Low T3 Group Research Articles

Low T3 vs low T3T4 euthyroid sick syndrome in septic shock patients: A prospective observational cohort study.

Both phases of euthyroid sick syndrome (ESS) are associated with worse prognosis in septic shock patients. Although there are still no indications for supplementation therapy, there is no evidence that both phases (initial and prolonged) are adaptive or that only prolonged is maladaptive and requires supplementation. To analyze clinical, hemodynamic and laboratory differences in two groups of septic shock patients with ESS. A total of 47 septic shock patients with ESS were divided according to values of their thyroid hormones into low T3 and low T3T4 groups. The analysis included demographic data, mortality scores, intensive care unit stay, mechanical ventilation length and 28-day survival and laboratory with hemodynamics. The Simplified Acute Physiology Score II score (P = 0.029), dobutamine (P = 0.003) and epinephrine requirement (P = 0.000) and the incidence of renal failure and multiple organ failure (MOF) (P = 0.000) were significantly higher for the low T3T4. Hypoalbuminemia (P = 0.047), neutrophilia (P = 0.038), lymphopenia (P = 0.013) and lactatemia (P = 0.013) were more pronounced on T2 for the low T3T4 group compared to the low T3 group. Diastolic blood pressure at T0 (P = 0.017) and T1 (P = 0.007), as well as mean arterial pressure at T0 (P = 0.037) and T2 (P = 0.033) was higher for the low T3 group. The low T3T4 population is associated with higher frequency of renal insufficiency and MOF, with worse laboratory and hemodynamic parameters. These findings suggest potentially maladaptive changes in the chronic phase of septic shock.

Transient low T3 syndrome in patients with COVID-19: a new window for prediction of disease severity.

To investigate the relationship of low T3 syndrome with disease severity in patients with COVID-19. The clinical data of 145 patients with COVID-19 were retrospectively collected, and patients were divided into a low T3 group and a normal T3 group. Logistic regression models were used to assess predictive performance of FT3. Receiver operating characteristic (ROC) analysis was used to evaluate the use of low T3 syndrome in predicting critical disease. Kaplan-Meier analysis was used to analyze the impact of low T3 syndrome on mortality. The prevalence of low T3 level among COVID-19 patients was 34.48%. The low T3 group was older, and had lower levels of hemoglobin, lymphocytes, prealbumin, and albumin, but higher levels of white blood cells, neutrophils, CRP, ESR, and D-dimer (all p<0.05). The low T3 group had greater prevalences of critical disease and mortality (all p <0.05). Multivariate logistic regression analysis showed that the Lymphocytes, free T3 (FT3), and D-dimer were independent risk factors for disease severity in patients with COVID-19. ROC analysis showed that FT3, lymphocyte count, and D-dimer, and all three parameters together provided reliable predictions of critical disease. Kaplan-Meier analysis showed the low T3 group had increased mortality (p<0.001). Six patients in the low T3 group and one patient in the normal T3 group died. All 42 patients whose T3 levels were measured after recovery had normal levels after discharge. Patients with COVID-19 may have transient low T3 syndrome at admission, and this may be useful for predicting critical illness.

Correlation and Prognostic Assessment of Low T3 Syndrome and Norepinephrine Dosage for Patients with Sepsis: A Retrospective Single-Center (Cohort) Study.

PurposeTo investigate the correlation and prognostic significance of low triiodothyronine (T3) syndrome and norepinephrine dosage in patients with sepsis and septic shock.MethodsThis single-center, retrospective, cohort study enrolled 169 patients with sepsis and septic shock that were admitted to the intensive care unit of First Hospital of Nanchang, Nanchang, China from June 2017 to July 2019. All included patients were followed up for 28 days or died, whichever was earlier. Patients with free T3 (FT3) of <3.1 pmol/L were considered with low T3 syndrome. The correlation and prognostic significance of the FT3 and maximum dosage of norepinephrine (MDN) within 72 h, as well as other clinical indicators, were analyzed by using correlation analysis, principal component analysis, receiver operating characteristic curve, Youden index, and logistic regression.ResultsA total of 138 patients were allocated to the low T3 group. FT3 inversely correlated with the Sequential Organ Failure Assessment (SOFA) score within 24 h, fluid resuscitation volume within 24 h, and lactic acid levels, and positively correlated with the mean arterial pressure. The critical values of age, SOFA, and MDN for predicting the 28-day mortality were 79.5 years, 8.5 points, and 0.61 µg/kg/min, respectively. The mortality of the low T3 and normal T3 groups was similar. Considering the MDN of 0.61 µg/kg/min as the cutoff value, the mortality between the two groups was significantly different.ConclusionAmong patients with sepsis and septic shock, FT3 was inversely correlated with the disease severity. An MDN ≥ 0.61 µg/kg/min within 72 h may be an important prognostic indicator.

