Abstract
The present editorial summarizes the last 2 calendar years of Advances in Clinical and Experimental Medicine (ACEM) publication (2021 and 2022). The specific aims were: 1) To clarify the classification of papers published in ACEM; 2) To present motivations behind choosing this classification; 3) To show how this classification is reflected in citations. Six categories of papers published in ACEM are presented: editorials, meta-analyses, reviews (including systematic reviews), multicenter studies, research-in-progress studies, and research letters; lack of clear definitions for editorials, research letters and research-in-progress studies is discussed. Thematic fields covered by all categories in 2021 and 2022 are presented and differences in this regard between 2021 and 2022 are highlighted. Reasons for not publishing case reports (CRs) are discussed, with some of the debate on this issue in medical literature summarized. The article type classification used in ACEM in only one of many possible solutions and may be modified in the future – it should be both clear for the authors and allow for orientation in the journal’s content. The motivation for choosing the employed categories stem both from their position on the accepted levels of evidence in evidence-based medicine (EBM) and their potential to be cited.
Key words: editorial, case report, meta-analysis, article type, research letter
Introduction
Genology is a branch of literary theory that is concerned with the study of artistic genres, e.g., types of novels (mystery, science-fiction, etc.). Similar studies are well established in film theory. While scholars, specialists in the fields mentioned above, reflect on evolution of different genres across time and frequently express doubt whether genres as a mode of classifying narrative works of art should still be seen as something more than mere convention, readers or viewers still intuitively use terms like ‘horror’ or ‘comedy’ to have some basic orientation in literature, cinema and television. In scientific publishing, there are also analogues of genres, called “types” or “categories” of scientific papers. This editorial focuses exclusively on these types/categories of medical articles and is an attempt of self-reflection of Advances in Clinical and Experimental Medicine (ACEM) editors on the classification of papers employed in this journal from submission by authors to publishing.
There is no universal list of scientific medical article types, as evidenced by the editorial policy documents or instructions for authors disseminated by respected journals, e.g., guidelines listed by the Yale Journal of Biology and Medicine,1 New England Journal of Medicine,2 The BMJ,3 Frontiers in Medicine,4 The Medical Journal of Australia,5 and Springer Publishing.6 The above guidelines are examples of editorial practices. However, the scientific discussion regarding this topic has taken 2 different directions. A similar classification was proposed by Peh and Ng,7 organizing the medical research into introduction, methods, results, and discussion (IMRAD). Röhrig et al.,8 on the other hand, classify medical research into primary research (including basic medical research, clinical research, and epidemiological research) and secondary research (including meta-analyses and reviews).
The declared scope of ACEM includes articles that deal with all clinical and experimental medicine. The journal’s scope is deliberately broad and general, since “advances” occur constantly in all fields of medicine and related sciences, and the leading research areas change as medical knowledge progresses. However, this does not mean that all types of articles are accepted. Since 2021, ACEM has been following a new classification of academic papers: 1) original papers (including randomized and nonrandomized clinical trials, retrospective studies, animal and cell line studies, and others); 2) meta-analyses; 3) reviews (including systematic reviews, scope, narrative, and other reviews); 4) multicenter studies; 5) research-in-progress (encompassing all types of experimental research in medicine); 6) research letters; and 7) editorials. In 2023, ACEM introduced a new category – editorial commentary. However, the present article covers the years 2021 and 2022, so it will not be discussed. Of other frequently encountered types of scientific medical papers, case reports and case series are not accepted in ACEM, which will be explained later in the text.
The classification used and the order of papers assigned to different categories in each issue reflect the hierarchy of evidence (levels of evidence) in evidence-based medicine (EBM): 1) editorials; 2) meta-analyses; 3) original papers; 4) reviews; and 5) research letters. Editorials opens an issue because they offer a more personal perspective and can serve as a guide from an experienced investigator to other, more focused studies. Editorials are followed by meta-analyses because, in clinical research, the best evidence of treatment efficacy comes mainly from meta-analyses of randomized controlled trials (RCTs).9, 10 Meta-analytic results are considered the most trustworthy source of evidence by the EBM literature.11, 12 Original papers are the primary source of new knowledge and represent the majority of each issue, with reviews offering theoretical summaries of complex issues, and research letters provide concise reports of original research findings.
Objectives
The specific aims of this editorial are as follows:
1) to present the classification of papers published in ACEM;
2) to clarify definitions of specific categories of papers which may not be entirely clear to all readers, and to provide context for these definitions from selected literature;
3) to outline the role played in ACEM by papers of different categories;
4) to present motivations behind choosing this classification (the scope of the journal is broad, but types of papers accepted are limited);
5) to explain why certain types of papers are not considered for publication in ACEM;
6) to provide recommendations for the Editorial Board of ACEM concerning possible modifications in classification used.
Since original papers constitute the broadest and largest group of papers, they will be analyzed later in another editorial by the same authors. Presenting papers of this type requires a different approach, focusing not on definitions but on thematic patterns observed in different years. Employing such an approach in the present paper would deviate from the main discourse and deform the structure of the paper.
