Biomedical results are often initially presented at scientific meetings. However, these results are not always published as full-text articles in scientific journals, hampering access to these data among researchers. Although some organizations publish conference proceedings in a book or journal supplement, these publications usually contain only the abstracts of presentations and not full reports. Consequently, some researchers aim to publish a fuller version of work presented at meetings in scientific journals, thus achieving maximum diffusion of their results. This process has come to be known as subsequent publication or full-text publication.1–3 Subsequent publication of results presented at the meetings of scientific societies or organizations has been studied in several scientific disciplines, including scientific documentation,4 pharmacy,5 marine biology,6 and several medical specialties such as radiology,7 traumatology and orthopedics,8 urology,9 drug dependence,10 pediatrics,11 and nephrology.12 In the field of cardiovascular research, 2 studies have been published: one on subsequent publication after the meetings of the Cardiac Society of Australia and New Zealand between 1999 and 2005 and another on the meeting of the International Stroke Conference in 2000.

Since 1987, the Spanish Society of Cardiology (SEC) has held a widely-attended annual meeting (approximately 4000 attendees) with a large number of presentations, both oral and in other formats; in the last few years, the number of these presentations has exceeded 1000. Given the relationship between the scientific impact of a meeting and its quality, it would be interesting for both the SEC and for the specialty of cardiology as a whole to identify subsequent full-text publications and their bibliometric characteristics, as well as the possible factors determining publication and nonpublication. The aim of this study was to follow up a sample of abstracts selected from 3 nonconsecutive meetings of the SEC and to analyze some of the bibliometric characteristics of subsequent full-text articles.

Of the 300 abstracts analyzed, 115 resulted in 147 full-text articles, representing a subsequent publication rate of 38.33%. The overall percentage of abstracts resulting in subsequent publications was 49%. The meeting with the highest publication rate was that held in 2005 (59%), followed by 2002 (45%) and 2008 (43%). Analysis of subsequent publication by subject area of the SEC revealed that the highest number of full-text articles corresponded to interventional cardiology (58.8%), followed by heart rhythm (55.81%), risk factors (53.13%) and ischemic heart disease (50%) (Table 1). Of the 115 abstracts converting to full-text publications, 88 (76.52%) resulted in 2 articles, 23 in 2 articles (20%), 3 in 3 articles (2.6%), and only 1 converted to 4 articles (0.84%).

Time to publication was 2 years in 30.61% (45 articles), followed by 1 year in 28.53% (42 articles), and less than 1 year in 14.97% (23 articles) (Fig. 1).

Figure 1.

Time between presentation of results at meetings and year of publication in full.

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The articles were published in 57 journals, of which 9 were Spanish journals and 48 were international journals (Table 2). The journals publishing the largest number of reports were Revista Española de Cardiología (n=55; 37.41%), the European Heart Journal (n=8; 5.44%) and the Journal of Cardiovascular Electrophysiology (n=5; 3.40%). Of these 57 journals, 17 published more than 1 article and, obviously, most were journals publishing cardiovascular research (47 journals), while the remaining 10 journals published articles on emergency medicine, diabetes, infectious diseases and clinical microbiology, nursing, and general and internal medicine, among other specialties.

The total number of citations received in Science Citation Index-Expanded was 1872, representing a mean citation rate of 12.73 per article. This number increased 14.4 when we excluded the 17 articles published in journals not included in the Web of Science: Clínica e Investigación en Arteriosclerosis (n=2), Current Cardiology Reviews (n=1), Enfermería Clínica (n=2), Expert Review of Cardiovascular Therapy (n=1), Investigación Cardiovascular (n=3), Mapfre Medicina (n=1), Revista de Medicina de la Universidad de Navarra (n=1), and SEMERGEN (n=1).

The journal receiving the highest number of citations was Revista Española de Cardiología (n=272), followed by the Journal of the American College of Cardiology (n=213), the European Heart Journal (n=204) and the Lancet (n=172) (Table 2). When the number of citations per article was taken into account, the highest number of citations was received by the Lancet, which published a single article that received 172 citations, followed by FEBS Letters, which published a single article with 127 citations. Other notable journals were Circulation with 54.67 citations per article and the Journal of the American College of Cardiology, with 53.25. The journal with the highest mean IF was the Lancet (IF=21.713), a journal in the first quartile of the subject category of general and internal medicine, followed by Circulation (IF=11.786), which is ranked highest in the subject category of cardiac and cardiovascular systems and the Journal of the American College of Cardiology (IF=10.113).

