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. 2017 Sep 29;18(1):99. doi: 10.1186/s10194-017-0809-z

Table 2.

- Summary table of levels of evidence [181] and grades of recommendations of manual therapies for primary headaches

Type of manual therapies Levels of evidence Grades of recommendations
Chiropractic therapy 1- C
Osteopathic Manipulative Treatment 1+ B
Myofascial technique 2- D
Multimodal Approach 2- D

Legend for Levels of evidence

1++ High quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias

1+ Well-conducted meta-analyses, systematic reviews, or RCTs with a low risk of bias

1- Meta-analyses, systematic reviews, or RCTs with a high risk of bias

2++ High quality systematic reviews of case control or cohort or studies; high quality case control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal

2+ Well-conducted case control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal

2- Case control or cohort studies with a high risk of confounding or bias and a significant risk that the relationship is not causal

3 Non-analytic studies, e.g., case reports, case series

4 Expert opinion

Legend for Grades of recommendations

A: At least one meta-analysis, systematic review, or RCT rated as 1++, and directly applicable to the target population; or a body of evidence consisting principally of studies rated as 1+, directly applicable to the target population, and demonstrating overall consistency of results

B: A body of evidence including studies rated as 2++, directly applicable to the target population, and demonstrating overall consistency of results; or extrapolated evidence from studies rated as1++ or 1 +

C: A body of evidence including studies rated as 2+, directly applicable to the target population and demonstrating overall consistency of results; or extrapolated evidence from studies rated as 2++

D: evidence level 3or4; or extrapolated evidence from studies rated as 2 +

GPP: recommended best practice based on the clinical experience of the guideline development group