The Association of Overt and Subclinical Hyperthyroidism with the Risk of Cardiovascular Events and Cardiovascular Mortality: Meta-Analysis and Systematic Review of Cohort Studies

[The effect of hypothyroidism on cardiovascular events and type 2 diabetes mellitus developing in rheumatoid arthritis]

AIM

To compare the frequency of cardiovascular events (CVE), to assess the risk of cardiovascular death using the mSCORE and the development of type 2 diabetes mellitus (DM) using the FINDRISC in patients with rheumatoid arthritis (RA) with and without hypothyroidism.

MATERIALS AND METHODS

The study included 149 patients (125 women, 24 men) with RA (median age - 57 [52; 61] years). In all patients, traditional factors of cardiovascular risk and glucose metabolism disorders (age, smoking status, total blood cholesterol, blood pressure, overweight, abdominal obesity - AO, heredity burdened by diabetes, insufficient physical activity, the lack of the necessary amount of berries, fruits and vegetables in the daily diet, history of hyperglycemia episodes), the 10-year risk of death from cardiovascular causes according to the mSCORE and the risk of developing type 2 DM according to the FINDRISС were assessed, a history of CVE (myocardial infarctions, and its revascularization, stroke) was recorded.

RESULTS

Hypothyroidism was diagnosed in 17.4% of RA patients. Patients with hypothyroidism (group 1) were more likely to have AO and less likely to consume unsufficient dietary fiber than patients with euthyroidism (group 2). Moderate, high and very high risk of development according to the mSCORE and FINDRISC was detected in 61.5% of hypothyroid patients and 48.8% euthyroid patients, according to mSCORE alone - in 30.8 and 44.7%, according to FINDRISC - in 0 and 2.4%, respectively (p>0.05 in all cases); 11.5% of patients in group 1 and 6.5% in group 2 suffered from CVE (OR 1.875, 95% CI 0.462-7.607; p=0.63).

CONCLUSION

It is necessary to evaluate the thyroid gland function, especially in patients with AO due to the high frequency of hypothyroidism in RA. Hypothyroidism did not have an independent effect on the severe CVЕ rates, as well as risk assessment according to the score and FINDRISC in RA patients. Theses, with and without hypothyroidism, were predominantly in the moderate, high, very high risk groups according to both scales.

Risks of suboptimal and excessive thyroid hormone replacement across ages

BACKGROUND

Hypothyroidism is prevalent at all ages and represents a non-communicable disease with preventable consequences.

METHOD

Narrative review.

REVIEW

In children and adolescents, the most devastating consequences of undertreatment with levothyroxine (LT4) are poor growth and development. Delayed treatment in congenital hypothyroidism can lead to permanent brain damage. In young to middle-aged adults, symptoms are often overlooked, and treatment delayed by many years. The resulting consequences are also at this age group compromised brain and physical function but less severe and partly reversible with treatment. The under-treated condition often results in a higher risk of, e.g., increased cardiovascular disease burden, obesity, hypertension, poor physical capacity, and poor quality of life. Excessive replacement is at all adult age groups associated with increased risk of cardiac death, osteoporosis, loss of muscle function, psychological instability and poor quality of life. In young fertile women, the consequences of undertreatment with LT4 are subnormal fertility, recurrent pregnancy loss, compromised fetal growth, and neurocognitive development. On the other hand, excessive LT4 treatment has been related to gestational hypertension, preeclampsia and preterm birth. In the elderly, care must be given to avoid confusing a slightly high age-related serum TSH with requirement for LT4 treatment in a truly hypothyroid patient. Excessive LT4 treatment in patients of high age is associated with an increased mortality.

CONCLUSION

Suboptimal and excessive LT4 replacement of the preventable non-communicable disease hypothyroidism requires more focus from the healthcare system and from the global political systems to prevent the personally devastating and socioeconomically challenging consequences.

Adequacy of thyroid hormone replacement for people with hypothyroidism in real-world settings: A systematic review and meta-analysis of observational studies

OBJECTIVE

Thyroid hormone under-replacement and over-replacement are associated with adverse health outcomes. This systematic review aimed to evaluate the extent of thyroid hormone replacement adequacy for patients with known hypothyroidism in real-word settings, excluding those receiving thyroid hormone suppressive therapy as thyroid cancer treatment.

