[Evidence-based guidelines and nephrological clinical practice: the GRADE system for rating of evidence].

It has become widely accepted that decision-making should be based on the best available evidence. The preparation of evidence-based guidelines in the interest of improving long-term outcomes has been a challenging task for many societies. Although nephrology is a relatively young medical discipline and therefore presumably well-disposed towards evidence-based decision making, many problems exist and evidence-based approaches to guidelines have also been widely criticized. One key issue has been the availability of only few and suboptimal randomized trials in this discipline. Considerable variation in the grading systems used to assess existing evidence in nephrology guidelines highlights the need for a better tool. Tools that rigidly assess existing evidence need to also explore the applicability to current practice. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system, developed and implemented in 2004 by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines panel, is the most advanced tool in this direction.