Introduction

Randomized Controlled Trials (RCTs) are the best design to assess the efficacy and safety of therapeutic interventions in medicine; they are considered the foundation of evidence-based medicine [1].

The abstract of RCTs provides the reader with a summary account of the study objectives, methods, results, and conclusions. Often without access to full text articles, clinicians and others, only have access to read the abstract of a research report to help guide their clinical decision making. However, inappropriate study methodology with incomplete or inaccurate reporting impedes sufficient understanding of the clinical indications and restricts the reader’s comprehension of the result’s validity [2, 3].

These inferences are likely higher among physicians in low- and middle-income countries due to the unavailability of full-text publications. Similarly, patients and the public do not always have access to journal articles. Furthermore, determining whether a full-text publication is worth purchasing is crucial. These factors highlight the importance of reporting quality, clarity, and accuracy during the initial evaluation of RCT abstracts [4].

To improve the completeness and transparency of reports of RCT abstracts, the Consolidation of the Standards of Reporting Trials for abstracts (CONSORT-A), was developed in 2008 [5]. It provides the basic information to properly evaluate the validity of trials and the applicability and clinical relevance of trial findings. CONSORT-A includes 16 checklist items describing the spectrum of the research study, including information about the objectives, design, participants, interventions and their effect on primary efficacy outcomes and harms, conclusions, registration name and number, and source of funding [6].

Endometriosis is a painful, chronic inflammatory disorder. More than 60% of women diagnosed with endometriosis have dysmenorrhea or chronic pelvic pain. RCTs of endometriosis pain have not been critically evaluated [7]. To enhance the quality of reporting for RCTs in the endometriosis and gynecology literature, and in all intervention studies, researchers are motivated to publish their reports in clear, transparent, and unambiguous language. They must provide a precise and thorough description of participants, who were recruited, excluded, lost to follow up or did not complete the study. Because failing to declare essential data may influence the interpretation of results [8].

Furthermore, interpretation bias, often referred to as spin, is defined as misleading reporting of findings of a scientific study to highlight that the intervention is beneficial, despite the ignorable differences of the primary endpoint, or to confound the reader from statistically non-significant results. The tool for spin estimation in RCTs identifies reporting practices that constitute an intentional or unintentional effort to spin the results [9].

Although multiple RCTs have been published on the treatment of endometriosis pelvic pain, the adherence to the CONSORT guidelines and the prevalence of spin has not been evaluated. Due to the prevalence of pain among endometriosis patients and the emphasis of guideline on conservative drug therapy instead of surgical interventions [10] as well as based on the above two statements the present study was designed to critically i) Assess the reporting quality of recently published RCT abstracts in endometriosis pelvic pain; (ii) Identify factors associated with reporting quality; (iii) Investigate the prevalence and characteristics of spin in these abstracts.

Methods

In this study, we searched all abstracts published in PubMed and Scopus databases. Available full-text articles that published from January 1st, 2010 to December 1st, 2023 were chosen. We chose this time horizon to provide researchers with enough time to implement CONSORT for abstracts since its publication in 2008.

Results

Study Characteristics of the Selected Reports:

From 239 retrieved articles in databases, 47 clinical trials met the eligibility criteria and were included in the study. The study flow chart is shown in Fig 1.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Fig 1. Flow diagram of the study demonstrating the identification, screening, and inclusion stages.

https://doi.org/10.1371/journal.pone.0302108.g001

Among these, most of articles were indexed in PubMed (45; 93.8%) and Scopus (45, 93.8%). Additionally, 43 (89.6%), 41 (85.4%) and 4 (8.3%) were indexed in EMBASE, ISI and ESCI, respectively. The article and the journal metrics for each study are shown in supplementary file (S1 File).

Assessing the characteristics of article abstracts, the average word count was 272.34 (±106.05) (min: 99, max: 734, median: 251, IQR: 78) and more than one-third (38.3%) of them had between 200 and 250 words. The mean of sample size was 227.59(±378.98) (min: 9, max: 1689, median: 83, IQR: 197). The mean Scopus citations was 41.11(±63.25) (min: 0, max: 321, median: 16). Taking into account the year of publication, document type, and disciplines the mean of FWCI is 3.24 (±4.05) (min: 0.14, max: 21.33, median: 1.70). Furthermore, we found that most articles described single center (n = 30, 63.8%) studies and were published in specific gynecological journals (n = 28, 59.6%). Almost half of the geographical area of the articles were in Europe and Asia (34.0% and 38.3%, respectively) (Table 1). Assessing the journal metrics, we found than the mean H-index of the journals was 167.20 (±198.08).

