Dataset Information

Search for unpublished data by systematic reviewers: an audit.

ABSTRACT:

Objectives

We audited a selection of systematic reviews published in 2013 and reported on the proportion of reviews that researched for unpublished data, included unpublished data in analysis and assessed for publication bias.

Design

Audit of systematic reviews.

Data sources

We searched PubMed and Ovid MEDLINE In-Process & Other Non-Indexed Citations between 1 January 2013 and 31 December 2013 for the following journals: Journal of the American Medical Association, The British Medical Journal, Lancet, Annals of Internal Medicine and the Cochrane Database of Systematic Reviews. We also searched the Cochrane Library and included 100 randomly selected Cochrane reviews.

Eligibility criteria

Systematic reviews published in 2013 in the selected journals were included. Methodological reviews were excluded.

Data extraction and synthesis

Two reviewers independently reviewed each included systematic review. The following data were extracted: whether the review searched for grey literature or unpublished data, the sources searched, whether unpublished data were included in analysis, whether publication bias was assessed and whether there was evidence of publication bias.

Main findings

203 reviews were included for analysis. 36% (73/203) of studies did not describe any attempt to obtain unpublished studies or to search grey literature. 89% (116/130) of studies that sought unpublished data found them. 33% (68/203) of studies included an assessment of publication bias, and 40% (27/68) of these found evidence of publication bias.

Conclusion

A significant fraction of systematic reviews included in our study did not search for unpublished data. Publication bias may be present in almost half the published systematic reviews that assessed for it. Exclusion of unpublished data may lead to biased estimates of efficacy or safety in systematic reviews.

SUBMITTER: Ziai H

PROVIDER: S-EPMC5640073 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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Publications

Search for unpublished data by systematic reviewers: an audit.

Ziai Hedyeh H Zhang Rujun R Chan An-Wen AW Persaud Nav N

BMJ open 20171006 10

<h4>Objectives</h4>We audited a selection of systematic reviews published in 2013 and reported on the proportion of reviews that researched for unpublished data, included unpublished data in analysis and assessed for publication bias.<h4>Design</h4>Audit of systematic reviews.<h4>Data sources</h4>We searched PubMed and Ovid MEDLINE In-Process & Other Non-Indexed Citations between 1 January 2013 and 31 December 2013 for the following journals: <i>Journal of the American Medical Association</i>, < ...[more]

PMID: 28988181

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Project description:ObjectiveTo quantify the association between long working hours and alcohol use.DesignSystematic review and meta-analysis of published studies and unpublished individual participant data.Data sourcesA systematic search of PubMed and Embase databases in April 2014 for published studies, supplemented with manual searches. Unpublished individual participant data were obtained from 27 additional studies.Review methodsThe search strategy was designed to retrieve cross sectional and prospective studies of the association between long working hours and alcohol use. Summary estimates were obtained with random effects meta-analysis. Sources of heterogeneity were examined with meta-regression.ResultsCross sectional analysis was based on 61 studies representing 333,693 participants from 14 countries. Prospective analysis was based on 20 studies representing 100,602 participants from nine countries. The pooled maximum adjusted odds ratio for the association between long working hours and alcohol use was 1.11 (95% confidence interval 1.05 to 1.18) in the cross sectional analysis of published and unpublished data. Odds ratio of new onset risky alcohol use was 1.12 (1.04 to 1.20) in the analysis of prospective published and unpublished data. In the 18 studies with individual participant data it was possible to assess the European Union Working Time Directive, which recommends an upper limit of 48 hours a week. Odds ratios of new onset risky alcohol use for those working 49-54 hours and ≥ 55 hours a week were 1.13 (1.02 to 1.26; adjusted difference in incidence 0.8 percentage points) and 1.12 (1.01 to 1.25; adjusted difference in incidence 0.7 percentage points), respectively, compared with working standard 35-40 hours (incidence of new onset risky alcohol use 6.2%). There was no difference in these associations between men and women or by age or socioeconomic groups, geographical regions, sample type (population based v occupational cohort), prevalence of risky alcohol use in the cohort, or sample attrition rate.ConclusionsIndividuals whose working hours exceed standard recommendations are more likely to increase their alcohol use to levels that pose a health risk.

Project description:BACKGROUND: Authors of systematic reviews have difficulty obtaining unpublished data for their reviews. This project aimed to provide an in-depth description of the experiences of authors in searching for and gaining access to unpublished data for their systematic reviews, and to give guidance on best practices for identifying, obtaining and using unpublished data. METHODS: This is a qualitative study analyzing in-depth interviews with authors of systematic reviews who have published Cochrane reviews or published systematic reviews outside of The Cochrane Library. We included participants who 1) were the first or senior author of a published systematic review of a drug intervention, 2) had expertise in conducting systematic reviews, searching for data, and assessing methodological biases, and 3) were able to participate in an interview in English. We used non-random sampling techniques to identify potential participants. Eighteen Cochrane authors were contacted and 16 agreed to be interviewed (89% response rate). Twenty-four non-Cochrane authors were contacted and 16 were interviewed (67% response rate). RESULTS: Respondents had different understandings of what was meant by unpublished data, including specific outcomes and methodological details. Contacting study authors was the most common method used to obtain unpublished data and the value of regulatory agencies as a data source was underappreciated. Using the data obtained was time consuming and labor intensive. Respondents described the collaboration with other colleagues and/or students required to organize, manage and use the data in their reviews, generally developing and using templates, spreadsheets and computer programs for data extraction and analysis. Respondents had a shared belief that data should be accessible but some had concerns about sharing their own data. Respondents believed that obtaining unpublished data for reviews has important public health implications. There was widespread support for government intervention to ensure open access to trial data. CONCLUSIONS: Respondents uniformly agreed that the benefit of identifying unpublished data was worth the effort and was necessary to identify the true harms and benefits of drugs. Recent actions by government, such as increased availability of trial data from the European Medicines Agency, may make it easier to acquire critical drug trial data.

Dataset Information

Search for unpublished data by systematic reviewers: an audit.

Objectives

Design

Data sources

Eligibility criteria

Data extraction and synthesis

Main findings

Conclusion

Publications

Search for unpublished data by systematic reviewers: an audit.

Similar Datasets

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