Grade of recommendation | Clarity of risk/benefit | Methodological strength of supporting evidence | Implications |
---|---|---|---|
1A | Risk/benefit clear | Randomized controlled trials (RCTs) without important limitations | Strong recommendation, can apply to most patients in most circumstances without reservation |
1 B | Risk/benefit clear | RCTs with important limitations (inconsistent results, methodological flaws) | Strong recommendations, likely to apply to most patients |
1 C+ | Risk/benefit clear | No RCTs but RCT results can be unequivocally extrapolated, or overwhelming evidence from observational studies | Strong recommendation, can apply to most patients in most circumstances |
1 C | Risk/benefit clear | Observational studies | Intermediate strength recommendation; may change when stronger evidence available |
2A | Risk/benefit unclear | RCTs without important limitations | Intermediate strength recommendation, best action may differ depending on circumstances or patients' or societal values |
2 B | Risk/benefit unclear | RCTs with important limitations (inconsistent results, methodological flaws) | Weak recommendation, alternative approaches likely to be better for some patients under some circumstances |
2 C | Risk/benefit unclear | Observational studies | Very weak recommendations; other alternatives may be equally reasonable |