DESIGN

Four electronic databases (Embase [Ovid], Medline [Ovid], PubMed and SCOPUS) were searched for published and unpublished observational studies until 12 December 2022. The results of the studies were meta-analysed to calculate pooled prevalence estimates for thyroid hormone supplementation adequacy, over-replacement and under-replacement. Quality assessment of studies was performed using the Joanna-Briggs appraisal tool for prevalence studies.

RESULTS

Seven studies with a total of 4230 patients were eligible for quantitative synthesis. The pooled prevalence estimates of adequate thyroid replacement, over-replacement and under-replacement were 0.55 (95% confidence interval [CI]: 0.49-0.60, p = .001), 0.20 (95% CI: 0.14-0.27, p = .001) and 0.24 (95% CI: 0.13-0.36, p = .001), respectively. Four studies subclassified hypothyroidism and hyperthyroidism into overt and subclinical. The pooled prevalence of overt and subclinical hyperthyroidism was 0.04 (95% CI: 0.00-0.11, p = .01) and 0.17 (95% CI: 0.09-0.27 p = .001), respectively. For overt and subclinical hypothyroidism, the pooled prevalence was 0.02 (95% CI: 0.01-0.03, p = .001) and 0.20 (95% CI: 0.12-0.29, p = .001), respectively.

CONCLUSIONS

On average, approximately half of patients with hypothyroidism are only treated to target euthyroidism. In real-world practice, a significant number of patients are over-treated or under-treated, leading to adverse healthcare outcomes. It is imperative that more effective thyroid monitoring strategies be implemented, with an emphasis on primary care thyroid function monitoring, to minimise inappropriate thyroid replacement treatments and optimise healthcare outcomes at a population level.

Hormonal influences on cerebral aneurysms: unraveling the complex connections

INTRODUCTION

Intracranial aneurysms (IAs) occur in 3-5% of the general population and are characterized by localized structural deterioration of the arterial wall with loss of internal elastic lamina and disruption of the media. The risk of incidence and rupture of aneurysms depends on age, sex, ethnicity, and other different factors, indicating the influence of genetic and environmental factors. When an aneurysm ruptures, there is an estimated 20% mortality rate, along with an added 30-40% morbidity in survivors. The alterations in hormonal levels can influence IAs, while the rupture of an aneurysm can have various impacts on endocrine pathways and affect their outcome.

AREA COVERED

This review explores the reciprocal relationship between endocrinological changes (estrogen, growth hormone, and thyroid hormones) and IAs, as well as the effects of aneurysm ruptures on endocrine fluctuations.

EXPERT OPINION

Based on the data presented in this paper, we recommend further exploration into the influence of hormones on aneurysm formation and rupture. Additionally, we propose conducting endocrine assessments for patients who have experienced a rupture of IAs. Monitoring hormonal changes in patients with IAs could serve as a potential risk factor for rupture, leading to interventions in the approach to managing IAs.

Pulmonary Embolism in Patients Admitted With Takotsubo Cardiomyopathy: Prevalence and Associated In-Hospital Adverse Events

Introduction  Takotsubo cardiomyopathy (TCM) is a poorly understood condition typically characterized by abnormal left ventricular wall motion without causative coronary artery disease and typically presents in post-menopausal women after the experience of a physical or emotional stressor. The pathophysiology of TCM is complex and multifactorial, resulting in complications with varied severity; one of the most concerning complications is thromboembolism, specifically, pulmonary embolism (PE), which is understudied in its relation to TCM. The purpose of this study was to characterize and evaluate the real-world prevalence and outcomes of PE in TCM. Methods  Data were derived from the National Inpatient Sample database from January 2016 to December 2019. The primary outcomes assessed were baseline and hospital admission characteristics and comorbidities for patients with TCM with and without PE. Outcomes for TCM patients with PE and predictors of mortality in TCM were also analyzed. Results  PE developed in 788 of 40,120 patients with TCM (1.96%). After multivariate adjustment, PE was found to be independently associated with intracardiac thrombus (adjusted odds ratio (aOR) 2.067; 95% confidence interval (CI): 1.198-3.566; p = 0.009) and right heart catheterization (RHC) (aOR: 1.971; 95% CI: 1.160-3.350; p = 0.012). Mortality in patients with TCM was associated with, among other factors, age in years at admission (aOR: 1.104; 95% CI: 1.010-1.017; p = 0.001), African American race (aOR: 1.191; 95% CI: 1.020-1.391; p = 0.027), Asian or Pacific Islander race (aOR: 1.637; 95% CI: 1.283-2.090; p = 0.001), coagulopathy (aOR: 3.393; 95% CI: 2.889-2.986; p = 0.001), liver disease (aOR: 1.446; 95% CI: 1.147-1.824; p = 0.002), atrial fibrillation (aOR: 1.460; 95% CI: 1.320-1.615; p = 0.001), and pulmonary embolism (aOR: 2.217; 95% CI: 1.781-2.760; p = 0.001). Conclusion  In a large cohort of patients admitted with TCM, we found the prevalence of PE to be 1.96%. PE, along with comorbidities such as coagulopathy and atrial fibrillation, was found to be a significant predictor of mortality in this patient cohort.

