The overall quality of the evidence was graded A, B, C, or D (Table 3). Table 4| GRADE system for grading quality of evidence Study design Starting grade of the quality of the evidence Step 2 Lower grade Step 3 Raise grade for observational studies RCTs High Study limitations: 2, very serious Strength of association: 1, large effect size (e.g., <0.5 or >2) 2, very large effect size (e.g., <0.2 or >5) Moderate Inconsistency: 2, very serious Evidence of a dose response gradient Observational studies Low Indirectness: 2, very serious All plausible confounding would reduce the demonstrated effect Very low Imprecision: 2, very serious Publication bias: 2, very serious GRADE, Grading of Recommendations Assessment, Development and Evaluation; RCT, randomized controlled trial. Table 5| KDIGO nomenclature and description for grading recommendations Grade Implications Patients Clinicians Policy Level 1 Strong We recommend Most people in your situation would want the recommended course of action, and only a small proportion would not. Most patients should receive the recommended course of action. The recommendation can be evaluated as a candidate for developing a policy or a performance measure. Level 2 Weak We suggest The majority of people in your situation would want the recommended course of action, but many would not. Different choices will be appropriate for different patients. Each patient needs help to arrive at a management decision consistent with her or his values and preferences. The recommendation is likely to require substantial debate and involvement of stakeholders before policy can be determined. Table 6| Determinants of the strength of recommendation Factors Comment Balance of bene ts and harms The larger the difference between the desirable and undesirable effects, the more likely a strong recommendation is provided. The narrower the gradient, the more likely a weak recommendation is warranted. 