ISSN 0211-6995 - printed version
ISSN 1989-2284 - electronic version

INSTRUCTIONS TO AUTHORS

• Scope and policy
• Supplements
• General format of papers
• Sending papers

Nefrología publishes articles on basic or clinical research relating to nephrology, arterial hypertension, dialysis and kidney transplants. It is governed by the peer review system and all original papers are subject to internal assessment and external reviews. Nefrología follows the publication requirements of the International Committee of Medical Journal Editors (ICMJE).

The Journal's main language of publication is Spanish, and articles written in English by non-Spanish authors are accepted. All contents of the regular issues are also available in English, and are easily accesible on the Journal's web site, along with the original version.

Nefrología publishes six issues per year (one every two months). There is also a Continuing Education edition (NEFROPLUS) and a series of special editions about topical subjects, such as Evidence-Based Nephrology issues.

Nefrología belongs to the Grupo Editorial Nefrología publisher, which is a S.E.N. member that manages printed and digital issues to publish scientific opinions regarding nephrology and continuing education in this area.

All the content and additional material published in Nefrología, NefroPlus and other editions from Nefrología or Grupo Editorial Nefrología are included on the Nefrología Web site (http://www.revistanefrologia.com/normas.php) (free access). Information regarding the method for sending papers and the complete rules of publication in the journal can be easily accessed from the site.

Supplements and Nefrologia's extraordinary supplements

These will be published following approval from the Editorial Committee and the Editor of Nefrología, who will specify their length and features and will assess the possible conflicts of interest with sources of financing. A monograph issue will be prepared by one or several specially assigned editors who will oversee the entire process. Supplements are subject to the peer review process. There are different types: a)Supplements, that form part of the journal's main body of articles and which are indexed in PubMed and incorporated into ISI-WOK and SciELO, of special interest for the Spanish Society of Nephrology (guidelines, consensus documents, annual Congress summaries, etc.), with summaries in English where applicable (see norms for articles) and fulfilling Medline's criteria for indexation in bibliographic databases; b) Nefrología Suplemento Extraordinario is a new journal publishing special issues which can be cited in Nefrología Extraordinary Supplement but not systematically indexed, publishing issues of Nefrología Basada en la Evidencia (see below), monograph themes, papers presented at meetings of special interest, etc.

Evidence-Based Nephrology

Supplements or special issues of Nefrología Basad en la Evidencia (Evidence-Based Nephrology) will be published containing structured summaries of research papers published in other nephrology journals, as well as editorial commentaries, reviews, structured analysis of clinical problems and other articles which deal with aspects relating to clinical questions of interest, recovering suitable bibliographies, critical readings of medical literature and applying the evidence to the patient. Regular issues may include specific articles on these topics. These supplements and the articles in regular issues will be prepared by several special editors assigned by the Editor of the journal to oversee the entire process. Specific regulations for publication in Nefrología Basada en la Evidencia are published in the first issue every year and can also be found on the Nefrologia Website, alongside all content and additional material.

1. General aspects: papers must only be sent through the Nefrología website http://www.revistanefrologia.com/modules.php?name=login&lo_mod=manuscritos.

2. Title: with a maximum of 150 characters including spaces, accompanied by a short title of less than 40 characters for page headings.

3. Authors: authors should indicate their full names, using initials when these are compound names, surnames and place of work. They will indicate which author should receive any correspondence along with this person's postal address and e-mail address. Where the author is a collaborative group, this must be identified by its name and information on those who form the group must be provided, with only those persons who have made a substantial intellectual contribution, accept direct responsibility for the paper and complete the conflict of interests declaration appearing as authors.

4. Financing: the authors will indicate the sources of financing for the work they are submitting for assessment.

5. Summary and main body of the paper: the instructions outlined above for each type of paper will be followed.

6. Bibliographical references: these will be identified in the text using numbers in superscript appearing consecutively according to the order in which they appear in the text, the tables and the figures. List bibliographical references using double spacing, numbered consecutively with numerals and without parentheses according to the order in which they appear in the text. The order of the references cited only in tables and figures will be that of the first mention of said tables and figures in the text. Names of journals will be abbreviated and without accents, in line with the style used in the Index Medicus. The format must be that used by the National Library of Medicine (http://www.nlm.nih.gov/bsd/uniform_requirements.html, and can be checked at http://www.ncbi.nlm.nih.gov/pubmed/citmatch (PubMed Single Citation Matcher). References are not translated and must follow the established international nomenclature.

Articles from online journals, internet pages and websites must be referenced by citing the access date ("accessed 18 July 2008") and the URL. The WebCite link can also be cited if one has been established (www.webcitation.org).

