Prognostic significance of high free T4 and low free T3 levels in non-thyroidal illness syndrome

FT4-to-FT3 ratio is a novel prognostic marker in subacute combined spinal cord degeneration patients

Objectives

The FT4-to-FT3 ratio (FFR) variations in patients with subacute combined spinal cord degeneration (SCSD) as a potentially useful prognostic indicator are still unknown. This study aimed to investigate the changes of FFR as a potentially valuable prognostic predictor in patients with SCSD.

Methods

This study included 144 consecutive SCSD patients who received standard diagnostic and therapeutic procedures between January 2015 and December 2021 and were admitted to the Department of Neurology at the First Affiliated Hospital of Bengbu Medical University. At the time of admission, we gathered data on all patients' demographics, daily routines, previous chronic conditions, medication histories, and other clinical details. For the purpose of measuring FFR, blood samples were specifically taken within 48 h of admission. The degree of neurological impairment of patients was assessed using the functional disability scale at the time of admission. At 6 months following discharge, the Modified Rankin Scale (mRS) was used to evaluate the clinical prognosis. To evaluate the relationship between the FFR and the risks of a poor outcome (mRS > 2), univariate and multivariate logistic regression analysis was utilized. The significance of the FT4/FT3 ratio in predicting the clinical outcomes in SCSD patients 6 months after discharge was assessed using the area under curve-receiver operating characteristic (AUC-ROC).

Results

About 90 patients (62.5%) of the 144 patients had poor outcomes, while 54 (37.5%) had favorable outcomes. Higher FFR at admission was independently linked to higher odds of a poor outcome, according to a logistic analysis. With an optimized cutoff value of >2.843, the FFR exhibited the maximum accuracy for predicting a poor outcome, according to the AUC‒ROC curve (AUC 0.731, P < 0.001; sensitivity, 77.8%; specificity, 83.3%). FFR was identified as an independent predictor of poor outcomes by multivariate logistic regression (OR, 2.244; 95% CI, 1.74-2.90; P < 0.001).

Conclusions

We discovered that in patients who had a bad result 6 months after discharge, the FFR had dramatically increased at the time of admission, providing a unique prognostic marker in patients with SCSD.

J-shaped association of free triiodothyronine to free thyroxine ratio with 5-year mortality among patients with chronic kidney disease: a prospective cohort study

PURPOSE

To investigate the association of free triiodothyronine to free thyroxine (FT3/FT4) ratio with 5-year mortality in patients with chronic kidney disease (CKD) using data from the National Health and Nutrition Examination Survey (NHANES) through 2001-2002 and 2007-2012.

METHODS

Two thousand four hundred twenty-four patients with CKD stage 1-5 were included. Patients' baseline characteristics were collected. Cox proportional hazards models were used to investigate the association of FT3/FT4 ratio with 5-year all-cause and cardiovascular mortality. Subgroup analysis was performed.

RESULTS

Within 5 years of follow-up duration, 425 (17.53%) deaths were recorded, and 154 patients died from cardiovascular disease. A J-shaped association between FT3/FT4 ratio and 5-year mortality was observed. After fully adjustment, the elevated FT3/FT4 ratio was significantly associated with a decreased 5-year all-cause mortality risk (HR: 0.79, 95% CI 0.63-0.99) among patients with CKD stage 1-5 when FT3/FT4 ratio < 4.71, and is significantly associated with an increased 5-year all-cause mortality risk in CKD patients with advanced CKD stages or low UACR when FT3/FT4 ratio ≥ 4.71 (HR: 2.74, 95% CI 1.20-6.29; HR: 3.09, 95% CI 1.12-8.57, respectively). The elevated FT3/FT4 ratio also showed a J-shaped association with the 5-year cardiovascular mortality which disappears after fully adjustment.

CONCLUSION

The FT3/FT4 ratio is closely associated with 5-year mortality risk among patients with CKD, indicating a potential role of FT3/FT4 ratio as a biomarker for mortality prediction in CKD patients.

