Table 2.
Prospective studies that analyzed thyroid function in COVID-19 patients during admission.
| Author, | Number of patients | Comorbidity | Severity | Thyroid function markers | Hyperthyroidism (%) | Main statistical findings |
|---|---|---|---|---|---|---|
| Local Month/year | Men’s n (%) – Age | Length of stay | Mortality | Inflammatory markers | NTIS (%) | Limitations |
| Muller et al. | 145 (COVID-19), 93 (ICU), 52 (non-ICU); 101 (non-COVID-19) |
Not mentioned | Moderate 35.9% Critical 64.1% |
TSH, FT4, FT3 | Overt thyrotoxicosis 11.8% Subclinical thyrotoxicosis 17.7% |
FT4 were higher in the COVID-19 ICU group (18.7 ± 5.4) than in the COVID-19 NICU (13.5 ± 4.6) group (p=0·016) but not in non-COVID-19 group (16.2 ± 2.4) (p=0·38). |
| Italy Set/2020 (117) |
89 (61.4%) COVID-19 ICU 65.3 ± 12.9 years COVID-19 non-ICU 70.3 ± 18.1 years |
COVID-19 ICU (23.8 ± 15.8 days) COVID-19 NICU (22.3 ± 15.5 days) |
COVID-19 ICU (18.7%) COVID-19 NICU (7.8%) |
PCR, D-dimer, ferritin, DHL. | Not mentioned | Small sample size. Reverse T3 and other biomarkers were not measured. |
| Khoo et al. | 334 | Hypertension 48,5% Diabetes 39,5% CVD 23,7% COPD 17,4% CKD 13,2% |
Moderate 89,3% Critical 10,7% |
TSH, FT4 | Overt thyrotoxicosis 0% Subclinical thyrotoxicosis 5.4% |
Patients with COVID-19 had lower TSH (1.03 mU/L) and FT4 (12.60 pmol/L) than patients without COVID-19: TSH (1.48 mU/L, P = 0.01) and T4L (13.11 pmol/L, P = 0.01). |
| United Kingdom Jan/2021 (118) |
203 (60,8%) 66,1 ± 16 years |
8 days (IQR 6-11). | 26% | CPR, cortisol, albumin | Not mentioned | Free T3 was not measured; therefore, patients with NTIS were not analyzed. |
| Guven et al. | 250 | Not mentioned | Moderate 50% Critical 50% |
TSH, FT4 | Overt thyrotoxicosis 4% Subclinical thyrotoxicosis 5.2% |
The FT3 level showed a negative correlation with length of hospital stay and CRP (r = −0.216, p=0.001; r = −0.383, P < 0.0001). |
| Turquia Mar/2021 (119) |
157 (63%) 68 (54-78) years |
9 days (IQR 5-15). | 15,2% | PCR, D-dimer, ferritin | 13% | Small sample size. Diabetic and nephropathy patients were excluded. |
| Lui et al | 367 | Hypertension 24,3% Diabetes 16,3% CVD 5,4% CVA 2,7% COPD 3,5% |
Mild 75,2% Moderate 21% Critical 3,8% |
TSH, FT3, FT4 | Subclinical thyrotoxicosis 8,2% |
Patients with NTIS had a higher risk of death (adjusted OR 3.18, 95% CI 1.23–8.25, p = 0.017), |
| China Apr/2021 (120) |
172 (46,9%) 54 ± 15 years |
8 days (IQR 6-13). | 1% | CPR, CPK, TGP, DHL | 7,4% | Most mild COVID-19 patients. Reverse T3 not measured. |
| Campi et al | 115 | Hypertension 64% Diabetes 17,5% Cardiopathy 6,3% CVA 4,2% Pneumopathy 3,1% |
Critical 100% (ICU) |
TSH, FT3, FT4, Tg, anti-Tg | Subclinical thyrotoxicosis: during admission (10,4%), during hospitalization (23,5%) |
Low TSH levels were found either at admission or during hospitalization in 39% of patients, associated with low FT3 in half of the cases. In the univariate analysis, the predictors of mortality were low FT3 (P <0.0001) and low FT4 (P = 0.01). |