Editorials
Similar to research letters (discussed in one of the following sections of this paper), editorials are often a source of confusion regarding their definition; however, while research letters are confused with other, distinct types of texts published in scientific journals, the concept of an editorial is so vague that each perspective seems to be equally deeply rooted in both tradition and practice. The first concept stems from the popular press, especially from prestigious newspapers and weekly journals of opinion, and views an editorial as mean of presenting the stance of the whole journal concerning a specific problem; in modern scientific journals, editorials understood as “content provided by the editors” can also direct readers’ attention to certain papers published in a given issue, announce calls for submissions or other initiatives, offer personal or more generalized reflection on a topic related to editing a scientific journal (e.g., propose definitions of different types of papers or instruct authors on how to prepare them), describe journal achievements, plans or policies, as well as present various guidelines and other similar documents. The second concept sees an editorial as an opinion piece that expresses reflections on topical issues, explains complex research, and/or highlights strengths, weaknesses and alternative interpretations of studies. The 2 above views are not mutually exclusive because editorials of both types can appear in a single journal, sometimes even in a single issue. Papers within this category are usually by-invitation only, although there are journals (e.g., British Journal of Anaesthesia) that accept unsolicited editorials after a pre-submission approval process.
The literature on editorials in scientific journals is diverse. Nundy et al. authored a chapter explaining the basic concepts of this scientific literary genre, presenting both of the above views and focusing of the role of an editorial as an opinion maker.13 This perspective was shared by Singh and Singh, who offered a more personal view and concentrated on expressiveness of opinions and style of formulating them.14 Van Teijlingen et al.15 provided more specific advice and examples of appropriately prepared editorials for prospective authors, while Gray concisely described 5 rules of writing and editing an editorial.16 However, the paper by Leslie and Hemmings Jr. had the broadest scope – they discussed how an editorial can be defined and described the structure of an excellent paper of this type, while also providing examples and more literature on the topic.17 Guidelines for authors publishing in Springer Open journals18 should also be mentioned – several journals established clear stipulations regarding word and reference count in an editorial; there can also be more or less severe limitations concerning tables and/or figures.
Editorials were introduced in ACEM in 2021 and are solicited from members of the Editorial Board and Scientific Committee, as well as from seasoned researchers among journal’s experienced peer-reviewers. Only editorials submitted by invitation are considered for publication. This category of papers was introduced to provide authors with an opportunity to present their own opinions, commentaries and perspectives concerning selected issues within a selected research field. Editorials are meant to provide readers with context, analysis and reflection regarding specific subjects or problems. The popularity of this type of paper in ACEM is increasing: 6 editorials were published in 2021 and 12 in 2022.
In 2021, the solicited editorials addressed a specific topic or issue in the field of medicine, research, or healthcare. They explored different aspects of medical research, clinical systems, and health-related concerns. For instance, some editorials discussed the issues of monitoring the kynurenine system19 and validating medical equipment.20
In 2022, these articles reflected the ongoing advances in the field of clinical and experimental medicine, addressing current issues, innovative treatments, and the impact of global events like the COVID-19 pandemic on medical research. The articles covered several problems, including the neurobiological advances of learned fear in humans21 and the comorbidities of depressive and anxiety disorders.22
Editorials provide a valuable forum for expressing viewpoints, shaping discussions, and guiding researchers in their work. Among the top 10 most cited works in the ACEM for the 2021–2022 period are 4 editorials, namely Tanaka and Vécsei19 (2nd most cited), Battaglia21 (3rd most cited) and Chen22 (4th most cited; all citation data as of September 30, 2023). Such high citation rates raise the question why this category of papers receives so much attention in the scientific community. In the opinion of the ACEM editorial staff, these reasons differ regarding specific papers. Below are the assumed reasons divided into categories for clarity.
Perspective and opinion: Editorials often present the perspectives, opinions, and insights of experts or key figures in a particular field. Researchers may cite editorials to support or align their own viewpoints or arguments.
Guidance and recommendations: Editorials may provide guidance, recommendations, or commentary on emerging trends, methodologies, or practices within a field. Researchers may cite editorials when discussing best practices or adopting recommended approaches.
Critical Analysis: Editorials provide a critical analysis of current research, policies, or developments. Therefore, researchers may cite editorials to support their evaluations or to acknowledge influential critiques.
Historical context: Editorials can provide a historical context for a particular field or topic. Citing editorials helps researchers anchor their work within the historical evolution of ideas, theories, or practices.
Debates and controversies: Editorials often focus on debates or address controversial topics within a field. Researchers may cite editorials to highlight or participate in ongoing discussions, acknowledging the influence of these debates on the field of study.
Expert commentary: Editorials may include expert commentary on scientific breakthroughs. Researchers may cite editorials to include authoritative perspectives and acknowledge the influence of recognized experts.
Editorial policies and journal direction: Editorials can discuss changes in editorial policies, journal direction, or broader trends in publishing. Researchers citing this type of editorials may refer to shifts in the academic landscape or to the direction of a particular journal.