Abstract 10993: Prognostic Value of Low T 3 Syndrome in Patients with Acute Decompensated Heart Failure in Osaka Prefectural Acute Heart Failure Registry (OPAR)

Backgrounds: It is widely recognized that thyroid dysfunction is a potential cause of heart failure (HF). In HF, one of the alterations of thyroid functions is referred to as low T 3 syndrome marked by a reduction in serum free triiodothyronine (T 3 ) with normal levels of thyroid-stimulating hormone (TSH). However, there is little information available about the association between low T 3 syndrome and future cardiac events in patients with acute decompensated heart failure (ADHF), relating to left ventricular ejection fraction (LVEF). Methods and Results: We studied 565 patients admitted for ADHF with survival discharge in our prospective cohort study. Laboratory data including free T 3 , thyroxine and TSH were obtained at discharge. Among the patients with euthyroid (0.35 μU/mL &lt;TSH &lt;4.94 μU/mL, n=438), there was 62 patients who were diagnoses as low T 3 syndrome (free T 3 ≦1.68 pg/mL). The primary end point of this study was all-cause death (ACD). During a mean follow up period of 2.9±1.4 years, 121 patients died. Study subjects were stratified into two LVEF subgroup as follows; 239 patients had LVEF&lt;50% (HFrEF), and 199 patients had LVEF≧50% (HFpEF). While 68 HFrEF parients died, 53 HFpEF patients died. Kaplan-Meier curve analysis revealed that patients with the low free T 3 group had the greater risk of ACD than those with the normal free T 3 group in both LVEF subgroup (log-rank p=0.0233 in HFrEF and p=0.0265 in HFpEF). Multivariate Cox analysis showed that free T 3 was significantly associated with ACD after multivariable adjustment for major confounders, such as age, sex, systolic blood pressure and plasma brain natriuretic peptide level in both LVEF subgroup (p=0.0039 in HFrEF, p=0.0487 in HFpEF). Conclusion: Low T 3 syndrome was significantly associated with poor outcome in ADHF patients with both HFrEF and HFpEF.

P1488RECOVERY OF LOW TRIIODOTHYRONINE CAN IMPROVE MORTALITY IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Low circulating triiodothyronine (T3) levels are the most frequently encountered thyroid functional test derangement in end-stage renal disease (ESRD) patients on hemodialysis. Low T3 is known as independent predictive value for all-cause mortality and, particularly, for cardiovascular-related death in patients with ESRD on hemodialysis. This study investigated that recovery of low T3 level to normal can lower mortality in ESRD patients on hemodialysis. Method We have constructed the 500 K-cohort of ESRD patients attending the hemodialysis center of 6 tertiary hospitals of South Korea to evaluate the mortality of the ESRD patients since 2016. From this prospective cohort, we invited patients with ESRD from June 2016 to May 2019 The participants were divided into four groups based on the change of the T3 level: normal group showed the normal T3 continuously, low group showed the low T3 continuously, recovery group showed the low T3 change to normal and decrease group showed the normal T3 change to low. We evaluate relationships between change of the T3 level and mortality. Statistical analysis was carried out by using SPSS. Results Of the total 500 patients in K-cohort, 333 patients were enrolled with detailed thyroid hormone profile including T3 level. 167 (50.2 %) patients out of the 333 patients showed low T3 level initially. Normal group include 126 patients(37.8%), low group include 135 patients(40.5%), recovery group include 32 patients(9.6%) and decrease group include 40 patients(12.0%). Patients with the low T3 level were older and more diabetic compare to those with normal T3 level. They had lower K-MMSE score than the others, Low T3 group had lower free T4 level but thyroid stimulating hormone(TSH) showed no significant different comparing normal T3 group. The mortality of normal group was lowest and that of decrease group was highest. The mortality of recovery group recovered to similar with that of the normal group and mortality of decrease group was highest. Lowering of T3 level would affect to mortality than low T3 level continuously. Conclusion Therefore, the change of T3 level is significantly associated with the mortality. Recover lower T3 to normal level can lower the mortality.

