The Association Between COVID-19 and Thyroxine Levels: A Meta-Analysis

Low triiodothyronine (T3) levels predict worse outcomes in autoimmune encephalitis-A meta-analysis of current literature

INTRODUCTION

An unusual association between thyroid dysfunction and autoimmune encephalitis (AE) was noticed when patients presented with low free triiodothyronine (fT3) levels and antithyroid antibodies. We conducted a meta-analysis to investigate whether thyroid dysfunction, that is, lower fT3 levels are associated with worsening clinical manifestations and prognosis in patients with AE.

METHODS

Literature search of five electronic databases was performed till April 5, 2023. Inclusion criteria were as follows: Observational studies reporting patients with all subtypes of AE and assessing thyroid dysfunction categorized as low fT3 and non-low fT3. Primary endpoints included modified Rankin scale (mRS) at admission, abnormal magnetic resonance imaging, length of stay, seizures, and consciousness declination.

RESULTS

Comprehensive literature search resulted in 5127 studies. After duplicate removal and full-text screening, six observational studies were included in this analysis. Patients with low fT3 were 2.95 times more likely to experience consciousness declination (p = .0003), had higher mRS at admission (p < .00001), had 3.14 times increased chances of having a tumor (p = .003), were 3.88 times more likely to experience central hypoventilation, and were 2.36 times more likely to have positivity for antithyroid antibodies (p = .009) as compared to patients with non-low fT3.

CONCLUSION

The findings of our study suggest that low fT3 levels might be related to a more severe disease state, implying the significance of thyroid hormones in AE pathogenesis. This finding is crucial in not only improving the early diagnosis of severe AE but also in the efficient management of the disease.

Association between the Systemic Immune-Inflammation Index and Thyroid Function in U.S. Adults

Background

The systemic immune-inflammation index (SII) is used as an indicator of prognosis for a wide range of diseases. Thyroid function has been found to be strongly associated with inflammation. The purpose of this investigation was to analyze the correlation between SII and various thyroid functions.

Methods

This study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. The association between SII and thyroid function was analyzed using weighted univariate and multivariate linear regression analyses. Subgroup analyses, interaction tests, and weighted restricted cubic spline (RCS) regression analyses were also employed to test this correlation.

Results

Of the 6,875 participants (age ≥ 20 years), the mean age was 46.87 ± 0.40 years. The adjusted model showed that lnSII was negatively correlated with FT3 (β = -0.0559, 95% CI -0.1060 to -0.0059,) and FT3/FT4 (β = -0.0920, 95% CI -0.1667 to -0.0173,). There was a positive correlation between lnSII and TT4 (β = 0.1499, 95% CI 0.0722-0.2276,). In subgroup analyses, lnSII still independently affected a wide range of thyroid functions. Weighted RCS analysis showed a nonlinear relationship between FT3 and lnSII.

Conclusion

Close relationships exist between SII and a variety of thyroid functions. SII can be used as an indicator to predict thyroid dysfunction. Control of inflammatory activity may be a protective measure against thyroid dysfunction. More large-scale prospective studies are necessary to further explore the correlation between SII and thyroid function and the role of obesity in this.

scapGNN: A graph neural network-based framework for active pathway and gene module inference from single-cell multi-omics data

Although advances in single-cell technologies have enabled the characterization of multiple omics profiles in individual cells, extracting functional and mechanistic insights from such information remains a major challenge. Here, we present scapGNN, a graph neural network (GNN)-based framework that creatively transforms sparse single-cell profile data into the stable gene-cell association network for inferring single-cell pathway activity scores and identifying cell phenotype-associated gene modules from single-cell multi-omics data. Systematic benchmarking demonstrated that scapGNN was more accurate, robust, and scalable than state-of-the-art methods in various downstream single-cell analyses such as cell denoising, batch effect removal, cell clustering, cell trajectory inference, and pathway or gene module identification. scapGNN was developed as a systematic R package that can be flexibly extended and enhanced for existing analysis processes. It provides a new analytical platform for studying single cells at the pathway and network levels.

