Levels of evidence | |
I | RCTs and/or systematic review or metanalysis of RCTs |
II | A single well designed RCT |
III | Cohort studies with concurrent or historical controls or their metanalysis |
IV | Case control studies or their metanalysis |
V | Case series without controls |
VI | Expert opinion, guidelines, documents coming from consensus conference |
Grade of recommendations | |
A | Highly recommended. From good quality level, even if not level I-II |
B | Not always recommended but must be taken in consideration |
C | Substantial uncertainty in favour or against |
D | Not recommended |
E | Highly not recommended |