1. ¹Department of Medicine, Tufts New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
2. ²Department of Medicine and Therapeutics, University of Aberdeen, Aberdeen, Scotland
3. ³Department of Public Health and Community Medicine, University of Sydney, Children's Hospital at Westmead, Westmead, Australia
4. ⁴Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
5. ⁵The University of Western Ontario, London, Ontario, Canada
6. ⁶Resolution Health Inc., San Jose, California, USA
7. ⁷Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
8. ⁸Department of Nephrology, Royal Melbourne Hospital, Victoria, Australia
9. ⁹Department of Medicine, University Hospital Wuerzburg, Wuerzburg, Germany
10. ¹⁰Department of Medicine, Ghent University Hospital, Ghent, Belgium
11. ¹¹Baylor College of Medicine, Houston, Texas, USA

Correspondence: K Uhlig, Tufts New England Medical Center, 750 Washington Street, Box 395, Boston, Massachusetts 02111, USA. E-mail: kuhlig@tufts-nemc.org

Received 28 June 2006; Revised 24 July 2006; Accepted 1 August 2006; Published online 27 September 2006.

Abstract

Considerable variation in grading systems used to rate the strength of guideline recommendations and the quality of the supporting evidence in Nephrology highlights the need for a uniform, internationally accepted, rigorous system. In 2004, Kidney Disease: Improving Global Outcomes (KDIGO) commissioned a methods expert group to recommend an approach for grading in future nephrology guidelines. This position statement by KDIGO recommends adopting the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach for the grading of evidence and guidelines on interventions. The GRADE approach appraises systematic reviews of the benefits and harms of an intervention to determine its net health benefit. The system considers the design, quality, and quantity of studies as well as the consistency and directness of findings when grading the quality of evidence. The strength of the recommendation builds on the quality of the evidence and additional considerations including costs. Adaptations of the GRADE approach are presented to address some issues pertinent to the field of nephrology, including (1) the need to extrapolate from studies performed predominantly in patients without kidney disease, and (2) the need to use qualitative summaries of effects when it is not feasible to quantitatively summarize them. Further refinement of the system will be required for grading of evidence on questions other than those related to intervention effects, such as diagnostic accuracy and prognosis.