The Prognostic Value of Thyroid-Stimulating Hormone in Patients with Coronary Artery Disease and Depression

Purpose

Patients with the comorbidity of coronary artery disease (CAD) and depression are very common and always have poor prognosis. The relationship between thyroid-stimulating hormone (TSH) levels and major cardiovascular event (MACE) in these patients is still unknown. We aimed to explore this association.

Patients and Methods

We enrolled 203 CAD patients proven by coronary angiography (CAG). In the meanwhile, they were all assessed to have depression symptom by professional psycho-cardiologists. After an average follow-up of 23.7 months, patients were divided into two groups (high TSH group with TSH ≥ 1.395μIU/mL and low TSH group with TSH < 1.395μIU/mL) according to the cut-off value of baseline TSH. The impact of two different TSH groups for adverse events in CAD patients with depression was evaluated.

Results

The average age of these patients was 64.9 years old. The two TSH groups had no significant difference in the comparison of other baseline data. Area under the receiver operating characteristic (ROC) curves (AUC) analysis indicated the well-discriminatory power of TSH levels for the occurrence of MACE (AUC = 0.61, 95% CI: 0.52–0.70, P = 0.03). In the KM survival analysis, high TSH group had a higher risk of MACE (P = 0.029). After multi-factor adjustment, there still existed a higher risk of MACE in high TSH group (HR = 2.05, 95% CI: 1.08–3.88, P = 0.028).

Conclusion

In patients with the comorbidity of CAD and depression, higher TSH levels are associated with the occurrence of MACE. More researches need to be conducted to prove this association and explore whether the drug-related TSH reduction can decrease the occurrence of adverse events in the future.

Subclinical Hypothyroidism Affects the Long-Term Outcomes of Patients Who Undergo Coronary Artery Bypass Grafting Surgery but Not Heart Valve Surgery

BACKGROUND

The aim of this study was to determine the associations between subclinical hypothyroidism (SCH) and long-term cardiovascular outcomes after coronary artery bypass grafting (CABG) or heart valve surgery (HVS).

METHODS

We retrospectively reviewed and compared all-cause mortality, cardiovascular mortality, and cardiovascular events in 461 patients who underwent CABG and 104 patients who underwent HVS.

RESULTS

During a mean±standard deviation follow-up duration of 7.6±3.8 years, there were 187 all-cause deaths, 97 cardiovascular deaths, 127 major adverse cardiovascular events (MACE), 11 myocardial infarctions, one unstable angina, 70 strokes, 30 hospitalizations due to heart failure, 101 atrial fibrillation, and 33 coronary revascularizations. The incidence of all-cause mortality after CABG was significantly higher in patients with SCH (n=36, 55.4%) than in euthyroid patients (n=120, 30.3%), with a hazard ratio of 1.70 (95% confidence interval, 1.10 to 2.63; P=0.018) after adjustment for age, sex, current smoking status, body mass index, underlying diseases, left ventricular dysfunction, and emergency operation. Interestingly, low total triiodothyronine (T3) levels in euthyroid patients who underwent CABG were significantly associated with increased risks of all-cause mortality, cardiovascular mortality, and MACE, but those associations were not observed in HVS patients. Both free thyroxine and thyroid-stimulating hormone levels in euthyroid patients were not related with any cardiovascular outcomes in either the CABG or HVS group.

CONCLUSION

SCH or low total T3 might be associated with a poor prognosis after CABG, but not after HVS, implying that preoperative thyroid hormonal status may be important in ischemic heart disease patients.

Normal-range thyroid-stimulating hormone levels and cardiovascular events and mortality in type 2 diabetes

AIMS

Thyroid dysfunction is a risk factor for cardiovascular disease. Whether thyroid function within the normal range is a risk factor for cardiovascular disease remains uncertain. The aim of this study is to evaluate whether plasma thyroid-stimulating hormone (TSH) levels in the normal range are a risk factor for cardiovascular disease and mortality in participants with type 2 diabetes mellitus with high cardiovascular risk.