From Emergence to Endemicity: A Comprehensive Review of COVID-19

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), later renamed coronavirus disease 2019 (COVID-19), was first identified in Wuhan, China, in early December 2019. Initially, the China office of the World Health Organization was informed of numerous cases of pneumonia of unidentified etiology in Wuhan, Hubei Province at the end of 2019. This would subsequently result in a global pandemic with millions of confirmed cases of COVID-19 and millions of deaths reported to the WHO. We have analyzed most of the data published since the beginning of the pandemic to compile this comprehensive review of SARS-CoV-2. We looked at the core ideas, such as the etiology, epidemiology, pathogenesis, clinical symptoms, diagnostics, histopathologic findings, consequences, therapies, and vaccines. We have also included the long-term effects and myths associated with some therapeutics of COVID-19. This study presents a comprehensive assessment of the SARS-CoV-2 virology, vaccines, medicines, and significant variants identified during the course of the pandemic. Our review article is intended to provide medical practitioners with a better understanding of the fundamental sciences, clinical treatment, and prevention of COVID-19. As of May 2023, this paper contains the most recent data made accessible.

Transcriptional changes in multiple endocrine organs from lethal cases of COVID-19

Altered circulating hormone and metabolite levels have been reported during and post-COVID-19. Yet, studies of gene expression at the tissue level capable of identifying the causes of endocrine dysfunctions are lacking. Transcript levels of endocrine-specific genes were analyzed in five endocrine organs of lethal COVID-19 cases. Overall, 116 autoptic specimens from 77 individuals (50 COVID-19 cases and 27 uninfected controls) were included. Samples were tested for the SARS-CoV-2 genome. The adrenals, pancreas, ovary, thyroid, and white adipose tissue (WAT) were investigated. Transcript levels of 42 endocrine-specific and 3 interferon-stimulated genes (ISGs) were measured and compared between COVID-19 cases (virus-positive and virus-negative in each tissue) and uninfected controls. ISG transcript levels were enhanced in SARS-CoV-2-positive tissues. Endocrine-specific genes (e.g., HSD3B2, INS, IAPP, TSHR, FOXE1, LEP, and CRYGD) were deregulated in COVID-19 cases in an organ-specific manner. Transcription of organ-specific genes was suppressed in virus-positive specimens of the ovary, pancreas, and thyroid but enhanced in the adrenals. In WAT of COVID-19 cases, transcription of ISGs and leptin was enhanced independently of virus detection in tissue. Though vaccination and prior infection have a protective role against acute and long-term effects of COVID-19, clinicians must be aware that endocrine manifestations can derive from virus-induced and/or stress-induced transcriptional changes of individual endocrine genes. KEY MESSAGES: • SARS-CoV-2 can infect adipose tissue, adrenals, ovary, pancreas and thyroid. • Infection of endocrine organs induces interferon response. • Interferon response is observed in adipose tissue independently of virus presence. • Endocrine-specific genes are deregulated in an organ-specific manner in COVID-19. • Transcription of crucial genes such as INS, TSHR and LEP is altered in COVID-19.

Thyroid Function Abnormalities and Outcomes in Hospitalized Patients with COVID-19 Infection: A Cross-Sectional Study

Thyroid gland can be affected by the COVID-19 infection. The pattern of thyroid function abnormality reported in COVID-19 is variable; in addition, some drugs used in COVID-19 patients like glucocorticoids and heparin can affect the thyroid function tests (TFT). We conducted an observational, cross-sectional study of thyroid function abnormalities with thyroid autoimmune profile in COVID-19 patients with varying severity from November 2020 to June 2021. Serum FT4, FT3, TSH, anti-TPO, and anti-Tg antibodies were measured before the initiation of treatment with steroids and anti-coagulants. A total of 271 COVID-19 patients were included in the study, of which 27 were asymptomatic and remaining 158, 39, and 47 were classified to mild, moderate and severe categories, respectively, according to MoHFW, India criteria. Their mean age was 49±17 years and 64.9% were males. Abnormal TFT was present in 37.2% (101/271) patients. Low FT3, low FT4, and low TSH were present in 21.03%, 15.9% and 4.5% of patients, respectively. Pattern corresponding to sick euthyroid syndrome was the most common. Both mean FT3 and FT3/FT4 ratio decreased with increasing severity of COVID-19 illness (p=0.001). In multivariate analysis, low FT3 was associated with increased risk of mortality (OR 12.36, 95% CI: 1.23-124.19; p=0.033). Thyroid autoantibodies were positive in 58 (27.14%) patients; but it was not associated with any thyroid dysfunction. Thyroid function abnormality is common among COVID-19 patients. Both low FT3 and FT3/FT4 ratio are indicators of disease severity while low FT3 is a prognostic marker of COVID-19 associated mortality.