A prognostic role for non-thyroidal illness syndrome in chronic renal failure:a systematic review and meta-analysis.

Chronic renal failure (CRF) is a serious disease that has become a burden on global and local economics and public health. In addition, non-thyroidal illness syndrome (NTIS) has become increasingly more prevalent in CRF patients. A data search was conducted on the PubMed/Medline, Cochrane Library, Web of Science, Embase, and CBM databases to identify studies up to November 1st, 2018, that compared low T3 and normal T3 levels in patients with CRF. Data analysis was done by calculating the relative risks (RR) and 95% confidence intervals (95% CI) and continuous variables were described by weighted mean difference (WMD) and 95% CI. The efficacy outcomes included renal function and mortality. The Newcastle-Ottawa Scale and Agency for Healthcare Research and Quality scale were used to assess the quality of the cohort and cross-sectional studies, respectively. A funnel plot was used to identify publication bias. Seventeen studies with a total of 4593 patients were finally included in the analysis. Among the 17 studies, 11 reported the mortality of CRF patients with low T3 and normal T3 levels. Subgroups were assigned according to different follow-up times and different methods of treatment. The mortality rate in the low T3 group was much higher than in the normal T3 group. 11 studies reported creatinine (Cr) results in patients with low T3 and normal T3 levels and our analysis found no significant differences between the two groups (95%CI: 0.46-0.25; P-heterogeneity = 0.000; P = 0.559). Five studies reported uric acid results and we found no significant differences between the two groups (95%CI: 0.08-0.22; P-heterogeneity = 0.438; P = 0.377). Five studies reported the urea levels in the two groups and our analysis found no significant differences (95%CI: 1.60-1.23; I2 = 0.0%; P-heterogeneity = 0.498;P = 0.798). Low T3 had a greater impact on the short-term prognosis of patients with CRF than on the long-term prognosis. NTIS did not cause substantial kidney damage.

Impact of low T3 syndrome on adverse cardiovascular events in adult patients with acute viral myocarditis

Objective: To determine the impact of low T3 syndrome on adverse cardiovascular events in adult patients with acute viral myocarditis. Methods: The study population consisted of 134 consecutive patients admitted between January 2002 and March 2018 with diagnoses of acute viral myocarditis (onset of symptoms<1 month,patients were divided into low serum free triiodothyronine (FT3, n=20) group and normal FT3 (n=114) group. General information, clinical presentation,electrocardiography at admission,laboratory tests,echocardiography features were analyzed. Low T3 syndrome was defined as a state with decreased FT3 and total triiodothyronine (TT3), normal or decreased free thyroxine (FT4) and total thyroxine (TT4) as well as normal thyroid stimulating hormone (TSH). Composite adverse cardiovascular events included death, persistent ventricular tachycardia (VT) or ventricular fibrillation (VF) and cardiac arrest. Risk factors related with composite adverse cardiovascular events in adult patients with acute viral myocarditis were analyzed by logistic regression analysis. Results: Systolic blood pressure was significantly lower (P<0.01),while heart rate (P=0.004) and the prevalence of VT/VF were significantly higher (P=0.017) in low T3 group than in the normal T3 group. Level of white blood cell,C response protein,fasting glucose (all P<0.01) as well as creatinine (P=0.035) were significantly higher, while level of FT3 and left ventricular ejection fraction (LVEF) were significantly lower (both P<0.01) in low T3 group than in normal T3 group. Multivariate logistic regression analysis revealed that LVEF at admission less than 40% (OR=6.615,95%CI 1.186-36.907, P=0.031) and FT3 level less than 1.79 ng/L (OR=9.131, 95%CI 1.577-52.857, P=0.014) were independent risk factors of increased composite adverse cardiovascular events in patients with acute viral myocarditis. Conclusion: Low FT3 increases the risk of adverse cardiovascular events in adult patients with acute viral myocarditis.