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 1. Trial characteristics of the 47 endometriosis RCTs.

https://doi.org/10.1371/journal.pone.0302108.t001

Evaluating the FWCI values according to the QoR (CONSORT values) shows a statistically significant correlation (r = 0.45, bootstrapping p-value: 0.003). As seen, the more the QoR the more is the FWCI.

Assessing the quality of the abstracts, we saw the total score for the quality varied between 5 and 15 (mean: 9.59, SD: 3.03, median: 9, IQR: 5). Furthermore, evaluating each item of CONSORT-A checklist, in titles of 26 (55.3%) papers, identified the study as randomized. In most of abstracts the eligibility criteria for participants was described. The detail of CONSORT items is shown in Table 2.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 2. The prevalence of reporting CONSORT-A checklist items.

https://doi.org/10.1371/journal.pone.0302108.t002

We compared the CONSORT-A total scores (QoR) for each indexing databases. Evaluating the quality of papers that indexed in Scopus, we observed a statistically difference between the scores of papers indexed in Scopus and papers that didn’t index in Scopus (QoR = 9.77±3.03 vs. 7.00±1.73; bootstrapping p-value: 0.005; Bca 95%CI for mean difference (MD): 1.11, 5.04). Comparing the QoR between other indexing databases we did not see any significant differences (bootstrapping p-value>0.05). Furthermore, assessing the QoR in different IF quartiles we saw a statistically significant difference between them (QoR for Q1, Q2, Q3, and Q4 respectively were 11.75±2.53, 7.83±1.17, 8.36±2.73, and 6.67±0.58; bootstrapping p-value:<0.001) in which the QoR for articles that published in Q1 journals were statistically more than the other quartiles. Evaluating the QoR in different years and between IF quartiles, we saw that the QoR was increased for all quartiles except for Q4 (Fig 2). Also, assessing the QoR based on being open access or not, we saw that the QoR in open access journals were significantly more (QoR in open access journals: 10.52±2.78, QoR in not open access journals: 8.11±2.89, p-value:0.007).

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Fig 2. Changing the quality of reporting the article abstracts according to different published years.

https://doi.org/10.1371/journal.pone.0302108.g002

A multivariable linear regression model was used to assess the impact of various independent variables on the Quality of Reporting (QoR) of Randomized Controlled Trial (RCT) abstracts. The independent variables included word count, indexing in databases (PubMed, Scopus, ISI), Field-Weighted Citation Impact (FWCI), publication in a gynecological journal, open access status, Impact Factor (IF), Cite Score, and H-index. The goal was to determine significant predictors of reporting quality in RCT abstracts.

Our findings revealed valuable insights into the relationship between these independent variables and the QoR of abstracts. As shown in Table 3, we observed that an increase of one unit in the word count of the abstract was associated with a significant increase in the mean QoR (beta = 0.015, p-value = 0.005). Furthermore, our analysis indicated that abstracts published in open-access journals exhibited a mean QoR approximately 2.02 units higher than those published in other types of journals (beta = 2.023, p-value = 0.023).

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 3. Factors affecting the quality of reporting the abstracts.

https://doi.org/10.1371/journal.pone.0302108.t003

Spin evaluation

Evaluating spin within each included paper, we found that 21 (44.7%) papers had statistically non-significant results. From these studies, 15(71.4%) had spin in both results and conclusion sections. The mean total score of spin intensity was 2.67±1.46 than wasn’t statistically different between studies with and without funding (mean difference (MD) = 0.17, P-value = 0.82). The prevalence of spin among all included articles was 38.29 (18 from 47 articles at least had spin in one of results or conclusion section). The trend of changing the spin during 2010–2023 is presented in Fig 3. As seen in Fig 3, the spin intensity was increasing from 2010 to 2023. Assessing the spin in subgroups of impact factor, we saw that in articles that had been published in journals with IF more than 3, the trend of spin is decreasing from 2010 to 2023 while in the other IF categories, the spin is increasing.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Fig 3. Trend of changing the spin intensity during 2010–2023.

https://doi.org/10.1371/journal.pone.0302108.g003

No association was found with type of study area (obstetrics or gynecology) (p-value = 0.247), number of authors (p-value = 0.584), and being open access or not (p-value = 0.719) with spin.