The prevalence, hospitalization outcomes and risk factors of euthyroid sick syndrome in patients with diabetic ketosis/ketoacidosis

BACKGROUND

To investigate the prevalence of euthyroid sick syndrome (ESS) and to evaluate the outcomes and risk factors associated with ESS among hospitalized patients with diabetic ketosis (DK) or diabetic ketoacidosis (DKA).

METHODS

Laboratory and clinical data of 396 adult hospitalized DK/DKA patients with or without ESS were collected and analyzed. Spearman linear analysis and multivariable logistic regression analyses were used to evaluate correlated factors of thyroid hormones and risk factors of ESS.

RESULTS

Most of the individuals were diagnosed with type 2 diabetes (359/396, 90.7%). The prevalence of ESS was 57.8% (229/396). Patients in ESS group were older and had a longer course of diabetes. Levels of thyroid hormones, serum lipids, and parameters reflecting acidosis were significantly decreased in ESS group. The proportion of patients with infection, acute renal injury and DKA was significantly higher in ESS group than in control group, accompanied by longer hospitalization stay and higher hospitalization costs. Free triiodothyronine positively correlates with albumin, eGFR, parameters reflecting acidosis and lipid profiles (All P < 0.001), and negatively correlates with age, onset age, 24-h urine albumin, hsCRP and WBC count (All P < 0.001). Hypoalbuminemia, low level of carbon dioxide combining power, high level of HbA1c and WBC, and co-infection are shown to be risk factors for ESS (OR = 0.866, 0.933, 1.112, 1.146, 1.929, respectively; All P < 0.05).

CONCLUSIONS

The prevalence of ESS was high in adult DK/DKA patients. Patients with ESS had inferior clinical and socioeconomic outcomes. Early recognition and management of patients with ESS may be necessary to improve outcome.

Analysis of clinical features and 7-year all-cause mortality in older male patients with non-thyroidal illness syndrome on general wards

PURPOSE

Older patients with non-thyroidal illness syndrome (NTIS) have a poor prognosis. However, there are few studies on the association of NTIS and mortality among older inpatients on general wards. In a 7-year retrospective observational study, we aimed to investigate the clinical features of NTIS and the association of NTIS and all-cause mortality in older inpatients.

METHODS

A total of 959 older male inpatients whose average age was 86.3 ± 8.1 years were enrolled and divided into the NTIS group and non-NTIS group. Cox models were performed to explore the association of thyroid hormone level and mortality.

RESULTS

Patients had more respiratory disease and chronic kidney disease in the NTIS than in the non-NTIS group, especially in primary nursing care, respiratory failure and haemodialysis patients; serum total protein, albumin, prealbumin, haemoglobin, uric acid and high-density lipoprotein cholesterol levels were lower, and urea nitrogen and fasting blood glucose levels were higher, in the NTIS than in the non-NTIS group. Patients in the NTIS group had a lower survival rate over 7 years follow-up (P < 0.01). A lower free T₃ level was associated with all-cause mortality with a HR of 1.50 (1.36, 1.66). Lower free T₄ level was associated with reduced all-cause mortality with a HR of 0.91 (0.88, 0.94) even after adjusting for confounding factors (P < 0.01).

CONCLUSIONS

Among older male inpatients, the survival rate was lower in the NTIS group. A reduced free T₃ level with low albumin and Hb levels was associated with all-cause mortality; moreover, a higher free T₄ in the normal range may be a strong predictor for long-term mortality risk in hospitalised older male patients.

