For scientific improvement, study findings should be shared at the congresses and symposiums. Researchers share their knowledge and experience with the audience, and receive feedbacks, which contributes to the maturation of the presented studies. If the reports presented at the congresses are accepted for publication in peer-reviewed journals, it indicates that these studies were conducted using scientific methods with reliable results.[1] Publication of the results of these studies in the international peerreviewed journals is the gold standard for sharing the information with a wide range of international colleagues.[2] Therefore, it should be aimed to publish the presented research in a peer-reviewed journal. Planning the study accordingly and preparing them for publication would be an important factor to increase the level of the quality of information and experience shared at congresses and symposiums.[3]

It has been reported that 31.6 to 69.1% of the reports presented at congresses in various areas of specialties are published in the international journals within four years.[4,5] In Turkey, studies addressing dermatology, radiology, rheumatology, and physiotherapy congresses report publication rates of the reports presented at the national congresses between 11.8 and 21.6%.[6,7]

In the present study, we aimed to determine the rate of publication of all proceedings presented at the 6th National Annual Congress of the Turkish Society of Thoracic Surgery in the international journals within the subsequent four years and to examine the variables related to rates for the published papers in Turkey.

Methods

To obtain the reports published in the international peer-reviewed journals, we searched all case reports and study abstracts accepted to the 6th National Congress of Thoracic Surgery, which was held in 2011, and published in the international peer-reviewed journals and the Turkish Journal of Thoracic and Cardiovascular Surgery, the official publication of the Turkish Society of Cardiovascular Surgery and the Turkish Society of Thoracic Surgery, using the PubMed database (http://www.ncbi.nlm.nih.gov/ pubmed).[8,9] All data of the reports presented at the congress were obtained using the abstract book provided to the participants during the congress. All oral, poster discussions, and poster presentations accepted to the congress were included in the study. For all presentations, the type of presentation, and name of the first author and affiliated institution were recorded. The presentations were categorized in four groups based on the researcher’s institution as university hospital, training and research hospital, state hospital; or labelled as multi-centered.

The PubMed and Journal of Thoracic and Cardiovascular Surgery online databases were searched entering the name and surname of the authors, specifically the first and the last authors, with title and keywords from the title.[10,11] In case there was no match, all publications of each researcher were scanned on an individual basis and the search was repeated in other databases. Abstracts of the publications resembling the title of reports in the abstract book were reviewed to ensure that the content was identical or derived from the report presented at the congress. For those reports that were confirmed to be published, date of publication, name of the journal, and any revision in the author list were noted. Date of publication was evaluated according to the month and year.

Statistical analysis
Statistical analysis was performed using the IBM SPSS version 20.0 software (IBM Corp., Armonk, NY, USA). Analyses were made using the Mann- Whitney U and chi-square tests. Numerical variables were expressed in mean and standard deviation, while categorical variables were expressed in percentage. A p value of <0.05 was considered statistically significant with 95% confidence interval.

Results

There were a total of 312 accepted abstracts at the 6th National Thoracic Surgery Congress in 2011, of which 23 were oral presentations, 61 were discussion poster discussions, and 228 were poster presentations. Of these presentations, 35 (11.2%) were published in the international peer-reviewed journals. According to the type of presentation, five of the oral presentations (21.7%), 10 of poster discussions (16.3%), and 20 of poster presentations (8.7%) were published. The publication rate for oral presentations was relatively higher than poster discussions and poster presentations; however, the difference was not statistically significant (p=0.163) (Table 1).

Table 1: Distribution and publication rates of the 6th National Thoracic Surgery Congress proceedings among different types of institutions

According to the type of institution, proceedings from the universities had the highest ratio of publication (64.4%), followed by studies from training and research hospitals (24.1%), multi-centered studies (8.9%), and state hospitals (2.5%), respectively. There was no significant difference in the rate of publication of presentations from different institutions (p=0.581).

A total of 48.6% of the published presentations had the list of the authors altered, irrespective of the order. A total of 12 (34.3%) papers had additional co-workers, in contrast to five (14.3%) which had lost at least an author. Additionally, 5.7% of the published papers had the name of the first author altered (Table 2).

Table 2: Distribution of revised author lists

The mean publication time for 35 papers was 12±2.8 months (range 3 to 42 months). Publishing time for oral presentations was relatively longer compared to others, whereas poster presentations had the shortest time. There was a statistically significant difference in the publication durations of different presentation types (p=0.005), although no significant difference between the durations and the institution of the presentations (p=0.153). When university hospitals were compared to training and research hospitals, there was no statistical difference in the publication durations (p=0.233).

