Table 2.
Main outcomes of the included studies
| Authors | Abnormal TFT | Low TSH levels | Normal TSH level | High TSH levels | TT3-TT4 | fT3-fT4 | Differences of TFT (COVID-19 vs controls) | Correlation of TFT vs COVID-19 severity | Correlation of thyroid dysfunction with COVID-19 mortality |
|---|---|---|---|---|---|---|---|---|---|
| Chen et al. | 32/50 (64%) | 28/501 (56%) | 32/501 (44%) | 0/501 (0%) |
Low TT3 15/50 (30%)7 Low TT4 3/50 (6%)7 |
NR | Yes | Yes | NR |
| Gao et al. | NR | 7/1002 (7%) | 85/1002 (85%) | 8/1002 (8%) | _ |
Low fT3 28/100 (28%)8 High fT3: none Low fT48 3/100 (3%) High fT48 17/100 (17%) |
NR | Yes | Yes |
| Khoo et al. | 45/334 (13.5%) | 18/3343 (5.4%) | 297/3343 (88.9%) | 19/3343 (5.7%) | _ |
fT3 not reported High fT4 none9 Low fT4 9 10/289 (3.4%) |
Yes | NR | NR |
| Lania et al. | 73/287 (25.4%) | 58/2874 (20.2%) | 214/2874 (74.6%) | 15/2874 (5.2%) | _ |
High fT3-fT4 31/73 (42%)10 Low fT3 and fT4 2/73 (2.8%)10 |
NR | NR | Yes |
| Lui et al. | 25/191 (13.1%) | 11/1915 (5.8%) | 179/1915 (93.7%) | 1/1915 (0.5%) | _ |
Low fT3 levels 12/191 (6.7%)12 Borderline-raised fT4 3/191 (1.6%)12 |
NR | Yes | NR |
| Muller et al. | 32/126 (25.4%) | 25/1266 (19.8%) | 94/1266 (74.6%) | 7/1266 (5.6%) | _ |
Higher fT4 levels vs controls11 No differences in fT3 levels11 |
Yes | No | NR |
| Zou et al. | 41/149 (27.5%) | NR | NR | NR | _ | Low fT3 41/149 (27.5%)13 | NR | Yes | No |
NA not available; Reference range TSH: 1Abbott (not reported), 2Roche (0.27–4.20 mUI/L), 3Abbott (0.3–4.20 mUI/L), 4Beckman (0.34–4.80 mUI(L), 5Cobas, ROCHE (0.27–4.2 mUI/L), 6ADVIA CentaurTSH3-Ultra (0.35–4.8 mIU/L); Reference Range Thyroid Hormones: 7Not reported, 8fT3 = 3.10–6.8 pmol/,L fT4 = 12–22 pmol/L, 9 fT4 = 9.0–23 pmol/L, 10fT4 = 7.8–17.29 pmol/L, fT3 = 3.38–6.45, 11fT4 = 10.3–21.9 pmol/L and fT3 = 3.1–7-7 pmol/L, 12 fT3 3.2–6.5 pmol/L, fT4 12–23 pmol/L,13 ESS- described as serum fT3 < 2.3 pg/mL NR, not reported