| Level of Recommendation | Criteria for analysis |
|---|---|
| A | Supported by at least two studies of level Ib or from a review level Ia (“it was shown”) |
| B | Supported by at least two independent studies of level II or extrapolations from studies of level I (“it is possible”) |
| C | Not supported by adequate studies of level I or II (“indications”) |
| D | Indications of experts (“there is no evidence”) |
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