Meta-analyses
Meta-analyses (MAs) are considered the most trustworthy source of evidence by the EBM literature.11, 12, 23 They have the capacity to compare and contrast results from different studies, and identify both patterns and sources of disagreement among study results, or other relationships highlighted by multiple studies.24 Therefore, MAs are considered the most valuable papers in ACEM and are always placed at the beginning of each issue, immediately following editorials. Moreover, the editors of ACEM aim to publish at least 1 paper from this category in every issue. In 2021, a decision was made to classify MAs separately from reviews, but due to complex resources and demanding research process involved in their preparation, first 6 MAs were published in ACEM only in 2022. Two thematic fields were prominent in these papers:
Diagnostic and therapeutic efficacy: Several of the articles focused on assessing the accuracy and efficacy of various diagnostic and therapeutic approaches. This included evaluating the accuracy of machine learning algorithms for the assessment of upper-limb motor impairments in patients with post-stroke hemiparesis25 and the efficacy of home-based exercise programs in knee osteoarthritis treatment.26
Disease comorbidity and risk factors: Another common theme was the exploration of how certain conditions or factors influence the risk and outcomes of specific diseases; e.g., the impact of diabetes on patients receiving reperfusion therapy for acute ischemic stroke,27 along with the role of tumor necrosis factor alpha promoter polymorphism in susceptibility to sepsis.28
Meta-analysis is one of the most thoroughly theoretically discussed type of papers – its complex methodology requires deep understanding in order to be properly translated into practice (i.e., a meta-analytic article fit for publication). Shorten and Shorten29 provided a precise definition and explanation of the term ‘meta-analysis’, while Haidich30 and Stangl and Berry31 presented it in the context of medical research. Egger and Smith32 and Egger et al.33 discussed its theoretical premises, and Levi et al.23 provided exhaustive reflection on both MAs and systematic reviews. Ahn and Kang34 and Uman35 discussed the common characteristics and mutual relations between systematic reviews and MAs, and explained the importance of articles of both types among all scientific medical papers in the context of hierarchy of scientific evidence.
There are several methodological problems regarding MAs, with publication bias and other types of bias being the most significant. These issues were discussed by Sterne et al.36 and Sterne and Egger,37 who used funnel plots to detect bias in MAs. Measuring inconsistency in papers from this category was reflected upon by Higgins,38 while Higgins and Thomas further discussed quantifying heterogeneity in a MA.39 Some limitations of MAs were pointed out by Naylor.40
Numerous guidelines concerning MAs have been released: among others, Hansen et al.41 who offered a general guide in 8 steps, while Herrera Ortiz et al.11 provided a guide concerning both systematic reviews and MAs. A useful tool in preparing MAs is the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist that was presented and explained by Liberati et al.,42 with an updated version of this checklist provided by Page et al.43 Cochrane Handbook for Systematic Reviews of Interventions is also an important resource of information and guidelines concerning this issue.44
Many otherwise diligently prepared papers in this category have more or less serious flaws in the statistical analyses. This cannot be overlooked since proper statistics are a crucial part of each MA, and methodological errors in this regard can disqualify the entire work from publication. Harrer et al.45 and Schwarzer et al.46 wrote 2 fundamental papers on how to conduct a MA using statistical methods and the R language. Other important sources on statistical methods in MAs are: Borenstein et al.47 (Introduction to Meta-Analysis), Borenstein48 (Common Mistakes in Meta-analysis and How to Avoid Them), Cooper et al.49 (The Handbook of Research Synthesis and Meta-analysis), Hedges and Olkin50 (Statistical Methods for Meta-analysis), Cooper51 (Research Synthesis and Meta-analysis: A Step-by-step Approach), Lipsey and Wilson52 (Practical Meta-analysis), Littell et al.53 (Systematic Reviews and Meta-analysis), and Pigott54 (Advances in Meta-analysis). Resources presenting the above issues in a specific medical context are (among others): Egger et al.55 (Systematic Reviews in Health Care: Meta-Analysis in Context), Sutton et al.56 (Methods for Meta-analysis in Medical Research) and Whitehead57 (Meta-Analysis of Controlled Clinical Trials). Rothstein et al.58 (Publication Bias in Meta-Analysis: Prevention, Assessment and Adjustments) and Hunter and Schmidt59 (Methods of Meta-analysis: Correcting Error and Bias in Research Findings) presented the issues of bias and error in a statistical context. Finally, Brockwell and Gordon60 provided a comparison of statistical methods used in MAs.
Reviews and systematic reviews
The number of reviews published annually in ACEM remains stable. In 2021, there were 15 reviews of various methodologies and 2 systematic reviews (SRs), compared to 16 reviews complemented by 6 MAs (presented above) in 2022. There were no SRs in 2022 and no MAs in 2021. Systematic reviews often include a MA component, which involves using statistical techniques to synthesize the data from several studies into a single quantitative estimate or summary effect size.23, 35 In 2021, Ambros-Antemate et al.25 published a combined SR and MA to assess the accuracy of machine learning algorithms for the assessment of upper-limb motor impairments in patients with post-stroke hemiparesis; that paper has been classified as a MA. While the concept of review seems to be understood intuitively in the scientific community, SR is a much more clearly defined concept and there is an abundance of literature clarifying it. The Centre for Reviews and Dissemination at the University of York in the UK provided a detailed guide61 on how to prepare SRs; a book covering this issue in detail was also published by Purssell and McCrae.62 An overview of SRs was prepared by Silva et al.,63 while Higgins et al.64 analyzed the process of synthesizing quantitative evidence in SRs of complex health interventions, and Munn et al. offered guidance for authors when choosing between a systematic or scoping review approach.65
Finally, the resource utilized by many authors of reviews and MAs (and frequently referred to in such papers) is the Cochrane Handbook for Systematic Reviews of Interventions helmed by experts from the Cochrane network led by Higgins et al.44
Two SRs published in ACEM in 2021 discussed 2 different topics. The article by Czubak et al.66 compared the clinical differences among COVID-19, SARS, influenza, and the common cold, while Springer et al.67 investigated whether the choice of a drug in pharmacologic cardioversion correlates with national and international guidelines pertaining this matter.