METHODS

We included 1265 participants with high cardiovascular risk, type 2 diabetes, and TSH within the normal range (0.35-5.00 mIU/L) from the Second Manifestations of ARTerial disease cohort. The primary outcome was major cardiovascular events (MACE; vascular death, stroke and myocardial infarction). Secondary outcomes of interest were the separate vascular outcomes and all-cause mortality. Cox proportional hazard models were used to evaluate the risk of plasma TSH levels on all outcomes.

RESULTS

A total of 191 MACE occurred during a total follow-up of 8183 years. Plasma TSH levels were not associated with MACE (hazard ratio (HR) per mIU/L TSH increase 0.93; 95% confidence interval (95%CI) 0.80-1.08). With a total of 54 strokes during the study period, plasma TSH was associated with a lower risk of stroke (HR per mIU/L 0.64, 95% CI 0.45-0.89). There was no association between plasma TSH levels and risk of myocardial infarction, vascular death, or all-cause mortality.

CONCLUSIONS

Higher TSH levels within the normal range are associated with a lower risk of stroke in high-risk patients with type 2 diabetes, but not associated with the risk of other cardiovascular events or mortality.

TSH inhibits eNOS expression in HMEC-1 cells through the TSHR/PI3K/AKT signaling pathway

OBJECTIVE

To investigate the effects of thyroid-stimulating hormone (TSH) on the expression of endothelial nitric oxide synthase (eNOS) in human microvascular endothelial cells (HMEC-1) and explore the potential mechanism.

MATERIALS AND METHODS

Expression of thyroid-stimulating hormone receptor (TSHR) in HMEC-1 cells was determined by immunofluorescence, reverse transcription-polymerase chain reaction (RT-PCR), and Western blotting. Cell proliferation and the production of nitric oxide (NO) and superoxide anion (SA) were measured after TSH treatment. eNOS expression and AKT phosphorylation were detected by Western blotting.

RESULTS

TSHR was expressed in HMEC-1 cells. TSH promoted HMEC-1 cell proliferation and SA production, but inhibited NO generation by dose-dependent blocking of mRNA and protein expression of eNOS. Mechanism studies demonstrated that TSH promoted AKT phosphorylation (P<0.05), and that LY294002 inhibited the reduction of eNOS expression by TSH. Moreover, TSH activated the AKT signaling pathway through binding to TSHR on HMEC-1 cells.

CONCLUSIONS

TSH inhibits NO production via the TSHR/AKT signaling pathway.

High-normal thyroid-stimulating hormone in euthyroid subjects is associated with risk of mortality and composite disease endpoint only in women

INTRODUCTION

The aim of the study was to evaluate whether serum thyroid-stimulating hormone (TSH) within the normal range in euthyroid subjects (having normal free triiodothyronine (fT3) and thyroxine (fT4)) is related to the risk of overall mortality or a composite endpoint of death and nonfatal events.

MATERIAL AND METHODS

In 614 middle-aged adult hospital screenees, free of uncontrolled diabetes at baseline, the association of sex-specific TSH tertiles with death was prospectively assessed using Cox regression, with the composite endpoint assessed using logistic regression in adjusted analyses, stratified by gender.

RESULTS

In total, 64 deaths and additional incident nonfatal events in 141 cases were recorded at a mean 7.55 years' follow-up. Multivariable linear regression revealed TSH to be significantly associated among men with age (p = 0.006), but in women inversely with fT3 and fT4 (p < 0.001, and p = 0.024 respectively). In logistic regression analysis, adjusted for age, fT3, fT4, systolic blood pressure and serum total cholesterol, sex-specific baseline TSH tertiles were associated in men neither with the risk of death nor with composite endpoint. In contrast, in women, the highest compared with the bottom TSH tertile predicted the risk of composite endpoint (relative risk: 2.02, 95% CI: 1.07-3.82) and, much more strongly, the mortality risk, independently of fT4 increments.

CONCLUSIONS

The significant association of higher range of normal serum TSH in euthyroid middle-aged adults with the risk of death and nonfatal adverse outcomes in women alone cannot be accounted for by the action of thyroid hormone and is consistent with involvement of TSH in the pro-inflammatory state.

