Preferred Reporting Items for Systematic Reviews and Meta-Analyses : The PRISMA Statement

Systematic reviews and meta-analyses have become increasinglyimportant in health care. Clinicians readthem to keep up to date with their field (1, 2), and they areoften used as a starting point for developing clinical practiceguidelines. Granting agencies may require a systematicreview to ensure there is justification for further research(3), and some health care journals are moving in this direction(4). As with all research, the value of a systematicreview depends on what was done, what was found, andthe clarity of reporting. As with other publications, thereporting quality of systematic reviews varies, limitingreaders’ ability to assess the strengths and weaknesses ofthose reviews.