To evaluate the factors influencing spin in the reporting of research findings, logistic regression analysis was conducted. The independent variables considered in the analysis included the word count of the abstract, indexing status in PubMed (yes/no), indexing status in Scopus (yes/no), indexing status in ISI (yes/no), FWCI, designation as a gynecological journal (yes/no), publication in an open-access journal (yes/no), IF, Cite Score, and H-index. These variables were entered into the univariable linear regression model to assess their individual relationships with the presence of spin. However, the analysis did not reveal any statistically significant relationships between the independent variables and the presence of spin in the abstracts. Additionally, the model encountered convergence issues specifically for the variables related to indexing in PubMed, Scopus, and ISI, indicating potential limitations in the modeling approach for these factors (Table 4).

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 4. Factors affecting the spin existence in abstracts.

https://doi.org/10.1371/journal.pone.0302108.t004

Discussion

We conducted an evaluation of the reporting quality of RCT abstracts, analyzing the influencing factors and the prevalence and characteristics of spin in these abstracts. To the best of our knowledge, this is the first study examining the RCT abstract’s adherence to the CONSORT statements regarding endometriosis-associated pelvic pain. The findings from this research are anticipated to offer valuable foundational insights for clinical decision-makers.

While CONSORT-A was designed to assist authors in improving the reporting of their RCT methods and results, our study revealed that the overall reporting quality of RCTs pertaining to endometriosis-related pelvic pain was found to be suboptimal. There is an apparent need to improve the quality of reporting of RCT abstracts, especially those related to key methodological domains.

Among the 16 checklist items outlined in CONSORT-A, only three items–namely, objectives, interventions, and conclusions–were adequately reported in the majority of abstracts (over 95%). However, none of the abstracts provided the required precise data. In the reporting quality of material and method section, trial design, type of randomization, the generation of random allocation sequences, the allocation concealment and blinding were most items identified that were suboptimal.

Glasziou et al. recommended that all research funders and institutions need to change research rewards and regulations to align with better and more complete reporting, they should consider how best to participate in campaigns against wasteful studies. Research funders provide input of resources; however, outputs are managed by journal publishers with similar motivations as other publishers. Few employ a publication officer to promote research outputs, including attention to publication ethics and use of reporting guidelines [12].

A complete explanation of trial design can provide readers with an accurate research ideas and enable readers to assess the validity of the results [8]. However, in our analysis, we found that 50% of studies reported the type of trial design in the methods section, while 35.4% of studies reported it in both the title and methods sections.

It is particularly concerning that two of the most important points in the methods section (allocation concealment and blinding details) are almost completely neglected, as this information is the key data to certify the authenticity of results. We found only 1 (2.9%) study explained the methods of allocation concealment and 20 (41.7%) studies reported the details of blinding, which was similar to the results in the field of anesthesiology [13], acupuncture [14] and plastic surgery [15].

Furthermore, to identify the selection bias, it is important to indicate how participants were allocated and randomized to the intervention. This information is crucial for readers to assess whether the trial findings might be biased in favor of the new therapy [5]. Moreover, our study specifically focuses on RCTs that address the issue of endometriosis pelvic pain. Within the context of patient reporting outcomes, we recognize and emphasize the vital significance of implementing blinding protocols.

Of 48 studies, only one abstract explained the details of randomization, and although 30 (62.5%) studies mentioned randomized assignment, they did not provide adequate information about sequence generation, implementation procedures and allocation concealment, items that have not improved since the release of CONSORT-A. Additionally, taking into account the subjectivity and susceptibility of pain assessment in endometriosis, precise designs and better interventions should be implemented to avoid result exaggeration or overestimation.

Can et al. [16] stated that only 1.6% of RCT abstracts reported randomization methods, and similar reports were also demonstrated by other researchers in internal medicine fields [17, 18].

The primary outcome of a clinical trial serves as the foundation for sample size estimation, yet, to guard against data dredging, its pre-specification in the registered protocol and primary manuscript is essential. Data dredging refers to the exploratory practice of analyzing large datasets in search of any statistically significant associations, regardless of initial hypotheses. While the majority of reviewed RCT abstracts (95.8%) outlined study objectives, only 39 (81.3%) explicitly stated the primary outcome, for the remaining abstracts, the primary outcome was extracted from the full text.

Since randomized controlled trials are included in medical guidelines and used by healthcare professionals, it is necessary to indicate the safety and effectiveness of the new therapy in the results section. On the other hand, as many specialists rely solely on abstracts of randomized controlled trials as the basis for clinical decision-making, it is important to mention adverse events in the abstracts [4]. Unfortunately, our analysis revealed that only 29.2% of the examined trials adequately reported significant harms or crucial adverse events in their abstracts. Furthermore, the analysis highlighted suboptimal adherence to two critical transparency components: trial registration and disclosure of funding sources.

