| Author | Confounding | Selection | Classification | Intended intervention | Missing data | Outcome | Report | Overall |
| Becker et al. [23] | Low | Low | Low | Low | Low | Low | Low | Low |
| Fischgrund et al. [24] | Low | Low | Low | Low | Low | Low | Low | Low |
| Khalil et al. [28] | Low | Low | Low | Low | Low | Low | Low | Low |
| Kim et al. [29] | Low | Low | Low | Low | Low | Low | Low | Low |
| Kim et al. [30] | Low | Low | Low | Low | Low | Low | Low | Low |
| Truumees et al. [31] | Low | Low | Low | Low | Low | Low | Low | Low |