Of all the reports published in 24 different peerreviewed journals, 49% were published in four major journals (the Journal of Thoracic and Cardiovascular Surgeons, Turkish Journal of Thoracic and Cardiovascular Surgery, Surgery Today, and European Journal of CardioThoracic Surgery) (Table 3).

Table 3: Distribution of published publications presented at the 6^th National Thoracic Surgery Congress proceedings according to the journals indexed in PubMed

Discussion

Our study is the first determine the factors associated with publication course of the proceedings presented at thoracic surgery congresses, addressing the abstracts presented at the National Thoracic Surgery Congress. Our results showed that only one of every nine, which corresponds to 11.2% of the abstracts, were converted to manuscripts and published in the international peer-reviewed journals within the subsequent four years. Several studies addressing the congresses of various specialties in Turkey, such as radiology, rheumatology, and dermatology, reported the ratio of publication of national congress proceedings in the international journals between 11.8 and 29.1%.[6,7] Similar studies from the United States, United Kingdom, and Australia reported this ratio between 29.8% and 61.6%.[12-15]

The Cochrane review revealed possible reasons for why the abstracts presented at congresses and meetings cannot be converted into publications as follows: researchers not giving the required priority to their studies, and their lack of time which should be mostly allocated to the academic studies.[16] Other possible reasons included the presence of previous studies with similar study designs and results, preconceived judgement about the rejection by the journals, study results not providing new scientific contributions, and presence of deficits and errors in statistical methodology.[8,17]

Although some studies did not find any significant difference between the publication rates of oral and poster presentations,[17-20] others showed that the publication rate of oral presentations was higher than poster presentations.[8,21,22] In general, well-designed studies with interesting results which have a higher scientific value are selected as oral presentations by the review committee of the abstracts, and these reports mature further with the feedbacks from the audience. These may be the main reasons why oral presentations had higher publication rates than poster presentations. Although the difference was not statistically significant, according to our results, oral presentations had 2.5 times higher publication rate than the poster presentations.

Based on the distribution of proceedings according to the affiliated institutions, the highest ratio was from the universities. In addition, when we consider that some of the studies from state hospitals might have been sent by physicians who completed their training and started their compulsory service in state hospitals, and that their studies might, indeed, be initiated while they were residents, it is possible that universities might even have a greater contribution in this rate. The reason why we did not find statistically significant difference between the institution types may be also related to the limited number of presentations. The publication rate of presentations from training and research hospitals was lower, and this can be due to several reasons, such as less time allocated for academic studies compared to universities, differences in training courses, and slower management of the publication course.

Of the publications included in this study, 48.6% had a revised author list, irrespective of its order. Considering that many studies are matured in time following its presentation at a congress and they are composed of specifically for publication afterwards, there may be additional collaborators working together throughout this period. On the other hand, we found that the first author changed during the publication process of some of these studies (5.7%).

In our study, the mean publication duration for the 35 reports issued in the international peer-reviewed journals was 12±2.8 (range 3 to 42) months. Considering the time spent for submission and evaluation processes, this result indicates that reports published in the international peer-reviewed journals were sent to the journals without losing considerable time after the congress. Additionally, poster presentations were often case reports and were sent to peer-reviewed journals sooner than the other types. It should be noted that clinical studies may take longer time for evaluation, maturation, data collection, interpretation, and inscription.

Several recommendations have been made for the publication of reports presented at congresses and scientific meetings. Some authors suggested a more selective approach during the evaluation of the abstracts.[23] Some required submission to a journal for publication to be accepted at the congress.[24] Periodic analysis of publication rates of the reports presented at a congress may be also beneficial. In addition, the Turkish Thoracic Society provides “Published Congress Presentation Award” to encourage researches for publication, which sets a good example as a motivation method in this respect.

In conclusion, we found similar rates of the publication rate of the reports presented at 6th National Congress of Thoracic Surgery to the other national congresses of different specialties in Turkey, but relatively lower compared to the rates at international congresses. We suggest that unpublished presentations should be interrogated and the underlying causes should be examined in detail to publish scientific studies in peer-reviewed journals and to share the information with a larger audience.

Acknowledgement
We would like to thank Selin Başbuğ Alıcı for her contributions in statistical analysis.

Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding
The authors received no financial support for the research and/or authorship of this article.

References

1) Uniform requirements for manuscripts submitted to biomedical journals. International Committee of Medical Journal Editors. JAMA 1997;277:927-34.

2) Schulte TL, Trost M, Osada N, Huck K, Lange T, Gosheger G, et al. Publication rate of abstracts presented at the Annual Congress of the German Society of Orthopaedics and Trauma Surgery. Arch Orthop Trauma Surg 2012;132:271-80.

