Background: Network meta-analysis could combine information from all randomized controlled trials when many treatment regimens already exist, to rank their benefits (harms) to choose the best option for patients. But we were unclear whether it could be applied into network meta-analysis.

Objectives: To evaluate whether GRADE approach could be applied into network meta-analysis and discussed the challenge of using GRADE approach for network meta-analysis.

Methods: We searched PubMed, the Cochrane library, Embase, ISI Web of Knowledge, and Google Scholar using ‘Network meta analysis’ OR ‘mixed treatment comparisons meta analyses’ OR ‘multiple treatments meta analysis’ in title/abstract without language, time, publication type restrictions at October 21, 2010 (updated at February 21, 2012). We included any network meta-analysis, regardless of the conditions or interventions. For the evaluation of quality of evidence, GRADE approach were used to specify high, moderate, low, and very low levels. Two trained authors independently selected studies, abstracted data, and assessed the qualities, and disagreement was resolved by a third author.

Results and Conclusions: They would be presented in the 20th Cochrane Collaboration.