Table 1 UK Kidney Association’s grading system for Recommendations’ strength and evidence quality

• Grade 1 Recommendation is a strong recommendation to do (or not do) something, where the benefits clearly outweigh the risks (or vice versa) for most, if not all patients (i.e. recommendations)

• Grade 2 Recommendation is a weaker recommendation, where the risks and benefits are more closely balanced or are more uncertain (i.e. suggestions)

• Grade A evidence means high-quality evidence that comes from consistent results from well-performed randomised controlled trials, or overwhelming evidence of some other sort

• Grade B evidence means moderate-quality evidence from randomised trials that suffer from serious flaws in conduct, inconsistency, indirectness, imprecise estimates, reporting bias, or some combination of these limitations, or from other study designs with special strength

• Grade C evidence means low-quality evidence from observational studies, or from controlled trials with several very serious limitations

• Grade D evidence is based only on case studies or expert opinion