亚临床甲状腺功能异常与心血管疾病的关系

临床研究显示,亚临床甲状腺功能异常与心血管疾病之间存在密切的关系.亚临床甲状腺功能减退通常伴有血脂异常、高凝状态、纤维蛋白溶解活性减低等心血管疾病危险因素,其与动脉粥样硬化、冠心病和心血管死亡的风险显著相关.另一方面,亚临床甲状腺功能亢进与心房颤动发生风险显著相关,但与心血管死亡风险的相关性尚不清楚.对于亚临床甲状腺功能异常进行治疗是否能够带来心血管获益,目前尚无确切结论.     

亚临床甲状腺功能异常与心血管疾病的关系

临床研究显示,亚临床甲状腺功能异常与心血管疾病之间存在密切的关系.亚临床甲状腺功能减退通常伴有血脂异常、高凝状态、纤维蛋白溶解活性减低等心血管疾病危险因素,其与动脉粥样硬化、冠心病和心血管死亡的风险显著相关.另一方面,亚临床甲状腺功能亢进与心房颤动发生风险显著相关,但与心血管死亡风险的相关性尚不清楚.对于亚临床甲状腺功能异常进行治疗是否能够带来心血管获益,目前尚无确切结论.     

增龄性亚临床甲状腺功能异常在抗衰老医学中的重要性

<正>神经和内分泌系统是人体两大中枢调控系统,二者相互协调,以维持人体内环境的平衡。甲状腺素分泌和释放受下丘脑-垂体-甲状腺轴调控,互为反馈,如亚临床甲状腺功能减退(及亢进)与促甲状腺释放激素(TSH)血清水平的升高(或降低)的关系。增龄性临床前甲状腺功能异常(又称亚临床甲状腺功能病STD)包括亚临床甲状腺功能减退(SHypo)、亚临床甲状腺功能亢进(SHyper)与一些疾病的相关关系必须给予重视。     

成人非老年亚临床甲状腺功能异常的管理

亚临床甲状腺功能异常在人群中普遍常见,其诊断依赖于实验室检查结果,分为亚临床甲状腺功能减退症和亚临床甲状腺功能亢进症.文章仅涉及成人非老年内源性亚临床甲状腺功能异常,结合近年国内外多个临床指南,重点介绍亚临床甲状腺功能减退和亚临床甲亢非妊娠和妊娠人群相关的管理内容.文章管理建议仅针对非老年(70岁以下的亚临床甲减和65...     

亚临床甲状腺疾病

亚临床甲状腺疾病是指无或有轻微甲状腺疾病相关症状、仅在实验室检查中或通过影像学手段发现的甲状腺异常，包括甲状腺意外结节、亚临床甲状腺功能亢进、轻微甲状腺功能减退先进。它们可影响正常的生理及代谢过程，部分患者可出现相关临床症状。亚临床甲状腺疾病应视患者的具体情况进行个体化处置。     

亚临床甲状腺功能减退症与心脏病

亚临床甲状腺功能减退症影响心血管系统,增加冠心病风险的报道近年增多,本文总结流行病学调查认为亚临床甲状腺功能减退症是冠心病的独立危险因素;并从影响血凝、血脂、脂蛋白a、C反应蛋白和同型半胱氨酸等指标探讨其增加血栓性疾病的风险因素;亚临床甲状腺功能减退症还会影响心脏传导功能并见心肌功能受损,以及L—T4激素替代治疗等方面,综述亚临床甲状腺功能减退症对心血管系统的影响。鉴于亚临床甲状腺功能减退症的病理改变具有可逆性,评估亚临床甲状腺功能减退症病人L—T4治疗潜在的益处和危险是必要的。这将为临床医生进行针对性的治疗提供依据。     

亚临床甲状腺疾病

亚临床甲状腺疾病是指无或有轻微甲状腺疾病相关症状、仅在实验室检查中或通过影像学手段发现的甲状腺异常 ,包括甲状腺意外结节、亚临床甲状腺功能亢进、轻微甲状腺功能减退等。它们可影响正常的生理及代谢过程 ,部分患者可出现相关临床症状。亚临床甲状腺疾病应视患者的具体情况进行个体化处置     