The correlation of metabolic syndrome with low triiodothyronine syndrome, subclinical hypothyroidism and hyperhomocysteinemia in the elderly

Objective To explore the correlation of metabolic syndrome(MS)with low triiodothyronine(T3)syndrome(LT3S, or It is known as ESS: euthyroid sick syndrome), subclinical hypothyroidism(SCH)and a high serum total homocysteine(tHcy)level(hyperhomocysteinemia)in elderly patients. Methods We retrospectively analyzed thyroid function, serum glucose, lipids and homocysteine(Hcy)level in 83 MS patients(MS group), 30 patients with low T3 syndrome(low T3 group), 41 patients with SCH(SCH group)and 80 healthy individuals(control group)aged over 60 years from January 2015 to March 2017 in outpatient and inpatient departments of our hospital.The correlations of thyroid function and serum Hcy level with MS components were analyzed by multiple Logistic regression model. Results The incidence of low T3 syndrome and SCH in MS patients was 37.3%(31/83)and 49.4%(41/83), respectively.Low T3 group versus control group showed the lower levels in free triiodothyronine, FT4, folic acid, and Hcy, with statistically significant differences(all P 5.5 mU/L had decreased FT3 which occurred later than the rise of TSH(P<0.05). Univariate correlation analysis showed that FT3 was negatively correlated with Hcy(P<0.01), and TSH was negatively correlated with high-density lipoprotein cholesterol(P<0.01). Multivariate linear regression analysis found linear correlations of TSH with triglyceride, high-density lipoprotein cholesterol, and Hcy(all P<0.05). Logistic regression analysis showed that FT3, Hcy and TSH are highly associated with hypertension after adjustment for gender and body mass index(all P<0.05). Decreased FT3(P<0.01), elevated Hcy(P<0.05), and increased TSH(P<0.05)were independent risk factors for MS in elderly patients. Conclusions The incidences of low T3 syndrome and SCH are increased with aging.FT3, TSH, and Hcy are independent risk factors for MS in the elderly. Key words: Metabolic syndrome X; Low T3 syndrome; Hypothyroidism; Homocysteine

Abstract P174: Free Triiodothyronine Level Correlates with Statin Responsiveness in Acute Myocardial Infarction

Background: Although thyroid hormone (TH) has important effects on lipid metabolism, the relationship between TH and statin responsiveness has never been investigated. We hypothesized that TH plays an important role in statin responsiveness in AMI patients. Methods: Consecutive 1091 hospitalized AMI patients in Fuwai hospital were enrolled. The study population was divided into three groups based on the intensity of statin treatment: low (n=221), moderate (n=712) and high (n=158). Lipid levels were measured after statin therapy lasting for 10-14 days. We explored the association between TH, lipid levels and achievement of low density lipoprotein cholesterol (LDL-C) lowering goals in patients with acute myocardial infarction (AMI) on statin therapy. Results: By general linear analysis, a significant linear trend between FT3 and LDL-C level (linear coefficient=-0.082, P =0.001) and FT3 and total cholesterol (TC) level (linear coefficient=-0.105, P =0.031) was observed in the moderate-intensity statin group. A more apparent linear trend was detected in the high-intensity statin group (for LDL-C: linear coefficient=-0.113, P =0.005; for TC: linear coefficient=-0.172, P=0.029, respectively). However, no significant correlation was observed in the low-intensity statin group. Compared with the low-T3 group (defined as FT3&lt;1.79 pg/ml), the OR (95% CI) for attaining a LDL-C&lt;3.0mmol/L was found to be 2.217 (1.001-4.839) in the higher FT3 group (&gt;2.95 pg/ml).The OR for attaining the more intensive goal (LDL-C&lt;1.8mmol/L) (95% CI) was 2.836 (1.014-5.182). Conclusions: Variation in FT3 levels is related to the lipid-lowering responsiveness of statins in AMI patients.

Relation of Low T3 to One-Year Mortality in Non-ST-Elevation Acute Coronary Syndrome Patients.

