Thyroxine changes in COVID-19 pandemic: A systematic review and meta-analysis.

Objective: COVID-19 infection may affect thyroid function. However, changes in thyroid function in COVID-19 patients have not been well described. This systematic review and meta-analysis assess thyroxine levels in COVID-19 patients, compared with non-COVID-19 pneumonia and healthy cohorts during the COVID-19 epidemic. Methods: A search was performed in English and Chinese databases from inception to August 1, 2022. The primary analysis assessed thyroid function in COVID-19 patients, comparing non-COVID-19 pneumonia and healthy cohorts. Secondary outcomes included different severity and prognoses of COVID-19 patients. Results: A total of 5873 patients were enrolled in the study. The pooled estimates of TSH and FT3 were significantly lower in patients with COVID-19 and non-COVID-19 pneumonia than in the healthy cohort (P < 0.001), whereas FT4 were significantly higher (P < 0.001). Patients with the non-severe COVID-19 showed significant higher in TSH levels than the severe (I2 = 89.9%, P = 0.002) and FT3 (I2 = 91.9%, P < 0.001). Standard mean differences (SMD) of TSH, FT3, and FT4 levels of survivors and non-survivors were 0.29 (P= 0.006), 1.11 (P < 0.001), and 0.22 (P < 0.001). For ICU patients, the survivors had significantly higher FT4 (SMD=0.47, P=0.003) and FT3 (SMD=0.51, P=0.001) than non-survivors. Conclusions: Compared with the healthy cohort, COVID-19 patients showed decreased TSH and FT3 and increased FT4, similar to non-COVID-19 pneumonia. Thyroid function changes were related to the severity of COVID-19. Thyroxine levels have clinical significance for prognosis evaluation, especially FT3.

The Independent Association of TSH and Free Triiodothyronine Levels With Lymphocyte Counts Among COVID-19 Patients.

Background: Both lymphopenia and thyroid dysfunction are commonly observed among COVID-19 patients. Whether thyroid function independently correlates with lymphocyte counts (LYM) remains to be elucidated. Methods: We included consecutive adults without known thyroid disorder admitted to Queen Mary Hospital for COVID-19 from July 2020 to April 2021 who had thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and LYM measured on admission. Results: A total of 541 patients were included. Median LYM was 1.22 x 109/L, with 36.0% of the cohort lymphopenic. 83 patients (15.4%) had abnormal thyroid function tests (TFTs), mostly non-thyroidal illness syndrome (NTIS). Patients with lymphopenia had lower TSH, fT4 and fT3 levels than those without. Multivariable stepwise linear regression analysis revealed that both TSH (standardized beta 0.160, p<0.001) and fT3 (standardized beta 0.094, p=0.023), but not fT4, remained independently correlated with LYM, in addition to age, SARS-CoV-2 viral load, C-reactive protein levels, coagulation profile, sodium levels and more severe clinical presentations. Among the 40 patients who had reassessment of TFTs and LYM after discharge, at a median of 9 days from admission, there were significant increases in TSH (p=0.031), fT3 (p<0.001) and LYM (p<0.001). Furthermore, patients who had both lymphopenia and NTIS were more likely to deteriorate compared to those who only had either one alone, and those without lymphopenia or NTIS (p for trend <0.001). Conclusion: TSH and fT3 levels showed independent positive correlations with LYM among COVID-19 patients, supporting the interaction between the hypothalamic-pituitary-thyroid axis and immune system in COVID-19.

A Prospective Observational Study of 42 Patients with COVID-19 infection and a History of Hepatitis C Virus Infection and Thyroid Disease with Follow-Up Thyroid Function and Autoantibody Testing.

