Table 1 Classification of the literature consulted, according to strength of evidence
From: Evidence based guidelines for complex regional pain syndrome type 1
Level of evidence for studies on intervention: | |
|---|---|
A1 | systematic reviews that comprise at least several A2 quality trials whose results are consistent |
A2 | high-quality randomized comparative clinical trials (randomized, double-blind controlled trials) of sufficient size and consistency |
B | randomized clinical trials of moderate quality or insufficient size, or other comparative trials (non-randomized, comparative cohort study, patient control study) |
C |    non-comparative trials |
D |    opinions of experts, such as project group members |
Level of evidence for conclusions: | |
1 | at least one systematic review (A1) or two independent grade A2 studies |
2 | at least two independent grade B studies |
3 | at least one grade A2, B or C study |
4 | opinions of experts, such as project group members |