The methodology employed is described in the MSC’s CPG development manual¹. The steps followed have been:

– Creation of the CPG working group comprised of a clinical team, a technical team and two coordinators (clinical and technical). The clinical team consists of a group of health care professionals (psychology, psychiatry, nursing and nutrition and dietetics specialists) involved in the study and treatment of eating disorders and an attorney, who are carrying out their activity in Catalonia and are linked to the Master Plan of Mental Health and Addictions of the Catalan Department of Health, and representatives of Spanish scientific societies, associations or federations who are involved in the care of eating disorders. The technical team is composed of CAHTA members who have a wealth of experience and knowledge on the development of evidence-based CPGs and on critical assessment, and research support staff. The working group has relied on the participation of a group of collaborating experts from all over Spain selected by the clinical coordinator for his expertise in the matter, as well as another group of CAHTA members who have collaborated in some of the following activities: defining the scope, search, documental management, initial review of literature and internal review. Representatives of the societies, associations or federations involved in this project and expert collaborators have taken part in defining the scope and objectives of the CPG, in the formulation of key clinical questions and in the review of the guide’s rough draft. The participants’ declaration of conflict of interests can be found in the section “Authors and Collaborations”.

– Formulation of key clinical questions in the following format: patient / intervention / comparison / outcome or result (PICO).

– The search for scientific evidence was structured in different stages:

1. Generic databases, meta-search engines and organizations that compile guidelines (National Guidelines Clearinghouse, National Electronic Library for Health, Tripdatabase, The Cochrane Library, Pubmed/Medline and BMJ Clinical Evidence) were consulted between 2003 and March 2007.
2. To complete the search, a manual search was performed for protocols, recommendations, narrative reviews, therapeutic orientations and guides on eating disorders elaborated by organisations pertaining to the health care administration, scientific societies, hospitals and other organizations of our setting. Some of these documents have inspired and served as a model for certain sections of this guide (see Annex 6.1.). This annex also lists documents created outside of Spain that have been excluded from the selection process due to low quality. However, some have been considered for the development of certain aspects of this CPG.
3. To respond to those questions unanswered by the CPGs, SRSE and assessment reports (AR) included or to update them, a search for randomised controlled trials (RCTs) was performed in Pubmed/Medline between March 2007 and October 2007.
4. The search for CPG/SRSE/AR in Tripdatabase and Pubmed/Medline was also updated up to October 2007.
5. Additional searches were carried out in Pubmed/Medline and Scopus for primary prevention of eating disorders due to the limited information available in the documents included (until June 2008). The effect of primary prevention interventions for eating disorders has been assessed in RCT or in SRSE of RCT.
6. A search was also performed for cohort studies and prognosis of eating disorders in the Scopus and Psycinfo databases during the period spanning from 2000 to 2008.
7. The Ginebrina Foundation was also consulted for Medical Training and Research and the documents provided by the working group and the references of the documents included were reviewed.

– Selection of Evidence. The most relevant documents were selected by applying predefined inclusion and exclusion criteria:

1. Inclusion criteria: guides, SRSE and ARs in certain languages (Spanish, Catalan, French, English and Italian) that dealt with the previously mentioned objectives. Minimum quality criteria were established for the guides, SRSE and ARs: the bibliographic bases consulted and/or the formulation process of recommendations (ad hoc defined criteria) had to be described.
2. Exclusion criteria: documents/guides that were not original, unavailable (wrong reference or electronic address), not directly related with the proposed objectives, already included in the bibliography of other documents/guides or that didn’t comply with minimum quality criteria.

Two independent reviewers examined the titles and/or summaries of the documents identified by the search strategy. If any of the inclusion criteria were not fulfilled, the document was excluded. If criteria were fulfilled, the complete document was requested and evaluated in order to decide whether it would be included or not. Discrepancies or doubts that arose during the process were resolved by consensus of the entire technical team.

– Quality assessment of the scientific evidence. Assessment of CPG quality was performed by a trained evaluator using the AGREE⁴⁵ instrument. Guides were considered of quality when they were classified as Recommended in the overall assessment. For SRSE/ARs and RCT, SIGN’s methodology checklists were applied by an evaluator, following the recommendations established in the MSC’s¹ CPG development manual. Classification of evidence has been carried out using the SIGN system (See Annex 1).

In Annex 6.2 results of the CPG’s search, selection and assessment of quality are described. In Annex 6.3. and Annex 6.4. NICE’s CPG³⁰ and AHRQ’s SRSE³¹ are respectively described, representing the main scientific base on which this guide is founded.

– Formulation of recommendations based on formal assessment or on SIGN’s considered judgement. The grading of recommendations has been performed using SIGN’s system (See Annex 1). Recommendations pertaining to the NICE CPG have been considered by the working group and have been classified as: adopted (and, hence, accepted; they have simply been translated into Spanish) or adapted (and, hence, modified: changes have been made with the purpose of contextualising them to our setting). Controversial recommendations or those lacking in evidence have been resolved by the working group’s consensus. The category of each recommendation appears in the chapters.

– Description of psychological therapies. Definitions are derived from the NICE³⁰ guide, from the SRSE where they have been assessed and from the working group itself (See Annex 4).

– Description of drugs (mechanism of action and approved indications in Spain) included in the CPG. The following websites have been consulted: Spanish Drug Agency (AGEMED) (https://agemed.es ) and Vademecum (http://www.vademecum.es ). It is recommended to read the technical chart of each drug before any therapeutic prescription given that the CPG only includes a very brief description of each drug and does not go into depth in terms of schemes, contraindications, etc. (See Annex 4).

– Legal aspects. To develop this chapter, aside from reviewing the current legislation in our country, several different articles and reference documents^{17, 46-49} have been consulted.

–To develop patient information (See Annex 3.1.), a search has been performed for pamphlets and other documents containing information for the patient/carer both in printed and electronic formats. To this end, all documents identified in the websites of three relevant organizations (www.feacab.org, www.itacat.com and www.adaner.org ) that comprise the majority of associations declared of public use at a national level through their different delegations and support groups and the material provided by the clinical coordinator have been reviewed.

Following the review of these documents, a content comparison table was elaborated from which the table of contents was developed. Once consensus of the final version had been reached by the working group and collaborating experts, the Association in Defence of Anorexia Nervosa and Bulimia Management (ADANER) and the Spanish Federation of Support Associations for Anorexia (FEACAB), which include most local organisations, carried out an external review, using a specifically designed questionnaire that inquired on the suitability of the information provided, the examples used, style and language, etc. Although this information is part of the CPG and must be delivered and explained to the patient/carer by health care professionals, we hope to edit individualised pamphlets that facilitate its dissemination.

– Formulation of research lines. They have been developed from the research lines that are included in AHRQ 2006³¹ (See chapter 15).

– The external reviewers of the CPG are a group of experts in eating disorders (psychiatry, psychology and genetics specialists) selected for being heads of eating disorder units in Spanish hospitals and/or authors of relevant publications on the matter. Representatives from certain organizations who were unable to be a part of the CPG working group for a variety of reasons also served as external reviewers. The final version of the guide’s text has been revised and approved by the group of authors.

– The updating of this CPG published in 2009 will be carried out after assessing new evidence that may arise in the next three years. Any changes made during this time will be reflected in the electronic format available at the GuíaSalud portal and the CAHTA website. To carry out guideline updating, the methodology proposed in the MSC’s¹ CPG development manual will be applied.

– Resources containing detailed information on the CPG methodological process are available at the GuíaSalud portal (www.guiasalud.es ).