Trends in Prevalence of Thyroid Dysfunction and its Associations With Mortality Among US Participants, 1988-2012

CONTEXT

Various dynamic factors could influence the prevalence and distribution of thyroid dysfunction.

OBJECTIVE

To provide national estimates and temporal trends in prevalence of thyroid dysfunction over the past 3 decades in United States and determine the impact of thyroid dysfunction on mortality in US adults.

METHODS

A cross-sectional analysis of data from 33 117 participants aged 12 years or older in the National Health and Nutrition Examination Survey III (1988-1994), 1999-2002, and 2007-2012.

RESULTS

The weighted mean age was 41.6 years, and 48.3% were men. In 2007 through 2012, the prevalence of subclinical and overt hypothyroidism, subclinical and overt hyperthyroidism was 4.3%, 0.33%, 3.2%, and 0.2% respectively. Eighty percent of individuals with thyroid dysfunction were previously undiagnosed. The prevalence of subclinical hypothyroidism and hyperthyroidism was stable, whereas overt hypothyroidism (0.54% [95% CI, 0.35-0.8] vs 0.33% [95% CI, 0.23-0.48]) and hyperthyroidism (0.8% [95% CI, 0.58-1.1] vs 0.2% [95% CI, 0.12-0.33]) were less prevalent in 2007-2012 compared to 1988-1994. Older age, White Americans, obesity, and positivity for thyroid peroxidase antibody and thyroglobulin antibody were risk factors for hypothyroidism, whereas older age, women, and Black Americans were risk factors for hyperthyroidism. Over a median follow-up of 17.2 years, no significant association was observed between any type of thyroid dysfunction with the risk of total or cardiovascular mortality. However, among individuals aged 65 years or older, subclinical hypothyroidism was associated with a higher risk of total mortality (hazard ratio, 1.17; 95% CI, 1.00-1.37; P = .05) and cardiovascular mortality (HR, 1.29; 95% CI, 1.04-1.62; P = .02).

CONCLUSIONS

The prevalence of subclinical thyroid dysfunction remained relatively unchanged, whereas that of overt thyroid dysfunction decreased. Subclinical hypothyroidism was associated with a higher mortality among individuals aged 65 years or older.

Thyroid Disorders and Peripheral Arterial Disease

Hypothyroidism and hyperthyroidism, both overt and subclinical, are associated with increased risk of cardiovascular morbidity and mortality. The association between thyroid-stimulating hormone levels and cardiovascular risk has been demonstrated in large epidemiological studies and meta-analyses and is now considered a U-shaped curve. Several pathophysiological mechanisms linking thyroid and cardiovascular disease are known; however, specific clinical complications of peripheral arterial disease as endpoints of clinical trials have not been adequately investigated. The potential mechanisms linking hypothyroidism and peripheral arterial disease are endothelial dysfunction, blood pressure changes, dyslipidemia, and low-grade systemic inflammation. The potential mechanisms linking hyperthyroidism and peripheral arterial disease are hyperdynamic circulation, elevated systolic blood pressure, hypercoagulability, and possibly increased arterial inflammation.

Higher Risk of Incident Hyperthyroidism in Patients With Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) has been linked to increased hyperthyroidism risk, but contributing factors are unclear.

OBJECTIVE

We aimed to investigate whether AF could predict hyperthyroidism and related risk factors.

METHODS

This retrospective cohort study was conducted in a tertiary medical institution and included patients aged 18 years or older with AF but without hyperthyroidism at diagnosis. The endpoint was defined as newly diagnosed hyperthyroidism during the follow-up period.

