Reporting Quality of Controlled-trial Abstracts from Chicken Research

Abstract

Background and Objective: Randomized controlled trials (RCTs) and non-RCTs are typically used for evaluating treatment effects in chicken research. The abstract is an important part of scientific reports that readers usually read first and then decide whether to read the entire article, so the information provided in the abstract should be adequate. The consolidated standards of reporting trials (CONSORT) for Abstracts checklist has been developed and used as a guideline to help authors prepare their manuscripts. This checklist has also been used as a tool to evaluate published abstracts. The objectives of this study were to evaluate the quality of reporting in abstracts of trials reporting randomization in their abstracts (RCT-A) and trials not reporting randomization in their abstracts (non-RCT-A) from chicken research and to identify the factors associated with reporting quality. Materials and Methods: PubMed was searched for abstracts of controlled trials involving chicken research published between 2006 and 2015. The abstracts were evaluated using the modified CONSORT for Abstracts checklist. The primary outcome was a median Overall Quality Score (OQS), which for each abstract was a sum of items recommended in the modified checklist. Some pre-specified factors were also evaluated for their association with reporting quality using simple and multiple ordinal logistic regression analyses. Results: A total of 949 abstracts (n = 262 for RCT-A and n = 687 for non-RCT-A) were included and evaluated. The OQS was significantly higher for RCT-A than non-RCT-A (median (interquartile range), 7.0 (6.0-7.0) vs 3.0 (3.0-4.0); p<0.001) but both median scores were still less than half of the maximum score of 15. The two most frequently reported items (>80%) were the objective and conclusions. Trial design, participants and interventions were adequately reported only in RCT-A. In contrast, identifying the study as a randomized trial in the title and including a clearly defined primary outcome, blinding, numbers analyzed, estimated effect size and its precision for the primary outcome, trial registration and funding in the abstracts were not reported or were reported in <5% of all abstracts. Four factors-year of publication, number of trials reported, number of experimental groups reported and sample size reported were associated with OQS. That is, abstracts with higher OQSs were published more recently, reported a single trial rather than multiple trials, reported the number of experimental groups and reported the sample size. These factors explained about 39.4% of the variance of OQS. Conclusion: The reporting qualities of both RCT-A and non-RCT-A from chicken research were suboptimal. Efforts should therefore be made to improve the transparency, completeness and detail of reporting in controlled-trial abstracts from chicken research, especially the development of specific guidelines based on the CONSORT for Abstracts checklist.