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Levels of Quality
| Underlying methodology | Quality rating |
|---|---|
| Randomized trials; or double-upgraded observational studies. | High |
| Downgraded randomized trials; or upgraded observational studies. | Moderate |
| Double-downgraded randomized trials; or observational studies. | Low |
| Triple-downgraded randomized trials; or downgraded observational studies; or case series/case reports. | Very low |
Adopted from Cochrane Handbook [42]: Levels of quality of a body of evidence in the GRADE approach