RESULTS

The study cohort included 8552 participants. Patients who developed new hyperthyroidism were younger and the proportion of females was higher. They had fewer comorbidities, including diabetes (26% vs 29%, P = .121), hypertension (51% vs 58%, P < .001), coronary artery disease (17% vs 25%, P < .001), stroke (16% vs 22%, P < .001), and end-stage renal disease (ESRD) (6% vs 10%, P = .001). The CHADS2 score was lower in patients with hyperthyroidism (1.74 vs 2.05, P = .031), but there was no statistically significant difference in the CHA2DS2-VASc and HAS-BLED score. Cox regression analysis identified younger age, female gender, history of congestive heart failure, hypertension, diabetes, non-ESRD status, and lower CHADS2 score but not CHA2DS2-VASc as independent predictors of incident hyperthyroidism during follow-up. We also propose a novel, simple risk stratification score (SAD HEC2 score) with excellent predictive power for incident hyperthyroidism during follow-up.

CONCLUSION

Our results provide insight into clinical risk factors for the development of hyperthyroidism in AF patients, as identified by the novel SAD HEC2 score. AF appears to be a common precursor of hyperthyroidism.

Is Thyroid Dysfunction Associated with Unruptured Intracranial Aneurysms? A Population-Based, Nested Case-Control Study from Korea

Background: Few risk factors for the development of intracranial aneurysms (IAs) are known. We investigated the potential role of thyroid diseases in IA development using nationwide real-world data. Methods: A nested case-control study within the National Health Insurance Service-National Sample Cohort data from 2002 to 2019 was performed. A total of 5335 patients with unruptured IA were matched by age and sex with 80,025 controls at a ratio of 1:15. We estimated the odds ratios (ORs) and corresponding confidence intervals [CIs] between thyroid diseases and unruptured IA using a multivariable conditional logistic regression model. Results: Tobacco smoking, use of antihypertensive medication, and hypothyroidism were significantly associated with an elevated risk for unruptured IA in univariate analysis. In multivariable analysis, a history of hypothyroidism was associated with unruptured IA (adjusted OR: 1.46 [CI: 1.26-1.69]). Among patients with hypothyroidism, long-term use of thyroid hormone for >5 years was associated with a reduced risk for unruptured IA (adjusted OR: 0.69 [CI: 0.48-0.99]). A history of hyperthyroidism was associated with a reduced risk for unruptured IAs (adjusted OR: 0.71 [CI: 0.54-0.93]). In secondary analyses of the data according to sex, the respective observed associations between hypothyroidism and hyperthyroidism and the risk of IAs were found to be statistically significant in females but not in males. Conclusions: Hypothyroidism is associated with an increased risk of unruptured IAs, whereas hyperthyroidism is associated with a reduced risk. Overall, the findings suggest that thyroid hormones may play a protective role in the development of unruptured IAs. Further studies are needed to clarify potential direct causality and the biologic mechanisms relating thyroid dysfunction and unruptured IA.

Hyperthyroidism: A Review

Importance

Overt hyperthyroidism, defined as suppressed thyrotropin (previously thyroid-stimulating hormone) and high concentration of triiodothyronine (T3) and/or free thyroxine (FT4), affects approximately 0.2% to 1.4% of people worldwide. Subclinical hyperthyroidism, defined as low concentrations of thyrotropin and normal concentrations of T3 and FT4, affects approximately 0.7% to 1.4% of people worldwide. Untreated hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes. It may lead to unintentional weight loss and is associated with increased mortality.

Observations

The most common cause of hyperthyroidism is Graves disease, with a global prevalence of 2% in women and 0.5% in men. Other causes of hyperthyroidism and thyrotoxicosis include toxic nodules and the thyrotoxic phase of thyroiditis. Common symptoms of thyrotoxicosis include anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance. Patients with Graves disease may have a diffusely enlarged thyroid gland, stare, or exophthalmos on examination. Patients with toxic nodules (ie, in which thyroid nodules develop autonomous function) may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes. Etiology can typically be established based on clinical presentation, thyroid function tests, and thyrotropin-receptor antibody status. Thyroid scintigraphy is recommended if thyroid nodules are present or the etiology is unclear. Thyrotoxicosis from thyroiditis may be observed if symptomatic or treated with supportive care. Treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease include antithyroid drugs, radioactive iodine ablation, and surgery. Treatment for subclinical hyperthyroidism is recommended for patients at highest risk of osteoporosis and cardiovascular disease, such as those older than 65 years or with persistent serum thyrotropin level less than 0.1 mIU/L.

