Thyroid hormones and platelet activation in COVID-19 patients

PURPOSE

To retrospectively describe the association between thyroid hormones (TH) and platelet activation, as represented by mean platelet volume (MPV), in a cohort of patients hospitalized for COVID-19 with no known thyroid disease, and to correlate these data with the severity of COVID-19 and the occurrence of death/ARDS (Acute Respiratory Distress Syndrome).

METHODS

103 patients with real-time polymerase chain reaction (RT-PCR) testing-confirmed COVID-19 and hospitalized were enrolled. Serum samples were collected from patients upon admission before starting any treatment. Chi-squared test was used to determine the association between euthyroid sick syndrome (ESS) and COVID-19 severity. Multivariate logistic regression was performed to evaluate the best independent predictors of COVID-19 deaths/ARDS.

RESULTS

39/103 (37.9%) of patients were found to have ESS, and this condition was an independent predictor for the severity of COVID-19 (p = 0.003). Lower TSH and lower FT3/FT4 ratio correlated with higher MPV (p = 0,001 and p = 0.010), with an opposite trend with respect to what has been documented in non-COVID patients. Increasing MPV and lower FT3 significantly increased the risk, in COVID-19 patients, of an adverse outcome of death/ARDS.

CONCLUSION

Increased platelet activation, as represented by increased MPV, has already been reported to correlate with COVID-19 severity, possibly as a consequence of cytokine release. We demonstrated, in a cohort of 103 patients with COVID-19, that MPV is inversely correlated to TH levels, in particular in the case of ESS, where downregulation of TH axis may occur in case of systemic cytokine inflammation and more severe outcomes (death/ARDS). That ESS itself may directly cause platelet activation, as demonstrated by higher MPV in these patients, is an interesting hypothesis which deserves further investigation.

Analysis of thyroid function in Japanese patients with coronavirus disease 2019

Thyroid dysfunction that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is becoming increasingly recognized. However, only a few reports in Japan have addressed this issue to date. In this study, we sought to clarify whether infection with SARS-CoV-2 affected thyroid hormone levels and whether these hormones could be better predictors of prognosis in patients with coronavirus disease 2019 (COVID-19). Accordingly, we retrospectively examined 147 cases wherein thyroid hormones were measured at the time of admission among 848 Japanese patients with COVID-19 admitted to the Hyogo Prefectural Kakogawa Medical Center. All patients underwent thyroid function testing upon hospital admission. More than half (59.1%) of the patients were euthyroid. Twenty-four percent of patients had serum thyroid-stimulating hormone (TSH) levels lower than the reference range with normal serum free thyroxine (fT4) levels, and 3.4% of the patients had low TSH with high fT4 levels. Over 70% of the patients with moderate and severe COVID-19 had low serum free triiodothyronine (fT3) levels. Serum TSH and fT3 levels were inversely correlated with disease severity. The mortality rate in patients with low serum fT3 levels was significantly higher than that in those with normal serum fT3 levels.

Clinical Significance of Low-Triiodothyronine Syndrome in Patients Requiring Non-Surgical Intensive Care - Triiodothyronine Is a Comprehensive Prognostic Marker for Critical Patients With Cardiovascular Disease

Background: Low-triiodothyronine (T₃) syndrome is a known complication in intensive care unit (ICU) patients, but the underlying mechanisms and prognostic impact are unclear.

Methods and Results: This study retrospectively enrolled 2,976 patients who required care in the ICU. Of these patients, 2,425 were euthyroid and were divided into normal (n=1,666; free T₃ [FT₃] ≥1.88 µIU/L) and low-FT₃ (n=759; FT₃ <1.88 µIU/L) groups. Multivariate logistic regression analysis revealed that prognostic nutritional index >46.03 (odds ratio [OR] 2.392; 95% confidence interval [CI] 1.904–3.005), age (per 1-year increase; OR 1.022; 95% CI 1.013–1.031), creatinine (per 0.1-mg/dL increase; OR 1.019; 95% CI 1.014–1.024), and C-reactive protein (per 1-mg/dL increase; OR 1.123; 95% CI 1.095–1.151) were independently associated with low FT₃. Survival rates (within 365 days) were significantly lower in the low-FT₃ group. A multivariate Cox regression model showed that low FT₃ was an independent predictor of 365-day mortality (hazard ratio 1.785; 95% CI 1.387–2.297). Low-T₃ syndrome was significantly more frequent in patients with non-cardiovascular than cardiovascular diseases (73.5% vs. 25.8%). Prognosis was significantly poorer in the low-FT₃ than normal group for patients with cardiovascular disease, particularly those with acute coronary syndrome and acute heart failure.

