Table 32: Quality of Evidence.
| Study Design | Level of Evidence |
Number of Eligible Studies |
|---|---|---|
| Large RCT, systematic reviews of RCTs | 1 | 1 + 1 (original + extension) |
| Large RCT, unpublished but reported to an international scientific meeting | 1(g) | |
| Small RCT | 2 | |
| Small RCT, unpublished but reported to an international scientific meeting | 2(g) | |
| Nonrandomized study with contemporaneous controls | 3a | |
| Nonrandomized study with historical controls | 3b | |
| Nonrandomized study presented at international conference | 3(g) | |
| Surveillance (database or register) | 4a | |
| Case series (multi-site) | 4b | |
| Case series (single site) | 4c | |
| Retrospective review, modeling | 4d | |
| Case series presented at international conference | 4(g) |
For each included study, levels of evidence were assigned according to a ranking system based on a hierarchy proposed by Goodman. (58) An additional sesignation “g” was added for preliminary reports of studies that have been presented at international scientific meetings.