Low T3 which is defined as decreased triiodothyronine (T3) and normal thyroid-stimulating hormone (TSH) and thyroxin (T4) levels is present in many acute diseases and is related to increased mortality. We studied low T3 level's relation to long-term mortality in non-ST-elevation acute coronary syndrome (NSTE-ACS) patients. T3, T4, and TSH levels of consecutive NSTE-ACS patients were measured. Patients with normal T4 and TSH levels, but low T3 level were defined as low T3 group. Patients with normal T3, T4, and TSH levels were defined as normal group. Clinical and laboratory findings in these two groups were compared. In addition, we examined low T3 level's relation to early and long-term mortality. Mean patient age was 61 ± 13 (67% male) and 31 (11%) patients had low T3 level. Free T3 values were negatively correlated with age, serum creatinine, and brain type natriuretic peptide values at the time of admission (r = -0.452, P < 0.0001; r = -0.255, P < 0.0001; r = -0.544, P < 0.0001, respectively). Mortality at 1 month and 1 year was higher in low T3 group (3% vs. 16%, P = 0.002; 6.4% vs. 23%, P = 0.003, respectively). In multivariate analysis, low T3 was found to be related to mortality at 1 year (OR: 2.6, 95% CI: 1.1-6.5, P = 0.02). In ROC analysis, free T3 had a good area under the curve (AUC) value for mortality at 1 year [AUC: 0.709 (95% CI: 0.619-0.799, SE: 0.0459)]. Low T3 is related to increased early and late mortality in NSTE-ACS patients. Free T3 levels may be used to identify NSTE-ACS patients with high mortality risk.

Low T3 State Is Correlated with Cardiac Mitochondrial Impairments after Ischemia Reperfusion Injury: Evidence from a Proteomic Approach.

Mitochondria are major determinants of cell fate in ischemia/reperfusion injury (IR) and common effectors of cardio-protective strategies in cardiac ischemic disease. Thyroid hormone homeostasis critically affects mitochondrial function and energy production. Since a low T3 state (LT3S) is frequently observed in the post infarction setting, the study was aimed to investigate the relationship between 72 h post IR T3 levels and both the cardiac function and the mitochondrial proteome in a rat model of IR. The low T3 group exhibits the most compromised cardiac performance along with the worst mitochondrial activity. Accordingly, our results show a different remodeling of the mitochondrial proteome in the presence or absence of a LT3S, with alterations in groups of proteins that play a key role in energy metabolism, quality control and regulation of cell death pathways. Overall, our findings highlight a relationship between LT3S in the early post IR and poor cardiac and mitochondrial outcomes, and suggest a potential implication of thyroid hormone in the cardio-protection and tissue remodeling in ischemic disease.

Prediction of infarct severity from triiodothyronine levels in patients with ST-elevation myocardial infarction.

Background/AimsThe aim of the present study was to evaluate the relationship between thyroid hormone levels and infarct severity in patients with ST-elevation myocardial infarction (STEMI).Methods We retrospectively reviewed thyroid hormone levels, infarct severity, and the extent of transmurality in 40 STEMI patients evaluated via contrast-enhanced cardiac magnetic resonance imaging.ResultsThe high triiodothyronine (T3) group (≥ 68.3 ng/dL) exhibited a significantly higher extent of transmural involvement (late transmural enhancement > 75% after administration of gadolinium contrast agent) than did the low T3 group (60% vs. 15%; p = 0.003). However, no significant difference was evident between the high- and low-thyroid-stimulating hormone/free thyroxine (FT4) groups. When the T3 cutoff level was set to 68.3 ng/dL using a receiver operating characteristic curve, the sensitivity was 80% and the specificity 68% in terms of differentiating between those with and without transmural involvement. Upon logistic regression analysis, high T3 level was an independent predictor of transmural involvement after adjustment for the presence of diabetes mellitus (DM) and the use of glycoprotein IIb/IIIa inhibitors (odds ratio, 40.62; 95% confidence interval, 3.29 to 502; p = 0.004).ConclusionsThe T3 level predicted transmural involvement that was independent of glycoprotein IIb/IIIa inhibitor use and DM positivity.

