The following is an extract from the 2009 guidelines of the Bundesaerzekammer (German Medical Association) www.arzt.de
Both the level of evidence based on underlying data and the level of recommendation, reflecting the risk-benefit ratio impact on recommendation for medical practice (table 7.3).
Level of recommendation | Risk-benefit ratio | Level of evidence | Assessment of the methodological validity of the underlying data | Overall assessment, classification | Implications | Key words |
---|---|---|---|---|---|---|
1 | Unambiguous | A | Randomised, controlled studies without essential methodological flaws with unambiguous results | 1 A | Strong recommendation. Valid for most patients |
shall |
1 | Unambiguous | C+ | No randomised, controlled studies, but unambiguous data available | 1 C+ | ||
1 | Unambiguous | B | Randomised, controlled study with methodological flaws. Despite unambiguous results of the study, it cannot be safely ruled out that methodical flaws have influenced the results | 1 B | Strong recommendation. Probably valid for most patients |
|
1 | Unambiguous | C | Observational studies without control group, but with convincing results | 1 C | Medium-strong recommendation, seems to be plausible, may be changed once improved data becomes available |
Should |
2 | Ambiguous | A | Randomised, controlled study without methodological reservations, but with conflicting results | 2 A | Medium-strong recommendation, depending on the individual case, a different course of action may be indicated. The interpretation of results by the Working Group Guidelines are taken into account in the recommendation |
|
2 | Ambiguous | C+ | No randomised, controlled studies, but data can be extrapolated from other studies | 2 C+ | Weak recommendation, depending on the individual case, a different course of action may be indicated. The interpretation of results by the Working Group Guidelines are taken into account in the recommendation |
Can |
2 | Ambiguous | B | Randomised, controlled study with severe flaws | 2 B | Weak recommendation, depending on the individual case, a different course of action may be indicated |
Can |
2 | Ambiguous | C | Observational studies, case reports | 2 C | Very Weak recommendation, depending on the individual case, a different course of action may be indicated |
Could |
Cross sectional guidelines for therapy with blood components and plasma derivatives, 4th revised edition 2009. Reproduced with permission from Bundesaertsekammer (German Medical Association). |