Transition from congress abstract to full publication for clinical trials presented at laser meetings

Full publication of results initially presented in abstracts

BACKGROUND

Abstracts of presentations at scientific meetings are usually available only in conference proceedings. If subsequent full publication of results reported in these abstracts is based on the magnitude or direction of the results, publication bias may result. Publication bias creates problems for those conducting systematic reviews or relying on the published literature for evidence about health and social care.

OBJECTIVES

To systematically review reports of studies that have examined the proportion of meeting abstracts and other summaries that are subsequently published in full, the time between meeting presentation and full publication, and factors associated with full publication.

SEARCH METHODS

We searched MEDLINE, Embase, the Cochrane Library, Science Citation Index, reference lists, and author files. The most recent search was done in February 2016 for this substantial update to our earlier Cochrane Methodology Review (published in 2007).

SELECTION CRITERIA

We included reports of methodology research that examined the proportion of biomedical results initially presented as abstracts or in summary form that were subsequently published. Searches for full publications had to be at least two years after meeting presentation.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and assessed risk of bias. We calculated the proportion of abstracts published in full using a random-effects model. Dichotomous variables were analyzed using risk ratio (RR), with multivariable models taking into account various characteristics of the reports. We assessed time to publication using Kaplan-Meier survival analyses.

MAIN RESULTS

Combining data from 425 reports (307,028 abstracts) resulted in an overall full publication proportion of 37.3% (95% confidence interval (CI), 35.3% to 39.3%) with varying lengths of follow-up. This is significantly lower than that found in our 2007 review (44.5%. 95% CI, 43.9% to 45.1%). Using a survival analyses to estimate the proportion of abstracts that would be published in full by 10 years produced proportions of 46.4% for all studies; 68.7% for randomized and controlled trials and 44.9% for other studies. Three hundred and fifty-three reports were at high risk of bias on one or more items, but only 32 reports were considered at high risk of bias overall.Forty-five reports (15,783 abstracts) with 'positive' results (defined as any 'significant' result) showed an association with full publication (RR = 1.31; 95% CI 1.23 to 1.40), as did 'positive' results defined as a result favoring the experimental treatment (RR =1.17; 95% CI 1.07 to 1.28) in 34 reports (8794 abstracts). Results emanating from randomized or controlled trials showed the same pattern for both definitions (RR = 1.21; 95% CI 1.10 to 1.32 (15 reports and 2616 abstracts) and RR = 1.17; 95% CI, 1.04 to 1.32 (13 reports and 2307 abstracts), respectively.Other factors associated with full publication include oral presentation (RR = 1.46; 95% CI 1.40 to 1.52; studied in 143 reports with 115,910 abstracts); acceptance for meeting presentation (RR = 1.65; 95% CI 1.48 to 1.85; 22 reports with 22,319 abstracts); randomized trial design (RR = 1.51; 95% CI 1.36 to 1.67; 47 reports with 28,928 abstracts); and basic research (RR = 0.78; 95% CI 0.74 to 0.82; 92 reports with 97,372 abstracts). Abstracts originating at an academic setting were associated with full publication (RR = 1.60; 95% CI 1.34 to 1.92; 34 reports with 16,913 abstracts), as were those considered to be of higher quality (RR = 1.46; 95% CI 1.23 to 1.73; 12 reports with 3364 abstracts), or having high impact (RR = 1.60; 95% CI 1.41 to 1.82; 11 reports with 6982 abstracts). Sensitivity analyses excluding reports that were abstracts themselves or classified as having a high risk of bias did not change these findings in any important way.In considering the reports of the methodology research that we included in this review, we found that reports published in English or from a native English-speaking country found significantly higher proportions of studies published in full, but that there was no association with year of report publication. The findings correspond to a proportion of abstracts published in full of 31.9% for all reports, 40.5% for reports in English, 42.9% for reports from native English-speaking countries, and 52.2% for both these covariates combined.

AUTHORS' CONCLUSIONS

More than half of results from abstracts, and almost a third of randomized trial results initially presented as abstracts fail to be published in full and this problem does not appear to be decreasing over time. Publication bias is present in that 'positive' results were more frequently published than 'not positive' results. Reports of methodology research written in English showed that a higher proportion of abstracts had been published in full, as did those from native English-speaking countries, suggesting that studies from non-native English-speaking countries may be underrepresented in the scientific literature. After the considerable work involved in adding in the more than 300 additional studies found by the February 2016 searches, we chose not to update the search again because additional searches are unlikely to change these overall conclusions in any important way.

Discrepancies between meeting abstracts and subsequent full text publications in hand surgery

PURPOSE

Research abstracts presented during the proceedings of an annual meeting are often cited and can influence clinical practice. Prior studies show that roughly 50% of abstracts at American Society for Surgery of the Hand meetings are eventually published. Yet, it is unknown how often the results or conclusions of published studies differ from the podium presentation. The objective of this study was to quantify the differences between abstracts presented during the annual meeting of the American Society for Surgery of the Hand and the resulting manuscripts.

METHODS

We retrospectively reviewed every abstract delivered as a podium presentation at the American Society for Surgery of the Hand annual meeting from 2000 to 2010. We searched the PubMed database for matching publications and compared authorship, country of origin, hypothesis, study design and methodology, changes in study groups or populations, results, and conclusions.