Reviews published in ACEM in 2021 covered a wide range of medical topics, including, among others: hematological manifestations and complications of COVID-19 (Erdinc et al.68) and machine learning in orthodontics (Liu et al.69).
The thematic scope of reviews published in ACEM in 2022 was more diverse and can be categorized as follows:
Medical conditions and their management: Many articles focused on various medical conditions and their diagnosis and management, e.g., chronic kidney disease.70
Transitional care and adolescents: Some articles discussed the transition of care, particularly in adolescents with specific urological conditions. This indicates a focus on the healthcare journey and needs of this specific age group.71
Biomarkers and diagnostics: Some articles focused on new biochemical, immune, and molecular markers for diagnostic and prognostic purposes in various medical conditions, including lung cancer.72
It should be emphasized that the most-cited article published in ACEM in the discussed period is a review. An article titled “Cerebral small vessel disease: A review” by Chojdak-Łukasiewicz et al.73 has been cited 22 times, while the SR by Czubak et al.66 gained 7 citations and achieved the 6th position in the citation ranking for the years 2021–2022 (as of September 30, 2023).
Multicenter studies
In contrast to other types of articles discussed further in this editorial, there is no ambiguity in defining a multicenter study (MS), that is, a clinical trial conducted at more than 1 medical center or clinic. The benefits of MSs include a larger number of participants, different geographic locations, the possibility of inclusion of a wider range of population groups, and the ability to compare results among centers, all of which increase the generalizability of the study. In light of these advantages, it is understandable that in several scientific medical journals (e.g., Frontiers in Public Health, BMJ Open and journals specializing in publishing clinical trials, e.g., Trials and Clinical Trials), MSs are a separate category of published papers. This is also the case in ACEM, in which such category was introduced in 2017.
The literature on MSs is not abundant, but there are several papers offering advice to researchers who are not entirely familiar with this concept. Das74 prepared an in-deep study on relevance, design and implementation of MSs, while Serra-Aracil et al.75 provided a guide on how to start and develop a multicenter prospective RCT. Marsh and Hawkins76 described statistical techniques most useful in analyzing data harnessed when performing such studies. More advanced knowledge was provided by Lane et al.77, who outlined approaches for enhancing the informativeness and quality of multicenter trials as formulated by the Trial Innovation Network. Bourin78 described specific requirements regarding multicenter trials, while Chung et al.79 focused on stipulations of state agencies in this context; basic principles in this regard were also summarized by Aisen and Schafer.80
A cross-sectional study assessing multicenter clinical trial protocols was published by Zhang et al.,81 while Seifirad and Alquran82 pointed out several shortcomings of MSs with large samples. A chapter in Handbook for Clinical Research: Design, Statistics, and Implementation by Hammond et al. is also devoted to this issue.83 Finally, there are 3 checklists which can be used for preparing MSs:
1) Consolidated Standards of Reporting Trials (CONSORT),84 designed for reporting randomized controlled trials, with several specialized versions;
2) Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT),85 a guideline for the minimum content of a clinical trial protocol; 33-item SPIRIT checklist applies to protocols for all clinical trials and focuses on content rather than format;
3) Transparent Reporting of Evaluations with Nonrandomized Designs (TREND)86 for reporting intervention evaluation studies using nonrandomized designs.
Two MSs were published in ACEM in the period 2021–2022, both in 2021 and both pertained to the COVID-19 pandemic. The study by Arnabat-Dominguez et al.87 concerned laser dentistry in daily practice during the COVID-19 pandemic, while a paper by Kusztal et al.88 inquired whether home-based therapy in Fabry disease is the answer to compelling patients’ needs during the COVID-19 pandemic. Both articles explored the benefits, risks, and recommendations for safe treatment in the context of the pandemic, and how patient needs are addressed.
Research-in-progress
Although research-in-progress (RiP) type of article is widely used in scientific publishing, it lacks clear definition. Only Heinrich et al. published an editorial summing up a debate among members of the editors of Advancing Scholarship and Research in Higher Education.89 Four participants did not offer a definition per se, but proposed 4 characteristics of RiP:
1) It cannot only present the research question and methodology, but must at least give some insights to answer the question, or at least to start answering the question;
2) It identifies opportunities to collaborate and indirectly or directly invites other researchers to join the presented research project, or at least to offer their suggestions regarding how to proceed;
3) It needs to have a meticulously prepared Discussion section – the readers have to learn why the incomplete research presented is actually important;
4) It has to include a Limitations section clearly stating that the main limitation of the presented research is that it is still in progress.
In ACEM, the second characteristic is not considered as a requirement. The other 3 characteristics outline how RiP paper is understood in this journal, especially regarding the first characteristic. If a RiP submission lacks adequate data, there is no sufficient evidence to warrant any judgments about the next steps that might be taken to conduct further research.
Two RiP articles were published in ACEM in 2021, and none in 2022. The paper by Dejnek et al.90 was an analysis and comparison of autologous platelet-rich plasma preparation systems used in the treatment of enthesopathies, while the study by Rudno-Rudzińska et al. analyzed effects of calcium electroporation, electrochemotherapy, and irreversible electroporation on quality of life and progression-free survival in patients with pancreatic cancer.91
Research letters
Research letters (RLs) were introduced in ACEM in April 2021. Although editorials and RiP papers also lack a clear definition, it is essential to note that RLs should never be mistaken for a “letter to the editor.” While the former one is a concise rendition of an original academic paper, reflecting original research findings, the latter one is a brief commentary on previously published academic papers in scholarly journals.
