Grades of scientific evidence supporting the recommendations formulated in the Maastricht III Consensus Report
| Grade of recommendation | Evidence level | Type of studies | |
|---|---|---|---|
| A | 1 | 1a | Systematic review of randomised controlled trials (RCT) of good methodological quality and with homogeneity |
| 1b | Individual RCT with narrow confidence interval | ||
| 1c | Non-controlled studies | ||
| B | 2 | 2a | Systematic review of cohort studies (with homogeneity) |
| 2b | Individual cohort studies (including low quality RCT, eg <80% follow-up) | ||
| 2c | Non-controlled cohort studies/ecological studies | ||
| 3 | 3a | Systematic review of case-control studies (with homogeneity) | |
| 3b | Individual case-control studies | ||
| C | 4 | Case series/poor quality cohort or case-control studies | |
| D | 5 | Expert opinion without explicit critical appraisal or based on physiology, bench research or “first principles” | |