperfunction was significantly related to the presence of symptoms of hyperthyroidism (P < 0.05) and low (<0.10 mU/L) TSH concentrations (P < 0.001). A stepwise multivariate Cox regression analysis showed that both symptoms and low TSH values were significant factors for progression to overt thyrotoxicosis.ConclusionsTSH concentration is the most powerful predictor in the outcome of patients with subclinical hyperthyroidism. Our results suggest that patients with values under 0.10 mU/L have the highest probability to develop overt thyroid hyperfunction. In patients with TSH values higher than this value, the risk of progression is notably lower.     

Subclinical thyroid dysfunction and cardiac function amongst minority ethnic groups in the UK: A cross sectional study

Background

Subclinical thyroid disease is associated with abnormal cardiovascular haemodynamics and increased risk of heart failure. The burden of raised/low thyroid stimulating hormone (TSH) levels amongst South Asian (SA) and African–Caribbean (AC) minority groups in the UK is not well defined. Given that these groups are particularly susceptible to CVD, we hypothesised that STD would reflect abnormal cardiac function and heightened cardiovascular risk in these ethnic groups.

Methods

We examined SA (n = 1111, 56% male, mean age 57.6 yrs) and AC (n = 763, 44% male, mean age 59.2 yrs) participants from a large heart failure screening study. Euthyroidism is defined as TSH (0.4 – 4.9 mlU/l), subclinical hypothyroidism is defined as a raised TSH with normal serum free thyroxine (FT4) concentrations (9–19 pmol/l). Subclinical hyperthyroidism is defined as a low TSH with both FT4 and free triiodothyronine (FT3) concentrations within range (2.6–5.7 pmol/l).

Results

Across ethnic groups, prevalence of subclinical hypothyroidism was 2.9% (95% CI 2.1–3.7), and of hyperthyroidism was 2.0% (1.4–2.7). Hyperthyroidism was more common amongst SA compared to AC (2.8% vs. 0.9%, P = 0.017), while rates of subclinical hypothyroidism were similar. On multivariate analysis of variations in subclinical thyroid function, ethnicity was not independently significant.

Conclusion

The prevalence of subclinical thyroid disorders amongst SA and AC minority groups in Britain reflects levels reported in other populations. The clinical cardiovascular significance of subclinical thyroid disease is unclear, and it does not appear to be ethnically specific.     

Thyroid dysfunction and anti-thyroid antibodies in Egyptian patients with systemic lupus erythematosus: Correlation with clinical musculoskeletal manifestations

Aim of the workTo study the prevalence of thyroid dysfunction and anti-thyroid antibodies (ATA) in Egyptian patients with systemic lupus erythematosus (SLE), and their association with musculoskeletal manifestations of the disease.Patients and methodsCross sectional study included 100 SLE patients and 100 matched controls. Clinical manifestations at any time during disease course were reported. Detailed musculoskeletal examination was done using Ritchie articular index (RAI), 44-Swollen joint count and fibromyalgic tender points. Phalen’s test was used to diagnose carpal tunnel syndrome. Free-thyroid hormones (FT3 and FT4), thyroid stimulating hormone (TSH), anti-thyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO) antibodies were measured.ResultsThe prevalence of thyroid dysfunction was significantly higher in patients than controls (18% vs. 4%, p = 0.003) and all were females. Prevalence of subclinical hypothyroidism (SCHT) and clinical hypothyroidism (CHT) is 10% (p = 0.002) and 4% (p = 0.121) versus non among controls while, that of subclinical hyperthyroidism (4%) was not significantly different. Prevalence of anti-TPO and anti-TG is higher in patients than controls (35% vs 11%, p < 0.001 and 22% vs. 6%, p = 0.001). All patients with SCHT had anti-TPO and half of them had anti-TG while all patients with CHT had both antibodies. Hypothyroidism was associated significantly with aging (p = 0.01), longer disease duration (p < 0.001), high BMI, high RAI scores, arthritis, positive Phalen’s test and fibromyalgia (p < 0.001 for all) in comparison to euthyroid patients.ConclusionHypothyroidism was more prevalent in SLE patients and its detection is recommended to reduce the risk of musculoskeletal related morbidity.     