Figure 2 shows the number of full-text publications resulting from each meeting and the citations received by these articles and shows the predominance of the meeting held in 2005, with 59 subsequent publications, which received 850 citations. Most of the journals publishing these reports were ranked in the first quartile of journals in the same subject category in Journal Citation Reports (23 journals, 40.35%); these journals published 43 articles (29.25% of the articles) (Fig. 3). A further 15 journals (26.32%) were ranked in the second quartile and published 79 articles (53.74%). In this second quartile, a notable finding was that Revista Española de Cardiología published 55 articles. Lastly, the 6 journals in the third quartile published 7 articles (4.76%) and 5 journals in the fourth quartile published 6 articles (4.08%). Eight journals with no IF published 12 articles (8.16%). The distribution of the journals and of the articles in the quartiles of Journal Citation Reports are illustrated in the 2 diagrams in Figure 3. The largest percentage of articles was grouped in journals in the second quartile, because of the high number of articles published by Revista Española de Cardiología.

Figure 2.

Full-text articles and the citations received by these articles by year of meeting.

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Figure 3.

Distribution of journals publishing full-text articles and distribution of articles by Journal Citation Reports quartiles. IF, impact factor.

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Fourteen articles received more than 30 citations in Science Citation Index-Expanded. The journals publishing these hot papers were highly varied and–except for Circulation, which published 3 reports, and the European Heart Journal, which published 2 articles–the remaining journals published only 1 report. These journals were the American Journal of Cardiology, the American Journal of Hypertension, Cytokine, FEBS Letters, Heart, the Journal of Cardiovascular Electrophysiology, the Journal of Pharmacology and Experimental Therapeutics, the Journal of the American College of Cardiology, and the Lancet.

Scientists frequently attend meetings for several reasons. On the one hand, meetings are an ideal forum to learn about new research tendencies and discuss ongoing research. On the other hand, meetings allow attendees to meet fellow professionals and to create or broaden their professional networks, thus increasing their prestige and reputation.1–3 The annual meetings of the SEC allow attendees to exchange ideas and present results of importance in their field. Although abstracts submitted to the meetings of the SEC are reviewed by experts who select those of the highest quality, the only way to ultimately validate these results continues to be their publication in peer-reviewed journals indexed in the international bibliographic databases, because this process involves more rigorous evaluation of a study's design, methods, and conclusions.

The overall percentage of abstracts accepted by meetings of the SEC that were subsequently published in full was 38%. This percentage is higher than that reported by Chand et al.13 for the meetings of the Cardiac Society of Australia and New Zealand (1995-2005), which was 28%. However, this percentage was lower than that reported by Sanossian et al.14 for the International Stroke Conference of 2000 of the American Stroke Association (62.3%), and by Goldman and Loscalzo21 for the American College of Cardiology Scientific Sessions; however, the latter study was published in 1980 and publication patterns may have changed considerably in the more than 30 years that have passed since then. Other biomedical specialties show widely diverging publication rates. For example, the publication rate was 37.7% in urology22 but was 51%, 62%, and 75% in pediatrics, emergency medicine, and gynecology, respectively.23–25 The publication rates of radiology meetings26–28 ranged from 9% to 37%. In some pharmacology meetings5 the publication rate was between 11% and 33%. In drug dependence,10 the publication rate of results presented at the meeting of the College on Problems of Drug Dependence in 1999 was 36.9%. In nonbiomedical subject categories, we identified widely differing publication rates, ranging from 13% for presentations at the Ninth ACRL Conference (Association of College Research Libraries),4 to 36.7% for results presented at meetings of the International Society for Scientometrics and Informetrics.20

The results obtained in the present study are in agreement with those of a meta-analysis published in 2003, which was based on 64 studies and concluded that one-third of the abstracts submitted to biomedical meetings were subsequently published in full.2 Moreover, this meta-analysis revealed that oral presentations were associated with a higher subsequent publication rate, suggesting that, in some meetings, only the highest quality abstracts are accepted as oral presentations. However, no contrasting evidence was available to support this possibility.2