The Influence of SARS-CoV-2 Infection on the Thyroid Gland

It is important to acknowledge the impact that COVID-19 has on the thyroid gland and how the thyroid gland status before and during infection affects SARS-CoV-2 severity. To this day those dependencies are not fully understood. It is known that the virus uses angiotensin-converting enzyme-2 as the receptor for cellular entry and it can lead to multiple organ failures due to a cytokine storm. Levels of proinflammatory molecules (such as cytokines and chemokines) which are commonly elevated during infection were significantly higher in observed SARS-CoV-2-positive patients. In terms of hypothyroidism, hyperthyroidism, and autoimmune thyroid diseases, there is no proof that those dysfunctions have a direct impact on the more severe courses of COVID-19. Regarding hyper- and hypothyroidism there was no consequential dependency between the frequency of SARS-CoV-2 infection morbidity and more severe post-infectious complications. When it comes to autoimmune thyroid diseases, more evaluation has to be performed due to the unclear relation with the level of antibodies commonly checked in those illnesses and its binding with the mentioned before virus. Nonetheless, based on analyzed works we found that COVID-19 can trigger the immune system and cause its hyperactivity, sometimes leading to the new onset of autoimmune disorders. We also noticed more acute SARS-CoV-2 courses in patients with mainly reduced free triiodothyronine serum levels, which in the future, might be used as a mortality indicating factor regarding SARS-CoV-2-positive patients. Considering subacute thyroiditis (SAT), no statistically important data proving its direct correlation with COVID-19 infection has been found. Nevertheless, taking into account the fact that SAT is triggered by respiratory tract viral infections, it might be that SARS-CoV-2 can cause it too. There are many heterogenous figures in the symptoms, annual morbidity distribution, and frequency of new cases, so this topic requires further evaluation.

Lower serum FT3 within the reference range is associated with mortality for older adults over 80 years of age with sarcopenia

OBJECTIVE

Thyroid hormones stimulate myogenesis and muscle contraction and regulate skeletal muscle cell metabolism. However, the association between thyroid hormone levels and mortality in sarcopenic older adults remains elusive. The aim of this study was to investigate the relationship between thyroid hormones and all-cause mortality in people over 80 years of age with sarcopenia.

METHODS

This study was performed on 264 sarcopenic patients aged 80 years and older. Serum levels of thyroid hormone, including free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were tested to evaluate thyroid status. Sarcopenia was defined using the criteria of the European Working Group on Sarcopenia in Older People. Mortality data were available for up to 38 months of follow-up. The correlation between FT3 and calf circumference (CC) or handgrip strength (HGS) was determined by Pearson correlation analysis. Kaplan-Meier analysis was used to compare the differences between FT3 tertile groups. Cox regression was used to analyze the mortality risk ratio of patients with different FT3 tertiles.

RESULTS

During the follow-up period, 88 older adults died. Non-Survivors had lower serum FT3 levels (3.7 ± 0.5 vs. 3.9 ± 0.7, P = 0.001) than the Survivor. Serum FT3 was positively associated with CC and HGS (r = 0.29, P < 0.001, r = 0.21, P = 0.002, respectively). The Kaplan-Meier curve analysis demonstrated a difference in mortality among the FT3 tertile groups (log-rank test, χ² = 11.83, P = 0.003). The high FT3 group had lower mortality compared with the low FT3 group (the adjusted HRs were 0.63 (95%CI: 0.41-0.96 P = 0.031).

CONCLUSION

Lower FT3 within the reference range is associated with higher mortality in adults over 80 years with sarcopenia and euthyroid. Routine assessment of FT3 may be an easy way to identify high-risk older adults with sarcopenia.

