| Grade of recommendation (GOR) | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grade A | Strongly recommended | ||||||||||||||||||||
| Grade B | Recommended | ||||||||||||||||||||
| Grade C1 | May be reasonable but there is insufficient evidence | ||||||||||||||||||||
| Grade C2 | Not recommended because of a lack of scientific evidence | ||||||||||||||||||||
| Grade D | Not recommended because of potentially harmful | ||||||||||||||||||||
| Levels of evidence (LOE) | |
|---|---|
| High | High-quality and consistent evidence from more than one randomized controlled trial or overwhelming evidence from observational studies. Further studies may not change the assessment. |
| Middle | Significantly problematic (inconsistent results, flawed methodology, indirect, or inaccurate) evidence from more than one randomized controlled trial or very strong evidence from observational studies. If further studies are performed, assessment is likely to change. |
| Low | Evidence from observational studies, unstructured clinical experience, or more than one seriously defective randomized controlled trial. All estimate effects are uncertain. |