| Italy Mai/2021 (98) |
97 (67%) 68.1 ± 14 years |
21 ± 19 days | 31.3% | PCR, Cortisol | 9% | Only severe COVID-19 patients. |
| Beltrao et al | 245 | Hypertension 66.5% Diabetes 44.6% DCV 13.8% Pneumopathy 4.4% |
Non-critical 73.9% Critical 26.1% |
TSH, FT3, FT4, TT3, rT3, Tg anti-Tg | Subclinical thyrotoxicosis 27.3% | fT3 levels were lower in critically ill compared with non-critical patients [fT3: 2.82 (2.46–3.29) pg/mL vs. 3.09 (2.67–3.63) pg/mL, p = 0.007]. Serum reverse triiodothyronine (rT3) was mostly elevated but less so in critically ill compared with non-critical patients [rT3: 0.36 (0.28–0.56) ng/mL vs. 0.51 (0.31–0.67) ng/mL, p = 0.001]. There is correlation between in-hospital mortality and serum fT3 levels (odds ratio [OR]: 0.47; 95% confidence interval [CI 0.29–0.74]; p = 0.0019), rT3 levels (OR: 0.09; [CI 0.01–0.49]; p = 0.006) and the product fT3 · rT3 (OR: 0.47; [CI 0.28–0.74]; p = 0.0026). |
| Brazil Nov/2021 (60) |
145 (59.1%) 62 (49-75) years |
6 (4–10) days | 16.7% | PCR, D-dimer, fIL-6, DHL, albumin | 6.5% | It is unclear whether a decrease in caloric intake, a weight loss, or a combination of these factors are the cause of decreased fT3 levels in COVID-19 critically ill patients. |
| Vizoso et al | 78 | Hypertension 55.1% Diabetes 25.6% CVD 15.4% COPD 12.8% Cancer 11.5% |
Critical 100% | TSH, FT3, FT4, T3, rT3 | Not mentioned | FT3 levels were lower in non-survivors (1.6 ± 0.2) vs survivors (1.8 ± 0.5) p = 0.02. |
| Spain Nov/2021 (121) |
55/78 (70.5%) Survivors 59 ± 12 Non-survivors 68 ± 12 |
Survivors 37 (22–83) days Non-survivors 18 (7–39) days |
29.5% | Not evaluated | 46.2% | Small sample size. Critical patients only. |
| Ilera et al. | 55 | Not mentioned | Mild 22% Moderate 27.1% Critical 50.8% |
TSH, FT3, TT3, FT4, TT4, anti-TPO | 0% | The T3/T4 ratio was significantly lower in patients with severe disease compared with those with mild/moderate infection [7.5 (4.5–15.5) vs. 9.2 (5.8–18.1); p =0.04] and lower in patients who died than in patients who were discharged [5.0 (4.53–5.6) vs. 8.1 (4.7–18.1); p = 0.03] |
| Argentina Dez/2021 (122) |
28 (50.9%) 56 (21-89) years |
Not mentioned | 7.4% | CPR, D-dimer, ferritin, DHL, VHS, fibrinogenin | 54.5% | Small sample size. |
| Sparano et al | 506 | Hypertension 51.3% Diabetes 17% CVD 26.9% COPD 7.1% Cancer 18.4% |
Mild/Moderate 73.7% Critical 26.3% |
TSH, FT3, FT4 | Overt thyrotoxicosis 12.4% | In Kaplan–Meier and Cox regression analyses, fT3 was independently associated with poor outcome and death (p = 0.005 and p = 0.037, respectively). A critical fT3 threshold for levels < 2.7 pmol/l (sensitivity 69%, specificity 61%) was associated with a 3.5-fold increased risk of negative outcome (95%CI 2.34–5.34). |
| Italy 2022 (123) |
62.3% 68.8 ± 1.6 years |
12.5 ± 9.1 days | 19% | IL-6, NT-ProBNP, PCR, procalcitonin, D-dímer, DHL, | 57% | Monocentric study, without a control group. Most mild patients. Reverse T3 levels were not evaluated. |