Endocrine Disorders and COVID-19

The multifaceted interaction between coronavirus disease 2019 (COVID-19) and the endocrine system has been a major area of scientific research over the past two years. While common endocrine/metabolic disorders such as obesity and diabetes have been recognized among significant risk factors for COVID-19 severity, several endocrine organs were identified to be targeted by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). New-onset endocrine disorders related to COVID-19 were reported while long-term effects, if any, are yet to be determined. Meanwhile, the "stay home" measures during the pandemic caused interruption in the care of patients with pre-existing endocrine disorders and may have impeded the diagnosis and treatment of new ones. This review aims to outline this complex interaction between COVID-19 and endocrine disorders by synthesizing the current scientific knowledge obtained from clinical and pathophysiological studies, and to emphasize considerations for future research.

Correlation between Thyroid Responses and Inflammatory Cytokines in Critically Ill COVID-19 Patients

Mechanisms involved in thyroid dysfunction in critically ill coronavirus disease 2019 (COVID-19) patients are not clear. Our objective was to correlate the thyroid response with the pro- and anti-inflammatory cytokines profile in critically ill COVID-19 patients. This was a prospective single-center study. We studied the relationship between continuous variables by using Pearson correlation and simple linear regression. Multiple logistic regression analysis was performed to analyze the factors independently associated with mortality. Seventy-eight patients were included in the study at intensive care unit (ICU) admission and 72 had a measurement of the thyroid and inflammatory profile at day 5. No significant correlations were found between thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4) and inflammatory cytokines at ICU admission. At day 5, fT4, was inversely correlated with IL-10 (p = 0.035). IL-10 was associated with maximum lactate (p < 0.001) and SOFA score values (p = 0.012). The multiple logistic regression analysis showed that there was a significant relationship between IL-10 (day 5) and in-hospital mortality after adjusting by age and severity of illness. In conclusion, we found that the thyroid hormone profile and inflammatory cytokines had a weak correlation at ICU admission. Associations of interest between fT4 and IL-10 were found at day 5. IL-10 at day 5 was found to be correlated with low fT4 and markers of organ failure and death.

Study of thyroid function among COVID-19-affected and non-affected people during pre and post-vaccination

The novel coronavirus COVID-19 has caused a global pandemic with many long-ranging effects on the physiological balance of the human body. The impact of COVID-19 on the thyroid axis remains uncertain. Our aim was to assess the long-term consequences of COVID-19 infection and its vaccination with thyroid hormones. Thirty laboratory-confirmed COVID-19-positive patients with no vaccination record, thirty COVID-19-negative patients with vaccination records, and ten healthy subjects were retrospectively, and cross-sectionally enrolled in this study. An ELISA assay was performed to evaluate thyroid function tests, including the total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH). We found decreased levels of TT3, average or low plasma T4 levels, and standard or slightly decreased TSH levels in unvaccinated COVID-19-positive patients than in the healthy group, while the vaccinated COVID-19-negative group had normal thyroid hormone levels compared to controls. The correlation between TT3 and TSH levels gradually shifted from no association to a negative pattern in the unvaccinated COVID-19-positive group. Again, a highly significant negative correlation between TSH and TT3 was observed on days above 150, although a slight fluctuation was noted on day 90. This pilot study from Bangladesh shows that abnormalities in thyroid function can be observed during COVID-19 infection and after vaccination, which gradually recovers over time.

Thyrotropin Levels in Patients with Coronavirus Disease 2019: Assessment during Hospitalization and in the Medium Term after Discharge

BACKGROUND

The objectives of this study were (1) to compare TSH levels between inpatients with critical versus non-critical coronavirus disease 19 (COVID-19), and (2) to describe the status of TSH levels three months after hospitalization.

METHODS

We collected data on adult patients hospitalized with COVID-19 at Amiens University Hospital. We compared TSH levels between inpatients with critical (intensive care unit admission and/or death) versus non-critical COVID-19. Thereafter, survivors were invited to return for a three-month post-discharge visit where thyroid function tests were performed, regardless of the availability of TSH measurement during hospitalization.