BACKGROUND Thyroiditis is an important extrahepatic association in chronic hepatitis C virus (HCV) infection. There have been reports of an association between SARS-CoV-2 infection and the onset or re-activation of autoimmune hypothyroidism. Therefore, we performed this prospective observational study of 42 patients with COVID-19 infection and a history of hepatitis C virus infection and thyroid disease with follow-up thyroid function and autoantibody testing. MATERIAL AND METHODS From April 2020 to October 2020, we performed a prospective observational study of patients with cured hepatitis C virus (HCV) infection and documented thyroid disease who became infected with SARS-CoV-2 (confirmed by SARS-CoV-2 RNA detection via reverse-transcription polymerase chain reaction [RT-PCT] from the upper respiratory tract, both nasal and pharyngeal swabs). Evaluation at 1 and 3 months after SARS-CoV-2 infection included serum determination of antithyroid antibodies (anti-thyroglobulin [anti-Tg] and antithyroid peroxidase [ATPO]), thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and evaluation of thyroid medication, with dose adjustment if required. RESULTS One-month follow-up showed that both patients with autoimmune thyroiditis as well as patients without antibodies had increased ATPO levels. Also, levels of TSH, fT3, and fT4 were significantly decreased. At 3-month follow-up, levels of ATPO were decreased in all patient groups and the levels of thyroid hormones increased to normal values. CONCLUSIONS This study supports previous reports of an association between SARS-CoV-2 infection and thyroid dysfunction associated with thyroid autoantibodies. Thyroid function tests may be considered as part of the laboratory work-up in patients with COVID-19.

The Impact of Interferon Beta-1b Therapy on Thyroid Function and Autoimmunity Among COVID-19 Survivors.

Background: Some studies have indicated that interferon (IFN) may be valuable in COVID-19. We aimed to evaluate the impact of short-term IFN on incident thyroid dysfunction and autoimmunity among COVID-19 survivors. Methods: We included consecutive adults without known thyroid disorder admitted to Queen Mary Hospital for COVID-19 from July 2020 to January 2021 who had thyroid function tests (TFTs) and anti-thyroid antibodies measured both on admission and at three months. Results: 226 patients were included (median age 55.0 years; 49.6% men): 135 were IFN-treated. There tended to be more abnormal TFTs upon reassessment in IFN-treated patients (8.1% vs 2.2%, p=0.080). 179 patients (65.4% IFN-treated) had a complete reassessment of anti-thyroid antibodies. There were significant increases in titres of both anti-thyroid peroxidase antibodies (anti-TPO: baseline 29.21 units [IQR: 14.97 - 67.14] vs reassessment 34.30 units [IQR: 18.82 - 94.65], p<0.001) and anti-thyroglobulin antibodies (anti-Tg: baseline 8.23 units [IQR: 5.40 - 18.44] vs reassessment 9.14 units [IQR: 6.83 - 17.17], p=0.001) in the IFN-treated group but not IFN-naïve group. IFN treatment (standardised beta 0.245, p=0.001) was independently associated with changes in anti-TPO titre. Of the 143 patients negative for anti-TPO at baseline, 8 became anti-TPO positive upon reassessment (seven IFN-treated; one IFN-naïve). Incident anti-TPO positivity was more likely to be associated with abnormal TFTs upon reassessment (phi 0.188, p=0.025). Conclusion: IFN for COVID-19 was associated with modest increases in anti-thyroid antibody titres, and a trend of more incident anti-TPO positivity and abnormal TFTs during convalescence. Our findings suggest that clinicians monitor the thyroid function and anti-thyroid antibodies among IFN-treated COVID-19 survivors, and call for further follow-up studies regarding the clinical significance of these changes.

Thyroid Hormone Profile and Its Prognostic Impact on the Coronavirus Disease 2019 in Korean Patients.

