Abstracts of randomized controlled trials in pediatric dentistry: reporting quality and spin

The research focus in pediatric dentistry has changed from publishing case reports to answering a focused problem [1]. With the introduction of evidence-based dentistry, clinicians are requested to make their clinical decisions through scientific evidence [2]. High-quality randomized controlled trials (RCTs) are considered evidence of the highest grade in the hierarchy of research designs and the gold standard in the evaluation of efficacy and safety of healthcare interventions [3], owing to their robust experimental design and execution. Despite excellent internal validity offered by well-designed RCTs, there are still concerns about the inaccurate reporting of study methods and results in published articles. This can introduce bias into conclusions and interpretations, and potentially mislead healthcare decision-making [4, 5].

Abstracts provide readers with a summary of trial information and are an essential means of disseminating research findings. Given the limited time and access constraints for critical reading, clinicians often rely only on abstracts to extract study information, decide whether to read full texts, or even make their clinical decisions. Therefore, accurate, complete and transparent reporting of abstract is crucial. In recognition of the importance of a well-written abstract, an extension of CONsolidated Standards Of Reporting Trials (CONSORT) statement has been released specifically for reporting of RCT abstracts in journals and conferences in 2008 [6]. However, the reporting quality of RCT abstract still remained inadequate in leading general medical journals and the field of dentistry [3, 7].

Currently, the CONSORT statement has been endorsed by hundreds of journals, requiring adherence to the guideline in their ‘Instructions to Authors’ [8], and a checklist of CONSORT items was provided to ensure reporting the key element. Nevertheless, authors can still intentionally or unintentionally misrepresent or misinterpret their study results, especially in RCTs with nonsignificant primary outcomes. Spin is defined as ‘use of specific reporting strategies, from whatever motive, to highlight that the experimental treatment is beneficial, despite a statistically nonsignificant difference for the primary outcome, or to distract the reader from statistically nonsignificant results’ [5]. Boutron et al. [5] were the first to define spin and developed spin strategies to systematically evaluate spin. Recent studies have indicated that the incidence of spin was common in biomedical research [9] and dentistry [10, 11]. Nevertheless, no guidelines on avoidance of spin have been developed.

As for now, the reporting quality and the incidence of spin among RCT abstracts in the field of pediatric dentistry have not been studied. Therefore, we aimed to (1) assess the reporting quality in recently published RCT abstracts in the field of pediatric dentistry; (2) identify factors associated with reporting quality; and (3) investigate the existence and characteristics of spin in these abstracts.

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist [12] for research reporting of observational studies was followed in this methodological study with a cross-sectional design (Additional file 1).

In this study, we evaluated the reporting quality of RCT abstracts published in five leading pediatric dental journals during the last 7 years. Our findings indicated that the reporting quality has much room for improvement, which was consistent with other research in the field of dentistry as a whole [3], endodontics [22], and orthodontics [18]. In addition, some essential aspects regarding methods and results were rarely reported, making it difficult for readers to assess the validity and reliability of RCT abstracts in pediatric dentistry.

The CONSORT statement and its extensions offer a standard way for authors to report their trials. This facilitates complete and transparent reporting while alleviating obstacles arising from inadequate or inaccurate reporting [6, 23, 24]. Earlier, Sarkis-Onofre et al. have concluded that active endorsement of the CONSORT statement by journals can improve the reporting quality of RCTs in dentistry [4]. CONSORT statement has been implemented by many journals [25, 26]. However, there were still discrepancies between specific instructions on how CONSORT should be used by authors in different journals and publishers, for instance, some journals may only require an accompanying completed CONSORT checklist in submission or request the inclusion of a CONSORT flow diagram [8]. In our study, only 22% abstracts mentioned used of CONSORT in Methods section. The effect of journal adherence to CONSORT guidelines has witnessed improvement in reporting quality [27]. Poor reporting quality as a consequence of not following CONSORT statement may prohibit clinicians from critically appraising the methodological quality and the validity of addiction RCT results, thus biasing the treatment effects in subsequent meta-analyses and clinical practice [28].

Among the 16 CONSORT quality items, only three items (interventions, objective, and conclusions) were adequately reported in most abstracts (> 80%), which were in line with the findings of previous studies in periodontology and implantology [29]. One possible explanation might be the structure format of RCT abstract required by journals which included headings of ‘Introduction, Methods, Results, and Conclusion’. Previous research has illustrated that highly structured RCT abstracts were associated with more complete trial reports in leading general medical [30]. Nevertheless, five journals we selected have requested submission of abstracts in structure formats in our study, preventing us from exploring the relationship between structure format and report quality in pediatric dentistry.

