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Appraisal of: Golder, S.,Loke, Y. K.,Wright, K.,Sterrantino, C. (2016). Most systematic reviews of adverse effects did not include unpublished data. Journal of Clinical Epidemiology, 77, 125-133.
Appraisal of: Golder, S.,Loke, Y. K.,Wright, K.,Sterrantino, C. (2016). Most systematic reviews of adverse effects did not include unpublished data. Journal of Clinical Epidemiology, 77, 125-133.
Reviewer(s):
Melissa Severn
Monika Mierzwinski-Urban
Full Reference:
Golder, S.,Loke, Y. K.,Wright, K.,Sterrantino, C. (2016). Most systematic reviews of adverse effects did not include unpublished data. Journal of Clinical Epidemiology, 77, 125-133.
Short description:
The authors aimed to estimate the extent to which unpublished data are sought and identified within systematic reviews of adverse effects by carrying out a retrospective analysis of systematic reviews published in 2014. Systematic reviews of adverse effects were identified by screening all records published in 2014 in the Database of Abstracts of Reviews of Effects (DARE).
Thirty-nine percent (136/348) of systematic reviews of adverse effects published in 2014 in DARE searched at least one source of unpublished data. Forty-eight percent of the systematic reviews that searched at least one source of unpublished data (65/136) were successful in identifying and including unpublished data. This suggests that the exercise may not be entirely fruitless, and the benefits of searching for unpublished adverse effects data potentially outweigh the time or costs involved.
The study findings show that the most successful sources for unpublished data are contacting experts/authors (38%), scanning conferences (36%), Proquest Dissertation and Theses (33%) (based on only 3 reviews), ClinicalTrials.gov (29%) and the US Food and Drug Administration (FDA) website (29%). Many of these figures, however, will be under estimates as not all the reviews indicated where the included studies were obtained.
Limitations stated by the author(s):
The number of reviews searching for or including unpublished data can only be estimated in this study because of poor reporting in the systematic reviews. For instance, few reviewers stated the results of contacting authors or industry and whether further data were obtained and at least two reviews searched unpublished data sources (ClinicalTrials.gov and current controlled trials.com) without listing these sources in the Section 2.
There is also a tendency to search the traditional bibliographic databases such as MEDLINE and Embase first. There may have been instances, therefore, where although no new studies were identified from searching data sources such as ClinicalTrials.gov, scanning conferences, or reference checking, the same studies were identified. In these instances, the duplicate studies may not have been recorded.
In addition, unpublished data may have contributed to the review by providing information on ongoing studies, useful background information or by informing the search process. The value of unpublished data to the systematic review overall, however, was not measurable.
Limitations stated by the reviewer(s):
No additional limitations detected by the reviewers.
Study Type:
Single study
Related Chapters:
Tags:
Grey literature
Dissertations
Ongoing trials
Conference abstracts
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