BACKGROUND: Data on the association between coronavirus disease 2019 (COVID-19) and thyroid have been reported, including overt thyrotoxicosis and suppression of thyroid function. We aimed to evaluate the thyroid hormone profile and its association with the prognosis of COVID-19 in Korean patients. METHODS: The clinical data of 119 patients with COVID-19, admitted in the Myongji Hospital, Goyang, South Korea, were retrospectively evaluated. The thyroid hormone profiles were analyzed and compared based on disease severity (non-severe disease vs. severe to critical disease). Clinical outcomes were analyzed according to the tertiles of thyroid hormones. RESULTS: Of the 119 patients, 76 (63.9%) were euthyroid, and none presented with overt thyroid dysfunction. Non-thyroidal illness syndrome was the most common manifestation (18.5%), followed by subclinical thyrotoxicosis (14.3%) among patients with thyroid dysfunction. Thyroid stimulating hormone (TSH) and triiodothyronine (T3) levels were significantly lower in patients with severe to critical disease than in those with non-severe disease (P<0.05). Patients in the lowest T3 tertile (<0.77 ng/mL) had higher rates of mechanical ventilation, intensive care unit admission, and death than those in the middle and highest (>1.00 ng/mL) T3 tertiles (P<0.05). COVID-19 patients in the lowest T3 tertile were independently associated with mortality (hazard ratio, 5.27; 95% confidence interval, 1.09 to 25.32; P=0.038) compared with those in the highest T3 tertile. CONCLUSION: Thyroid dysfunction is common in COVID-19 patients. Changes in serum TSH and T3 levels may be important markers of disease severity in COVID-19. Decreased T3 levels may have a prognostic significance in COVID-19 related outcome.

Non-thyroidal illness syndrome and SARS-CoV-2-associated multisystem inflammatory syndrome in children.

PURPOSE: COVID-19 disease may result in a severe multisystem inflammatory syndrome in children (MIS-C), which in turn may alter thyroid function (TF). We assessed TF in MIS-C, evaluating its impact on disease severity. METHODS: We retrospectively considered children admitted with MIS-C to a single pediatric hospital in Milan (November 2019-January 2021). Non-thyroidal illness syndrome (NTIS) was defined as any abnormality in TF tests (FT3, FT4, TSH) in the presence of critical illness and absence of a pre-existing hormonal abnormality. We devised a disease severity score by combining severity scores for each organ involved. Glucose and lipid profiles were also considered. A principal component analysis (PCA) was performed, to characterize the mutual association patterns between TF and disease severity. RESULTS: Of 26 (19 M/7F) patients, median age 10.7 (IQR 5.8-13.3) years, 23 (88.4%) presented with NTIS. A low FT3 level was noted in 15/23 (65.3%), while the other subjects had varying combinations of hormone abnormalities (8/23, 34.7%). Mutually correlated variables related to organ damage and inflammation were represented in the first dimension (PC1) of the PCA. FT3, FT4 and total cholesterol were positively correlated and characterized the second axis (PC2). The third axis (PC3) was characterized by the association of triglycerides, TyG index and HDL cholesterol. TF appeared to be related to lipemic and peripheral insulin resistance profiles. A possible association between catabolic components and severity score was also noted. CONCLUSIONS: A low FT3 level is common among MIS-C. TF may be useful to define the impact of MIS-C on children's health and help delineate long term follow-up management and prognosis.

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.

Association between Thyroid Function and Prognosis of COVID-19: A Retrospective Observational Study.

Background: Coronavirus disease 2019 (COVID-19) is a severe infectious illness. It has been reported that COVID-19 has an effect on thyroid function. However, the association between thyroid function and prognosis of COVID-19 is still unclear.Methods: This retrospective study included patients with COVID-19 admitted to Tongji Hospital in Wuhan from January 28 to April 4, 2020. Demographic, epidemiological, clinical, laboratory, treatment, and outcome data were collected from patients with laboratory-confirmed COVID-19. Patients without history of thyroid disease who had a thyroid function test at admission were enrolled in the final analysis. Risk factors of in-hospital death were explored using univariable and multivariable Cox regression analyses. Survival differences were assessed with Kaplan-Meier curves and log-rank test.Results: A total of 127 patients were included in this study, with 116 survivors and 11 non-survivors. The serum levels of thyroid stimulating hormone (TSH) [0.8 (0.5-1.7) vs. 1.9 (1.0-3.1) µIU/mL, P = .031] and free triiodothyronine (FT3) [2.9 (2.8-3.1) vs. 4.2 (3.5-4.7) pmol/L, P < .001] were lower in non-survivors than in survivors, and a low FT3 state (defined as FT3 < 3.1 pmol/L) at admission accounted for a higher proportion in non-survivors than in survivors (72.7% vs. 11.2%, P < .001). Univariate Cox regression analysis showed that FT3 level (HR 0.213, 95% CI: 0.101-0.451, P < .001) and the low FT3 state (HR 14.607, 95% CI: 3.873-55.081, P < .001) were negatively and positively associated with the risk of in-hospital death, respectively. Furthermore, multivariate Cox regression analysis revealed that a low FT3 state was associated with an increased risk of in-hospital death after adjusting for confounding factors (HR 13.288, 95% CI: 1.089-162.110, P = .043). Moreover, Kaplan-Meier curves indicated a lower survival probability in COVID-19 patients with a low FT3 status.Conclusion: Serum FT3 level is lower in non-survivors among moderate-to-critical patients with COVID-19, and the low FT3 state is associated with an increased risk of in-hospital mortality of COVID-19.

