Level of evidence | Explanation |
---|---|
1 | Meta-analysis of randomized controlled trials, good quality randomized controlled trials or 'all or none' studies in which no treatment is not an option |
2 | 'Low quality' randomized controlled trials (< 80% follow up), meta-analysis of good quality prospective 'cohort studies' or well designed controlled study without randomization |
3 | Good quality retrospective 'case-control'-studies or comparative studies |
4 | Consensus, usual practise, disease-oriented evidence, and/or expert opinion |
Strength of recommendation | Explanation |
A | Use of agent is recommended ("do it") |
B | Use of agent should be considered ("probably do it") |
C | Use of agent may be considered ("is not recommended") |