When there are more than six authors, the first six will be cited and then "et al." will be used at the end and for accepted articles that have yet to be published, Forthcoming (formerly 'In press') and the publication date, if known, will be mentioned after the name of the journal (Nefrologia. Forthcoming 2010).

For more information on how to cite bibliographical references see Citing Medicine in: http://www.ncbi.nlm.nih.gov/books/NBK7256/.

It is recommended to cite an appropriate number of references without omitting related articles published in Nefrologia journal in recent years.

For online versions and as proof of same, we advise that for those references where the website does not get the link directly, the author to provide the corresponding hyperlink with the summary in PubMed, inserting it into the reference [PubMed] and added at the end. The same can be done with the full text, inserting it into the reference [Article]. In particular, for those references that are not in PubMed, the DOI can be added at the end and linked using http:/dx.doi.org/ followed by its own DOI.

7. Tables and figures: all will be cited in the text (between parentheses, without abbreviations or hyphens) and will be numbered consecutively with numerals, without superscript, according to the order in which they are cited. Tables and figures will be accompanied by a short title (less than 15 words) and footnotes or figure captions with a minimum font size of 10, including the explanation of the abbreviations and symbols used. Explanatory footnotes for tables will be marked using lower case letters in superscript in alphabetical order (a-z), without symbols. Each table or figure, with its title and its specific footnote, will se sent in a separate file to the text, clearly identified with the name (name-t1.doc or name-f1.jpg, for example). Sub-divided figures (Figure 2a, 2b, 2c), will be treated as a single figure (one single file, title and note). Files should not exceed 10 Mb. In the case of additional tables or figures that are only published online or are sent only for the reviewer, these will also be included separately without being referenced in the text and this status will be mentioned.

Tables will be presented without vertical lines in .DOC format (MS Word), double-spaced, using Times New Roman, font size 12. They will be created using cells, not drawing elements, text boxes or tabulations and without line breaks. Tables created using WordPerfect must first be converted to .DOC. If another uncommon font type is used, it is better to embed it in the document. The result of conversion to HTML can be seen in Microsoft Word using the View Web Layout option.

Figures will be presented in an electronic graphics format that is suitable for publication on the website (.JPG or .GIF), with 300-600 ppp resolution (2,000-4,000 pixels), unzipped, without frames around them and with white (not transparent) backgrounds. Graphs and figures created using PowerPoint and Excel should be converted into a .JPG or .GIF file (use the Save as function). Nefrología may request that the authors send figures in a high-resolution format (.TIF o .EPS) if the paper is accepted for publication. Any encrypted or protected file cannot be converted or used. If a table or figure has already been published, the authors must provide the copyright owner's written permission, where applicable, so that it may be copied in print and electronic format and the source must be cited.

8. Mathematical and chemical formulas: if these cannot be used as inserted text then they can be included as illustrations, and when they are not indicated as figures, their position in the text will be marked by inserting the word Equation followed by the corresponding consecutive number between square brackets ([Equation1], [Equation2], etc.). We recommend you use Equation Editor in English. Linear chemical formulas will be written without subscript, like CO2.

9. Special characters: if their use cannot be avoided then they must be incorporated into the text through special editors, choosing between the proposed options. The Insert symbol option in MSWord may not be converted correctly and so it is preferable to use Times New Roman font symbols or Greek characters. To see the result, it can be converted to HTML (View Web Layout option).

10. The use of SI units (www.bipm.org/en/si/) is recommended and alternatively, if other units are used, the SI units can be mentioned beside these between brackets. Names of species (in full the first time these are mentioned), genes, mutations, genotypes and alleles will be written in italics. For human genes, you can check the HUGO database (www.genenames.org/index.html). Prefixes and gene products will be written without italics (c-fos, CSF1R). The common international name will be used for medicines.

Structure of papers and research articles

Papers, and research articles in particular must be structured as follows: a) Presentation with the authors' declarations (see below) and comments on why the authors believe that the paper would be of interest to NEFROLOGIA and its readers (what contributions the research makes, etc.); b) Title, in Spanish and English, maximum 150 characters and also a short title with less than 40 characters; c) Authors, with their full names and using initials if they wish, their place of work (department, organization, city, province -where applicable- and country), and collaborative group where applicable, specifying the make-up of same; d) Summary of 50-250 words, divided into sections (background, objectives, methods, results, conclusions and clinical trial registration number, where applicable), with two versions, one in Spanish and one in English, not including bibliographical references; e) Keywords in Spanish and in English, from 3 to 10 (these can be searched in the MeSH list of Index Medicus at www.nlm.nih.gov/mesh/MBrowser.html and in Spanish in the DeCS list of the IBECS database at http://decses.bvsalud.org/E/homepagee.htm); f) Text divided into sections such as Introduction, Methods (with sub-sections where required), Results (with sub-sections and aligned with the previous sections where applicable) and Discussion, including the conclusions at the end; g) Abbreviations, if there are any which have not already been defined; h) Potential conflicts of interest, information on financial assistance received; i) Acknowledgements; j) Bibliographical references, and k) Tables and Figures, with footnotes and figure captions.