Normal Adrenal and Thyroid Function in Patients Who Survive COVID-19 Infection.

CONTEXT: The COVID-19 pandemic continues to exert an immense burden on global health services. Moreover, up to 63% of patients experience persistent symptoms, including fatigue, after acute illness. Endocrine systems are vulnerable to the effects of COVID-19 as many glands express the ACE2 receptor, used by the SARS-CoV-2 virion for cellular access. However, the effects of COVID-19 on adrenal and thyroid gland function after acute COVID-19 remain unknown. OBJECTIVE: Our objectives were to evaluate adrenal and thyroid gland function in COVID-19 survivors. METHODS: A prospective, observational study was undertaken at the Clinical Research Facility, Imperial College NHS Healthcare Trust, including 70 patients ≥18 years of age, at least 3 months after diagnosis of COVID-19. Participants attended a research study visit (8:00-9:30 am), during which a short Synacthen test (250 µg IV bolus) and thyroid function assessments were performed. RESULTS: All patients had a peak cortisol ≥450 nmol/L after Synacthen, consistent with adequate adrenal reserve. Basal and peak serum cortisol did not differ according to disease severity or history of dexamethasone treatment during COVID-19. There was no difference in baseline or peak cortisol after Synacthen or in thyroid function tests, or thyroid status, in patients with fatigue (n = 44) compared to those without (n = 26). CONCLUSION: Adrenal and thyroid function ≥3 months after presentation with COVID-19 was preserved. While a significant proportion of patients experienced persistent fatigue, their symptoms were not accounted for by alterations in adrenal or thyroid function. These findings have important implications for the clinical care of patients after COVID-19.

A prospective, observational clinical trial on the impact of COVID-19-related national lockdown on thyroid hormone in young males.

Trying to manage the dramatic coronavirus disease 2019 (COVID-19) infection spread, many countries imposed national lockdown, radically changing the routinely life of humans worldwide. We hypothesized that both the pandemic per se and the consequent socio-psychological sequelae could constitute stressors for Italian population, potentially affecting the endocrine system. This study was designed to describe the effect of lockdown-related stress on the hypothalamic-pituitary-thyroid (HPT) axis in a cohort of young men. A prospective, observational clinical trial was carried out, including patients attending the male infertility outpatient clinic before and after the national lockdown for COVID-19 pandemic. The study provided a baseline visit performed before and a follow-up visit after the lockdown in 2020. During the follow-up visit, hormonal measurements, lifestyle habits and work management were recorded. Thirty-one male subjects were enrolled (mean age: 31.6 ± 6.0 years). TSH significantly decreased after lockdown (p = 0.015), whereas no significant changes were observed in the testosterone, luteinising hormone, follicle-stimulating hormone, estradiol and prolactin serum levels. No patient showed TSH serum levels above or below reference ranges, neither before nor after lockdown. Interestingly, TSH variation after lockdown was dependent on the working habit change during lockdown (p = 0.042). We described for the first time a TSH reduction after a stressful event in a prospective way, evaluating the HPT axis in the same population, before and after the national lockdown. This result reinforces the possible interconnection between psychological consequences of a stressful event and the endocrine regulation.