Association of Thyroid Function With Life Expectancy With and Without Cardiovascular Disease: The Rotterdam Study

IMPORTANCE

Variations in thyroid function within reference ranges are associated with an increased risk of cardiovascular disease (CVD) and mortality. However, the impact of thyroid function on life expectancy (LE) and the number of years lived with and without CVD remains unknown.

OBJECTIVE

To investigate the association of thyroid function with total LE and LE with and without CVD among euthyroid individuals.

DESIGN, SETTING, AND PARTICIPANTS

The Rotterdam Study, a population-based, prospective cohort study. We included participants without known thyroid disease and with thyrotropin and free thyroxine (FT4) levels within the reference ranges.

MAIN OUTCOMES AND MEASURES

Multistate life tables were used to calculate total LE and LE with and without CVD among thyrotropin and FT4 tertiles. Life expectancy estimates in men and women aged 50 years and older were obtained using prevalence, incidence rates, and hazard ratios for 3 transitions (healthy to CVD, healthy to death, and CVD to death), adjusting for sociodemographic and cardiovascular risk factors.

RESULTS

The mean (SD) age of the 7785 participants was 64.7 (9.8) years, and 52.5% were women. Over a median follow-up of 8.1 (interquartile range, 2.7-9.9) years, we observed 789 incident CVD events and 1357 deaths. Compared with those in the lowest tertile, men and women in the highest thyrotropin tertile lived 2.0 (95% CI, 1.0 to 2.8) and 1.4 (95% CI, 0.2 to 2.4) years longer, respectively, of which, 1.5 (95% CI, 0.2 to 2.6) and 0.9 (95% CI, -0.2 to 2.0) years longer without CVD. Compared with those in the lowest tertile, the difference in life expectancy for men and women in the highest FT4 tertile was -3.2 (95% CI, -5.0 to -1.4) and -3.5 (95% CI, -5.6 to -1.5) years, respectively, of which, -3.1 (95% CI, -4.9 to -1.4) and -2.5 (95% CI, -4.4 to -0.7) years without CVD.

CONCLUSIONS AND RELEVANCE

At the age of 50 years, participants with low-normal thyroid function live up to 3.5 years longer overall and up to 3.1 years longer without CVD than participants with high-normal thyroid function. These findings provide supporting evidence for a reevaluation of the current reference ranges of thyroid function and can help inform preventive and clinical care.

Associations between the levels of thyroid hormones and lipid/lipoprotein levels: Data from National Health and Nutrition Examination Survey 2007-2012

Data from National Health and Nutrition Examination Survey for the years 2007-2012 were used to investigate associations between thyroid hormones and lipid/lipoprotein levels for a representative sample of general US population aged ≥20 years. There were no statistically significant differences for adjusted high density lipoprotein levels among thyroid function groups, namely, subclinical hyperthyroid (SCHPR), clinical hyperthyroid (CHPR), euthyroid (EU), clinical hypothyroid (CHYP), and subclinical hypothyroid (SCHYP). For the general US population, positive associations for thyroid stimulating hormones (TSH) and negative associations for free thyroxine (FT4) levels were observed with total cholesterol (TC, p<0.01), apolipoprotein B (APOB, p<0.01), and triglycerides (TG, p<0.01). A 10% increase in TC levels was associated with a 2% increase in TSH levels and 0.8% decrease in FT4 levels. Among EU subjects, TG levels were positively correlated with TSH (p<0.01) and negatively correlated with FT4 (p<0.01). For CHYP subjects, TG levels were negatively correlated with TSH (p<0.01). For iodine deficient participants, low density lipoprotein levels (LDL) were lower for SCHPR when compared with EU or CHYP (p<0.01). TC levels were usually lower for SCHPR than for EU, CHYP, and SCHYP but the differences were not necessarily statistically significant. For all participants and for iodine replete participants, TG levels for SCHPR were lower than for CHYP (p<0.01). CHYP and SCHYP had higher levels of TG than other three thyroid function groups. APOB levels were lower for SCHPR than for EU and CHYP for all participants and for iodine replete participants (p<0.01). There was a positive association between the four quartiles of thyroid stimulating hormones and TC, TG, and APOB. There was also an inverse association between the quartiles of free thyroxine levels and LDL, TC, TG, and APOB.