On the authors' own initiative or at the request of the reviewers, supplementary information may be provided in the form of a PowerPoint presentation, video, audio files, Excel files, SAS, SPSS with original data, etc., which will not be published in the print edition but in the electronic version on the website. Videos should be sent in AVI format or as Quicktime files (.mov).

Nefrología journal regularly publishes the following content: 1) Originals; 2) Short originals; 3) Reviews; 4) Short reviews; 5) Editorial; 6) Editorial commentaries; 7) Case reports; 8) Letters to the Editor; 9) Other sections: special articles, forums, summaries of congresses, nephrology images, notes on techniques, diagnostic problems, etc.

1) Originals: papers on empirical research of a maximum length of 5,000 words, excluding the title, key words: bibliographical references (with a maximum of 50 references), tables and figure captions, with a maximum of nine tables and figures.

Special originals (Special articles):

a) Description of clinical trials: A clinical trial is defined as any research project which prospectively assigns human subjects to intervention and comparison groups in order to study the cause-effect relationship between the intervention and a health result.

- Randomized controlled trials (where subjects are assigned to groups at random): for a clinical trial to be considered for publication in NEFROLOGIA journal requires its prior registration in a public registry of clinical trials which is accepted by the ICMJE. This policy is applied to any clinical trial which began recruiting subjects after January 1st, 2008. For trials where recruiting started before this date, we ask that it was registered before April 1st, 2008. The content of the clinical trials must comply with CONSORT statement in its sections and in the flow diagram1.

- Non-randomized trials (where subjects are assigned to intervention or comparison groups at random): it is recommended that authors follow the guidelines of the TREND statement.

b) Description of diagnostic tests: we recommend that authors follow the guidelines of the STARD initiative.

c) Description of meta-analysis: we recommend that the authors of meta-analysis of randomized controlled trials follow the guidelines of the QUOROM statement, and that authors of meta-analysis on observational studies follow the guidelines of the MOOSE group.

d) Cohort studies, case studies, case-control and cross-sectional studies: we recommend that the authors follow the guidelines of the STROBE statement.

Sending an article to the Journal implies that it is original, has not been published, except in summary form and that it has only been sent to Nefrología. It also means that, if accepted, it becomes the Journal's property and, therefore, total or partial publication must be authorized by the Editor. The Editorial Committee reserves the right to modify the style or shorten the texts which require it, while respecting the content of the original.

2) Short originals: these follow the same norms as the previous articles, but with a maximum length of 2,500 words, structured summary of 50-250 words, a maximum of four tables or figures and 25 bibliographical references.

3) Editorials: requested by the editors or proposed by the authors, with a maximum length of 2,000 words, no summary, with two tables or figures, and a maximum of 30 bibliographical references.

4) Editorial commentaries: requested by the editors or proposed without solicitation by the authors, commentaries on articles published in the same issue or previous issues of the Journal. The purpose is to put the subject matter of the article in question into the context of current knowledge, to highlight its main contributions, as well as the "grey areas of knowledge" or areas which the research should examine in more detail. The maximum length is 3,500 words, no summary, with a maximum of three tables or figures and 40 bibliographical references. It also includes a "Key concepts" section where the article's main ideas will be summarized in point form using short sentences.

5) Reviews: reviews carrying out exhaustive analysis on specific themes in nephrology. The reviews are requested by the editors or referred on the authors' initiative. These will follow the peer review system. The maximum length is 5,000 words, a maximum of nine tables or figures and a maximum of 150 bibliographical references. It includes a 50-250 word summary which is structured if it is a systematic review (objective, data sources, selection of studies, data extraction, data summary, conclusions). It also includes a "Key concepts" section where the article's main ideas will be summarized in point form using short sentences. Articles for NefroPlus (Continuing Professional Education) will follow the same norms as the Reviews.

6) Short reviews: reviews on very specific themes, written in a concise and clear manner. Maximum length of 3,500 words, a maximum of six tables or figures, and a maximum of 50 bibliographical references. It includes a 50-250 word summary. It also includes a "Key concepts" section where the article's main ideas will be summarised in point form using short sentences.