Conclusions and Relevance

Hyperthyroidism affects 2.5% of adults worldwide and is associated with osteoporosis, heart disease, and increased mortality. First-line treatments are antithyroid drugs, thyroid surgery, and radioactive iodine treatment. Treatment choices should be individualized and patient centered.

Cardiovascular outcomes in subclinical thyroid disease: an update

PURPOSE OF REVIEW

Subclinical thyroid disease is defined by a thyroid stimulating hormone (TSH) level outside of the normal range with normal circulating thyroid hormone levels. Excess adverse cardiovascular outcomes have been observed in certain patient populations with subclinical hypothyroidism (SCH) and hyperthyroidism (SCHr). The role of thyroid hormone and antithyroid treatments for subclinical thyroid disease remains debated.

RECENT FINDINGS

Cardiovascular disease appears to be a major mediator of all-cause mortality in patients with SCH, in particular those aged at least 60 years of age. In contrast, pooled clinical trial results did not find that levothyroxine reduced the incidence of cardiovascular events or mortality in this patient population. The association between SCHr and atrial fibrillation is well established; however, a 5-year follow-up of older patients with mild (TSH 0.1-0.4 mIU/l) SCHr found no increased incidence of atrial fibrillation. Separately, SCHr was associated with derangements in endothelial progenitor cell function that may underlie vascular disease independent from effects on cardiac function.

SUMMARY

The impact of treatment of subclinical thyroid disease on cardiovascular outcomes remains uncertain. Additional prospective and trial data are needed to evaluate treatment effects on cardiovascular outcomes in younger populations.

Lower free triiodothyronine levels are associated with higher all-cause and cardiovascular mortality in people with diabetes-NHANES 2007-2012

OBJECTIVE

Thyroid hormone plays a key role in maintaining cardiovascular system homeostasis. However, there is limited evidence regarding the correlation between normal range thyroid hormone levels and all-cause mortality or cardiovascular mortality among individuals with diabetes.

METHOD

This retrospective study analyzed data from 1,208 individuals with diabetes who participated in the National Health and Nutrition Survey (NHANES) conducted in the United States between 2007 and 2012. Weighted Kaplan-Meier (KM) analysis and Cox proportional hazards models were used to explore the association between thyroid hormone indices and mortality.

RESULTS

The Weighted Kaplan-Meier (KM) analysis revealed statistically significant differences in survival probabilities across free triiodothyronine (FT3), free thyroxine (FT4), FT3/FT4 ratio and thyroid-stimulating hormone (TSH) groups (p < 0.05 or < 0.001). In the multivariate adjusted Cox proportional hazards models, higher levels of FT3 were founded to be associated with decreased all-cause mortality (HR (95% CI), 0.715 (0.567, 0.900)), cardio-cerebrovascular mortality (0.576 (0.408, 0.814)) and cardiovascular mortality (0.629 (0.438, 0.904)). Notably, this correlation was more significant among individuals over the age of 60, as indicated by the results of the nonlinear regression analysis.

CONCLUSION

FT3 is an independent predictor of all-cause death, cardio-cerebrovascular and cardiovascular death in euthyroid subjects with diabetes.

Role of thyroid hormones-induced oxidative stress on cardiovascular physiology

Thyroid hormones (THs) play an essential role in the maintenance of cardiovascular homeostasis and are involved in the modulation of cardiac contractility, heart rate, diastolic function, systemic vascular resistance, and vasodilation. THs have actions on cardiovascular physiology through the activation or repression of target genes or the activation of intracellular signals through non-genomic mechanisms. Hyperthyroidism alters certain intracellular pathways involved in the preservation of the structure and functionality of the heart, causing relevant cardiovascular disorders. Reactive oxygen species (ROS) play an important role in the cardiovascular system, but the exacerbated increase in ROS caused by chronic hyperthyroidism together with regulation on the antioxidant system have been associated with the development of cardiovascular dysfunction. In this review, we analyze the role of THs-induced oxidative stress in the cellular and molecular changes that lead to cardiac dysfunction, as well as the effectiveness of antioxidant treatments in attenuating cardiac abnormalities developed during hyperthyroidism.