The risk of cardiovascular events in patients with subclinical hypothyroidism:An updated meta-analysis based on 53813 participants

Background Subclinical hypothyroidism is a metabolism disease with elevated thyroid stimulating hormone (TSH) and normal thyroid hormone levels. Patients with subclinical hypothyroidism can have abnormal lipid metabolism,hypertension,coagulation dysfunction,vascular endothelial dysfunction. However,the relationship between subclinical hypothyroidism and cardiovascular events is still uncertain. Methods Prospective studies on the association between subclinical hypothyroidism and coronary heart disease were searched in Pub Med,Embase,Wanfang databases and the Cochrane Library. The incidences of coronary heart disease,cardiac death,heart failure and all-cause death were compared between subclinical hypothyroidism group and euthyroidism group. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were used as summary statistics. Results Thirteen eligible studies incorporating 53813 participants were included in this meta-analysis. No significant differences were found in the comparison of the risk of CHD (9.67% vs. 7.74%,OR=1.09,P=0.19),cardiac death (7.80% vs. 4.74%,OR=1.34,P=0.06),all-cause death (13.26% vs. 13.63%,OR=1.05,P=0.77) and heart failure (7.12% vs. 4.29%,OR=1.24,P=0.22) between the subclinical hypothyroidism group and euthyroidism group. Conclusions Our results indicate that subclinical hypothyroidism might not increase the risk of cardiovascular disease.     

Subclinical hypothyroidism is associated with coronary artery disease in older persons

BACKGROUND: We report the prevalence of coronary artery disease (CAD) associated with subclinical hypothyroidism in older persons. METHODS: We investigated the prevalence of subclinical hypothyroidism and its association with dyslipidemia and with CAD in 170 women and 110 men, mean age 75 +/- 9 years, in an academic nursing home. RESULTS: Of 280 persons, 18 (6%) had subclinical hypothyroidism, 18 (6%) had treated clinical hypothyroidism, 13 (5%) had subclinical hyperthyroidism, and 231 (83%) were euthyroid. Dyslipidemia occurred in 15 of 18 persons (83%) with subclinical hypothyroidism, in nine of 18 persons (50%) treated for hypothyroidism, in six of 13 persons (46%) with subclinical hyperthyroidism, and in 128 of 231 euthyroid persons (55%) (p <.025 comparing subclinical hypothyroidism with euthyroidism and p <.005 comparing subclinical hypothyroidism with treated hypothyroidism and with subclinical hyperthyroidism). CAD was present in 10 of 18 persons (56%) with subclinical hypothyroidism, in nine of 18 persons (50%) with treated hypothyroidism, in 5 of 13 persons (38%) with subclinical hyperthyroidism, and in 38 of 231 euthyroid persons (16%) (p <.001 comparing subclinical hypothyroidism with euthyroidism; p <.005 comparing treated hypothyroidism with euthyroidism; and p <.05 comparing subclinical hyperthyroidism with euthyroidism). CONCLUSIONS: Subclinical hypothyroidism was associated with a high prevalence of dyslipidemia and a high prevalence of CAD.     

Circulating lipids and minor abnormalities of thyroid function

OBJECTIVE: We determined the effect of subclinical hyperthyroidism (defined as low circulating TSH with normal serum free T4) and subclinical hypothyroidism (raised serum TSH with normal free T4) on fasting levels of blood lipids. DESIGN: Prospective study of lipid concentrations in patients identified as having abnormal TSH. PATIENTS: Patients were identified in a population screening study of those over 60 years, with persistently low TSH with normal free T4 (n = 27) or high TSH but normal free T4 (n = 57). Patients were matched to controls with normal serum TSH by age, sex and body mass index. MEASUREMENTS: Serum TSH, free T4, free T3, total cholesterol, low density lipoprotein (LDL) cholesterol and high density lipoprotein (HDL) cholesterol. RESULTS: Serum free T4 measurements were significantly higher in those with subclinical hyperthyroidism than in their controls (P < 0.001) and lower in those with subclinical hypothyroidism than in matched controls (P < 0.001). Measurement of fasting lipids in patients and controls revealed a marked (12.2%) reduction in serum total cholesterol in subclinical hyperthyroidism (P < 0.01); no significant difference in fasting lipids between patients with subclinical hypothyroidism and controls was observed. CONCLUSIONS: Differences in free T4 between those with low or high TSH and controls with normal TSH suggest that abnormalities of TSH directly reflect thyroid hormone excess and deficiency. A reduction in cholesterol in those with subclinical hyperthyroidism suggests a direct influence of thyroid hormone excess on lipid metabolism in these patients.     