Conclusions: Low-T₃ syndrome was associated with aging, inflammatory reaction, malnutrition, and renal insufficiency and could lead to adverse outcomes in patients admitted to a non-surgical ICU.

Relevance of TSH evaluation in elderly in-patients with non-thyroidal illness

BACKGROUND

Non-thyroidal illness (NTI) is frequent in hospitalized patients. Its recovery is characterized by a raise in TSH levels. However, the clinical significance of high TSH levels at admission in hospitalized elderly patients with NTI remains uncertain.

AIM

To explore the relevance of baseline TSH evaluation in hospitalized elderly patients with NTI.

METHODS

We examined the participants with NTI (n = 123) from our previous study (Sforza, 2017). NTI was defined as: low T3 (< 80 ng/dL) and normal or low total T4 in the presence of TSH values between 0.1 and 6.0 mU/L. Thyroid function tests were performed on day 1 and day 8 of the hospital stay. Positive TSH changes (+ ΔTSH) were considered when the day-8 TSH value increased more than the reference change value for TSH (+ 78%). Multiple logistic regression was used to evaluate the independent association of baseline TSH, sex, clinical comorbidities (by ACE-27) and medications with + ΔTSH.

RESULTS

Out of 123 patients (77 ± 8 years, 52% female), 34 showed a + ΔTSH. These patients had a lower TSH at admission (p < 0.001) and intra-hospital mortality (p = 0.003) than the others. In multiple logistic regression, TSH > 2.11 mU/L at baseline was associated with reduced odds to show + ΔTSH [odds ratio (95 CI) 0.29 (0.11-0.75); p = 0.011] in a model adjusted by age, sex and ACE-27.

DISCUSSION

Inappropriately higher TSH levels at admission in hospitalized elderly patients were associated with a reduced ability to raise their TSH levels later on. The present results confront the idea that TSH levels at admission are irrelevant in this clinical context.

Relation of thyroid hormone abnormalities with subclinical inflammatory activity in patients with type 1 and type 2 diabetes mellitus

Thyroid hormone (TH) abnormalities are common in patients with diabetes mellitus (DM). These thyroid hormone abnormalities have been associated with inflammatory activity in several conditions but this link remains unclear in DM. We assessed the influence of subclinical inflammation in TH metabolism in euthyroid diabetic patients. Cross-sectional study involving 258 subjects divided in 4 groups: 70 patients with T2DM and 55 patients with T1DM and two control groups of 70 and 63 non-diabetic individuals, respectively. Groups were paired by age, sex, and body mass index (BMI). We evaluated the association between clinical and hormonal variables [thyrotropin, reverse T3 (rT3), total and free thyroxine (T4), and triiodothyronine (T3)] with the inflammation markers C-reactive protein (hs-CRP), serum amyloid A (SAA), and interleukin-6 (IL-6). Serum T3 and free T3 were lower in patients with diabetes (all P < 0.001) compared to the control groups. Interleukin-6 showed positive correlations with rT3 in both groups (P < 0.05). IL-6 was independently associated to FT3/rT3 (B = -0.193; 95% CI -0.31; -0.076; P = 0.002) and FT4/rT3 (B = -0.107; 95% CI -0.207; -0.006; P = 0.039) in the T1DM group. In the T2DM group, SAA (B = 0.18; 95% CI 0.089; 0.271; P < 0.001) and hs-CRP (B = -0.069; 95% CI -0.132; -0.007; P = 0.03) predicted FT3 levels. SAA (B = -0.16; 95% CI -0.26; -0.061; P = 0.002) and IL6 (B = 0.123; 95% CI 0.005; 0.241; P = 0.041) were related to FT4/FT3. In DM, differences in TH levels compared to non-diabetic individuals were related to increased subclinical inflammatory activity and BMI. Altered deiodinase activity was probably involved. These findings were independent of sex, age, BMI, and HbA1c levels.

Thyroid abnormalities

Thyroid abnormalities and nonthyroidal illness complicate human immunodeficiency virus (HIV) infection. Among the effects that result from HIV and other opportunistic infections, distinctive features of HIV infection include early lowering of reverse tri-iodothyromine (T3) levels, with normal free T3 levels. Later, some patients develop an isolated low free thyroxine level. After highly active antiretroviral therapy, the immune system reconstitutes in a way that leads to dysregulation of the autoimmune response and the appearance of Graves disease in 1% to 2% of patients. Opportunistic thyroid infections with unusual organisms are most commonly asymptomatic, but can lead to acute or subacute thyroiditis.