This view is neither universally accepted nor obvious. For example, Rutkowski and Dohan Ehrenfest mentioned a concept of RL as an autonomous format for the rapid publication of data, with a three-part structure (introduction, description of the methods and results, and discussion), with a word limit of 1,500 and 25 references.92 Research letters written in this way can disclose and discuss an innovative concept before its full demonstration in the following publications. There are even entire scientific journals devoted only to RLs understood as above, e.g., Nanoletters. In ACEM, a RL is defined as a brief, but scientifically important study which is basically a shorter form of an original paper. The text structure (Background – Objectives – Materials and methods – Discussion – Limitations – Conclusions) remains the same as in an original work. Research letters are peer reviewed and subject to a stringent editorial review. Moreover, RL are indexed in all databases, including PubMed and Scopus, and the number of points assigned for such publication is identical as for original papers. However, a RL contains a maximum of 1,500 words, as opposed to 3,500 words in an original article, and may contain at most 2 tables and 2 figures. The number of references is not limited. Authors of original papers considered by the editors too brief for publication will be asked to change the category of the manuscript into a RL.
This concept has one element in common with the idea of Rutkowski and Dohan Ehrenfest92 – the speed of publication (RLs are published ahead of print online faster than original papers – but it is important to note that they are peer-reviewed like any other paper). A definition more similar to this from ACEM’s was provided by Kukafka et al. when RLs were introduced in the Journal of Medical Internet Research in 2022 – in their view, they should convey “[…] new, early, or sometimes preliminary research findings, including interesting observations from ongoing research with significant implications that justify concise and rapid communication”.93 Conversely, the Canadian Journal of Kidney Health and Disease defines a RL not only regarding its size (500–1,500 words, up to 10 references and 1 figure or 1 table) but also its scope – RL in this journal is a “ […] publication of results which deserve dissemination, usually because they may be useful to others, but do not advance the field to the same extent as a full original clinical research paper”.94 Finally, the editors of the Chest point out that RLs should be “of high quality, be novel, or have potential clinical impact, but should not be advanced or large enough to warrant publication of a complete original research manuscript”, limit the article parameters to 1,000 words, 10 references and 2 tables and/or figures, and stipulate a structure with Introduction, Methods, Discussion and Conclusions, which is, at least in broad terms, in concert with the definition adopted in ACEM.95
There were 5 RLs published in ACEM in 2021 and 14 in 2022 – this type of papers has been introduced in this journal in April 2021, but nevertheless these numbers show its growing popularity. The RLs released in 2021 dealt with diverse research problems: 27-gauge sutureless vitrectomy under topical anesthesia,96 the influence of comorbidities on mortality in bronchiectasis,97 and ST-segment depression in atrioventricular nodal reentrant tachycardia.98 They included a pilot study,96 a prospective observational study,97 and a presentation of preliminary results.98
In 2022, RLs in ACEM covered a much broader field – the following 3 categories dominated:
The health impact of COVID-19: Several articles addressed concerns like ocular complaints in students during the pandemic,99 and differences in the incidence of symptoms among medical staff working with COVID-19 patients.100
Women’s health: Some articles focused on women’s health issues, e.g., changes in the stomatognathic system in women working with COVID-19 patients.100
Orthopedic and musculoskeletal studies: There have been studies related to orthopedic and musculoskeletal conditions, such as distal radius fractures in the elderly.101
It is important to note that these RLs fulfilled the role of rapid research dissemination – findings regarding COVID-19 pandemic are a good example.
Case reports: Why are they not published in ACEM?
In January 2021, ACEM implemented a policy precluding publication of case reports (CRs) of any type, while case series are considered for publication only very rarely – in situations when choosing this type of scientific article is the sole way to tackle, e.g., an issue related to an orphan disease or a very rare tumor. Of note, in the 2 discussed years (2021–2022), no case series has been published. Such tendency is observed in several other scientific medical journals, e.g., PLoS One, Anesthesiology, Anesthesia and Analgesia, and Journal of Stomatology do not accept CRs at all. Although Dikensoy et al.102 stated that the majority of high-impact journals adopted such policy, there are no data to support this claim. There are also examples of a more nuanced stance: For example, the New England Journal of Medicine (NEJM) does not accept stand-alone CRs; however, articles of other types in this journal may include CRs.
In the literature, it is contented (but not proven) that the vast majority of CRs are very rarely cited or not cited at all (Edelmayer et al. introduced the term “case report classics” to denote the relatively small minority of frequently cited CRs, but noted that most of them were published before 1990s).103 This has been shown, i.a., by Erivan et al., who performed a retrospective bibliometric analysis of all articles affecting the impact factor (IF) calculated for the year 2017 published in 77 journals covering the field of orthopedics.104 Individually, in 2017, each CR was cited 0.86 times ±1.4 (0–13) on average. Case reports published in 2015 had a mean of 0.96 ±1.49 (0–13) citations, while those published in 2016 had a mean of 0.76 ±1.29 (0–13) citations (p = 0.002). Of all the CRs, 571 (30%) were not cited at all in 2017. After a statistical analysis, Erivan et al. concluded that in 69 instances, the IF would have increased if the journal had not published any CR. Conversely, the IF improved in 8 instances by publishing CR. Papers which are not cited or very scarcely cited increase the denominator (number of papers) but not the numerator (number of citations) in the calculation of IF. This issue was also analyzed by Nabil and Samman in oral and maxillofacial surgery journals.105 They revealed that CRs had a low citation rate with an average of less than 1. There were 38 (7.2%) CRs with more than 5 citations and 30% of the citing articles were also CRs. The publication of CRs negatively affected journal’s impact factor, which correlated directly with the percentage of CRs published in a journal.
