Study | Design | Initial GRADE | Risk of bias interpretation | GRADE | |
Cotton et al
31 | Prospective, randomised trial | High | High*
| Serious limitations, downgrade one level. | Moderate ⊕⊕⊕ |
Jones and Frazier 25 | Retrospective | Low | High*
| Serious limitations, downgrade one level. | Very low⊕ |
Nessen et al
26 | Retrospective analysis of prospectively collected dataset | Low | Unclear†
| No serious limitations, do not downgrade. | Low⊕⊕ |
Perkins et al
29 | Retrospective review | Low | High*
| Serious limitations, downgrade one level. | Very low⊕ |
Spinella et al
30 | Retrospective | Low | Unclear†
| No serious limitations, do not downgrade. | Low⊕⊕ |
Yazer et al
8 | Prospective, historical controls | Low | High*
| Serious limitations, downgrade one level. | Very low⊕ |
*High: plausible bias that seriously weakens confidence in the results. Crucial limitation for one criterion, or some limitations for multiple criteria, sufficient to lower confidence in the estimate of effect.
†Unclear: plausible bias that raises some doubt about the results.
GRADE, Grading of Recommendations Assessment, Development and Evaluation.