RESULTS

Among 448 inpatients with COVID-19, TSH assay data during hospitalization were available for 139 patients without prior thyroid disease. Patients with critical and non-critical forms of COVID-19 did not differ significantly with regard to the median (interquartile range) TSH level (0.96 (0.68-1.71) vs. 1.27 mIU/L (0.75-1.79), p = 0.40). Abnormal TSH level was encountered in 17 patients (12.2%); most of them had subclinical thyroid disease. TSH assay data at the three-month post-discharge visit were available for 151 patients without prior thyroid disease. Only seven of them (4.6%) had abnormal TSH levels. Median TSH level at the post-discharge visit was significantly higher than median TSH level during hospitalization.

CONCLUSIONS

Our findings suggest that COVID-19 is associated with a transient suppression of TSH in a minority of patients regardless of the clinical form. The higher TSH levels three months after COVID-19 might suggest recovery from non-thyroidal illness syndrome.

Thyroid Dysfunction among the Patients with Critical COVID-19

Objective

Since the angiotensin-converting enzyme (ACE) is the functional receptor for SARS-CoV-2, predominantly expressed by the alveoli, SARS-CoV-2 primarily involves the lungs. Aside from the lungs, ACE is expressed in other organs, including the thyroid gland. This study aimed to evaluate the incidence of thyroid dysfunction (TD) in patients admitted to the intensive care unit (ICU) with critical COVID-19, with inflammatory markers and disease severity, compared to patients with normal thyroid function.

Materials and Methods

This retrospective study included 52 patients admitted to the ICU with PCR-confirmed critical COVID-19 between April 2020 and September 2021.Thyroid function tests were obtained within the first three days after ICU admission. TD was defined as the detection of any abnormal level in thyroid-stimulating hormone (TSH), free thyroxine hormone (FT4), and free triiodothyronine hormone (FT3).None of the patients had a prior history of thyroid disease or received medications related to thyroid diseases.

Results

TD was detected in 34 patients (65.4%). The majority of patients (67%) required extracorporeal membrane oxygenation (ECMO), with a higher frequency in patients with TD (74%). Patients with and without TD were similar concerning age, gender, and the need for ECMO. Patients with TD had significantly decreased levels of TSH, FT3, and FT4 (p=0.002, <0.001, =0.005, respectively); a significantly greater acute physiology and chronic health evaluation II (APACHE-II) score (p=0.048); a significantly higher white blood cell count (p=0.031) and elevated levels of procalcitonin (p=0.003), C-reactive protein (p=0.049) and cardiac troponin T (p=0.025). Other parameters, such as ICU stay, sequential organ failure assessment [SOFA] score, and mortality, did not differ significantly (p=0.449, p=0.315, p=0.142, respectively).

Conclusion

Our findings suggest that patients admitted to the ICU with critical COVID-19 are at an increased risk for the development of TD, which should also be taken into account in relation to inflammatory markers, cardiac troponin T levels, and APACHE-II scores.

Thyroid function changes and COVID-19 severity: egg or chicken?

The novel coronavirus disease 2019 (COVID-19) produced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious infectious disease. In addition to typical flu-like symptoms, COVID-19 can also cause extrapulmonary spread and systemic inflammation, potentially causing multiorgan dysfunction, including thyroid dysfunction. Thyroid function changes in patients with COVID-19 have been widely reported, but the results are inconsistent. Based on available data, SARS-CoV-2 infection can lead to changes in thyroid function, and the degree of thyroid function changes was positively correlated with the severity of COVID-19, which involved multiple potential mechanisms. In contrast, current evidence was insufficient to prove that thyroid function changes could induce the progression of COVID-19 clinical deterioration.

Thyroid Function and COVID-19 Susceptibility and Its Severity: A Two-Sample Mendelian Randomization Study