In the opinion of the ACEM editorial staff, the research discussed above cannot serve as an argument supporting the decision of excluding CRs from papers considered for publication in a given journal. The key mission of every scientific journal is to disseminate research results. All bibliometric measures such as IF, Scopus CiteScore or others were created to assess the efficiency of such dissemination, and not to become an objective in themselves. Therefore, excluding specific types of papers from a journal to artificially boost citation statistics could be considered ethically questionable.
However, there are other reasons for repudiating CRs. The debate whether CRs should still be an important part of scientific medical publishing is still ongoing and no consensus has been reached so far. They are certainly not without scientific merit, as argued, among others, by Firat et al.,106 Bhattacharrya et al.,107 Nieder et al.,108 Yitschaky et al.,109 Carey,110 Carey,111 Albrecht et al.,112 and Edelmayer et al.103 It is important to note that the above studies discussed this issue regarding several different fields of medical research and not only in general terms. However, as stated by Greenhalgh,113 CRs are placed at the bottom of the hierarchy of clinical evidence, along with case series, because of their inherent methodological limitations, including lack of statistical sampling.
In 2021, the Institutional Review Board of the Johns Hopkins University School of Medicine stated that “[a] case report is a medical/educational activity that does not meet the Department of Health and Human Services (DHHS) definition of «research», which is a «systematic investigation, including research development, testing and evaluation, designed to develop or contribute to generalizable knowledge»”.114 Case reports are not based on controlled, experimental research and present only an individual clinical picture of a given patient, while results of RCTs or MAs are considered more reliable and influential in the field of medicine they belong to.
Given the controversial perception of CRs in the medical literature, the Editorial Board of ACEM on the one hand is not interested in publishing them, but on the other hand has no intention of discouraging authors from utilizing this form of scholar contribution. In the last 30 years, with the emergence of digital publishing, a considerable number of journals have appeared that are dedicated solely to disseminating valuable CRs (e.g., BMJ Case Reports, Journal of Medical Case Reports, and American Journal of Case Reports). Several authors offered valuable advice on where to direct studies of such type for publication. Rison et al.115 provided detailed criteria for informed choice (there are journals of debatable value operating in this field), while Akers116 compiled an exhaustive list of journals with such a profile, and the library of the George Washington University (Washington, D.C., USA) established a detailed website on this topic, including an up-to-date list of journals that peer-review and publish CRs.117
Effectiveness of the article categorization in ACEM and standardization of papers in ACEM
The types of papers distinguished in ACEM have proved to be a useful tool, since they are deliberately broadly defined and therefore relatively capacious – among them, only the MS, MS and SR types have strict definitions that entail specific stipulations. The presented classification encompasses most of the scientific medical papers of value met in other journals, even if the categorization used in the most respected ones is more detailed. We purposefully avoid formulating subcategories, e.g., regarding different types of reviews – only a SR is discerned because of clear delimitations of this type of paper, while every other type of review article is simply a review in light of the ACEM rules, and no specific stipulations are made for specific subtypes of reviews. Every paper which includes original experimental or clinical research can be submitted as an original paper; should it be too brief for a full-fledged article; it will be reclassified as a RL – if the authors consent. This is to avoid bias and to minimize the possibility that authors will abstain from submitting a manuscript to ACEM because their paper does not fit into any category.
The only limitation observed concerns RLs. Authors of short papers receive a proposal to reclassify them as RLs – before or after the initial acceptance for publication. Since the introduction of RLs in ACEM, several authors (we are unable to provide an exact figure) decided to withdraw their papers in response to such proposal, citing either stipulations made by granting or evaluating institutions (which may only recognize original papers as fulfilling their assessment criteria), or the lower prestige that RLs would, in their opinion, have in their resumes. Such cases are evaluated individually – while the former argument is often a basis for reconsidering the matter, the latter still poses a challenge since – while holding professional opinion of a researcher in high regard – we have not yet been able to find any research results that would substantiate claims of lower prestige of RLs compared to original papers.
Within the scope of this paper, it is impossible to authoritatively state whether the described classification is optimal to reflect the breadth and depth of research in clinical and experimental medicine. However, one argument can be based on the checklists introduced as mandatory for all authors submitting manuscripts to ACEM since January 2021. These tools have been proposed during the last 30 years by various collective bodies within the scientific community and pooled together in the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) network website (https://www.equator-network.org). The most commonly used checklists are:
– Consolidated Standards for Reporting Trials (CONSORT) checklist for clinical trials;
– STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist for observational studies;
– Critical Appraisal Skills Programme (CASP) checklist for qualitative studies;
– Animal Research: Reporting of In Vivo Experiments (ARRIVE) checklist be followed in the preparation of studies involving live animals, from mammals to fish and invertebrates.
– Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist for all MAs and reviews.