Effect of the Marine Exercise Retreat Program on Thyroid-Related Hormones in Middle-Aged Euthyroid Women

This study aimed to investigate the effects of a marine exercise retreat program on thyroid-related hormone levels. A total of 62 middle-aged euthyroid women participated in a 6-day marine exercise retreat program. Using thyroid-stimulating hormone (TSH) and free thyroxine (fT4) hormone levels, the participants were divided into high and low-hormone-level groups. Despite decreased TSH and fT4 levels after the program, the factors influencing changes in each group were different. TSH levels were influenced by changes in the normalized low frequency (nLF) of heart rate variability and carbon monoxide (CO) from all the participants, and changes in body fat percentage, nLF, and nitrogen dioxide (NO2) exposure level in the high TSH group. fT4 levels were influenced by changes in body mass index (BMI), NO2 exposure, and particulate matter diameter of 10 µm or less (PM10) exposure in all participants. Changes in BMI and CO exposure influenced the low fT4 group. Lastly, changes in the exercise stress test affected the high fT4 group. Thus, the marine exercise retreat program affected euthyroid thyroid-related hormone levels, and influencing factors differ depending on the initial value of the hormone.

Serum albumin and FT3/FT4 ratio as additional co-morbidity parameters to predict mortality as a new approach: The Haseki Scoring Index (updated Charlson Comorbidity Index)

BACKGROUND

Charlson Comorbidity Index (CCI) is the common and valid method to predict mortality by classifying comorbidities such as cardiovascular, metabolic, renal, hepatic, pulmonary diseases, and malignancy. Novel risk factors are not included in the Charlson Comorbidity Index, such as thyroid hormone index (FT3/FT4 ratio) and serum albumin levels. In the present study, we aimed to assess whether the thyroid hormone index and albumin are useful clinical parameters in short and long-term mortality.

METHODS

In the retrospective cohort study with a 5 year follow up, the data of 1292 patients who were hospitalized between January 1st-June 30th of 2014 were examined. Three months mortality as short term and 5-year mortality as long term were evaluated.

RESULTS

Three months and 5 years mortality rates for 1064 patients were analyzed. We showed that hypoalbuminemia and thyroid hormone index had statistically significant effects on short and long-term mortality. According to ROC analysis it was demonstrated that the scoring system including biochemical parameters such as thyroid hormone index and serum albumin level was more significant for 3-month mortality. In addition, both scoring systems are equal in demonstrating long-term mortality.

CONCLUSION

Thyroid hormone index and albumin could improve the prognostic performance of the original Charlson Comorbidity Index in short term mortality. The combined score may offer improvements in comorbidity summarization over existing scores.

Possible Contributions of Nongenomic Actions of Thyroid Hormones to the Vasculopathic Complex of COVID-19 Infection

BACKGROUND

Integrin αvβ3 is a cell membrane structural protein whose extracellular domain contains a receptor for L-thyroxine (T4). The integrin is expressed in rapidly dividing cells and its internalization is prompted by T4. The protein binds viruses and we have raised the possibility elsewhere that action of free T4 (FT4)-when he latter is increased in the nonthyroidal illness syndrome (NTIS) known to complicate COVID-19 infecction-may enhance cellular uptke of SARS-CoV-2 and its receptor.

OBJECTIVE

Because T4 also acts nongenomically via the integrin to promote platelet aggregation and angiogenesis, we suggest here that T4 may contribute to the coagulopathy and endothelial abnormalities that can develop in COVID-19 infections, particularly when the lung is primary affected.

DISCUSSION AND CONCLUSIONS

Elevated FT4 has been described in the NTIS of COVID-19 patients and may be associated with increased illness severity, but the finding of FT4 elevation is inconsistent in the NTIS literature. Circulating 3,5',3'-triiodo-L-thyronine (reverse T3, rT3) are frequently elevated in NTIS. Thought to be biologically inactive, rT3in fact stimulates cancer cell proliferation via avb3 and also may increase actin polymerization. We propose here that rT3 in the NTIS complicating systemic COVIF-19 infection may support coagulation and disordered blood vessel formation via actin polymerization.