Several observational studies have confirmed the relationship between thyroid hormones and coronavirus disease 2019 (COVID-19), but this correlation remains controversial. We performed a two-sample Mendelian randomization (MR) analysis based on the largest publicly available summary datasets. Summary statistics with 49 269 individuals for free thyroxine (FT4) and 54 288 for thyroid stimulating hormone (TSH) were used as exposure instruments. Genome-wide association studies of susceptibility (cases = 38 984; controls = 1 644 784), hospitalization (cases: 9986 = controls = 1 877 672), and very severe disease (cases = 5101; controls = 1 383 241) of COVID-19 were used as the outcome. We used the inverse-variance weighted (IVW) method as the primary analysis, and utilized MR-Egger regression, weighted median, and robust adjusted profile score (RAPS) for sensitivity analysis. Genetic predisposition to higher serum levels of FT4 within the normal range was negatively associated with the risk of COVID-19 hospitalization (odds ratio [OR] = 0.818; 95% CI, 0.718-0.932; P = 2.6 × 10-3) and very severe disease (OR = 0.758; 95% CI, 0.626-0.923; P = 5.8 × 10-3), but not susceptibility. There is no evidence that genetically predicted circulating TSH levels are associated with COVID-19 susceptibility and severity risk. Neither apparent pleiotropy nor heterogeneity were detected in the sensitivity analysis. In summary, we found that higher FT4 levels may reduce the risk of COVID-19 severity, suggesting that thyroid function testing may be required for patients with COVID-19.

Schilddrüse und SARS-CoV-2

Es gibt verschiedene Wechselwirkungen zwischen einer SARS-CoV-2-Infektion und der Schilddrüse, bidirektional in beide Richtungen: Bei einer schweren COVID-19-Infektion sind Veränderungen der Schilddrüsenhormonspiegel ein Marker für eine schlechtere Prognose. SARS-CoV‑2 scheint sowohl direkt mit Thyreozyten zu interagieren als auch das Immunsystem zu modulieren und Immunthyreopathien triggern zu können. Bereits 2020 wurde die „SARS-CoV-2-assoziierte Thyreoiditis“ bei Patienten mit COVID-19 beschrieben, die ähnlich einer subakuten Thyreoiditis verläuft, allerdings typischerweise schmerzlos. Es gibt inzwischen verschiedenste Berichte über das Auftreten einer chronischen Immunthyreoiditis und eines Morbus Basedow sowohl nach Virusinfektion als auch nach Impfung. Eine bestehende Schilddrüsenerkrankung scheint weder mit einem höheren Risiko für eine SARS-CoV-2-Infektion noch mit einem schwereren Krankheitsverlauf assoziiert zu sein. In der vorliegenden Arbeit wird der derzeitige Wissensstand bezüglich Schilddrüse und SARS-CoV‑2 zusammengefasst.

Thyroid hormones act as modulators of inflammation through their nuclear receptors

Reciprocal crosstalk between endocrine and immune systems has been well-documented both in physiological and pathological conditions, although the connection between the immune system and thyroid hormones (THs) remains largely unclear. Inflammation and infection are two important processes modulated by the immune system, which have profound effects on both central and peripheral THs metabolism. Conversely, optimal levels of THs are necessary for the maintenance of immune function and response. Although some effects of THs are mediated by their binding to cell membrane integrin receptors, triggering a non-genomic response, most of the actions of these hormones involve their binding to specific nuclear thyroid receptors (TRs), which generate a genomic response by modulating the activity of a great variety of transcription factors. In this special review on THs role in health and disease, we highlight the relevance of these hormones in the molecular mechanisms linked to inflammation upon their binding to specific nuclear receptors. In particular, we focus on THs effects on different signaling pathways involved in the inflammation associated with various infectious and/or pathological processes, emphasizing those mediated by NF-kB, p38MAPK and JAK/STAT. The findings showed in this review suggest new opportunities to improve current therapeutic strategies for the treatment of inflammation associated with several infections and/or diseases, such as cancer, sepsis or Covid-19 infection.

The Potential of Thyroid Hormone Therapy in Severe COVID-19: Rationale and Preliminary Evidence

Tissue hypoxia is one of the main pathophysiologic mechanisms in sepsis and particularly in COVID-19. Microvascular dysfunction, endothelialitis and alterations in red blood cell hemorheology are all implicated in severe COVID-19 hypoxia and multiorgan dysfunction. Tissue hypoxia results in tissue injury and remodeling with re-emergence of fetal programming via hypoxia-inducible factor-1α (HIF-1a)-dependent and -independent pathways. In this context, thyroid hormone (TH), a critical regulator of organ maturation, may be of relevance in preventing fetal-like hypoxia-induced remodeling in COVID-19 sepsis. Acute triiodothyronine (T3) treatment can prevent cardiac remodeling and improve recovery of function in clinical settings of hypoxic injury as acute myocardial infarction and by-pass cardiac surgery. Furthermore, T3 administration prevents tissue hypoxia in experimental sepsis. On the basis of this evidence, the use of T3 treatment was proposed for ICU (Intensive Care Unit) COVID-19 patients (Thy-Support, NCT04348513). The rationale for T3 therapy in severe COVID-19 and preliminary experimental and clinical evidence are discussed in this review.