FREE THYROID HORMONES AND MORTALITY IN CAUCASIANS UNDERGOING ANGIOGRAPHY: THE LUDWIGSHAFEN RISK AND CARDIOVASCULAR HEALTH (LURIC) STUDY

OBJECTIVE

Alterations in thyroid hormone functions are associated with mortality and morbidity. Data on euthyroid individuals are very limited and controversial. We therefore investigated the relationship between circulating thyroid hormones and all-cause and cardiovascular (CV) mortality in participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study and their association with morbidity.

METHODS

LURIC, a prospective, observational study of a hospital-based cohort of Caucasians, was recruited between June 1997 and May 2001 at the Ludwigshafen General Hospital, Ludwigshafen, Germany. Mortality was recorded for a follow-up period of 10 years. The current investigation includes 2,507 patients without overt thyroid disease who all underwent coronary angiography. Blood was drawn before angiography. We evaluated the association between thyroid hormone concentrations and mortality.

RESULTS

Low free triiodothyronine (FT3) (hazard ratio [HR], 1.00 versus 0.54; lowest versus highest quartile) and high free thyroxine (FT4) (HR, 1.52 versus 1.00; highest versus lowest quartile) were significant predictors of all-cause and CV mortality, independent of age and sex. Thyroid-stimulating hormone showed no consistent correlation with mortality.

CONCLUSION

High FT4 and low FT3 concentrations are significantly related to all-cause and CV mortality. These findings suggest that free thyroid hormones should be measured and considered in patients at intermediate to high risk of coronary heart disease.

ABBREVIATIONS

BMI = body mass index CAD = coronary artery disease CCI = Charlson Comorbidity Index CI = confidence interval CV = cardiovascular eGFR = estimated glomerular filtration rate FT3 = free triiodothyronine FT4 = free thyroxine HR = hazard ratio T3 = triiodothyronine T4 = thyroxine TSH = thyroid-stimulating hormone.

Prognostic value of thyroid-stimulating hormone within reference range in patients with coronary artery disease

BACKGROUND

Thyroid-stimulating hormone (TSH) in the upper part of reference range is associated with cardio-metabolic disorders. The association of TSH within reference range with prognosis of patients with coronary artery disease (CAD) after percutaneous coronary intervention (PCI) remains poorly investigated.

METHODS

The study included 8010 consecutive patients with CAD who were treated with PCI. All patients had a TSH level within reference range (0.3 to 4.0 mU/L). The primary outcome was 3-year all-cause mortality.

RESULTS

TSH tertiles were: 1st tertile (0.3 mU/L to <1.02 mU/L; n=2694), 2nd tertile (1.02 mU/L to <1.67 mU/L; n=2654) and 3rd tertile (1.67 mU/L to 4.00 mU/L; n=2662). The primary outcome (3-year mortality) occurred in 753 patients: 240 deaths in the 1st, 227 deaths in the 2nd and 286 deaths in the 3rd TSH tertile (Kaplan-Meier estimates of mortality 10.2%, 9.8% and 12.3%; adjusted hazard ratio [HR]=1.31, 95% confidence interval [CI] 1.04-1.66 for each tertile increase). TSH level was associated with 30-day mortality (mortality estimates, 1.6% in the 1st, 1.6% in the 2nd and 3.5% in the 3rd TSH tertile; adjusted HR=2.30 [1.33-3.97] for each tertile increase) but not with 30-day to 3-year mortality (mortality estimates, 8.6% in the 1st, 8.2% in the 2nd and 8.8% in the 3rd TSH tertile; P=0.603). The incidence of cardiogenic shock or peri-PCI bleeding was increased in patients in the upper TSH tertile.

CONCLUSION

In patients with CAD undergoing PCI, TSH level in the upper part of reference range was associated with increased risk of mortality after PCI.