The Association of TSH and Thyroid Hormones With Lymphopenia in Bacterial Sepsis and COVID-19.

CONTEXT: Lymphopenia is a key feature of immune dysfunction in patients with bacterial sepsis and coronavirus disease 2019 (COVID-19) and is associated with poor clinical outcomes, but the cause is largely unknown. Severely ill patients may present with thyroid function abnormalities, so-called nonthyroidal illness syndrome, and several studies have linked thyrotropin (thyroid stimulating hormone, TSH) and the thyroid hormones thyroxine (T4) and 3,5,3'-triiodothyronine (T3) to homeostatic regulation and function of lymphocyte populations. OBJECTIVE: This work aimed to test the hypothesis that abnormal thyroid function correlates with lymphopenia in patients with severe infections. METHODS: A retrospective analysis of absolute lymphocyte counts, circulating TSH, T4, free T4 (FT4), T3, albumin, and inflammatory biomarkers was performed in 2 independent hospitalized study populations: bacterial sepsis (n = 224) and COVID-19 patients (n = 161). A subgroup analysis was performed in patients with severe lymphopenia and normal lymphocyte counts. RESULTS: Only T3 significantly correlated (ρ = 0.252) with lymphocyte counts in patients with bacterial sepsis, and lower concentrations were found in severe lymphopenic compared to nonlymphopenic patients (n = 56 per group). Severe lymphopenic COVID-19 patients (n = 17) showed significantly lower plasma concentrations of TSH, T4, FT4, and T3 compared to patients without lymphopenia (n = 18), and demonstrated significantly increased values of the inflammatory markers interleukin-6, C-reactive protein, and ferritin. Remarkably, after 1 week of follow-up, the majority (12 of 15) of COVID-19 patients showed quantitative recovery of their lymphocyte numbers, whereas TSH and thyroid hormones remained mainly disturbed. CONCLUSION: Abnormal thyroid function correlates with lymphopenia in patients with severe infections, like bacterial sepsis and COVID-19, but future studies need to establish whether a causal relationship is involved.

Thyroid Function Abnormalities in COVID-19 Patients.

Purpose: The novel coronavirus COVID-19, has caused a worldwide pandemic, impairing several human organs and systems. Whether COVID-19 affects human thyroid function remains unknown. Methods: Eighty-four hospitalized COVID-19 patients in the First Affiliated Hospital, Zhejiang University School of Medicine (Hangzhou, China) were retrospectively enrolled in this study, among which 22 cases had complete records of thyroid hormones. In addition, 91 other patients with pneumonia and 807 healthy subjects were included as controls. Results: We found that levels of total triiodothyronine (TT3) and thyroid stimulating hormone (TSH) were lower in COVID-19 patients than healthy group (p < 0.001). Besides, TSH level in COVID-19 patients was obviously lower than non-COVID-19 patients (p < 0.001). Within the group of COVID-19, 61.9% (52/84) patients presented with thyroid function abnormalities and the proportion of thyroid dysfunction was higher in severe cases than mild/moderate cases (74.6 vs. 23.8%, p < 0.001). Patients with thyroid dysfunction tended to have longer viral nucleic acid cleaning time (14.1 ± 9.4 vs. 10.6 ± 8.3 days, p = 0.088). To note, thyroid dysfunction was also associated with decreased lymphocytes (p < 0.001) and increased CRP (p = 0.002). The correlation between TT3 and TSH level seemed to be positive rather than negative in the early stage, and gradually turned to be negatively related over time. Conclusion: Thyroid function abnormalities are common in COVID-19 patients, especially in severe cases. This might be partially explained by nonthyroidal illness syndrome.

The spectrum of thyroid function tests during hospitalization for SARS COV-2 infection.

