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

The Influence of Autoimmune Thyroid Diseases on Viral Pneumonia Development, Including COVID-19: A Two-Sample Mendelian Randomization Study

The association between thyroid function and viral pneumonia has undergone extensive examination, yet the presence of a causal link remains uncertain. The objective of this paper was to employ Two-Sample Mendelian Randomization (MR) analysis to investigate the connections between three thyroid diseases and thyroid hormone indicators with viral pneumonia and COVID-19. We obtained summary statistics datasets from seven genome-wide association studies (GWASs). The primary method used for estimating relationships was inverse-variance weighting (IVW). In addition, we employed weighted median, weighted mode, MR-Egger, and MR-PRESSO as supplementary analytical tools. Sensitivity analyses encompassed Cochran's Q test, MR-Egger intercept test, and MR-PRESSO. Our study revealed significant causal relationships between having a genetic predisposition to autoimmune thyroid disease (AITD) and an increased susceptibility to viral pneumonia (odds ratio [OR]: 1.096; 95% confidence interval [CI]: 1.022-1.176). Moreover, it demonstrated a heightened susceptibility and severity of COVID-19 (OR for COVID-19 susceptibility, COVID-19 hospitalization, and COVID-19 critical illness, with 95% CIs of 1.016, 1.001-1.032; 1.058, 1.003-1.116; 1.045, 1.010-1.081). However, no statistically significant associations were found between TSH, FT4, subclinical hypo- or hyperthyroidism, and the risk of viral pneumonia incidence, or the susceptibility and severity of COVID-19 (all p > 0.05). This study establishes a cause-and-effect relationship between AITD and the development of viral pneumonia, as well as the susceptibility and severity of COVID-19.

Effects of SARS-CoV-2 infection on hypothyroidism and subclinical hypothyroidism: a meta-analysis

Background

In recent years, the outbreak of COVID-19 caused by SARS-CoV-2 has been witnessed globally. However, the impact of SARS-CoV-2 infection on thyroid dysfunction and subclinical thyroid dysfunction remains unclear. Therefore, this meta-analysis aimed to assess the effects of SARS-CoV-2 infection on thyroid dysfunction and its relationship with the severity of COVID-19.

Methods

We systematically searched databases including PubMed, Willey Library, Embase, Web of Science, CNKI, Wanfang, and VIP. We focused on randomized controlled trials, case-control studies, and cohort studies published between December 2019 and August 2023, examining the association between SARS-CoV-2 infection and hypothyroidism, with a specific emphasis on the severity of the infection. The quality of the research was assessed using the Newcastle-Ottawa Scale (NOS), while statistical analysis was conducted using the meta and metafor packages in R 4.2.1 software.

Results

For the meta-analysis, a total of eight articles were identified based on strict inclusion and exclusion criteria. For the association between SARS-CoV-2 infection and hypothyroidism, three studies (266 samples) comparing TSH levels of COVID-19 and control groups showed no difference in TSH levels [SMD=-0.04,95%CI(-1.22,1.15),P=0.95]. Additionally, two studies examining TT3 (a sample of 176 cases) and two studies examining TT4 (a sample of 176 cases) also showed no difference in TT3 and TT4 between the COVID-19 group and the control group, respectively. However, when evaluating the severity of COVID-19, six studies (565 samples) showed that TSH in the severe group was significantly lower than in the mild group [SMD = -0.55, 95% CI (-0.96, -0.14)], while FT3 was also lower in the severe group [SMD = -0.96, 95% CI (-1.24, -0.67)]. No noticeable differences were observed between the severe and mild groups in their TT3, FT4, and TT4 levels.

Conclusion

SARS-CoV-2 infection may have detrimental effects on thyroid function in individuals with severe symptoms. More research is needed to confirm and explore this relationship.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023486042.

Clinical features and long-term survival in idiopathic pulmonary arterial hypertension with thyroid dysfunction: insights from a national multicentre prospective study

Background

Our objective was to clarify the characteristics and long-term survival of idiopathic pulmonary arterial hypertension (IPAH) patients with thyroid dysfunction and compare them with IPAH without thyroid dysfunction.

Methods

A retrospective analysis was conducted using prospectively collected data. IPAH patients with thyroid dysfunction at baseline were included. Patients with other subgroups of PAH and Group 2-5 pulmonary hypertension were excluded. IPAH patients with euthyroid function were matched 1:1 to IPAH patients with thyroid dysfunction by age and sex.

Results

In total, 148 IPAH patients with thyroid dysfunction were included. Patients with hyperthyroidism, hypothyroidism, subclinical hyperthyroidism and subclinical hypothyroidism accounted for 16.2%, 18.9%, 8.1% and 56.8%, respectively. IPAH patients with hyperthyroidism showed the highest mixed venous oxygen saturation (SvO2) and the lowest pulmonary vascular resistance (PVR) at baseline among subgroups, while patients with subclinical hypothyroidism had the lowest SvO2 and highest PVR (p<0.05). Compared with IPAH without thyroid dysfunction, patients with hyperthyroidism (9.14 versus 13.86 WU; p<0.05) and hypothyroidism (10.70 versus 13.86 WU; p<0.05) showed significantly lower PVR. The haemodynamic profiles of patients with subclinical hypothyroidism were similar to IPAH with euthyroid function except for lower right atrial pressure (6 versus 8 mmHg; p=0.009). The long-term survival of patients with clinical thyroid dysfunction was better than IPAH without thyroid dysfunction, while that of those with subclinical diseases was comparable to the latter, even after adjusting for baseline haemodynamics and treatment.