Thyroid-Stimulating Hormone Predicts Total Cholesterol and Low-Density Lipoprotein Cholesterol Reduction during the Acute Phase of COVID-19

A complex dysregulation of lipid metabolism occurs in COVID-19, leading to reduced total cholesterol (TC), LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C) levels, along with a derangement of thyroid function, leading to reduced thyroid-stimulating hormone (TSH) levels. This study aimed to explore the association between TSH levels during COVID-19 and the variation (Δ) of lipid profile parameters in the period preceding (from 1 month up to 1 year) hospital admission due to COVID-19. Clinical data of 324 patients (mean age 76 ± 15 years, 54% males) hospitalized due to COVID-19 between March 2020 and March 2022 were retrospectively analyzed. The association between TSH levels at hospital admission and either Δ-TC, Δ-LDL-C, or Δ-HDL-C over the selected time frame was assessed through univariable and multivariable analyses. TSH levels were below the lower reference limit of 0.340 μUI/mL in 14% of COVID-19 patients. A significant reduction of plasma TC, LDL-C, and HDL-C was recorded between the two time points (p < 0.001 for all the comparisons). TSH was directly associated with Δ-TC (rho = 0.193, p = 0.001), Δ-LDL-C (rho = 0.201, p = 0.001), and Δ-HDL-C (rho = 0.160, p = 0.008), and inversely associated with C-reactive protein (CRP) (rho = −0.175, p = 0.004). Moreover, TSH decreased with increasing COVID-19 severity (p < 0.001). CRP and COVID-19 severity were inversely associated with Δ-TC, Δ-LDL-C, and Δ-HDL-C (p < 0.05 for all associations). A significant independent association was found between TSH and either Δ-TC (β = 0.125, p = 0.044) or Δ-LDL-C (β = 0.131, p = 0.036) after adjusting for multiple confounders including CRP and COVID-19 severity. In conclusion, lower levels of TSH may contribute to explain TC and LDL-C reduction in the acute phase of COVID-19.

Thyroid Function, Inflammatory Response, and Glucocorticoids in COVID-19

The ongoing COVID-19 pandemic calls for extensive research on various medical topics. Since the beginning of the pandemic, multiple studies investigated the impact of SARS CoV-2 on thyroid function. However, crucial data, such as trend progression over time or influence of commonly used drugs, might still be missing. We checked the thyroid function in 174 patients with PCR-confirmed COVID-19. Our research covered three separate time points of hospitalization (days 1, 4, and 10). We did not exclude patients treated with glucocorticoids but, instead, compared them with patients not treated with steroids. We correlated the results of thyroid function tests with markers of systemic inflammation. We checked if abnormal thyroid function can predict unfavorable outcomes defined as combined primary endpoint and/or secondary endpoints; the combined primary endpoint was the occurrence of death, mechanical ventilation, non-invasive ventilation, vasopressor infusion, or prolonged hospital stay, and the secondary endpoint was any of the listed events. In general, 80.46% of evaluated patients displayed abnormalities in thyroid function tests over at least one time point throughout the observation. We noticed a high prevalence of features typical for thyroid dysfunction in non-thyroidal illness (NTI). Free triiodothyronine (fT3) concentration was significantly lower in the group requiring glucocorticoids. Patients displaying abnormal thyroid function were statistically more likely to meet the predefined combined primary endpoint. We found that fT3 measured at admission could be perceived as an independent predictor of endpoint completion for all analyzed groups. Thyroid involvement is common in COVID-19. Our study supports the idea of thyroid function abnormalities being important clinical tools and allowing early recognition of possible detrimental outcomes of the disease.