Table 1 Recommendation grading (according to the "Guide d’analyse de la littérature et gradation des recommandations" - Literature analysis and recommendation grading guide, HAS, January 2000)
Level of scientific proof provided by the literature (for clinical studies) | Recommendation grading |
|---|---|
Level 1 | |
● High-power randomised comparative studies | A |
● Meta-analysis of randomised comparative studies | Scientific proof established |
● Decision analysis based on well-conducted studies | |
Level 2 | |
● Low-power randomised comparative studies | B |
● Well-conducted non-randomised comparative studies | Scientific proof presumed |
Level 3 | |
● Case–control studies | |
C | |
Level 4 | Low level of proof |
● Comparative studies with major bias | |
● Retrospective studies | |
● Case series |