Minor perturbations of thyroid homeostasis and major cardiovascular endpoints—Physiological mechanisms and clinical evidence

It is well established that thyroid dysfunction is linked to an increased risk of cardiovascular morbidity and mortality. The pleiotropic action of thyroid hormones strongly impacts the cardiovascular system and affects both the generation of the normal heart rhythm and arrhythmia. A meta-analysis of published evidence suggests a positive association of FT4 concentration with major adverse cardiovascular end points (MACE), but this association only partially extends to TSH. The risk for cardiovascular death is increased in both subclinical hypothyroidism and subclinical thyrotoxicosis. Several published studies found associations of TSH and FT4 concentrations, respectively, with major cardiovascular endpoints. Both reduced and elevated TSH concentrations predict the cardiovascular risk, and this association extends to TSH gradients within the reference range. Likewise, increased FT4 concentrations, but high-normal FT4 within its reference range as well, herald a poor outcome. These observations translate to a monotonic and sensitive effect of FT4 and a U-shaped relationship between TSH and cardiovascular risk. Up to now, the pathophysiological mechanism of this complex pattern of association is poorly understood. Integrating the available evidence suggests a dual etiology of elevated FT4 concentration, comprising both ensuing primary hypothyroidism and a raised set point of thyroid function, e. g. in the context of psychiatric disease, chronic stress and type 2 allostatic load. Addressing the association between thyroid homeostasis and cardiovascular diseases from a systems perspective could pave the way to new directions of research and a more personalized approach to the treatment of patients with cardiovascular risk.

Yearly Incidence of Stroke and Bleeding in Atrial Fibrillation with Concomitant Hyperthyroidism: A National Discharge Database Study

Background: Hyperthyroidism is associated with atrial fibrillation (AF), and the latter is a major risk factor for stroke. Aim: We aimed to investigate the yearly incidence of stroke and bleeding in AF patients with and without concomitant hyperthyroidism from the French National Hospital Discharge Database. Methods: Admissions with AF between January 2010 and December 2019 were retrospectively identified and retrieved from the French national database. Incidence rates of ischaemic stroke and bleeding were compared in AF patients with and without concomitant hyperthyroidism. The associations of risk factors with ischaemic stroke were assessed by Cox regression. Results: Overall 2,421,087 AF patients, among whom 32,400 had concomitant hyperthyroidism were included in the study. During the follow-up (mean: 2.0 years, standard deviation SD: 2.2 years), the yearly incidence of ischaemic stroke was noted to be 2.6 (95% confidence interval CI: 2.5−2.8) in AF patients with concomitant hyperthyroidism, and 2.3 (95%CI: 2.3−2.4) in non-thyroid AF patients. Hyperthyroidism was noted as an independent risk factor for ischaemic stroke (adjusted hazard ratio aHR: 1.133, 95%CI: 1.080−1.189) overall, particularly within the first year of hyperthyroidism diagnosis (aHR 1.203, 95%CI 1.120−1.291), however, the association became non-significant in subsequent years (aHR 1.047, 95%CI 0.980−1.118). Major bleeding incidence was lower in the hyperthyroid AF group in comparison to the non-thyroid AF group (incidence ratio: 5.1 vs. 5.4%/year, p < 0.001). The predictive value of CHA2DS2VASc and HAS-BLED scores for ischaemic stroke and bleeding events, respectively, did not differ significantly between AF patients with or without concomitant hyperthyroidism. Conclusions: Hyperthyroidism seems to be an independent risk factor of ischaemic stroke in AF patients, particularly within the first year of hyperthyroidism diagnosis.

Association of Mild Thyroid Dysfunction and Adverse Prognosis Among Chinese Patients With Acute ST Segment Elevation Myocardial Infarction

AIMS

Thyroid hormones widely affect the cardiovascular system, but the effects of mild thyroid dysfunction on the clinical prognosis of patients with acute ST segment elevation myocardial infarction (STEMI) remains unclear. Our aims were to analyze the relations between mild thyroid dysfunction at admission and clinical outcomes in Chinese patients with STEMI.

METHODS

A total of 1,176 STEMI patients with the available data of thyroid function and follow-up were analyzed, including 348 patients with mild thyroid dysfunction [subclinical hypothyroidism (n=81), hyperthyroidism (SHyper) (n=51), and low triiodothyronine syndrome (LT3S) (n=216)] and 828 patients with euthyroid function. During a median 4.4-year follow-up, in-hospital mortality, cardiac and all-cause mortalities were subsequently compared among the four groups.

