Table 1 Level of evidence assessment [14]

1

Evidence from a systematic review of all relevant randomized controlled trials (RCTs), or evidence-based clinical practice guidelines based on systematic reviews of RCTs

2

Evidence obtained from at least one well-designed randomized controlled trial (RCT)

3

Evidence obtained from well-designed controlled trials without randomization, quasi-experimental

4

Evidence from well-designed case-control and cohort studies

5

Evidence from systematic reviews of descriptive and qualitative studies

6

Evidence from a single descriptive or qualitative study

7

Evidence from the opinion of authorities and/or reports of expert committees