Selective outcome reporting in randomized clinical trials using the third molar surgery model.

Selective outcome reporting (SOR) can threaten the validity of results found in clinical trials. Some studies in the literature have analyzed SOR in dentistry, but there is no study that has observed SOR in clinical trials in oral and maxillofacial surgery. Impacted third molar surgery is one of the most used models in clinical trials to study mainly analgesic and anti-inflammatory drug interventions. Our study aimed to evaluate the prevalence of SOR in publications employing the third molar extraction clinical trial model, and to verify whether there was an association between the statistical significance of outcomes and other characteristics that could lead to SOR. A systematic search was performed on the ClinicialTrials.gov platform for randomized clinical trial protocols, using the condition of third molar extraction. The corresponding published articles were sourced in PubMed, Scopus, and Embase databases, and compared with the registered protocols regarding the methodological data, in terms of: sample calculation, primary outcome identification, end-point periods, insertion of new outcomes in the publication, and results of outcomes. 358 protocol records were retrieved; 87 presented their corresponding articles. SOR was identified in 28.74% of the publications, and had a significant relationship with changes in the protocol, insertions of new outcomes, and discrepancies in the types of study. General risk of bias was found to be low. There were associations between SOR and the discrepancies in terms of the type of study, the choice of new outcome, and changes in the history of protocol records. The prevalence of SOR in clinical research using the third molar extraction surgery model is moderate. The quality of the scientific reporting of the results and, consequently, the certainty of evidence relating to the intervention tested can be overstated, increasing the chances of misinterpretation by health professionals.

Protocol registration improves reporting quality of systematic reviews in dentistry.

BACKGROUND: The aims of this study were to assess whether the previous registration of a systematic review (SR) is associated with the improvement of the quality of the report of SRs and whether SR registration reduced outcome reporting bias. METHODS: We performed a search in PubMed for SRs in dentistry indexed in 2017. Data related to SR registration and reporting characteristics were extracted. We analyzed if the reporting of 21 characteristics of included SRs was associated with the prospective registration of protocols or reporting of a previously established protocol. The association between prospective registering of protocols, reporting of funding and number of included studies versus outcome reporting bias was tested via multivariable logistic regression. RESULTS: We included 495 SRs. One hundred and 62 (32.7%) SRs reported registering the SR protocol or working from a previously established protocol. Thirteen reporting characteristics were described statistically significant in SRs registered versus SRs that were not. Publication bias assessment and Report the number of participants showed the highest effects favoring the register (RR 1.59, CI 95% 1.19-2.12; RR 1.58, CI 95% 1.31-1.92 respectively). Moreover, Registration was not significantly linked with the articles' reporting statistical significance (OR 0.96, CI 95% 0.49-1.90). CONCLUSION: There is a positive influence of previously registering a protocol in the final report quality of SRs in dentistry. However, we did not observe an association between protocol registration and reduction in outcome reporting bias.

A low proportion of systematic reviews in physical therapy are registered: a survey of 150 published systematic reviews.

BACKGROUND: Systematic reviews provide the best evidence about the effectiveness of healthcare interventions. Although systematic reviews are conducted with explicit and transparent methods, discrepancies might occur between the protocol and the publication. OBJECTIVES: To estimate the proportion of systematic reviews of physical therapy interventions that are registered, the methodological quality of (un)registered systematic reviews and the prevalence of outcome reporting bias in registered systematic reviews. METHODS: A random sample of 150 systematic reviews published in 2015 indexed on the PEDro database. We included systematic reviews written in English, Italian, Portuguese and Spanish. A checklist for assessing the methodological quality of systematic reviews tool was used. Relative risk was calculated to explore the association between meta-analysis results and the changes in the outcomes. RESULTS: Twenty-nine (19%) systematic reviews were registered. Funding and publication in a journal with an impact factor higher than 5.0 were associated with registration. Registered systematic reviews demonstrated significantly higher methodological quality (median=8) than unregistered systematic reviews (median=5). Nine (31%) registered systematic reviews demonstrated discrepancies between protocol and publication with no evidence that such discrepancies were applied to favor the statistical significance of the intervention (RR=1.16; 95% CI: 0.63-2.12). CONCLUSION: A low proportion of systematic reviews in the physical therapy field are registered. The registered systematic reviews showed high methodological quality without evidence of outcome reporting bias. Further strategies should be implemented to encourage registration.