Serum T3 Level Can Predict Cardiovascular Events and All-Cause Mortality Rates in CKD Patients with Proteinuria

Background: Patients with proteinuria frequently show changes in thyroid hormone levels. Serum T3 depression predicts a negative outcome in chronic kidney disease (CKD) patients and may be associated with cardiovascular complications or chronic inflammation. Few studies have explored the relationship between thyroid hormone dysregulation and clinical outcome in patients with proteinuria. Methods: We reviewed thyroid function test results obtained from 211 patients with 24 h urinary protein excretion greater than 150 mg/day and found a correlation of thyroid hormone level with cardiovascular events and mortality. Results: T3 decreased with age (p = 0.001) and 24 h urine albumin (p = 0.028). Free T4 decreased in accordance with 24 h urine protein and serum creatinine (p = 0.034 and p = 0.033, respectively). In the Kaplan–Meier survival analysis, lower cumulative survival, higher cardiovascular events, and mortality were found in the low T3 group compared with the normal T3 group (p = 0.000, p = 0.013, and p = 0.001, respectively). In Cox regression analysis, we observed that, with low T3, decreased sodium, and old age, the incidence of cardiovascular complications (p = 0.000, p = 0.016, and p = 0.000, respectively), cardiovascular mortality (p = 0.000, p = 0.048, and p = 0.001, respectively), and all-cause mortality (p = 0.000, p = 0.017, and p = 0.000, respectively) increased. Conclusion: In CKD patients with proteinuria, low T3 concentration predicted all-cause mortality and cardiovascular event independently of the severity of proteinuria.

Factors Influencing Peripheral Conversion of Thyroxine to Tri-Iodothyronine in Athyreotic Individuals during Levothyroxine Replacement

Background: Tri-iodothyronine (T3) is the main active hormone, and 20% of this is derived from the thyroid gland and 80% is from the peripheral tissue according to 5'-monodeiodination of thyroxine (T4). In the previous studies, normal T3 levels were achieved with traditional levothyroxine (LT4) therapy alone in athyreotic patients, but there has been no data about the factors influencing peripheral conversion of LT4. The aim of this study was to determine the factor(s) influencing peripheral conversion of LT4 to T3 in athyreotic patients during LT4 replacement. Methods: The patients who underwent total-thyroidectomy for any cause, and mostly for thyroid cancers, at Asan Medical Center between 2000 and 2008 were enrolled. The free T4, T3 and thyroid stimulating hormone (TSH) levels and age, gender, weight, height, body mass index (BMI) and the T4 dose were measured. Only patients with normal ranges of free T4 and TSH were included in the analysis. Results: A total of 143 patients were enrolled. The mean T3, free T4 and TSH levels were 143.7 ng/dL, 1.4 ng/dL and 1.6 /mL, respectively. The mean weight and BMI were 62.9 kg and 24.6 kg/, respectively. We divided them into two groups according to the serum T3 level and we compared the characteristics of the groups. There were no differences in age, the gender distribution, the T4 dose/weight and the BMI between the low T3 group (T3 122 ng/dL, n = 14) and the normal T3 group (T3 > 122 ng/dL, n = 129). In the low T3 group, the mean body weight was significantly lower than that of the normal T3 group ( vs. , respectively, P = 0.025). Conclusion: Lean body mass seems to be an important factor for determining the peripheral conversion of T4 to T3 in human. This suggest that a combination of T3/T4 is better than T4 only when we treat the patients with hypothyroidism and who have a negligible amount of functioning thyroid tissue, if they have a low lean body mass.

Clinical Analysis on Alteration of Thyroid Hormones in the Serum of Patients with Acute Ischemic Stroke

Low T3 has been associated with increased short-term mortality in intensive care unit and long-term mortality in cardiovascular disease. The objective of this retrospective study is to investigate associations of thyroid hormone status with clinical severity and outcome in acute ischemic stroke, and whether there is association between the pituitary axis abnormality and the anterior/posterior circulation involvement. Patients with no history of thyroid abnormality who presented first ever stroke were studied. Total T3, T4, TSH levels, basic and clinical characteristics were collected and categorized. Neurological impairment was assessed using NIHSS and modified Rankin Scale. Twenty-nine patients (61%) had T3 ≤ 75 ng/dL. Low T3 group had significant higher NIHSS compared to normal T3 group. There was a significant negative correlation between T3 levels and NIHSS scores on admission. A significantly smaller percentage of patients with low T3 showed favorable neurological function improvement by both NIHSS and mRS measures compared to those with normal T3. There was no significant difference for anterior or posterior circulation involvement between low T3 and normal T3 groups. It is suggested that low T3 is associated with worse neurological outcome. The severity of low T3 may be a predictor of functional improvement in acute ischemic stroke.