Transparent, accurate and complete description in methodology and results of the abstract were crucial for readers to critically appraise the efficacy or safety of intervention in a trial. However, inadequate reporting was common in medical research [22, 27], the same goes for our findings. In this study, a majority of items in the Methods and Results sections (including participant, outcome in the Methods section, blinding, numbers analyzed, recruitment outcome in the Results section, harms) and trial registration and funding were reported adequately only in less than 10% of the abstracts. No abstracts reported randomization. Such serious results should attract attention from publishers, editors, researchers, and readers.

Despite differences in reporting, trial design and execution, inadequate reporting in trial reports often leads to the omission or distortion of important methodology and results details [31]. This can mislead reader’s clinical decision making and result in avoidable research waste. The CONSORT for Abstracts guidelines has placed huge emphasis on the clear and sufficient detailed reporting of essential items in abstracts, such as outcome in the Method and Results section, participant, sequence generation and allocation concealment in randomization. [6] Previous research has pointed out that participant is important to determine the generalizability and applicability of the finding, and the lack of sequence generation and allocation concealment in randomization could generate exaggerated treatment effects and might interfere with clinicians’ assessment [6, 29]. As for the outcome, primary outcome should be clearly stated, which is the prespecified most appropriate outcome variable to address the study objectives, and usually the one used in the sample size calculation [32]. Insufficient reporting of outcome as shown in our study was a common issue in medical research [33, 34]. This indicated that not enough details of primary outcome were provided. The lack of clarity hinders clinicians or statisticians from fully understanding the precise measurements being assessed, thereby compromising the reproducibility of trials. [35].

In our study, after multivariable linear regression analysis, only flow diagram remained as a significant predictor of abstract reporting quality, indicating that RCTs reported use of flow diagram were significantly associated with higher OQS. The finding mirrored the results in previous studies [18, 36] and possible explanations might be that the use of a diagram showing participants flow was recommended by CONSORT guidelines [32]. They demonstrate the knowledge the CONSORT statements and/or trials [3]. The CONSORT has provided the structured flow diagram. Nevertheless, authors often present diagrams with different structures, ignoring some important elements such as the number of participants who actually receive allocated treatment [36]. Therefore, standardization and implementation of CONSORT flow diagram by journals is still needed.

This study was the first to appraise spin in pediatric dentistry, and 51 RCT abstracts which have nonsignificant primary outcomes were included for evaluation. Given the small sample size of included abstracts, we did not conduct regression analysis to explore potential factors associated with the presence of spin. Our study displayed that the occurrence of spin was high among RCT abstracts in pediatric dentistry (78.4%). Publication year was a nonsignificant factor associated with spin. The prevalence of spin has shown a great variation in different research areas and study designs [9]. In the field of dentistry, spin has been explored in dentistry as a whole (61.7%) [37], endodontics (85.0%) [22], orthodontics (62.2%) [16], and periodontology and implantology (69.9%) [17]. The prevalence of spin in academic publications necessitates research to investigate its impact and develop appropriate measurements for addressing this issue.

The frequencies of spin strategies in Results and Conclusions sections mirrored the findings in orthodontics [16]. Since we only included abstracts of superiority RCTs, the primary aim of this trial should concentrate on between-group comparison to show whether the investigated intervention was superior to a commonly accepted treatment or placebo [38]. Accounting for the limitation of word count, the most important result that should be clearly reported was the primary outcome, including results in each group, estimated effect size and its precision [6]. Authors who solely focus on the results of within-group comparisons in a superiority trial, risk misinterpreting it as a before-after study. This can result in inappropriate conclusions, such as claiming treatment equivalence, which distorts readers and impacts clinicians’ assessment about treatment application.

Abstracts with spin can impact clinicians’ interpretation of trial results and the dissemination of content in press releases and news coverage [39, 40]. The presence of spin in academic publications can be attributed to various factors. With the editors’ preference for publishing positive findings, researchers under publication pressure tend to manipulate or selectively report study findings to satisfy their vested interests [41]. This can introduce spin in publications. Besides, the absence of clear guidelines leaves researchers and reviewers with limited standardized guidance on how to accurately and objectively report research findings, increasing the likelihood of spin [37]. As for now, previous studies have identified some related factors associated with spin. Wu et al. [17] found that multi-center RCTs were less likely to have spin in abstracts in periodontology and implantology. In orthodontics, a significantly lower presence of spin was found in studies with international collaboration and trial registration [16]. These relevant factors gave insight into finding ways to address spin for publication.

In summary, the reporting quality of RCT abstracts in pediatric dentistry is suboptimal. The prevalence of spin among RCT abstracts in pediatric dentistry is high. Joint efforts from researchers and other stakeholders are needed to improve reporting quality and minimize spin presence.