FT3/FT4 ratio is correlated with all-cause mortality, cardiovascular mortality, and cardiovascular disease risk: NHANES 2007-2012

BACKGROUND

Thyroid hormones play a vital role in maintaining the homeostasis of the cardiovascular system. The FT3/FT4 ratio can be used to evaluate the rate of T4-to-T3 conversion, reflecting the peripheral sensitivity of thyroid hormones. There is no study to investigate its relationship with death and cardiovascular disease (CVD) in the general population.

METHODS

This retrospective cohort study involved 8,018 participants with measured thyroid function and no prior thyroid disease who participated in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2012. Mortality status was determined by routine follow-up using the National Death Index through December 31, 2015.

RESULTS

During a median of 87 months of follow-up, we observed 699 all-cause deaths, including 116 cardiovascular deaths. In multivariate adjusted models, higher free thyroxine (FT4) was linked to increased all-cause mortality (HR, 1.15 per SD; 95% CI, 1.09-1.22), cardiovascular mortality (HR, 1.18 per SD; 95% CI, 1.01-1.39), and CVD risk (HR, 1.17 per SD; 95% CI, 1.08-1.27). Higher free triiodothyronine (FT3) was linked to decreased all-cause mortality (HR 0.81 per SD; 95% CI, 0.70-0.93). Higher FT3/FT4 ratio was linked to decreased all-cause mortality (HR, 0.77 per SD; 95% CI, 0.69-0.85), cardiovascular mortality (HR, 0.79 per SD; 95% CI, 0.62-1.00), and CVD risk (HR, 0.82 per SD; 95% CI, 0.74-0.92). The FT3/FT4 ratio stratified findings were broadly consistent with the overall results.

CONCLUSIONS

FT3, FT4, and the FT3/FT4 ratio were all independent predictors of all-cause death. FT4 and the FT3/FT4 ratio, but not FT3, were independent predictors of cardiovascular mortality and CVD risk. Along with FT3 and FT4, we should pay equal attention to the FT3/FT4 ratio in the general population.

The serum free triiodothyronine to free thyroxine ratio as a potential prognostic biomarker of chronic kidney disease in patients with glomerular crescents: A retrospective study

BACKGROUND

Crescent formation indicates severe glomerular pathology, and hypothyroidism usually predicts poor prognosis for severe diseases. However, the relationship between thyroid function and the progression of chronic kidney disease (CKD) is unclear. This study analysed the prognostic predictive value of the serum free triiodothyronine (FT3) to free thyroxine (FT4) ratio and its correlation with renal function in patients with CKD with crescent formation.

METHODS

This single-centre study included 162 CKD patients with glomerular crescents confirmed by renal pathology between March 2012 and December 2014. According to the first tertile (0.284) of FT3/FT4 ratio, the patients were divided into high and low FT3/FT4 ratio groups. Kaplan-Meier and Cox regression analyses were performed to evaluate the prognostic value of the FT3/FT4 ratio.

RESULTS

The age, haemoglobin, eGFR, urinary albumin-to-creatinine ratio, cardiac troponin T, N-terminal brain natriuretic peptide precursor, FT3, FT4, percentage of total crescents in non-globally sclerotic glomeruli, prevalences of hypertension, moderate to severe renal tubulopathy and crescentic nephritis, and proportion of patients receiving glucocorticoids and immunosuppressants were significantly different between high and low FT3/FT4 ratio groups (P < 0.05). Multivariate Cox regression analysis showed that when compared with patients with a high FT3/FT4 ratio (>0.284), those with intermediate and low FT3/FT4 ratios (≤0.284) had an increased risk of the long-term composite endpoint (P < 0.05 for various adjustment models).

CONCLUSIONS

A low FT3/FT4 ratio is associated with increased mortality and worse outcome risk in CKD patients with crescent pathology.

