Level of Evidence

Level of Evidence A

Data derived from multiple randomized clinical trials or meta-analyses of such studies.

Level of Evidence B

Level of Evidence B-R: Data derived from one or more randomized trials or meta-analysis of such studies.

Level of Evidence B-NR: Data derived from one or more non-randomized trials or meta-analysis of such studies.

Level of Evidence C

Level of Evidence C-LD: Non randomized observational studies with limitations in design or execution or Metanalysis of such studies.

Level of Evidence C-EO: Consensus opinion of experts based on clinical experience.