RESULTS

Of 798 total abstracts, we analyzed 719 involving the hand, wrist, and brachial plexus. Fifty-six different journals published 393 of the abstracts, for a 49% publication rate. Mean time to publication was 18 months with a median of 14 and maximum of 122 months. There were inconsistencies between the results and/or conclusions in 14% of full-length articles compared with the abstract presented at the meeting. A total of 9% of articles were published with fewer subjects. Authorships changes were noted in 54% of publications.

CONCLUSIONS

Abstracts represent preliminary investigations and major and minor changes occur before subsequent publication. Caution should be exercised in referencing abstracts or altering clinical practice based on their content.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic/decision analysis IV.

Fate of abstracts presented at the 2004-2008 International Liver Transplantation Society meetings

Only 20.5% to 61.6% of abstracts presented at biomedical meetings are subsequently published as full-length articles. The aim of this study was to analyze the abstract-to-publication rate of International Liver Transplantation Society (ILTS) meeting abstracts. Abstracts presented at 5 consecutive annual ILTS meetings (2004-2008) were included to ensure a minimum follow-up period of 4 years. For each abstract, a PubMed Central search was conducted with the first author's name and affiliation along with keywords from the title. The following abstract characteristics were examined and used to obtain the abstract-to-publication rate: (1) the year of presentation, (2) the presentation category (plenary session, concurrent oral presentation, or poster presentation), (3) the type of study (randomized clinical study, case report, other clinical study, or basic science study), (4) the first author's discipline (surgery, medicine, anesthesiology/critical care medicine, pathology, radiology, or pharmacology), and (5) the location of the authors (ie, an English-speaking or non-English-speaking country). A total of 2345 abstracts (469 ± 144 abstracts per meeting) were presented, and 913 of those abstracts (38.9%) were expanded into full-length publications. It took 46 months for 90% of the abstracts to be published as full-length journal articles. The abstract-to-publication rates differed with the year of abstract presentation (50.2% in 2004, 45.9% in 2005, 47.6% in 2006, 30.6% in 2007, and 30.3% in 2008; P < 0.001), with the presentation category (49.6% for plenary sessions, 48.5% for concurrent oral presentations, and 34.8% for poster presentations; P < 0.001), and with the type of study (66.7% for randomized clinical studies, 63.1% for basic science studies, 36.7% for other clinical studies, and 35.0% for case reports; P < 0.001). Abstracts from authors from non-English-speaking countries had a higher publication rate (41.1% versus 33.6%, P < 0.001). No differences were found between first authors' disciplines.

Extent of publication bias in different categories of research cohorts: a meta-analysis of empirical studies

BACKGROUND

The validity of research synthesis is threatened if published studies comprise a biased selection of all studies that have been conducted. We conducted a meta-analysis to ascertain the strength and consistency of the association between study results and formal publication.

METHODS

The Cochrane Methodology Register Database, MEDLINE and other electronic bibliographic databases were searched (to May 2009) to identify empirical studies that tracked a cohort of studies and reported the odds of formal publication by study results. Reference lists of retrieved articles were also examined for relevant studies. Odds ratios were used to measure the association between formal publication and significant or positive results. Included studies were separated into subgroups according to starting time of follow-up, and results from individual cohort studies within the subgroups were quantitatively pooled.

RESULTS

We identified 12 cohort studies that followed up research from inception, four that included trials submitted to a regulatory authority, 28 that assessed the fate of studies presented as conference abstracts, and four cohort studies that followed manuscripts submitted to journals. The pooled odds ratio of publication of studies with positive results, compared to those without positive results (publication bias) was 2.78 (95% CI: 2.10 to 3.69) in cohorts that followed from inception, 5.00 (95% CI: 2.01 to 12.45) in trials submitted to regulatory authority, 1.70 (95% CI: 1.44 to 2.02) in abstract cohorts, and 1.06 (95% CI: 0.80 to 1.39) in cohorts of manuscripts.

CONCLUSION

Dissemination of research findings is likely to be a biased process. Publication bias appears to occur early, mainly before the presentation of findings at conferences or submission of manuscripts to journals.

[Publication rate for oral presentations made at the Journées Dermatologiques de Paris meeting]

BACKGROUND

The fate of oral presentations presented at a dermatological meeting has not been assessed to date. Our aim was to determine the publication rate for oral presentations presented at the "Journées dermatologiques de Paris" (JDP) meeting in peer-reviewed journals. Our secondary goals were to identify factors associated with publication and to examine the consistency of reporting of research findings presented in the conference abstract and subsequent full publication.

METHODS

Abstracts presented orally at the JDP 1999-2004 were identified in the book of congress abstracts. Two independent operatives performed a Medline search cross-referencing lead and last authors and keywords.

RESULTS

The publication rate was 57.6% with mean time to publication of 20.3months. The median impact factor was 2.8. Factors associated with subsequent publication were study topic (p=0.04 for oncology) and study type (p=0.03 for fundamental research and p=0.005 for randomized controlled trials). The congress abstracts and full-text publication differed primarily in terms of sample size and data given in the "Results" section.

DISCUSSION

More than half of all abstracts presented orally at the JDP congress are subsequently published in journals with a median impact factor comparable to those seen for other scientific congresses for which similar analysis has been conducted. These results confirm the scientific quality of this particular congress, in addition to its vocation of continuous medical training.