Article type
Year
Abstract
Background: In systematic reviews, selective reporting may develop for a variety of reasons, for example, due to the use of multiple measurement scales, outcomes or time points and selective inclusion of specific outcomes. There is paucity of information on selective reporting based on comparisons between review protocols and final systematic review reports.
Objectives: To assess discrepancies between protocols and published reviews in oral health systematic reviews (COHG) on the Cochrane Database of Systematic Reviews (CDSR).
Methods: Information on the reported outcomes from all COHG systematic reviews in CDSR and the corresponding protocols was recorded by two reviewers independently.
Results: One-hundred and fifty-two reviews were included; the median number of labelled primary and secondary outcomes was two (range: 0 to 11) and four (range: 0 to 36) respectively both in the protocols and reviews. For primary outcomes, 11.2% (17/152) were downgraded to secondary outcomes, 9.9% (15/152) were omitted and 18.4% (28/152) were introduced in the final publications. For secondary outcomes, 2.0% (3/152) were upgraded to primary, 12.5% (19/152) were omitted and 30.9% (47/152) were newly introduced in the publication. Overall, 45.4% (69/152) of reviews had at least one discrepancy that was justified in 14.5% (10/69) reviews. Sixty-three reviews included meta-analyses. For primary outcomes the risk of reporting significant results was lower for both downgraded (RR 0.52, 95% CI 0.17 to 1.58; P value 0.24) and upgraded or newly introduced outcomes (RR 0.77, 95% CI 0.36 to 1.64; P value 0.50) compared to outcomes with no discrepancies. For primary outcomes the risk for reporting significant results was higher for upgraded or newly introduced outcomes compared to downgraded outcomes (RR 1.19, 95% CI 0.65 to 2.16; P value 0.57). None of the comparisons reached statistical significance.
Conclusion: There is evidence that discrepancies between outcomes of pre-published protocols and final reviews continue to be common, on the basis of this analysis of SRs published within the COHG. Alternative solutions to reduce the prevalence of this issue may need to be explored.
Objectives: To assess discrepancies between protocols and published reviews in oral health systematic reviews (COHG) on the Cochrane Database of Systematic Reviews (CDSR).
Methods: Information on the reported outcomes from all COHG systematic reviews in CDSR and the corresponding protocols was recorded by two reviewers independently.
Results: One-hundred and fifty-two reviews were included; the median number of labelled primary and secondary outcomes was two (range: 0 to 11) and four (range: 0 to 36) respectively both in the protocols and reviews. For primary outcomes, 11.2% (17/152) were downgraded to secondary outcomes, 9.9% (15/152) were omitted and 18.4% (28/152) were introduced in the final publications. For secondary outcomes, 2.0% (3/152) were upgraded to primary, 12.5% (19/152) were omitted and 30.9% (47/152) were newly introduced in the publication. Overall, 45.4% (69/152) of reviews had at least one discrepancy that was justified in 14.5% (10/69) reviews. Sixty-three reviews included meta-analyses. For primary outcomes the risk of reporting significant results was lower for both downgraded (RR 0.52, 95% CI 0.17 to 1.58; P value 0.24) and upgraded or newly introduced outcomes (RR 0.77, 95% CI 0.36 to 1.64; P value 0.50) compared to outcomes with no discrepancies. For primary outcomes the risk for reporting significant results was higher for upgraded or newly introduced outcomes compared to downgraded outcomes (RR 1.19, 95% CI 0.65 to 2.16; P value 0.57). None of the comparisons reached statistical significance.
Conclusion: There is evidence that discrepancies between outcomes of pre-published protocols and final reviews continue to be common, on the basis of this analysis of SRs published within the COHG. Alternative solutions to reduce the prevalence of this issue may need to be explored.