Table 1.
Meta-analytical calculations comparing baseline levels of blood-based biomarkers in responders and non-responders to ketamine.
| Blood-based biomarker | Number of studies | Sample size (responders/non-responders) | SMD (95% confidence interval) | p value | I2 |
|---|---|---|---|---|---|
| Neurotrophic factors | |||||
| Brain-derived neurotrophic factor (pg/ml) | 11 | 332 (161/171) | −0.04 (−0.30, 0.23) | 0.77 | 16% |
| Vascular endothelial growth factor (pg/ml) | 3 | 154 (88/66) | 0.08 (−0.25, 0.42) | 0.62 | 0% |
| Inflammatory markers | |||||
| Interleukin 6 (pg/ml) | 6 | 260 (128/132) | −0.04 (−0.36, 0.29) | 0.83 | 29% |
| Tumor necrosis factor α (pg/ml) | 6 | 260 (128/132) | −0.10 (−0.40, 0.21) | 0.54 | 22% |
| Interleukin 10 (pg/ml) | 4 | 196 (101/95) | −0.18 (−0.47, 0.11) | 0.23 | 0% |
| Interleukin 8 (pg/ml) | 3 | 186 (92/94) | −0.07 (−0.36, 0.22) | 0.62 | 0% |
| C-reactive protein (CRP) (mg/L) | 3 | 113 (47/66) | −0.28 (−0.67, 0.10) | 0.15 | 0% |
*
Responder = participant with least 50% improvement in depression.
**
Positive values for standardized mean difference (SMD) indicate that baseline levels of the biomarker are higher in responders than in non-responders while negative SMD(s) indicate that baseline levels of the biomarker are lower in responders than in non-responders.