Subclinical Hypothyroidism and Cardiovascular Disease

Subclinical hypothyroidism (SCH) is a common disorder that is characterized by elevated thyroid-stimulating hormone levels in conjunction with free thyroxine concentrations within the normal reference range. Thyroid hormones are known to affect the heart and vasculature and, as a result, the impact of SCH on the cardiovascular (CV) system has recently become an important topic of research. Strong evidence points to a link between SCH and CV risk factors such as alterations in blood pressure, lipid levels, and atherosclerosis. Additionally, accumulating evidence indicates that SCH is associated with metabolic syndrome and heart failure. The present review proposes that SCH may be a potentially modifiable risk factor of CV disease and mortality. However, large-scale clinical trials with appropriate power investigating the risks and benefits of SCH treatment are required to determine whether these benefits can be achieved with levothyroxine therapy.

Thyroid hormones and mortality risk in euthyroid individuals: the Kangbuk Samsung health study

CONTEXT

Hyperthyroidism and hypothyroidism, both overt and subclinical, are associated with all-cause and cardiovascular mortality. The association between thyroid hormones and mortality in euthyroid individuals, however, is unclear.

OBJECTIVE

To examine the prospective association between thyroid hormones levels within normal ranges and mortality endpoints.

SETTING AND DESIGN

A prospective cohort study of 212 456 middle-aged South Korean men and women who had normal thyroid hormone levels and no history of thyroid disease at baseline from January 1, 2002 to December 31, 2009. Free T4 (FT4), free T3 (FT3), and TSH levels were measured by RIA. Vital status and cause of death ascertainment were based on linkage to the National Death Index death certificate records.

RESULTS

After a median follow-up of 4.3 years, 730 participants died (335 deaths from cancer and 112 cardiovascular-related deaths). FT4 was inversely associated with all-cause mortality (HR = 0.77, 95% confidence interval 0.63-0.95, comparing the highest vs lowest quartile of FT4; P for linear trend = .01), and FT3 was inversely associated cancer mortality (HR = 0.62, 95% confidence interval 0.45-0.85; P for linear trend = .001). TSH was not associated with mortality endpoints.

CONCLUSIONS

In a large cohort of euthyroid men and women, FT4 and FT3 levels within the normal range were inversely associated with the risk of all-cause mortality and cancer mortality, particularly liver cancer mortality.

The effect of L-thyroxine substitution on lipid profile, glucose homeostasis, inflammation and coagulation in patients with subclinical hypothyroidism

AIMS

Subclinical hypothyroidism (SH) is associated with increased risk for atherosclerosis, mainly attributable to dyslipidaemia and hypercoagulability. However, conflicting data exist regarding the effect of L-thyroxine substitution on these parameters. The purpose of this study was to assess the effect of L-thyroxine therapy on lipidaemic profile, coagulation markers, high-sensitivity C-reactive protein (hsCRP) and glucose homoeostasis in SH patients.

METHODS

It was a prospective open-label study. The following parameters were measured before and 6 months after intervention: anthropometric data, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apolipoproteins B (apoB) and A1 (apoA1), lipoprotein (a) [Lp(a)], fasting plasma glucose and insulin, homoeostasis model assessment-insulin resistance (HOMA-IR), hsCRP, antithrombin III (AT-III), protein C (PC), protein S (PS), fibrinogen and homocysteine.

RESULTS

Thirty-two patients (30 women) aged 52.1 ± 13.9 years with SH completed the study. Baseline mean TSH levels were 6.79 ± 2.58 mIU/ml. Achievement of euthyroidism significantly reduced systolic blood pressure (BP) in patients with SH (from 135.2 ± 18.5 to 129.7 ± 15.8 mmHg, p = 0.03) and diastolic BP only in those with baseline TSH levels > 7 mIU/ml (from 79.5 ± 9.8 to 72.1 ± 7.3 mmHg, p = 0.03). No significant changes in body weight, TC, LDL-C, HDL-C, TG, apoB, glucose, insulin, HOMA-IR, hsCRP, AT-III, PC, PS, fibrinogen or homocysteine levels were noticed after restoration of euthyroidism, except for a decrease in apoA1 (p = 0.04) and an increase in Lp(a) levels (p = 0.02).

CONCLUSIONS

Except for a reduction in systolic and diastolic BP, thyroid substitution therapy does not affect lipidaemic profile, systematic inflammation, glucose homoeostasis or coagulation in patients with SH.

