Table 3 Results on publication bias
Outcome feature sets | Fail safe n | Z Kendall’s τ | p | Egger’s t test (df) | p | Missing studies (side) | After adjusting |
|---|---|---|---|---|---|---|---|
Cohort 1: COVID-19 patients versus non-COVID-19 control | |||||||
 KYN/TRP (overall) | 10.499 | 0.089 | 0.464 | 0.989 (8) | 0.175 | 3 (left) | SMD = 0.573 0.003; 1.144) |
 KYN/TRP (serum) | 11.244 | 0.679 | 0.248 | 1.223 (2) | 0.172 | 0 |  |
 KYN/TRP (plasma) | 4.373 | 0.563 | 0.286 | 0.347 (4) | 0.372 | 1 (left) | SMD = 0.462 (− 0.155; 1.080) |
 KYN (overall) | 11.647 | 0.494 | 0.310 | 0.269 (6) | 0.398 | 2 (left) | SMD = 0.961 (0.584; 1.338) |
 TRP (overall) | − 11.267 | 0.150 | 0.440 | 0.947 (5) | 0.193 | 1 (Right) | SMD = − 0.817 (− 1.618; − 0.017) |
 KA (overall) | 2.478 | 0.000 | 0.500 | 0.720 (2) | 0.273 | 0 |  |
 KA/(KYN + TRP) (Overall) | 1.673 | 1.162 | 0.122 | 0.549 (8) | 0.298 | 1 (Left) | SMD = 0.023 (− 0.358;0.405) |
 (KYN + KA)/TRP (overall) | 9.818 | 0.804 | 0.210 | 1.213 (8) | 0.129 | 2 (Left) | SMD = 0.579 0.0007; 1.157) |
 KA/KYN (Overall) | − 5.376 | 0.247 | 0.402 | 1.598 (6) | 0.080 | 0 |  |
Cohort 2: severe/critical COVID-19 patients versus mild/moderate COVID-19 patients | |||||||
 KYN/TRP (Overall) | 10.226 | 1.251 | 0.105 | 2.362 (7) | 0.025 | 1 (Left) | SMD = 0.876 (0.562; 1.189) |
 KYN (overall) | 7.758 | 0.187 | 0.425 | 0.129 (4) | 0.451 | 0 |  |
 TRP (overall) | -5.887 | 1.959 | 0.025 | 5.897 (3) | 0.004 | 0 |  |