Prevalence of thyroid disorders in untreated adult celiac disease patients and effect of gluten withdrawal: an Italian multicenter study

OBJECTIVES: Many afflictions have been associated with celiac disease, but chance associations may exists. The aim of this study was to establish, by means of a multicenter prospective study, the prevalence of thyroid impairment among adult patients with newly diagnosed celiac disease and to evaluate the effect of a 1-yr gluten withdrawal on thyroid function. METHODS: A total of 241 consecutive untreated patients and 212 controls were enrolled. In 128 subjects a thorough assessment, including intestinal biopsy, was repeated within 1 yr of dietary treatment. Thyroid function was assayed by measuring the levels of TSH, free T3, free T4, thyroperoxidase, and thyroid microsome antibodies. RESULTS: Thyroid disease was 3-fold higher in patients than in controls (p < 0.0005). Hypothyroidism, diagnosed in 31 patients (12.9%) and nine controls (4.2%), was subclinical in 29 patients and of nonautoimmune origin in 21. There was no difference regarding hyperthyroidism, whereas autoimmune thyroid disease with euthyroidism was present in 39 patients (16.2%) and eight controls (3.8%). In most patients who strictly followed a 1-yr gluten withdrawal (as confirmed by intestinal mucosa recovery), there was a normalization of subclinical hypothyroidism. Twenty-five percent of patients with euthyroid autoimmune disease shifted toward either a subclinical hyperthyroidism or subclinical hypothyroidism; in these subjects, dietary compliance was poor. In addition, 5.5% of patients whose thyroid function was normal while untreated developed some degree of thyroid dysfunction 1 yr later. CONCLUSIONS: The greater frequency of thyroid disease among celiac disease patients justifies a thyroid functional assessment. In distinct cases, gluten withdrawal may single-handedly reverse the abnormality.     

Prevalence of thyroid disease in patients with obstructive sleep apnea

Objectives

Studies have suggested that ethnicity and environment may influence thyroid disease. We aim in this study to determine the prevalence of thyroid disease among Saudi (Arab) patients with laboratory-diagnosed obstructive sleep apnea (OSA) and the characteristics and predictors of thyroid disease associated with OSA.

Methods

Serum thyroid-stimulating hormone (TSH) and free-thyroxine (FT4) levels were measured in all patients referred to the sleep disorders center for an overnight sleep study. The levels were measured within 4 weeks of the sleep study. Type I attended polysomnography (PSG) was performed for all patients.

Results

During the study period, 271 patients with OSA and a mean age of 48.7 ± 14.1 yr, a body mass index (BMI) of 37.7 ± 9.6 kg/m² and an AHI of 55.2 ± 37/hr as well as 76 non-OSA patients with a mean age of 40.8 ± 14.9 yr, a BMI of 33.7 ± 8.9 kg/m² and an AHI of 3.8 ± 3.1/hr underwent thyroid function tests. In the OSA patients, the prevalence of newly diagnosed clinical hypothyroidism was 0.4%, and the prevalence of newly diagnosed subclinical hypothyroidism was 11.1%. In the non-OSA patients, the prevalence of newly diagnosed clinical hypothyroidism was 1.4%, and the prevalence of newly diagnosed subclinical hypothyroidism was 4%. There were no cases of clinical or subclinical hyperthyroidism in the studied group. Female gender was the only predictor of clinical hypothyroidism.

Conclusion

In the OSA patients, the prevalence of newly diagnosed clinical hypothyroidism was low; however, subclinical hypothyroidism was common among patients with OSA.