Thyroid Function and Anti-thyroid Antibodies in Pediatric Anti-NMDAR Encephalitis

Objective: Recent studies found that changes of thyroid antibodies (ATAbs), thyroid hormone, and non-thyroidal illness syndrome (NTIS) characterized by thyroid hormone inactivation with low triiodothyronine and high reverse triiodothyronine followed by suppressed thyroid-stimulating hormone (TSH) in adult anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis were associated with disease severity. This study aimed to explore thyroid function and ATAbs in pediatric anti-NMDAR encephalitis and their clinical association. Methods: We retrospectively analyzed the clinical data of 51 pediatric cases with anti-NMDAR encephalitis hospitalized in Guangzhou Women and Children's Medical Center from August 2016 to 2019. Results: A percentage of 52.9% of patients belonged to the ATAb (+) group, with 26 cases both positive for anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TGAb), and one patient only positive for TPOAb. A percentage of 62.7% of patients had at least one abnormality in terms of FT₃, free thyroxin (FT₄), or TSH levels. Meanwhile, 45.1% of patients were diagnosed with NTIS. Among 25 cases retested for thyroid function 2 months after the initial test, the respectively decreased FT₃ and FT₄ in 13 and 11 cases on admission returned to normal or closer normal than before; TPOAb in eight cases and TGAb in 12 cases were changed from positivity to negativity. Compared with onset, the level of TPOAb and TGAb at relapse remained stable or significantly decreased, respectively. Compared with the ATAb (-) group, the ATAb (+) group had an older onset age, a higher ratio of movement disorders, elevated rate of sleep disorders, increased anti-nuclear antibody positivity rate, and higher ratio of more than one course of intravenous immunoglobulin treatment. There were no significant differences between the NTIS and non-NTIS groups in clinical characteristics. Conclusion: Anti-thyroid antibody positivity, abnormality of FT₃, FT₄, or TSH levels and NTIS are frequent in pediatric anti-NMDAR encephalitis. Thyroid antibody and thyroid hormone abnormalities could be improved through the course of treatment of anti-NMDAR encephalitis. Cases with ATAbs (+) are at older onset ages and more likely to be treated by intravenous immunoglobulin therapy more than once. Unlike adult anti-NMDAR encephalitis, NTIS might not be associated with the clinical characteristics of anti-NMDAR encephalitis in pediatric patients.

T3 as predictor of mortality in any cause non-critically ill patients

BACKGROUND

Low T3 syndrome refers to a set of thyroid hormone metabolism alterations present in the disease state. A correlation between low T3 and poor clinical outcomes in the intensive care unit is more established. Nonetheless, studies on non-critically ill patients are few and controversial.

OBJECTIVE

To evaluate the prevalence and predictive value of low T3 levels on 30-day and 6-month mortality in non-critically ill patients. Secondary outcomes evaluated the length of hospital stay, overall mortality, and hospital readmission.

DESIGN

Prospective cohort study.

METHODS

A total of 345 consecutive patients from the Internal Medicine ward of a tertiary hospital in southern Brazil were included and followed from October 2018 to April 2019 (6 months). Levels of total serum T3 were measured weekly, from admission to discharge, and correlated with 30-day and 6-month mortality.

RESULTS

Prevalence of low T3 was 36.6%. Low T3 levels were associated with higher 30-day hospital mortality (15.1% vs 4.1%, P < 0.001) and higher 6-month overall mortality (31.7% vs 13.2%, P < 0.001). Total serum T3 at admission was an independent predictor of 30-day hospital mortality.

CONCLUSION

Low T3 levels are a prevalent condition among non-critically ill patients, and this condition is associated with poor clinical outcomes in this population. Total serum T3 levels, alone or in association with other predictive scores, were demonstrated to be an easy and valuable tool for risk stratification and should be further employed in this setting.

Thyroid hormone alterations in critically and non-critically ill patients with SARS-CoV-2 infection

OBJECTIVE

Following the evolution of COVID-19 pandemic, reports pointed on a high prevalence of thyroiditis-related thyrotoxicosis. Interpretation of thyroid tests during illness, however, is hampered by changes occurring in the context of non-thyroidal illness syndrome (NTIS). In order to elucidate these findings, we studied thyroid function in carefully selected cohorts of COVID-19 positive and negative patients.

