General GTG

Question 1

Grade of recommendation: A

Answer 1

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

Question 2

Grade of recommendation: B

Answer 2

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 1++ or 1+

Question 3

Grade of recommendation: C

Answer 3

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++

Question 4

Grade of recommendation: D

Answer 4

Evidence level 3 or 4;or
Extrapolated evidence from studies rated as 2+

Question 5

Classification of evidence levels: 1++

Answer 5

High-quality meta-analyses,systematic
reviews of randomised controlled trials
or randomised controlled trials with a
very low risk of bias

Question 6

Classification of evidence levels: 1+

Answer 6

Well-conducted meta-analyses, systematic
reviews of RCTs
or RCT + low risk of bias

Question 7

Classification of evidence levels: 1-

Answer 7

Meta-analyses, systematic reviews of RCT or
RCT + high risk of bias

Question 8

Classification of evidence levels: 2++

Answer 8

High-quality systematic reviews of case–control or cohort studies or high-quality
case–control or cohort studies with a very low risk of confounding, bias or chance and a high probability that the
relationship is causal

Question 9

Classification of evidence levels: 2+

Answer 9

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

Question 10

Classification of evidence levels: 2-

Answer 10

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

Question 11

Classification of evidence levels: 3

Answer 11

Non-analytical studies, e.g. case reports, case series

Question 12

Classification of evidence levels: 4

Answer 12

Expert opinion