The strength of a recommendation indicates the extent to which one can be confident that adherence to the recommendation will do more good than harm. The quality of a body of evidence refers to the extent to which our confidence in an estimate of effect is sufficient to support a Grading the quality of evidence for each outcome across studies. Following GRADE, the quality of a body of evidence pertaining to a particular outcome of interest was initially categorized on the basis of study design. For questions of interventions, the initial quality grade was High if the body of evidence consisted of RCTs, Low if it consisted of observational studies, and Very Low if it consisted of studies of other study designs. For questions of interventions, the Work Group decided to use only RCTs. The grade for the quality of evidence for each intervention outcome pair was then lowered if there were serious limitations to the methodological quality of the aggregate of studies, if there were important inconsistencies in the results across studies, if there was uncertainty about the directness of evidence including limited applicability of the findings to the population of interest, if the data were imprecise (a low event rate [0 or 1 event] in either arm or a CI spanning a range 41) or sparse (only 1 study or total N o500), or if there was thought to be a high likelihood of bias. Once consensus is reached in a group meeting, the final grade for the quality of the evidence for an intervention outcome pair could be one of the following four grades: High , Moderate , Low or Very Low (Table 11). CKD subgroup analyses. 