7) Clinical cases: description of clinical cases with a maximum length of 2,500 words and structured into an introduction, description of case including diagnostic procedures, development, treatment and conclusions. Include a table with analytical data and, if possible, some graphs showing the development of the case and some figures, with a maximum of five in total. It must be presented in an attractive, clear and concise way, and with an educational purpose, above all. Nefrología will publish cases which are exceptional in their presentation or in the use of diagnostic or therapeutic procedures. The majority of the clinical cases which are accepted will be published in NefroPlus, which is Nefrología's Continuing Professional Education edition.

8) Letters to the Editor: relating to articles previously published in NEFROLOGIA or which provide succinct or preliminary information on clinical experiments or clinical cases of interest. The letters to the Editor will be structured into the following sections: Comments on published articles, brief notification of research or clinical experiments and brief case reports, with a maximum length of 1,000 words (two tables or figures) and 15 bibliographical references.

9) Nephrology images: illustrative images on aspects of nephrology, which can include images of pathology, radiology, skin lesions, etc. indicating scale by using markers within the microphotographs. Each article may contain up to four illustrations, with sufficient contrast, clearness and a figure caption including the title. Images must be accompanied by a text of 500 words maximum. Either this text or the figure captions must mention the details that are being highlighted in the figures with characters a-z, numbers, symbols or with arrows, which must be of a size that is clearly legible even after the image has been scaled down. It can be accompanied by a maximum of 3 references. In the case of images of people, these people must not be identifiable or there must be mention of written permission for publishing the image. Images may be published in Nefrología or in NefroPlus.

10) Notes on techniques: descriptions of new techniques in the clinic and in the laboratory or imaging, vascular access techniques, etc, as well as modifications to existing techniques. These may be up to 2,000 words in length, with summary, two tables or figures and 20 references.

11) Diagnostic problems: a diagnosis is proposed based on a previous statement, with a single question and a concise answer. One illustrative diagram is allowed.The text will have a maximum length of 500 words, with no summary and a maximum of five references.

12) Other content: such as, for example, Evidence-Based Nephrology, Controversies in Nephrology, Statistical Data (original articles with data and analysis of records such as dialysis and transplants, etc.), are published on an occasional basis and each particular cases has its own characteristics as defined by the editor.

Authors' declarations

1) They participated in designing, conducting, or analysing and interpreting the findings of the paper.

2) They participated in the writing of same or in reviewing its intellectual content.

3) They approve the final draft of the paper attached to this declaration.

4) They approve sending it for publication in Nefrologia.

5) The sources of financing are expressly declared in the paper (especially those which could raise a conflict of interest).

6) People cited in the acknowledgements have given their approval for this.

7) The article has not been published in any other journal nor been sent for publication at the same time.

8) The intellectual rights to the paper are transferred to Nefrología, as well as the right to allow the copying of data or illustrations in other publications.

9) It is understood that all those who sign their names to the text assume responsibility for its content. The authors may indicate the degree to which each author has contributed in preparing every aspect of the article (concept, design, execution, analysis, interpretation of the results, writing).

Conflicts of interest

When submitting a paper to be assessed by the Editing Committee, the authors must send a declaration of conflicts of interests with the content of the article. This declaration must describe the relationship between the authors and companies which may have an economic interest in the information contained in the paper. This relationship must include, among others, grants received, travel payments or receiving funds for consultancy services. The absence of potential conflicts of interest will also be declared.

Nefrología does not accept papers sent via the standard postal service. Papers may only be sent online through www.revistanefrologia.com. You must be registered with the website in advance in order to send an original for publication in Nefrología journal. Any registered or new user must log in or register in the Log In section. With the correct username and password, users can access a private area according to their access permissions.

In the Papers menu you can proceed to create a New Paper following a six-step process: 1) journal selection, section of the journal in which you wish to publish the paper and original language; input title, short title, summary, text content and comments; 2) keywords and bibliographical references; 3) authors, address(es) for correspondence, declarations collected from and by the authors, sources of financing, disclaimers; 4) tables, figures and other attached documents; 5) declaration of conflict of interest, redundancy and authors' approval, and 6) preview and sending of paper, which begins the review and editor approval process.

Printing profs

Printing proofs will be sent to the author listed for correspondence in .PDF format (you must have the Acrobat Reader® program installed). Only minor corrections will be allowed, such as correcting typing errors, a comment or note inserted into the document itself or as text on replying to the e-mail to which it is attached (and with the .PDF), within a deadline of two days after being received. If nothing is received within the established deadline, the proofs will be considered accepted. If you have any problem, query or suggestion in relation to how papers are sent to Nefrología journal, you can contact the support personnel at revistanefrologia@senefro.org, who will contact you as soon as possible.

All the information regarding the process of sending papers and the comprehensive rules of publication can be easily accessed from the journal's site.