Registration enhance reporting quality and makes trial information publicly available, thereby making authors responsible and helping to reduce publication bias and selective outcome reporting as it allows readers with limited access to full-text manuscripts to compare abstract study findings with those defined a priori in studies [15]. However, our analysis identified that only 22 (45.8%) of the investigated RCT abstracts disclosed clinical trial registration information. While the impact of funding on research outcomes is well documented in existing literature, this critical information is typically absent from research summaries [5]. In this study, only 12 (25%) of the analyzed RCT abstracts disclosed their funding sources in this study. The lack of transparency regarding these critical details highlights a gap in reporting practices within the literature. It is important to consider the presence of confounding factors that may impact the reporting of this aspect of the manuscript. One such factor could be the word limit imposed by some journals on abstracts, which may hinder the comprehensive inclusion of all necessary information in RCT abstracts.

Our findings indicated a positive correlation between the word count of the abstract and QoR in RCTs addressing endometriosis pelvic pain. A more detailed and comprehensive abstract was associated with a notable increase in QoR, emphasizing the importance of thorough reporting in enhancing the quality of research summaries. Moreover, our analysis demonstrated that RCT abstracts published in open-access journals exhibited a significantly higher mean QoR compared to those published in other types of journals, with an approximate difference of 2.02 units. This underscores the potential impact of journal accessibility on reporting quality, underscoring the role of open access initiatives in fostering transparent and high-quality reporting in scientific research.

Interestingly, we also explored the influence of journal impact factor on reporting quality and found contrasting results compared to previous studies [4]. While higher impact factors were associated with better reporting quality in some research, our study did not find a significant impact of journal impact factor on reporting quality in the context of endometriosis pelvic pain RCT abstracts. Overall, our results provide valuable insights into the factors influencing the reporting quality of RCT abstracts in the context of endometriosis pelvic pain research. By identifying key predictors of reporting quality, such as word count and open access status, our findings contribute to the ongoing efforts to enhance transparency and accuracy in the reporting of clinical trials.

Furthermore, we observed that (15/21) of endometriosis pain RCTs with a non-significant primary outcome had evidence of spin in results and conclusion sections. Spin was more frequently observed in the conclusion sections of abstracts, and authors most commonly emphasized statistically significant secondary outcomes or misinterpreted a non-significant P-value as evidence of equivalence between intervention and control.

The implications of these results are manifest: Misrepresentation of study results misleads gynecologists into accepting interventions as beneficial despite non-significant primary outcomes, which can influence the decision and choice of a particular type of intervention.

The busy specialists and clinicians may not be able to identify and classify spin in the abstracts and may recommend rather unproven remedies.

Consistent with previous studies [19] no association was found with type of journal area (obstetrics or gynecology) and number of authors with onset of spin. Furthermore, no association has been observed between the presence of spins and funding sources.

There are few comparable reports in the field of obstetrics and gynecology. Chow et al. identified spin in 33% of abstracts from RCTs featuring non-significant primary endpoints across the five prominent obstetrics and gynecology journals, with a higher incidence of 46% in the conclusion sections [19]. These figures appear to be marginally lower than the findings in our study or those reported in the psychology literature [20], where spin was identified in 56% of the studies. Similarly, in the field of cardiology [21], spin was detected in 67% of the included texts.

As it mentioned in our study spin was found 66% in both results and conclusion sections of abstracts with non-significant primary outcomes published in 2010 and 2023. This is a notable finding that concerns the obstetrics and gynecology scientific community and it may be necessary to take safety precautions. To counteract the effects of spin and promote higher quality reporting in science, researchers, peer reviewers, clinicians and healthcare decision-makers should be made more aware of the presence of spin within RCTs. All journal editors should be aware and continue to monitor for spin to reduce the risk of reporting bias.

Conclusion

This study adds to growing evidence that RCT abstracts in the gynecological literature may benefit from improvements, especially in smaller gynecologic subspecialties. Our results also suggest that spin is present in a number of RCTs with non-significant primary endpoints in the obstetrics and gynecology literature. The existence of such interpretive biases is of concern to the scientific community, as spins can influence decision-making in research, clinical, and healthcare systems. This highlights the need to advance strategies to counteract the effects of spin and promote better quality reporting in the scientific papers.

Supporting information