3) Cartwright R, Khoo AK, Cardozo L. Publish or be damned? The fate of abstracts presented at the International Continence Society Meeting 2003. Neurourol Urodyn 2007;26:154-7.

4) Marx WF, Cloft HJ, Do HM, Kallmes DF. The fate of neuroradiologic abstracts presented at national meetings in 1993: rate of subsequent publication in peer-reviewed, indexed journals. AJNR Am J Neuroradiol 1999;20:1173-7.

5) Yoo S, Oh G, Wang JC. Publication rates of presentations made at annual meetings of the American Orthopaedic Society for Sports Medicine and the Arthroscopy Association of North America. Am J Orthop (Belle Mead NJ) 2002;31:367-9.

6) Kaya Mutlu E, Çelik D, Mutlu C, Razak Özdinçler A. Publication rates of oral presentations accepted at Advances in Physiotherapy Symposiums Turk J Physiother Rehabil 2013;24:145-9.

7) Seçil M, Uçar G, Sentürk C, Karasu S, Dicle O. Publication rates of scientific presentations in Turkish national radiology congresses. Diagn Interv Radiol 2005;11:69-73.

8) Peng PH, Wasserman JM, Rosenfeld RM. Factors influencing publication of abstracts presented at the AAO-HNS Annual Meeting. Otolaryngol Head Neck Surg 2006;135:197-203.

9) Donegan DJ, Kim TW, Lee GC. Publication rates of presentations at an annual meeting of the american academy of orthopaedic surgeons. Clin Orthop Relat Res 2010;468:1428-35.

10) Macdonald AL, Parsons C, Davenport M. Outcome of abstracts presented at the British Association of Paediatric Surgeons congresses (1999-2008). J Pediatr Surg 2012;47:386-90.

11) Li SF, Umemoto T, Crosley P, Cassidy C. SAEM abstracts to articles: 1997 and 1999-2001. Acad Emerg Med 2004;11:985-7.

12) Oliveira LR, Figueiredo AA, Choi M, Ferrarez CE, Bastos AN, Netto JM. The publication rate of abstracts presented at the 2003 urological Brazilian meeting. Clinics (Sao Paulo) 2009;64:345-9.

13) Kleweno CP, Bryant WK, Jacir AM, Levine WN, Ahmad CS. Discrepancies and rates of publication in orthopaedic sports medicine abstracts. Am J Sports Med 2008;36:1875-9.

14) Schnatz PF, Romegialli A, Abrantes J, Marakovits K, Cunningham D, O’Sullivan DM. The North American Menopause Society: from abstract to publication. Menopause 2008;15:996-1001.

15) Yoon PD, Chalasani V, Woo HH. Conversion rates of abstracts presented at the Urological Society of Australia and New Zealand (USANZ) Annual Scientific Meeting into full-text journal articles. BJU Int 2012;110:485-9.

16) Scherer RW, Langenberg P, von Elm E. Full publication of results initially presented in abstracts. Cochrane Database Syst Rev 2007;2:000005.

17) Balasubramanian SP, Kumar ID, Wyld L, Reed MW. Publication of surgical abstracts in full text: a retrospective cohort study. Ann R Coll Surg Engl 2006;88:57-61.

18) Ng L, Hersey K, Fleshner N. Publication rate of abstracts presented at the annual meeting of the American Urological Association. BJU Int 2004;94:79-81.

19) Rodriguez JL, Laskin DM. Subsequent publication of oral and maxillofacial surgery meeting abstracts. J Oral Maxillofac Surg 2012;70:1261-4.

20) Winnik S, Raptis DA, Walker JH, Hasun M, Speer T, Clavien PA, et al. From abstract to impact in cardiovascular research: factors predicting publication and citation. Eur Heart J 2012;33:3034-45.

21) Dahllöf G, Wondimu B, Maniere MC. Subsequent publication of abstracts presented at the International Association of Paediatric Dentistry meetings. Int J Paediatr Dent 2008;18:91-7.

22) Lee DJ, Yuan JC, Prasad S, Barão VA, Shyamsunder N, Sukotjo C. Analysis of abstracts presented at the prosthodontic research section of IADR General Sessions 2004-2005: demographics, publication rates, and factors contributing to publication. J Prosthodont 2012;21:225-31.

23) Özyurt S, Kaptanoğlu AF. 2004-2008 yılları arasında iki yılda bir yapılan ulusal dermatoloji kongrelerinde sunulan özetlerin yayınlanma oranları. Dermatoz 2012;3:7-11.

24) de Andrade VA, Carpini S, Schwingel R, Calderan TR, Fraga GP. Publication of papers presented in a Brazilian Trauma Congress. Rev Col Bras Cir 2011;38:172-6.