Authors' objectives:

1. To examine the issue of quality assessment of randomised controlled trials (RCTs) included in meta-analyses.

2. To provide empirically based recommendations on how to conduct meta-analyses with respect to quality assessment.

Authors' recommendations: Indexing inconsistencies within and across databases pose challenges in searching for systematic reviews or meta-analyses. Our results suggest that it is necessary to search multiple databases to identify all relevant information. Journal indexers, authors and editors should collaborate to develop and implement criteria to help users of systematic reviews and meta-analyses identify relevant publications. The systematic reviewers, methodologists and journal editors surveyed believed that assessment of trial quality was important. This contrasts with the infrequent reporting of trial quality in published meta-analyses. Future studies should address the issue of quality assessment. Consistent reporting of the design features of RCTs may help to enhance the rigour and clinical interpretability of meta-analyses. Among a sample of meta-analyses from the database, individual components and scales were the methods most commonly used to assess trial quality. However when quality assessments were made, in most cases they were not incorporated into the analysis. This is important because the incorporation of quality assessments can alter the estimate of the benefit of intervention, regardless of which method of assessment is used. The results from these studies also suggest that certain characteristics of the design and execution of RCTs impact on the probability of bias, and further research is needed on this. Investigations are also needed to clarify the value of masking studies before quality assessment and to determine the advantages of the various approaches to incorporate quality assessments into the analyses. Until such empirical evidence is presented, the guidelines outlined below are a useful tool with which meta-analysts, editors, peer reviewers and readers can deal with issues pertaining to quality assessment of randomised trials included in a meta-analysis.

Authors' methods: Overview

Project Status: Completed

URL for project: http://www.hta.ac.uk/943

Year Published: 1999

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

Copyright: 2009 Queen's Printer and Controller of HMSO