Table 1.
GRADE system to evaluate the level of evidence and recommendation
| Grade of recommendation | Clarity of risk/benefit | Quality of supporting evidence | Implications |
|---|---|---|---|
| 1A Strong recommendation, high-quality evidence | Benefits clearly outweigh risk and burdens, or vice versa | RCTs without important limitations or overwhelming evidence from observational studies | Strong recommendation, applies to most patients in most circumstances without reservation |
| 1B Strong recommendation, moderate-quality evidence | Benefits clearly outweigh risk and burdens, or vice versa | RCTs with important limitations (inconsistent results, methodological flaws, indirect analyses, or imprecise conclusions) or exceptionally strong evidence from observational studies | Strong recommendation, applies to most patients in most circumstances without reservation |
| 1C Strong recommendation, low-quality, or very low-quality evidence | Benefits clearly outweigh risk and burdens, or vice versa | Observational studies or case series | Strong recommendation but subject to change when higher quality evidence becomes available |
| 2A Weak recommendation, high-quality evidence | Benefits closely balanced with risks and burden | RCTs without important limitations or overwhelming evidence from observational studies | Weak recommendation, best action may differ depending on the patient, treatment circumstances, or social values |
| 2B Weak recommendation, moderate-quality evidence | Benefits closely balanced with risks and burden | RCTs with important limitations (inconsistent results, methodological flaws, indirect, or imprecise) or exceptionally strong evidence from observational studies | Weak recommendation, best action may differ depending on the patient, treatment circumstances, or social values |
| 2C Weak recommendation, low-quality or very low-quality evidence | Uncertainty in the estimates of benefits, risks, and burden; benefits, risk, and burden may be closely balanced | Observational studies or case series | Very weak recommendation; alternative treatments may be equally reasonable and merit consideration |