Conclusion

IPAH patients with clinical hyper- and hypothyroidism had better haemodynamics and survival than those without thyroid dysfunction, while patients with subclinical hypothyroidism had similar haemodynamics and survival profiles to the latter.

Long-term effects of COVID-19 on the endocrine system - a pilot case-control study

Background

Coronavirus disease 2019 (COVID-19) has permanently changed the world. Despite having been a pandemic for nearly 3 years, the mid- and long-term complications of this disease, including endocrine disorders, remain unclear. Our study aimed to evaluate the lasting effects of COVID-19 on the endocrine system 6 months after initial infection.

Methods

We compared patients who underwent COVID-19 to age- and sex-matched subjects from a population-based study conducted before the pandemic. We evaluated differences in multiple parameters related to metabolism and the endocrine system including fasting glucose, insulin, lipids, body composition, thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroglobulin (aTG) and anti-thyroid peroxidase (aTPO) antibodies, prolactin, cortisol, testosterone, and estradiol.

Results

We found significantly lower levels of fT3 and fT4, accompanied by higher levels of TSH and aTPO antibodies, in COVID-19 survivors. Moreover, we found that patients who underwent SARS-CoV2 infection had higher levels of prolactin and lower levels of testosterone than controls. Interestingly, differences in testosterone levels were observed only in male subjects. We did not detect significant differences in body composition or metabolic and glycemic parameters between cases and controls, except for significantly higher values of the HOMA2-B index in COVID-19 survivors.

Conclusion

Our study indicates that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection might have long-term consequences on the endocrine system, including the suppressed function of the thyroid gland, prolactin, and male sex hormone secretion. Moreover, we showed that in a 6-month follow-up, COVID-19 had no consequences on glycemic parameters, lipid profiles, liver function, body composition, cortisol levels, and estradiol levels.

Long-term outcome of thyroid abnormalities in patients with severe Covid-19

OBJECTIVE

We have previously observed thyroid dysfunction, i.e. atypical thyroiditis (painless thyrotoxicosis associated with non-thyroidal illness syndrome), in patients with severe acute respiratory syndrome coronavirus 2 disease (Covid-19). This study aimed to analyse the evolution of thyroid dysfunction over time.

METHODS

One hundred eighty-three consecutive patients hospitalised for severe Covid-19 without known thyroid history were studied at hospital admission (baseline). Survivors were offered 12-month longitudinal follow-up including assessment of thyroid function, autoantibodies and ultrasound scan (US). Patients showing US focal hypoechoic areas suggestive of thyroiditis (focal hypoechogenicity) also underwent thyroid 99mTc or 123I uptake scan.

RESULTS

At baseline, after excluding from TSH analysis, 63 out of 183 (34%) Covid-19 patients commenced on steroids before hospitalisation, and 12 (10%) showed atypical thyroiditis. Follow-up of 75 patients showed normalisation of thyroid function and inflammatory markers and no increased prevalence of detectable thyroid autoantibodies. Baseline US (available in 65 patients) showed focal hypoechogenicity in 28% of patients, of whom 82% had reduced thyroid 99mTc/123I uptake. The presence of focal hypoechogenicity was associated with baseline low TSH (P = 0.034), high free-thyroxine (FT4) (P = 0.018) and high interleukin-6 (IL6) (P = 0.016). Focal hypoechogenicity persisted after 6 and 12 months in 87% and 50% patients, respectively, but reduced in size. After 9 months, thyroid 99mTc/123I uptake partially recovered from baseline (+28%) but was still reduced in 67% patients.

CONCLUSIONS

Severe Covid-19 induces mild transient thyroid dysfunction correlating with disease severity. Focal hypoechogenicity, associated with baseline high FT4, IL6 and low TSH, does not seem to be related to thyroid autoimmunity and may persist after 1 year although decreasing in size. Long-term consequences seem unlikely.

The prognostic utility of serum thyrotropin in hospitalized Covid-19 patients: statistical and machine learning approaches

PURPOSE

To assess the prognostic value of serum TSH in Greek patients with COVID-19 and compare it with that of commonly used prognostic biomarkers.

METHODS

Retrospective study of 128 COVID-19 in patients with no history of thyroid disease. Serum TSH, albumin, CRP, ferritin, and D-dimers were measured at admission. Outcomes were classified as "favorable" (discharge from hospital) and "adverse" (intubation or in-hospital death of any cause). The prognostic performance of TSH and other indices was assessed using binary logistic regression, machine learning classifiers, and ROC curve analysis.

RESULTS

Patients with adverse outcomes had significantly lower TSH compared to those with favorable outcomes (0.61 versus 1.09 mIU/L, p < 0.001). Binary logistic regression with sex, age, TSH, albumin, CRP, ferritin, and D-dimers as covariates showed that only albumin (p < 0.001) and TSH (p = 0.006) were significantly predictive of the outcome. Serum TSH below the optimal cut-off value of 0.5 mIU/L was associated with an odds ratio of 4.13 (95% C.I.: 1.41-12.05) for adverse outcome. Artificial neural network analysis showed that the prognostic importance of TSH was second only to that of albumin. However, the prognostic accuracy of low TSH was limited, with an AUC of 69.5%, compared to albumin's 86.9%. A Naïve Bayes classifier based on the combination of serum albumin and TSH levels achieved high prognostic accuracy (AUC 99.2%).

CONCLUSION

Low serum TSH is independently associated with adverse outcome in hospitalized Greek patients with COVID-19 but its prognostic utility is limited. The integration of serum TSH into machine learning classifiers in combination with other biomarkers enables outcome prediction with high accuracy.

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.