RESULTS

Compared with the euthyroid group, STEMI patients in the SHyper and LT3S groups faced obviously increased risks of in-hospital death [odds ratio (OR): 5.007, 95% confidence interval (CI): 1.246-20.124, p = 0.023 and OR: 2.491, 95% CI: 1.054-5.887, p = 0.037, respectively) even after adjustment for various confounding factors. During a median 4.4-year follow-up, STEMI patients with LT3S at baseline had higher cardiovascular mortality [hazard ratio (HR): 1.880, 95% CI: 1.178-2.998, p = 0.008] and all-cause mortality HR: 1.647, 95% CI: 1.072-2.531, p = 0.023] than those with euthyroid at baseline, whereas no significantly increased mortality was found for STEMI patients with SCH and SHyper at baseline.

CONCLUSIONS

STEMI patients with SHyper at admission had increased risk of in-hospital mortality, and STEMI patients with LT3S at baseline had worse prognosis and higher incidences of in-hospital mortality and cardiovascular and all-cause deaths compared with euthyroid patients.

Platelet abnormalities in autoimmune thyroid diseases: A systematic review and meta-analysis

Background

Some degree of platelet index abnormality has been found clinically in the autoimmune thyroid disease (AITD), but the findings are not uniform.

Methods

The PubMed, Web of Science, Cochrane Library, and Embase databases were searched for relevant articles published up to August 16th, 2022, with no restrictions on the language of the articles. Reference lists of eligible articles were also searched. A random effect model was used to pool the standardized mean difference (SMD) and 95% confidence interval (95% CI) of platelet count (PLT), mean platelet volume (MPV), and platelet distribution width (PDW) between AITD patients and healthy controls, and subgroup analyses were performed.

Results

A total of 19 articles with 6173 people (3824 AITD patients and 2349 healthy people) were included in the meta-analysis. The results showed that PLT and MPV values were significantly increased in AITD patients when compared with healthy people (SMD: 0.164, 95% CI: 0.044 to 0.285; SMD: 0.256, 95% CI: 0.013 to 0.500), while no significant difference was found in PDW between the AITD group and the control group (SMD: 0.060, 95% CI: -0.164 to 0.284). Subgroup analysis according to disease type and thyroid function revealed that for PLT, this difference was only found in the Hashimoto's thyroiditis (HT) and hypothyroid groups, but not in the Graves' disease (GD) and hyperthyroid groups. For MPV, the results were the opposite of those for PLT: MPV was significantly higher in the GD, hyperthyroid, and euthyroid groups than in the control group, but not in the HT and hypothyroid groups. Sensitivity analysis showed that the stability of the pooled MPV was not good. No publication bias was found.

Conclusions

PLT and MPV are significantly elevated in patients with AITD, with PLT being more significantly elevated in HT and hypothyroidism, and MPV being more significantly increased in GD and hyperthyroidism. Appropriate clinical attention can be paid to the thyroid function of patients when abnormal platelet indices are found, and conversely, the consequences of abnormal platelet parameters such as elevated MPV lead to an increased occurrence of cardiovascular events, which should also be addressed in the AITD population.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022341823.

Weight Gain and Body Composition Changes during the Transition of Thyroid Function in Patients with Graves' Disease Undergoing Radioiodine Treatment

OBJECTIVE

This study aimed at investigating the dynamic changes in the body weight and body composition in a group of patients with Graves' disease undergoing radioiodine therapy.

METHODS

Seventeen patients with Graves' disease undergoing ¹³¹I treatment and forty-three euthyroid controls were recruited. Body weight, BMI, and body composition via bioelectrical impedance were measured for the participants at baseline, hypothyroid stage, and euthyroid stage.

RESULTS

Body weight increased significantly during the transition from hyperthyroidism to euthyroidism. However, there were no significant changes in body fat %, lean mass %, and bone mineral %. The body weight of 9 patients at the euthyroid stage exceeded their premorbid weight, while the remaining 8 patients' weight did not exceed the premorbid weight. In the group with excessive weight gain, both body fat and lean mass increased significantly. However, in the group without excessive weight gain, only lean mass increased significantly. The patients with excessive weight gain had significantly higher body fat %, while lower lean mass % compared to patients without excessive weight gain at baseline and at the euthyroid stage. Moreover, body fat % of patients with excessive weight gain was significantly higher than that of controls, while lean mass % was significantly lower than that of controls. There was no difference of body fat % and lean mass % between patients without excessive weight gain and controls.

