Tools for assessing quality and risk of bias by levels of evidence

Tools for assessing methodological quality or risk of bias in randomized controlled trials (RCTs) and non-randomized studies (NRS) were reviewed. The van Tulder scale and Cochrane's assessment of risk of bias are the two most useful methodological quality evaluation tools for RCTs. Cochrane's tool includes sequence generation, allocation of sequence concealment, blinding, incomplete outcome data, selective outcome reporting, and other potential sources of bias. The Cochrane Collaboration Group recommends the Downs and Black instrument and the Newcastle-Ottawa Scale for evaluating the quality of NRS. In conclusion, this study offers useful information to physicians about tools for assessing the quality of evidence in clinical guidelines. Further research is needed to provide an essential core for evidence-based decision making regarding levels and/or grades of recommendations.

Translational medicine related tools for quality assessments of clinical trials and the trial reports / 中华临床营养杂志

Objective and fair clinical trials are the main methods for assessing the clinical significances of the experimental findings. The development of translational medicine highly relies on high-quality clinical trials as well as trial reports. Although the definition of"quality of clinical trials"and"quality of trial reports"differs from each other, they are closely related and can be consistent in most circumstance in the context of"scientific integrity". The quality of trial reports can be basically assessed by their internal and external properties. The quality of a randomized trial can be assessed by Jadad scale and Cochrane collaboration's tool for assessing risk of bias, and the quality of a non-randomized trial by risk of bias tool and Newcastle-Ottawa scale. However, since Jadad scale lacks appropriate appraisal of allocation concealment and is too simple in evaluating blind method, assessment of allocation concealment should be added. A more widely accepted approach for assessing the quality of random trials is the combination of Jadad scale and Schulz's approach to allocation concealment till recent years.For non-randomized cohort studies and case-control studies, Newcastle-Ottawa scale might be suitable at present time.