妊娠中晚期孕妇甲状腺功能异常和自身抗体筛查的研究

目的 研究妊娠中晚期孕妇甲状腺功能异常及自身抗体阳性的患病率,探讨在孕妇群体中进行甲状腺筛查的必要性.方法 研究对象为2006年6月至2008年2月期间在上海交通大学附属第一人民医院就诊的妊娠中晚期孕妇,以问卷调查方式采集病史资料,根据孕妇是否有甲状腺疾病既往史、家族史或其他相关疾病既往史,分为高甲状腺疾病风险组(高风险组)和低甲状腺疾病风险组(低风险组).对所有孕妇检测血清FT3、FT4、TSH、甲状腺过氧化物酶抗体(TPOAb)和促甲状腺激素受体抗体水平.结果 共筛查孕妇2 101名,发现有各种甲状腺功能异常或甲状腺抗体阳性712例(33.89％).高风险组孕妇中有较高比例的甲状腺功能异常,而低风险组1 983名孕妇中亦有2.27％(45例)诊断为甲状腺功能减退,11.60％(230例)为亚临床甲状腺功能减退,0.20％(4例)为甲状腺功能亢进,1.06％(21例)为亚临床甲状腺功能亢进,6.45％(128例)为低甲状腺素血症,10.74％(213例)甲状腺功能正常但TPOAb阳性.在TPOAb阳性孕妇中,甲状腺功能异常者更多见.其中79.74％甲状腺功能异常或TPOAb阳性孕妇经本次筛查发现.结论 妊娠中晚期孕妇中进行甲状腺筛查可发现33.89％孕妇存在甲状腺功能异常或TPOAb阳性,TPOAb阳性孕妇出现甲状腺功能异常的患病率增加.如果仅对高风险孕妇进行甲状腺筛查,则可能导致高达79.74％患者漏诊.     

亚临床甲状腺功能紊乱对急性心力衰竭患者远期预后的影响

目的评价亚临床甲状腺功能紊乱对急性心力衰竭患者远期预后的影响。方法纳入420例急性心力衰竭(AHF)患者。入院24 h内测定甲状腺激素、脑利钠肽(BNP)并行超声心动图检查。应用Logistic回归和Cox风险模型分析亚临床甲状腺功能紊乱与全因死亡的关系。结果在6~49个月随访期间,119例(28.3%)患者死亡,甲状腺功能正常组与亚临床甲状腺功能减退(SHypo)组、亚临床甲状腺功能亢进(SHyper)组的全因死亡率存在差异(分别为26.5%、51.1%、34.5%,log-rankχ~2=6.172,P=0.046)。多因素Cox风险模型分析显示,年龄、BNP、左室射血分数、甲状腺激素、游离甲状腺激素、SHypo(危险比:1.147,95%CI:0.971~1.352,P=0.012)是AHF患者全因死亡的预测因素。血清三碘甲状腺原氨酸,游离三碘甲状腺原氨酸和SHyper不是全因死亡的预测因素。结论 SHypo是AHF患者的全因死亡独立预测因素,而SHyper不是全因死亡预测因素。     

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。     

Pericardial effusion associated with subclinical hypothyroidism

Previous studies have suggested that subclinical thyroid dysfunction, as manifested by abnormalities in thyroid-stimulating hormone (TSH) levels, are associated with detrimental effects on the cardiovascular system. Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including atrial fibrillation and atrial flutter. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Subclinical hypothyroidism is defined by elevated serum levels of TSH with normal levels of free thyroid hormones. Subclinical hypothyroidism is characterized by abnormal lipid metabolism, cardiac dysfunction, diastolic hypertension conferring an elevated risk of atherosclerosis, and ischemic heart disease. It has been reported that sub-clinical hypothyroidism is associated with both, a significant risk of coronary heart disease at baseline and at follow-up and that mortality from cardiovascular causes is significantly higher at follow-up. However subclinical thyroid dysfunction is currently the subject of numerous studies and remains controversial, particularly as it relates to cardiovascular morbidity and mortality and clinical applications. Pericardial effusion can be present in systemic disorders including hypothyroidism. We present a case of subclinical hypothyroidism in a 41-year-old Italian woman with an ubiquitary pericardial effusion. Also this case focuses attention on subclinical hypothyroidism.     

Cardiovascular risk with subclinical hyperthyroidism and hypothyroidism: pathophysiology and management

Previous studies have suggested that subclinical thyroid dysfunction, as manifested by abnormalities in thyroid-stimulating hormone (TSH) levels, are associated with detrimental effects on the cardiovascular system. Subclinical hypothyroidism is characterized by abnormal lipid metabolism, cardiac dysfunction, diastolic hypertension conferring an elevated risk of atherosclerosis, and ischemic heart disease. Similarly, patients with subclinical hyperthyroidism have nearly 3 times the likelihood of atrial fibrillation over a 10-year follow-up interval, raising the question of whether patients with subclinical hyperthyroidism should be treated to prevent atrial fibrillation. A single measurement of low serum TSH in individuals aged 60 years or older has been reported to be associated with increased mortality from all causes and in particular from circulatory and cardiovascular disease in a 10-year follow-up study. Subclinical thyroid dysfunction is currently the subject of numerous studies and remains controversial, particularly as it relates to cardiovascular morbidity and mortality and clinical applications.     

