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Reporting characteristics of non-primary publications of results of randomized trials: a cross-sectional review.

Hopewell S, Collins GS, Hirst A, Kirtley S, Tajar A, Gerry S, Altman DG - Trials (2013)

Bottom Line: We also compared consistency of information in non-primary publications with that reported in the primary publication.Non-primary publications often analyzed and reported multiple different outcomes (16% reported >20 outcomes) and in 10% (n = 7) it was unclear how many outcomes had actually been assessed; in 42% (n = 29) it was unclear whether the analyses reported were pre-specified or exploratory.Only 39% (n = 27) of non-primary publications described the primary outcome of the randomized trial, 6% (n = 4) reported its numerical results and 9% (n = 6) details of how participants were randomized.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Statistics in Medicine, University of Oxford, Botnar Recpsearch Building, Windmill Road, Oxford, UK. sally.hopewell@csm.ox.ac.uk

ABSTRACT

Background: For a randomized trial, the primary publication is usually the one which reports the results of the primary outcome and provides consolidated data from all study centers. Other aspects of a randomized trial's findings (that is, non-primary results) are often reported in subsequent publications.

Methods: We carried out a cross-sectional review of the characteristics and type of information reported in non-primary reports (n = 69) of randomized trials (indexed in PubMed core clinical journals in 2009) and whether they report pre-specified or exploratory analyses. We also compared consistency of information in non-primary publications with that reported in the primary publication.

Results: The majority (n = 56; 81%) of non-primary publications were large, multicenter trials, published in specialty journals. Most reported subgroup analyses (n = 27; 39%), analyzing a specific subgroup of patients from the randomized trial, or reported on secondary outcomes (n = 29; 42%); 19% (n = 13) reported extended follow-up. Less than half reported details of trial registration (n = 30; 43%) or the trial protocol (n = 27; 39%) and in 41% (n = 28) it was unclear from reading the abstract that the report was not the primary publication for the trial. Non-primary publications often analyzed and reported multiple different outcomes (16% reported >20 outcomes) and in 10% (n = 7) it was unclear how many outcomes had actually been assessed; in 42% (n = 29) it was unclear whether the analyses reported were pre-specified or exploratory. Only 39% (n = 27) of non-primary publications described the primary outcome of the randomized trial, 6% (n = 4) reported its numerical results and 9% (n = 6) details of how participants were randomized.

Conclusion: Non-primary publications often lack important information about the randomized trial and the type of analyses conducted and whether these were pre-specified or exploratory to enable readers to accurately identify and assess the validity and reliably of the study findings. We provide recommendations for what information authors should include in non-primary reports of randomized trials.

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Identification of non-primary publication from PubMed citations indexed from July to December 2009.
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Figure 1: Identification of non-primary publication from PubMed citations indexed from July to December 2009.

Mentions: The PubMed publication type search term ‘Randomized Controlled Trial’ identified 644 possible reports of randomized trials in the specified time window. After screening the titles and abstracts of all retrieved citations, we reviewed 591 full text articles (see Figure 1 for reasons for exclusion) resulting in 85 reports of non-primary publications; 16 were excluded as they did not include a comparison group. This resulted in 69 reports of non-primary publications; in 42 (61%) the comparison between groups was as randomized and in 27 (39%) the comparison was not as randomized. If a publication reported both types of comparison then we selected the one where the comparison between groups was as randomized.


Reporting characteristics of non-primary publications of results of randomized trials: a cross-sectional review.

Hopewell S, Collins GS, Hirst A, Kirtley S, Tajar A, Gerry S, Altman DG - Trials (2013)

Identification of non-primary publication from PubMed citations indexed from July to December 2009.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3733891&req=5

Figure 1: Identification of non-primary publication from PubMed citations indexed from July to December 2009.
Mentions: The PubMed publication type search term ‘Randomized Controlled Trial’ identified 644 possible reports of randomized trials in the specified time window. After screening the titles and abstracts of all retrieved citations, we reviewed 591 full text articles (see Figure 1 for reasons for exclusion) resulting in 85 reports of non-primary publications; 16 were excluded as they did not include a comparison group. This resulted in 69 reports of non-primary publications; in 42 (61%) the comparison between groups was as randomized and in 27 (39%) the comparison was not as randomized. If a publication reported both types of comparison then we selected the one where the comparison between groups was as randomized.

Bottom Line: We also compared consistency of information in non-primary publications with that reported in the primary publication.Non-primary publications often analyzed and reported multiple different outcomes (16% reported >20 outcomes) and in 10% (n = 7) it was unclear how many outcomes had actually been assessed; in 42% (n = 29) it was unclear whether the analyses reported were pre-specified or exploratory.Only 39% (n = 27) of non-primary publications described the primary outcome of the randomized trial, 6% (n = 4) reported its numerical results and 9% (n = 6) details of how participants were randomized.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Statistics in Medicine, University of Oxford, Botnar Recpsearch Building, Windmill Road, Oxford, UK. sally.hopewell@csm.ox.ac.uk

ABSTRACT

Background: For a randomized trial, the primary publication is usually the one which reports the results of the primary outcome and provides consolidated data from all study centers. Other aspects of a randomized trial's findings (that is, non-primary results) are often reported in subsequent publications.

Methods: We carried out a cross-sectional review of the characteristics and type of information reported in non-primary reports (n = 69) of randomized trials (indexed in PubMed core clinical journals in 2009) and whether they report pre-specified or exploratory analyses. We also compared consistency of information in non-primary publications with that reported in the primary publication.

Results: The majority (n = 56; 81%) of non-primary publications were large, multicenter trials, published in specialty journals. Most reported subgroup analyses (n = 27; 39%), analyzing a specific subgroup of patients from the randomized trial, or reported on secondary outcomes (n = 29; 42%); 19% (n = 13) reported extended follow-up. Less than half reported details of trial registration (n = 30; 43%) or the trial protocol (n = 27; 39%) and in 41% (n = 28) it was unclear from reading the abstract that the report was not the primary publication for the trial. Non-primary publications often analyzed and reported multiple different outcomes (16% reported >20 outcomes) and in 10% (n = 7) it was unclear how many outcomes had actually been assessed; in 42% (n = 29) it was unclear whether the analyses reported were pre-specified or exploratory. Only 39% (n = 27) of non-primary publications described the primary outcome of the randomized trial, 6% (n = 4) reported its numerical results and 9% (n = 6) details of how participants were randomized.

Conclusion: Non-primary publications often lack important information about the randomized trial and the type of analyses conducted and whether these were pre-specified or exploratory to enable readers to accurately identify and assess the validity and reliably of the study findings. We provide recommendations for what information authors should include in non-primary reports of randomized trials.

Show MeSH