DESIGN

Cohort observational study.

METHODS

We measured TSH, FT4, T3 within 24 h of admission in 196 patients without thyroid disease and/or confounding medications. In this study, 102 patients were SARS-CoV-2 positive; 41 admitted in the ICU, 46 in the ward and 15 outpatients. Controls consisted of 94 SARS-CoV-2 negative patients; 39 in the ICU and 55 in the ward. We designated the thyroid hormone patterns as consistent with NTIS, thyrotoxicosis and hypothyroidism.

RESULTS

A NTIS pattern was encountered in 60% of ICU and 36% of ward patients, with similar frequencies between SARS-CoV-2 positive and negative patients (46.0% vs 46.8%, P = NS). A thyrotoxicosis pattern was observed in 14.6% SARS-CoV-2 ICU patients vs 7.7% in ICU negative (P = NS) and, overall in 8.8% of SARS-CoV-2 positive vs 7.4% of negative patients. In these patients, thyroglobulin levels were similar to those with normal thyroid function or NTIS. The hypothyroidism pattern was rare.

CONCLUSIONS

NTIS pattern is common and relates to the severity of disease rather than SARS-CoV-2 infection. A thyrotoxicosis pattern is less frequently observed with similar frequency between patients with and without COVID-19. It is suggested that thyroid hormone monitoring in COVID-19 should not differ from other critically ill patients.

Prognostic significance of low TSH concentration in patients with COVID-19 presenting with non-thyroidal illness syndrome

BACKGROUND

Low free triiodothyronine (FT3) levels are related to a poor prognosis deterioration in patients with COVID-19 presenting with non-thyroidal illness syndrome (NTI). This study was designed to explore whether free thyroxin (FT4) or thyroid stimulating hormone (TSH) levels affected the mortality of patients with COVID-19 presenting with NTI.

METHODS

Patients with COVID-19 complicated with NTI who were treated at our hospital were included in this retrospective study. Patients were divided into low TSH and normal TSH groups, as well as low and normal-high FT4 group, according to the reference range of TSH or FT4 levels. The 90-day mortality and critical illness rates were compared among patients with low and normal TSH levels, as well as among patients with low FT4 levels and normal-high FT4 levels; in addition, differences in demographic and laboratory data were compared. A Kaplan-Meier analysis and Cox proportional hazards models were used to assess the associations of TSH and FT4 levels with mortality.

RESULTS

One hundred fifty patients with low FT3 levels and without a history of thyroid disease were included, 68% of whom had normal FT4 and TSH levels. Critical illness rates (74.07% VS 37.40%, P = 0.001) and mortality rates (51.85% VS 22.76%, P = 0.002) were significantly higher in the low TSH group than in the normal TSH group. Although no significant difference in the critical illness rate was found (P = 0.296), the mortality rate was significantly higher in the low FT4 group (P = 0.038). Low TSH levels were independently related to 90-day mortality (hazard ratio = 2.78, 95% CI:1.42-5.552, P = 0.003).

CONCLUSIONS

Low FT4 and TSH concentrations were associated with mortality in patients with COVID-19 presenting with NTI; moreover, low TSH levels were an independent risk factor for mortality in these patients.

The significance of high thyroxine in hospitalized patients with low thyroid-stimulating hormone

PURPOSE

There is scarce data about the interpretation of high thyroid hormone levels in hospitalized patients. We wished to investigate the significance of high thyroxine (T4) in hospitalized patients with low TSH.

METHODS

We conducted a retrospective study of data from patients in nonsurgical departments. Three groups of random patients with low TSH were defined and compared: 123 patients with only high FT4 levels (T4 group), 82 with high FT3 levels with or without high FT4 level (T3 group), and 119 with low FT3 and FT4 level in the lower half of the norm and below (NTIS group).