The Prevalence and Prognostic Effects of Subclinical Thyroid Dysfunction in Dilated Cardiomyopathy Patients: A Single-Center Cohort Study

BackgroundSubclinical thyroid dysfunction may be a risk factor for mortality in patients with heart failure and may be associated with dilated cardiomyopathy (DCM). This was a cohort study to examine the possible association between subclinical thyroid dysfunction and all-cause mortality in DCM patients, because the current evidence on this association remains elusive.Methods and ResultsA total of 963 DCM patients were evaluated for thyroid function. Of these patients, 7.1% (n = 68) had subclinical hyperthyroidism (defined as serum thyroid-stimulating hormone [TSH] <0.35 μIU/mL), 84.7% (n = 816) had euthyroidism (TSH 0.35-5.5 μIU/mL), and 8.2% (n = 79) had subclinical hypothyroidism (TSH >5.5 μIU/mL). There was a significant difference in all-cause mortality rates between patients with euthyroidism and patients with subclinical hyper- and hypothyroidism (21%, 38.2%, and 26.6%, respectively; log-rank χ² = 13.104; P = .001) with mean follow-up of 3.5 years. After adjustment for other confounding factors at baseline, QRS duration, N-terminal pro–B-type natriuretic peptide, New York Heart Association functional class, left atrial diameter, and subclinical hyperthyroidism (hazard ratio 1.793, 95% CI 1.010–3.183; P = .046) emerged as significant predictors of all-cause mortality.ConclusionDCM patients with subclinical hyper- and hypothyroidism had higher all-cause mortality rates. However, only subclinical hyperthyroidism, not subclinical hypothyroidism, was an independent predictor for increased risk of all-cause mortality.     

Subclinical hyperthyroidism in patients with type 2 diabetes

Both subclinical hyperthyroidism and type 2 diabetes (T2D) have been associated with an increase in cardiovascular disease risk and mortality. We aimed to assess the prevalence of newly diagnosed subclinical hyperthyroidism in a cohort of patients with T2D, and also to analyse the relationships between diabetes-related characteristics and the presence of subclinical hyperthyroidism. 933 diabetic patients without previous history of thyroid disease (45.4% females, mean age 66.3 years, median duration of diabetes 10 years) were evaluated. A sample of 911 non-diabetic subjects without known thyroid dysfunction was studied as control group. Serum concentrations of thyrotropin were measured in all subjects. Subclinical hyperthyroidism was present in 4.3% of female and 3.5% of male diabetic patients. Relative risk was significant only for the female gender (OR 3.69, 95% CI 1.56-8.71). In comparison with diabetic patients without thyroid hyperfunction, patients with subclinical hyperthyroidism were older, had longer duration of diabetes, showed lower fasting glucose levels, had greater proportion of goitre and diet therapy, and had lower proportion of treatment with oral agents. Logistic regression analysis showed that age and the presence of goitre were significantly related to subclinical hyperthyroidism in patients with T2D. The risk for subclinical hyperthyroidism is increased in women with T2D. Advanced age and the presence of goitre are significantly and independently related with the presence of subclinical hyperthyroidism in diabetic population.     

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.     

Relationship of low-density lipoprotein (LDL) particle size to thyroid function status in Koreans

Objective  Dyslipidaemia is a well-known manifestation of thyroid dysfunction. Recently, small low-density lipoprotein (LDL) particle size has been linked with development of cardiovascular disease. To better understand the effects of thyroid dysfunction on the development of cardiovascular disease, we examined LDL particle size and lipid profiles in subjects with different thyroid function.
Methods  Included were 46 patients with overt hypothyroidism, 57 patients with subclinical hypothyroidism, 46 patients with overt hyperthyroidism, 51 patients with subclinical hyperthyroidism, and 110 age- and sex-matched healthy control subjects. We measured LDL particle size and lipid profiles in these subjects.
Results  No significant differences were found in LDL particle size between the groups with different thyroid function. Serum total cholesterol and LDL-cholesterol levels were significantly higher in the cases of hypothyroidism than in the cases of hyperthyroidism and the healthy control subjects. Serum triglyceride levels were higher in subjects with overt hypothyroidism than in those with overt hyperthyroidism or healthy control subjects.
Conclusions  LDL particle size, the emerging risk factor for atherosclerosis, did not appear to be significantly affected by the degree of thyroid dysfunction. Increased risk of atherosclerosis in hypothyroidism does not appear to be associated with LDL particle size, the non-traditional cardiovascular risk factor.     

A clinical and therapeutic approach to thyrotoxicosis with thyroid-stimulating hormone suppression only

Subclinical hyperthyroidism is defined as normal serum free thyroxine (T4) and triiodothyronine (T3) concentrations and persistently suppressed thyroid stimulating hormone (TSH) concentrations. The most common cause of subclinical hyperthyroidism is the use of suppressive doses of L-thyroxine for treatment of hypothyroidism or, less commonly, diffuse nontoxic goiter or thyroid carcinoma (exogenous subclinical hyperthyroidism). Endogenous subclinical hyperthyroidism may be caused by a variety of thyroid disorders that result in overproduction and release of thyroid hormones from the gland with normal/high 24-hour thyroid radioiodine uptake or by inflammation in the thyroid resulting in release of excess thyroid hormones and low 24-hour thyroid radioiodine uptake. Several groups have investigated whether persistent endogenous or exogenous subclinical hyperthyroidism, like overt hyperthyroidism, causes symptoms, adverse effects on the cardiovascular and the skeletal systems, and increased mortality, whether endogenous subclinical hyperthyroidism evolves to overt thyrotoxicosis, and whether or not it should be treated. The present report reviews the most important and recent studies of subclinical hyperthyroidism and attempts to draw conclusions based upon the literature and the authors' experience.