There are several other tools of this kind, not presented here, which can be accessed through the EQUATOR website. The authors assume that these checklists reflect the aforementioned breadth and depth of research in clinical and experimental medicine – and because the authors of papers published in ACEM choose various checklists, this broadness of scope translates also to the contents of each category in the employed classification. The checklists also allow for the standardization of the papers’ structure and other features – to a reasonable extent – to facilitate better conformity with established standards in scientific medical publishing. These checklists have been extensively discussed in a paper by Misiak and Kurpas.118
Comparison to other journals
A comparative study of the classification strategy employed in different journals could be useful in assessing the efficacy and reliability of such categorization. However, differences in scope and editorial and marketing strategy between different journals could make such comparison biased or otherwise unreliable. A large number of different types of papers can usually be found in journals published by enormous transnational entities like, e.g., Taylor & Francis, Springer Nature or Elsevier, which aim to standardize such classification across several titles owned by a respective publisher (at least concerning the most prestigious journals in the portfolio of a given publisher). Even the nomenclature used varies significantly between journals – Editor Resources by Taylor & Francis state that there are more than 1,400 (sic!) different article type headings in use in that publisher’s journals alone.119 The same publisher provided a glossary of article types for early career researchers, which, while relatively concise, provides a classification that: 1) is more detailed than that used in ACEM (it includes, e.g., method articles); 2) is not compatible with categorization used in several journals owned by this publisher (e.g., Scandinavian Journal of Gastroenterology); and 3) uses nomenclature different from ACEM (e.g., an original paper is called a research paper).120 In a single journal, such a detailed categorization could lead to confusion among authors regarding which type of paper their manuscript should be assigned to during submission. Therefore, we reasoned that the categories used in ACEM should be as broad as possible to reflect only the general types of manuscripts – based on the methodological approach (original papers, reviews, MAs that need to be discerned from reviews, RiP papers and MSs), to emphasize papers written by invitation and providing an opinion (editorials), and to set aside articles shorter than others, but nonetheless important (RLs). Our point is that any subdivision within these broad categories would not serve any purpose worth the effort in a single journal of broad scope (all clinical and experimental medicine).
The policy of each journal regarding 1) what classification of papers is used, and 2) which categories from this classification are considered for review and which are excluded and desk-rejected from a given journal, stems from the scope of a journal and the strategy of journal development adopted by its Editorial Board. The stipulations of institutions that evaluate the work of researchers heavily influences both policies of editors and authors’ choices of specific article types (e.g., multiple evaluating bodies require scientists to publish full-text original papers in the first place). Therefore, differences in the employed categorizations may result from strictly scientific, editorial, or external factors, which are not always possible to identify.
To sum up: Such a comparison would provide valuable arguments for shaping journal’s policy in this respect, but performing it with due diligence and adequately broad scope would require a separate study of comparable, if not larger, size; otherwise, superficial conclusions based on a skewed selection of the materials might be misleading.
Promoting open science
Advances in Clinical and Experimental Medicine is an Open Access journal employing the Gold Open Access model, which means that articles can be accessed at no cost on the journal’s website immediately following publication. There are no embargos, paywalls, subscriptions, or other modes of payment of any kind. All articles are published in Open Access model and distributed under the terms of the Creative Commons Attribution 3.0 Unported (CC BY 3.0) License. The publisher and editors of ACEM support the principles of the Budapest Open Access Initiative (https://www.budapestopenaccessinitiative.org). Dissemination of science understood as the main goal of scientific journal should also encompass registered preprints; therefore, encourages the publication of preprints on preprint servers such as BioRxiv, MedRxiv or ResearchSquare, as well as on authors’ or institutional websites. During submission of a manuscript to ACEM, the authors must disclose that the paper has already been released as a preprint and provide a link to the preprint. Our journal endorsed this practice in January 2022; since then, there have been 6 papers published in 2022 and 3 by the September 2023 issue that were previously published as registered preprints. This issue will be addressed in another editorial by the same authors.
Ensuring the public availability of raw data facilitates the transparency of research and enables its replicability. Several papers published in ACEM include a disclaimer in which authors offer to share raw data upon request. Papers published online as ahead of print since November 2023 include a mandatory disclaimer at the end of the main body of the article as follows: “The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request”. Supplementary material is a peer-reviewed material directly relevant to the conclusion of a paper that cannot be included in the printed version for reasons of space or medium limitations (e.g., movie clips or sound files). If a paper accepted for publication in ACEM is accompanied by supplementary data of any kind (in many cases, these are statistical data), the Editorial Office requires that all such files be deposited in the Zenodo repository (https://zenodo.org) and that a single DOI be obtained for the entire package. Each file should be numbered (Supplementary Table 1, Supplementary Fig. 1, etc.) and a one-sentence description of its contents should be provided. Both the description and the DOI are placed in a separate subsection titled “Supplementary data” at the end of the manuscript. Neither ACEM nor the journal’s publisher (Wroclaw Medical University) are in any way associated with the Zenodo repository, either financially or organizationally. We are simply recommending this entity as a reliable and cost-free third-party data storage opportunity. This policy was introduced in January 2022 and so far, 17 papers published in 2022 and 25 until the September 2023 issue have had the supplementary materials made available as described above. This issue will be covered in another editorial by the same authors.