Blood thrombogenicity is independently associated with serum TSH levels in post-non-ST elevation acute coronary syndrome

CONTEXT

Higher serum TSH levels, both within the reference range and in those with subclinical hypothyroidism (SCH), have been associated with increased risk of atherosclerosis and cardiovascular (CV) events in a number of cross-sectional and longitudinal studies.

OBJECTIVE

Our objective was to evaluate blood thrombogenicity in patients post-non-ST elevation acute coronary syndrome (NSTE-ACS) in relation to their thyroid function. DESIGN, PATIENTS, AND OUTCOME MEASURE: At 1 week after troponin-positive NSTE-ACS, 70 patients who had been treated with optimal antiplatelet and secondary prevention therapy were studied. Patients with known thyroid disease or on medications affecting thyroid function were excluded. Blood thrombogenicity was assessed using the ex vivo Badimon perfusion chamber.

RESULTS

Serum TSH was associated with higher thrombus burden (β = .30; P = .01) independent of other well-established CV risk factors. Patients with SCH (n = 12; 17%) had a higher thrombus burden than euthyroid individuals as evidenced by the area of the thrombus: mean (SD) 23 608 (10 498) vs 16 661 (10 902) μm(2)/mm (P = .02). However, this association was not evident when the analysis was limited to patients with serum TSH within the reference range. In addition, neither serum free T4 nor free T3 had any significant association with thrombus area.

CONCLUSION

Serum TSH levels, particularly in the SCH range, are associated with higher thrombus burden despite optimal recommended secondary prevention therapy after NSTE-ACS. This may explain the higher CV risk seen in SCH patients. Future trials to assess the effect of individualized antithrombotic as well as thyroid hormone replacement therapy to reduce atherothrombotic risk in this population are needed.

Triiodothyronine and free thyroxine levels are differentially associated with metabolic profile and adiposity-related cardiovascular risk markers in euthyroid middle-aged subjects

BACKGROUND

We have previously shown that in healthy young men, a less favorable body composition is associated with higher free triiodothyronine (fT3) levels within the euthyroid range. Besides, a higher free-triiodothyronine-to-free-thyroxin (fT3-to-fT4) ratio has been related to a less favorable metabolic phenotype and more placental growth in pregnant women. In the present study, we therefore investigated whether serum thyrotropin (TSH), thyroid hormone levels, and the fT3-to-fT4 ratio are associated with metabolic and adiposity-related cardiovascular risk markers in a healthy population of middle-aged euthyroid men and women.

METHODS

Thyroid parameters were measured in 2524 generally healthy subjects from the Asklepios Study (35-55 years, mean age 46 years). Analyses were restricted to 2315 subjects (1138 women and 1177 men), not using thyroid medication, not having anti-TPO levels above clinical cutoff values or TSH levels outside the reference range (0.27-4.2 mU/L). Twenty-seven percent of the women and 47.5% of the men were overweight, while 13% of women and 17% of men were obese. Twenty percent of the subjects were active smokers. Serum thyroid function parameters were determined by electrochemiluminescence.

RESULTS

fT3 and the fT3-to-fT4 ratio were positively related to body mass index (BMI), waist circumference, and components of metabolic syndrome, that is, triglycerides, systolic and diastolic blood pressure, and fasting plasma glucose, and negatively with HDL-cholesterol levels, whereas fT4 was negatively associated with BMI, waist circumference, and triglycerides (p<0.001). TSH related positively with total cholesterol levels (p<0.01), triglycerides, and systolic and diastolic blood pressure (p<0.001). The fT3-to-fT4 ratio was further positively associated with the adiposity-related inflammation markers interleukin-6 and high-sensitivity C-reactive protein and to pulse wave velocity. All associations were adjusted for sex, age, height, and smoking, and most associations persisted after additional adjustment for weight or waist circumference.

CONCLUSION

In healthy euthyroid middle-aged men and women, higher fT3 levels, lower fT4 levels, and thus a higher fT3-to-fT4 ratio are consistently associated with various markers of unfavorable metabolic profile and cardiovascular risk.