OBJECTIVE: Alterations in thyroid function tests (TFTs) have been recorded during SARS-CoV-2 infection as associated to either a destructive thyroiditis or a non-thyroidal illness. METHODS: We studied 144 consecutive COVID-19 patients admitted to a single center in intensive or subintensive care units. Those with previous thyroid dysfunctions or taking interfering drugs were excluded. Differently from previous reports, TSH, FT3, FT4, thyroglobulin (Tg), anti-Tg autoantibodies (TgAb) were measured at baseline and every 3-7 days. C-reacting protein (CRP), cortisol and IL-6 were also assayed. RESULTS: The majority of patients had a normal TSH at admission, usually with normal FT4 and FT3. Low TSH levels were found either at admission or during hospitalization in 39% of patients, associated with low FT3 in half of the cases. FT4 and Tg levels were normal, and TgAb-negative. TSH and FT3 were invariably restored at the time of discharge in survivors, whereas were permanently low in most deceased cases, but only FT3 levels were predictors of mortality. Cortisol, CRP and IL-6 levels were higher in patients with low TSH and FT3 levels. CONCLUSIONS: Almost half of our COVID-19 patients without interfering drugs had normal TFTs both at admission and during follow-up. In this series, the transient finding of low TSH with normal FT4 and low FT3 levels, inversely correlated with CRP, cortisol and IL-6 and associated with normal Tg levels, is likely due to the cytokine storm induced by SARS-Cov-2 with a direct or mediated impact on TSH secretion and deiodinase activity, and likely not to a destructive thyroiditis.

Potential Interaction Between SARS-CoV-2 and Thyroid: A Review.

The novel coronavirus disease 2019 (COVID-19) produced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is sweeping the world in a very short time. Although much has been learned about the clinical course, prognostic inflammatory markers, and disease complications of COVID-19, the potential interaction between SARS-CoV-2 and the thyroid is poorly understood. In contrast to SARS-CoV-1, limited available evidence indicates there is no pathological evidence of thyroid injury caused by SARS-CoV-2. However, subacute thyroiditis caused by SARS-CoV-2 has been reported for the first time. Thyroid dysfunction is common in patients with COVID-19 infection. By contrast, certain thyroid diseases may have a negative impact on the prevention and control of COVID-19. In addition, some anti-COVID-19 agents may cause thyroid injury or affect its metabolism. COVID-19 and thyroid disease may mutually aggravate the disease burden. Patients with SARS-CoV-2 infection should not ignore the effect on thyroid function, especially when there are obvious related symptoms. In addition, patients with thyroid diseases should follow specific management principles during the epidemic period.

Thyroid Function Analysis in 50 Patients with COVID-19: A Retrospective Study.

Background: Since the outbreak of the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, it has affected >200 countries, areas, or territories in 6 continents. At present, whether COVID-19 has an effect on thyroid function is unclear. The aim of this study was to evaluate thyroid function in patients with COVID-19. Methods: Clinical manifestations, laboratory results, and chest computed tomography scans were retrospectively reviewed for 50 patients with laboratory-confirmed COVID-19 without a history of thyroid disease who underwent thyroid function testing during their course of COVID-19 infection and after recovery. They were admitted to the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China, between January and March 2020. Healthy participants who underwent routine physical checkups and non-COVID-19 pneumonia patients with a similar degree of severity during the same period were included in the study as the control group. Thyroid hormone and thyrotropin (TSH) levels were analyzed and compared between the COVID-19 and control groups. Results: TSH lower than the normal range was present in 56% (28/50) of the patients with COVID-19. The levels of TSH and serum total triiodothyronine (TT3) of the patients with COVID-19 were significantly lower than those of the healthy control group and non-COVID-19 pneumonia patients. The more severe the COVID-19, the lower the TSH and TT3 levels were, with statistical significance (p < 0.001). The degree of the decreases in TSH and TT3 levels was positively correlated with the severity of the disease. The total thyroxine (TT4) level of the patients with COVID-19 was not significantly different from the control group. All the patients did not receive thyroid hormone replacement therapy. After recovery, no significant differences in TSH, TT3, TT4, free triiodothyronine (fT3), and free thyroxine (fT4) levels were found between the COVID-19 and control groups. Conclusions: The changes in serum TSH and TT3 levels may be important manifestations of the courses of COVID-19.

The impact of COVID-19 on routine patient care from a laboratory perspective.