Relationship between low T3 syndrome and NT-proBNP levels in non-cardiac patients

Objectives — A low T3syndrome was described in patients with heart failure (HF), and it appears to be associated with adverse outcome, representing an independent predictor of mortality. However, it is not known if low T3 levels contribute to the pathophysiology of HF. On the other hand, it has been seen that an elevation of brain natriuretic peptides (BNP and NT-proBNP) may represent a warning signal for future cardiovascular disease and may be an early marker of diastolic dysfunction. Therefore we tested the hypothesis that low levels of free-triiodothyronine (FT3) are sufficient to determine an increased concentration of the amino-terminal fragment of pro-brain natriuretic peptide (NT-proBNP), as the result of an initial and asymptomatic cardiac impairment.Methods — A total of 52 consecutive non-cardiac patients underwent thyroid function profile evaluation and NT-proBNP determination. On the basis of FT3 values they were divided in two subgroups: a low T3group (19patients) and a normal T3group (33patients).Results — The median NT-proBNP concentration of patients with low T3syndrome was significantly higher than in those with normal FT3 (370 vs. 120 pg/ml, P=0.002). There is a strong and inverse correlation between FT3 and Log NT-proBNP (R = –0.47, P < 0.001); this relation persists in a multivariable regression analysis, after adjustment for other potentially confounding variables (P=0.008).Conclusion — In absence of overt cardiovascular disease, patients with low T3syndrome present an increased concentration of NT-proBNP. These data suggest that low FT3 levels may be a contributing factor for the development of cardiac dysfunction.

The effect of serum free fatty acid on serum free thyroid hormone fractions in low T3 syndrome

We studied the role of serum free fatty acid (FFA) in the elevation of serum dializable fraction of T4 (DFT4) and evaluated the serum free T4 (FT4) level in low T3 syndrome. Serum DFT4 and DFT3 were measured by equilibrium dialysis method with phosphate buffer, and serum FFA concentration was obtained by gas chromatography. In patients with nonthyroidal systemic illnesses who showed reduced serum total T3 (TT3) and normal total T4 (TT4) (low T3 group, TT3 48 +/- 14 ng/dl, n = 10), mean (+/- SD) DFT4 value (0.032 +/- 0.05%) was significantly higher than that of the group of systemic illnesses with normal TT3 and TT4 (normal T3 group, TT3 79 +/- 7 ng/dl, n = 10). Mean TT4 value of low T3 group (6.5 +/- 1.0 micrograms/dl) was lower than that of normal T3 group (8.6 +/- 2.4 microgram/dl, p less than 0.02). There was no difference in mean absolute FT4 (AFT4) value between the two groups (2.07 +/- 0.46 vs 2.19 +/- 0.53 ng/dl). On the other hand, there was no significant difference in DFT3 value between the groups (0.274 +/- 0.043 vs 0.247 +/- 0.035%), and mean AFT3 of low T3 group (1.29 +/- 0.39 pg/ml) was low than that of normal T3 group (1.92 +/- 0.26 pg/ml, p less than 0.01). In cases of low and normal T3 groups (n = 20), serum thyroxine binding globulin (TBG) concentration had a negative correlation with DFT3 (r = -0.707, p less than 0.001), but not with DFT4. Although there were no significant differences in serum albumin and TBG concentrations between the two groups, the mean serum total FFA concentration and molar ratio of FFA to albumin in low T3 group (579 +/- 249 microM and 1.31 +/- 0.61) were significantly higher than those in normal T3 group (345 +/- 170 microM and 0.75 +/- 0.32, p less than 0.05 and less than 0.025, respectively). All of FFA concentrations in low T3 group, especially oleate, were higher than those in normal T3 group. Moreover, the higher the total FFA concentration was, the greater was the percent fraction of oleate. DFT4 values were significantly increased by the addition of 1 mM oleate to the sera of low T3 group, and this effect was more marked in the sera of the patients with lower albumin concentration.(ABSTRACT TRUNCATED AT 400 WORDS)