The journal publishing the largest number of full reports of results presented at the meeting of the SEC was Revista Española de Cardiología, but publication in international journals with IF was common. This finding is unsurprising, given that Revista Española de Cardiología is the official journal of the SEC and, moreover, enjoys international prestige, as demonstrated by its inclusion in the main bibliographic databases, including Science Citation Index-Expanded, and that its IF places it in the top half of the world ranking for its subject category and it is second of all Spanish journals–irrespective of subject category–in the Journal Citation Reports-Science Edition (IF=3.204 in 2012). Despite biases, criticisms and controversies, IF continues to be one of the indicators most widely used to evaluate journal quality.29,30 Consequently, the high percentage of articles published in journals ranked in the top half of the cardiac and cardiovascular system subject category of Journal Citation Reports (up to 83%) can be taken as an objective indicator of the quality of presentations at meetings of the SEC.

The publication rate differed by section of the SEC. This rate was highest for pediatric cardiology/congenital heart disease and was lower for heart failure, transplantation and cardiomyopathy. The possible reasons for differences by subject area are unclear. A previous study14 reported a high publication rate for studies on vascular physiopathology and experimental ischemia, and a lower publication rate for those on cardiovascular risk and diagnosis, but the authors offered no possible explanations for these findings.

In agreement with the results of other studies,10,14,20,31 our results indicate that time to full publication was usually 2 years, although some full-text articles were published later. One explanation for this finding is that some abstracts may contain the results of the initial stages of research projects that will take several years to complete; another explanation is that the authors may decide to broaden and improve their research project with the aim of publishing their results in international journals with high IF.7 A possible explanation for the finding that the publication rate was lowest (43%) for the 2008 meeting could be that insufficient time has passed for publication of some of the results, such as those of follow-up studies or works in progress, which can require 5 years for full publication.32

Publication rates are higher for the meetings of some scientific societies than for others, but the reasons for this difference are unclear and are difficult to elucidate because they are multifactorial. One factor that could lead to a higher publication rate might be greater or lesser rigor in the selection of abstracts: meetings whose scientific committee apply rigorous selection procedures will have higher subsequent publication rates, while those tending to accept all–or almost all–submitted abstracts will obviously have a lower publication rate. If correct, this hypothesis would support the view that the publication rate of a meeting is an effective indicator of its overall quality, a concept that includes its organization, academic quality, scientific program, institutional support, and the application of rigorous selection criteria when accepting results for presentation, among other factors.1–3,7

Another factor that could influence publication or nonpublication is subsequent publication of conference proceedings. Authors whose results have been fully published in conference proceedings may not feel the need to publish their work in a journal, although this would not apply to poster presentations. In some subject areas, conference proceeding may be the only publication outlet and may even be a more important information source than journals.32

Several reasons have been identified for the nonpublication of results presented in abstracts submitted to meetings.14 The most commonly cited reason is lack of time, in some specialties due to the high burden of clinical workload, as well as teaching or management commitments;3,25,33 additional reasons are a lack of resources and research funds. Other major obstacles to publication are the low priority given to publication by some researchers and confusion surrounding which investigator–or investigators–is responsible for drafting the manuscript. Only a minority of authors attributed nonpublication to methodological defects.14,26,34 Nonpublication can also be due to personal reasons, such as a negative attitude among some investigators who believe their work to be of sufficient interest for presentation at a conference but not to be of adequate quality for acceptance in a peer-reviewed journal.33

More than one-third of the results presented at annual meetings of the SEC are subsequently published as full-text articles in journals indexed in bibliographic databases. Revista Española de Cardiología publishes the highest number of these articles, but publication in other high-IF journals is common. The nonpublication of more than 60% of these abstracts deprives the scientific community of potentially interesting results, and consequently researchers presenting their results at meetings of the SEC should be encouraged to submit them for publication in full. Our study leaves some unanswered questions, which could be analyzed in future work. For example, it would be interesting to determine the association between some of the variables of studies presented at meetings of the SEC and their subsequent publication, such as the type of presentation (oral or poster), originality, design, methodological quality, and the positive or negative direction of their results.

This study was supported by the Spanish Society of Cardiology/Spanish Heart Foundation.

None declared.