Limitations
First and foremost, we provided no description of practical application of the discussed theoretical concepts, i.e., case studies showing how the presented article types translate into concrete papers published in ACEM. As mentioned above, the categories used in ACEM are deliberately broad and presented on the journal’s website121 only in general terms (RiP) or only by their names, because ACEM editors assume that the understanding of an original paper or a MA is rather obvious for a professional researcher. The only types referred to more extensively are RLs (because of the terminological confusion discussed above) and reviews (due to several types of reviews discussed in the literature, a link to a paper by Grant and Booth122 presenting a typology of reviews – 14 review types and associated methodologies – is provided as a reference and guide). Therefore, there are no strict definitions per se stated as stipulations for the authors that can later be translated into practice. However, one can observe such translation regarding checklists discussed above, which predefine especially the structure of the paper, and within in – particularly the Materials and methods section. Moreover, the choice of the papers considered for publication from all submitted manuscripts and the final form of the chosen papers (following all revisions) are to a greater extent the result of the professional experience, journal’s policy, and the decision of Section Editors than the employed paper classification. The stipulations stemming from this categorization and those found in the checklists play more a gatekeeping than shaping role. Manuscripts that do not conform to these rules, or that do not fit into any of the categories used, are desk-rejected during the initial verification by the Managing Editor or the preliminary review by the Section Editor before they can be sent to peer-review.
Second, no suggestions were formulated for an eventual modification of the article type classification utilized in ACEM in the future. We only became more aware that we should conduct a study on this issue in the future.
Third, meaningful comparisons with paper category policies in other scientific medical journals were deemed to be outside the scope of the present study and should be the subject of future studies.
Fourth, original papers were not reflected upon for the reasons stated in objectives, which renders the picture of paper categorization in ACEM more cohesive, but also incomplete. This issue will be addressed in further papers by the same authors.
Finally, the potential influence of publications in ACEM on medical research or policy changes has not been discussed. The Editorial Office of ACEM does not have any tools that would allow for tracking such influence. However, the section editors of our journal attempt to shape the distribution of topics in the journal through calls for submissions. In 2021 and 2022, there were 4 calls for submissions: 1) Heart failure: recent advances and future perspectives in diagnosing, prognosticating and management; 2) Gastroenterology in the face of local and global challenges; 3) Nephrology in the face of local and global challenges; and 4) Metabolic pathways in carcinogenesis: Mechanism, diagnosis and treatment. The response to each call was clearly visible in the stream of manuscripts submitted to the journal, and 14 of these submissions were published – 2 in 2021 (both from call No. 4) and 12 in 2022 (from 3 other calls – 6 from No. 3, 3 from No, 2 and 3 from No. 1). This topic will be covered in another editorial by the same authors.
Recommendations for the ACEM Editorial Board
Although, as stated above, we think that the categorization we use covers the scope of ACEM, even a brief comparison with other journals (as in the “Comparison with other journals” section) shows that there may be paper categories/types that could prove useful in achieving an even broader diversification of content. Exploring a wider range of medical topics and specialties would allow to cater to a more diverse readership. Such broadening should mean incorporating types of articles as for now explicitly (CR) or implicitly (book reviews) excluded from ACEM. A change in this respect could facilitate the inclusion of multidisciplinary perspectives by encouraging submissions that integrate insights from various medical disciplines to provide a more holistic view of healthcare. Therefore, we propose to prepare a report on the chosen article categories employed in different scientific medical of comparable (i.e., more general) scope to identify promising new types of articles to be introduced in ACEM and assess them in the light of ACEM’s to-date policies and needs as defined by the Editorial Board. Such a report would not necessarily be a full-fledged comparative study as discussed in the “Comparison with other journals” section, nor should it pretend to be a complete view of the issue of paper classification in medical literature as a whole. However, even a partial view could provide valuable suggestions. We will never achieve an ideal classification, but we should not refrain from modifications – ACEM must evolve along with all other scientific medical journals.
Conclusions
The article type classification used in ACEM in only one of many possible solutions and may be modified in the future – it should be both clear for the authors and allow easy orientation in the journal’s content for the readers. The motivation for choosing the employed categories stems from 3 reasons: 1) their position on the accepted levels of evidence in EBM and their potential to be cited; 2) the usefulness and comprehensibility of the chosen categorization for authors, who should be able to assign their paper to an appropriate category without delving into theoretical considerations. It is also obvious that the presented classification of papers is to some extent arbitrary – the important thing is not to exclude any types of papers from consideration based on arbitrary decisions.
It turned out that in the case of 2 types of articles – editorials and RLs – formulating definitions by the authors was necessary because opinions expressed in the literature as well as practice among editors of other journals varied and were sometimes contradictory. Editorials as understood in ACEM proved to be a powerful category of paper, attracting both renowned researchers and high number of citations; reflection on them revealed their diverse roles and strengthened the dedication of ACEM editors to promote this form of scientific publication. Research letters seem still not widely known in the researcher community and are often confused with other types of papers, like short communications or letters to the editor. Although the authors sustain their decision to exclude case reports from consideration in ACEM, an overview of the literature showed that the debate regarding importance of this category is far from over; the hierarchy of evidence in medicine is not put to question, but a low position in this hierarchy is not an argument for abandoning this type of scientific medical publication altogether.
Moreover, certain types of papers are related to specific sources of problems – while RLs are perceived as controversial by some authors due to their purported inferiority in comparison to original papers, MAs often show deficiencies in statistical analyses of the data; to provide guidance to the readers, we have dedicated an entire paragraph to a presentation of the most important publications on this topic.
Future editorials will explore 3 issues:
1) Original papers as the type of article forming the bulk of manuscripts both submitted to and published in ACEM – their diversity and thematic patterns over the years;
2) Preprints as a mode of promoting open science – and ACEM’s policy in this regard;
3) Public availability of raw data as a way to facilitate the transparency of research and enable its replicability – and ACEM’s policy in this regard.