Publication bias and meta-analyses - A practical example

摘要: Objectives: Publication bias is widely appreciated, but considerable time and effort are needed to locate obtain data from unpublished randomized controlled trials (RCTs), those published in non-English language journals or reported the gray literature; for this publication, we will call collection of “gray+ literature.” However, excluding such systematic reviews could introduce give rise misleading conclusions.Methods: We aimed explore quantify impact inclusion gray+ literature on results all completed individual patient (IPD) coordinated by our group (13 meta-analyses). For each IPD review, were calculated RCTs fully English gray+ literature.Results: The meta-analyses based only that tended more favorable than included gray+ literature. Although most cases addition gray+ data gave less encouraging results, moving estimated treatment effect toward a null result, direction was not always predictable.Conclusions: recommend should at least attempt identify gray+thinsp;literature and, where possible, them.