RESULTS

The primary cause of admission in the T4 and NTIS groups was infectious disease, 20.3% and 40.3%, respectively; while in the T3 group it was cardiovascular disease (31.7%). The T4 group but not T3 group had epidemiological and clinical characteristics similar to the NTIS group. The T4 group had a significant correlation between increased CRP levels and decreased FT3 (r = 0.366, p < 0.001) similar to the NTIS group. The T3 group had a borderline correlation between increased FT3 and FT4 levels (r = 0.208, p = 0.061) but the T4 group did not.

CONCLUSIONS

The combination of low TSH and high FT4 levels in hospitalized patient is usually caused by nonthyroidal illness combined with drug effects. This thyroid function disturbance is common in hospitalized patients and if the FT3 level is below the middle of the norm, treatment is probably unnecessary.

Changes in thyroid function in patients with liver failure and their clinical significance: A clinical study of non-thyroidal illness syndrome in patients with liver failure

BACKGROUND

Non-thyroidal illness syndrome (NTIS) develops in a large proportion of critically ill patients and is associated with high risk for death. We aimed to investigate the correlation between NTIS and liver failure, and the short-term mortality of patients with these conditions.

METHODS

The clinical data of 87 patients with liver failure were collected retrospectively, 73 of them were randomly selected for an observational study and to establish prognostic models, and 14 for model validation. Another 73 sex- and age-matched patients with mild chronic hepatitis were randomly selected as a control group. Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were measured. The clinical characteristics of patients with liver failure and NTIS were analyzed. The follow-up of patients lasted for 3 months. Additionally, the values for predicting short-term mortality of model for end-stage liver disease (MELD), Child-Turcotte-Pugh (CTP), chronic liver failure-sequential organ failure assessment (CLIF-SOFA) scores, FT3-MELD model, and FT3 were evaluated.

RESULTS

The observation group had significantly lower FT3 (2.79 ± 0.71 vs. 4.43 ± 0.75 pmol/L, P < 0.001) and TSH [0.618 (0.186-1.185) vs. 1.800 (1.570-2.590) mIU/L, P < 0.001], and higher FT4 (19.51 ± 6.26 vs. 14.47 ± 2.19 pmol/L, P <0.001) than the control group. NTIS was diagnosed in 49 of the patients with liver failure (67.12%). In the observation group, patients with NTIS had a higher mortality rate than those without (63.27% vs. 25.00%, P = 0.002). Across the whole cohort, the 3-month mortality was 50.68%. The international normalized ratios (INR) were 2.40 ± 1.41 in survivors and 3.53 ± 1.81 in deaths (P = 0.004), the creatinine (Cr) concentrations were 73.27 ± 36.94 µmol/L and 117.08 ± 87.98 µmol/L (P = 0.008), the FT3 concentrations were 3.13 ± 0.59 pmol/L and 2.47 ± 0.68 pmol/L (P < 0.001), the MELD scores were 22.19 ± 6.64 and 29.57 ± 7.99 (P < 0.001), the CTP scores were 10.67 ± 1.53 and 11.78 ± 1.25 (P = 0.001), and the CLIF-SOFA scores were 8.42 ± 1.68 and 10.16 ± 2.03 (P < 0.001), respectively. FT3 was negatively correlated with MELD score (r = -0.430, P < 0.001). An FT3-MELD model was established by subjecting FT3 concentration and MELD score to logistic regression analysis using the following formula: Logit(P) = -1.337 × FT3+0.114 × MELD+0.880. The area under the receiver operating characteristic (ROC) curve was 0.827 and the optimal cut-off value was 0.4523. The corresponding sensitivity and specificity were 67.6% and 91.7%. The areas under the ROC curve for FT3 concentration, MELD score, CTP score, and CLIF-SOFA score were 0.809, 0.779, 0.699, and 0.737, respectively.

CONCLUSIONS

Patients with liver failure often develop NTIS. FT3-MELD score perform better than CTP and CLIF-SOFA scores in predicting mortality in patients with liver failure. Thus, the FT3-MELD model could be of great value for the evaluation of the short-term mortality of such patients.