KDIGO Clinical Practice Guideline for Acute Kidney Injury
Grading the quality of evidence and the strength of recommendations

Grading the quality of evidence and the strength of recommendations

The grading approach followed in this guideline is adopted from the GRADE system.^40,41 The strength of each recommendation is rated as level 1 which means ‘‘strong’’ or level 2 which means ‘‘weak’’ or discretionary. The wording corresponding to a level 1 recommendation is ‘‘We recommend ... should’’ and implies that most patients should receive the course of action. The wording for a level 2 recommendation is ‘‘We suggesty ... might’’ which implies that different choices will be appropriate for different patients, with the suggested course of action being a reasonable choice in many patients. In addition, each statement is assigned a grade for the quality of the supporting evidence, A (high), B (moderate), C (low), or D (very low). Table 1 shows the implications of the guideline grades and describes how the strength of the recommendations should be interpreted by guideline users.

Furthermore, on topics that cannot be subjected to systematic evidence review, the Work Group could issue statements that are not graded. Typically, these provide guidance that is based on common sense, e.g., reminders of the obvious and/or recommendations that are not sufficiently specific enough to allow the application of evidence. The GRADE system is best suited to evaluate evidence on comparative effectiveness. Some of our most important guideline topics involve diagnosis and staging or AKI, and here the Work Group chose to provide ungraded statements. These statements are indirectly supported by evidence on risk relationships and resulted from unanimous consensus of the Work Group. Thus, the Work Group feels they should not be viewed as weaker than graded recommendations.

Table 1 | Implications of the strength of a recommendation