CONCLUSION

¹³¹I treatment caused significant weight gain in patients with Graves' disease. An undesirable body composition at presentation may be a risk factor for excessive weight gain after hyperthyroidism treatment.

Thyroid and heart, a clinically relevant relationship

BACKGROUND

Thyroid disorders, both overt and subclinical, are highly prevalent conditions in the general population. Although a clear relationship between overt thyroid dysfunctions and cardiovascular complications has long been established, data regarding subclinical thyroid dysfunction are by far more controversial.

PURPOSE

The present review will be aimed at providing a summary of most recent evidence coming from meta-analyses regarding the complex relationship between thyroid dysfunction and cardiovascular disease.

CONCLUSIONS

The review will summarize, in the first part, the physiopathological link between thyroid hormone imbalances and the cardiovascular system. In the second part the review will outline the evidence coming from meta-analyses regarding the cardiovascular risk related with both overt and subclinical thyroid dysfunctions. Particular attention will be put towards studies showing data stratified for patient's age, TSH levels and pre-existing cardiovascular disease. Finally, an overview regarding the effects of specific therapy for subclinical thyroid diseases in terms of amelioration of cardiovascular outcomes will be included.

Cardiovascular Outcomes in Thyroid Cancer Patients Treated With Thyroidectomy: A Meta-analysis

CONTEXT

Thyroid dysfunction is associated with an increased risk of cardiovascular disease (CVD) in the general population; however, it remains controversial whether differentiated thyroid cancer (DTC) treatment, including thyroidectomy and thyroid-stimulating hormone suppression, further increases the risk of CVD.

OBJECTIVE

This study aimed to evaluate the risk of CVD in patients with DTC.

METHODS

We performed a review of observational studies on associations between DTC and cardiovascular outcomes, indexed in MEDLINE, Embase, and Web of Science. We excluded studies that evaluated CVD as comorbidity before DTC diagnosis and those that used active surveillance without thyroidectomy as an intervention. Risk estimates were pooled using random- and fixed-effects models when 3 or more studies reported on the outcome of interest. Echocardiographic and hemodynamic parameters were examined.

RESULTS

Eighteen studies were included in the quantitative analysis (193 320 cases with DTC and 225 575 healthy controls). DTC was associated with an increased risk of atrial fibrillation (pooled risk ratio [RR] = 1.55 [95% CI: 1.30-1.84]), coronary artery disease (RR = 1.10 [1.00-1.21]), cerebrovascular accidents (RR = 1.15 [1.09-1.20]), and all-cause mortality (RR = 1.95 [1.03-3.69]). DTC was associated with higher diastolic blood pressure (standardized mean difference [SMD], 0.22 [0.01-0.42]), heart rate (0.37 [0.17-0.57]), left ventricular mass index (0.66 [0.45-0.88]), and interventricular septal thickness (0.91 [0.33-1.49]) and lower early to late ventricular filling velocities (-0.42 [-0.79 to -0.05]), but not with ejection fraction.

CONCLUSION

Patients with DTC are at an increased risk of atrial fibrillation, CVD, increased heart rate, and left ventricular mass development.

Antithyroid Drug Treatment in Graves' Disease

Graves' disease is associated with thyrotropin (TSH) receptor stimulating antibody, for which there is no therapeutic agent. This disease is currently treated through inhibition of thyroid hormone synthesis or destruction of the thyroid gland. Recurrence after antithyroid drug (ATD) treatment is common. Recent studies have shown that the longer is the duration of use of ATD, the higher is the remission rate. Considering the relationship between clinical outcomes and iodine intake, recurrence of Graves' disease is more common in iodine-deficient areas than in iodine-sufficient areas. Iodine restriction in an iodine-excessive area does not improve the effectiveness of ATD or increase remission rates. Recently, Danish and Korean nationwide studies noted significantly higher prevalence of birth defects in newborns exposed to ATD during the first trimester compared to that of those who did not have such exposure. The prevalence of birth defects was lowest when propylthiouracil (PTU) was used and decreased by only 0.15% when methimazole was changed to PTU in the first trimester. Therefore, it is best not to use ATD in the first trimester or to change to PTU before pregnancy.