Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data: the PRISMA-IPD Statement.
OBJECTIVE
Systematic reviews and meta-analyses of individual participant data (IPD) aim to collect, check, and reanalyze individual-level data from all studies addressing a particular research question and are therefore considered a gold standard approach to evidence synthesis. They are likely to be used with increasing frequency as current initiatives to share clinical trial data gain momentum and may be particularly important in reviewing controversial therapeutic areas.


OBJECTIVE
To develop PRISMA-IPD as a stand-alone extension to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Statement, tailored to the specific requirements of reporting systematic reviews and meta-analyses of IPD. Although developed primarily for reviews of randomized trials, many items will apply in other contexts, including reviews of diagnosis and prognosis.


METHODS
Development of PRISMA-IPD followed the EQUATOR Network framework guidance and used the existing standard PRISMA Statement as a starting point to draft additional relevant material. A web-based survey informed discussion at an international workshop that included researchers, clinicians, methodologists experienced in conducting systematic reviews and meta-analyses of IPD, and journal editors. The statement was drafted and iterative refinements were made by the project, advisory, and development groups. The PRISMA-IPD Development Group reached agreement on the PRISMA-IPD checklist and flow diagram by consensus.


RESULTS
Compared with standard PRISMA, the PRISMA-IPD checklist includes 3 new items that address (1) methods of checking the integrity of the IPD (such as pattern of randomization, data consistency, baseline imbalance, and missing data), (2) reporting any important issues that emerge, and (3) exploring variation (such as whether certain types of individual benefit more from the intervention than others). A further additional item was created by reorganization of standard PRISMA items relating to interpreting results. Wording was modified in 23 items to reflect the IPD approach.


CONCLUSIONS
PRISMA-IPD provides guidelines for reporting systematic reviews and meta-analyses of IPD.
Centre for Reviews and Dissemination, University of York, York, United Kingdom.
Lesley A
LA
Stewart
All-Ireland Hub for Trials Methodology Research, Queen's University Belfast, Belfast, United Kingdom.
Mike
M
Clarke
Radbound Institue of Health Sciences, Radboudumc, Nijmegen, the Netherlands.
Maroeska
M
Rovers
Research Institute of Primary Care and Health Sciences, Keele University, Keele, United Kingdom (initial work carried out at School of Health and Population Sciences, University of Birmingham, Birmingham, United Kingdom).
Richard D
RD
Riley
Centre for Reviews and Dissemination, University of York, York, United Kingdom.
Mark
M
Simmonds
Centre for Rural Economy, School of Agriculture, Food and Rural Development Newcastle University, Newcastle, United Kingdom (work carried out at the Centre for Reviews and Dissemination, University of York, United Kingdom).
Gavin
G
Stewart
MRC Clinical Trials Unit at UCL, London, United Kingdom.
Jayne F
JF
Tierney
D057189:Checklist; D003627:Data Interpretation, Statistical; D017408:Guidelines as Topic; D015201:Meta-Analysis as Topic; D011643:Publishing / Q000592:standards; D011897:Random Allocation; D035842:Research Subjects; D000078202:Systematic Reviews as Topic