BACKGROUND: Globally, few studies have examined the effect of the COVID-19 pandemic on routine patient care and follow-up. OBJECTIVES: To evaluate the effect of the COVID-19 response on biochemical test requests received from outpatient departments (OPDs) and peripheral clinics serviced by the National Health Laboratory Service Chemical Pathology Laboratory at Tygerberg Hospital, Cape Town, South Africa (SA). Request volumes were used as a measure of the routine care of patients, as clinical information was not readily available. METHODS: A retrospective audit was conducted. The numbers of requests received from OPDs and peripheral clinics for creatinine, glycated haemoglobin (HbA1c), lipid profiles, thyroid-stimulating hormone (TSH), free thyroxine, free tri-iodothyronine (fT3), serum and urine protein electrophoresis, serum free light chains and neonatal total serum bilirubin were obtained from 1 March to 30 June for 2017, 2018, 2019 and 2020. RESULTS: The biggest impact was seen on lipids, creatinine, HbA1c, TSH and fT3. The percentage reduction between 1 March and 30 June 2019 and between 1 March and 30 June 2020 was 59% for lipids, 64% for creatinine and HbA1c, 80% for TSH and 81% for fT3. There was a noteworthy decrease in overall analyte testing from March to April 2020, coinciding with initiation of level 5 lockdown. Although an increase in testing was observed during June 2020, the number of requests was still lower than in June 2019. CONCLUSIONS: This study, focusing on the short-term consequences of the SA response to the COVID-19 pandemic, found that routine follow-up of patients with communicable and non-communicable diseases was affected. Future studies are necessary to evaluate the long-term consequences of the pandemic for these patient groups.

Thyroid Function Before, During, and After COVID-19.

CONTEXT: The effects of COVID-19 on the thyroid axis remain uncertain. Recent evidence has been conflicting, with both thyrotoxicosis and suppression of thyroid function reported. OBJECTIVE: We aimed to detail the acute effects of COVID-19 on thyroid function and determine if these effects persisted on recovery from COVID-19. DESIGN: A cohort observational study was conducted. PARTICIPANTS AND SETTING: Adult patients admitted to Imperial College Healthcare National Health Service Trust, London, UK, with suspected COVID-19 between March 9 to April 22, 2020, were included, excluding those with preexisting thyroid disease and those missing either free thyroxine (FT4) or thyrotropin (TSH) measurements. Of 456 patients, 334 had COVID-19 and 122 did not. MAIN OUTCOME MEASURES: TSH and FT4 measurements were recorded at admission, and where available, in 2019 and at COVID-19 follow-up. RESULTS: Most patients (86.6%) presenting with COVID-19 were euthyroid, with none presenting with overt thyrotoxicosis. Patients with COVID-19 had a lower admission TSH and FT4 compared to those without COVID-19. In the COVID-19 patients with matching baseline thyroid function tests from 2019 (n = 185 for TSH and 104 for FT4), TSH and FT4 both were reduced at admission compared to baseline. In a complete case analysis of COVID-19 patients with TSH measurements at follow-up, admission, and baseline (n = 55), TSH was seen to recover to baseline at follow-up. CONCLUSIONS: Most patients with COVID-19 present with euthyroidism. We observed mild reductions in TSH and FT4 in keeping with a nonthyroidal illness syndrome. Furthermore, in survivors of COVID-19, thyroid function tests at follow-up returned to baseline.

Thyroid disorders and SARS-CoV-2 infection: From pathophysiological mechanism to patient management.

The World Health Organization (WHO) declared the COVID-19 epidemic to be a global pandemic in March 2020. COVID-19 is an infection caused by SARS-CoV-2, a coronavirus that utilizes the angiotensin-2 converting enzyme to penetrate thyroid and pituitary cells, and may result in a "cytokine storm". Based on the pathophysiological involvement of the pituitary-thyroid axis, the current review discusses the diagnosis of abnormal thyroid function test, and the management of patients presenting with thyrotoxicosis, thyroid-associated orbitopathy and hypothyroidism in the context of SARS-CoV-2 infection.