Background

The development of the evidence-based clinical practice guideline elaboration Programme for the NHS is being carried out 2ithin the framework of the development of the Quality Plan of the Ministry of Health and Consumer Affairs (MSC), through the National Health System (NHS)’s Quality Agency.

In the initial phase of this Programme (2006), the development of eight CPGs has been prioritised. A collaboration agreement has been established between the ISCIII and health technology assessment agencies and units and the Iberoamerican Cochrane Centre. The Health Sciences Institute of Aragón is in charge of the Programme’s coordination activities.

In the bilateral agreement between the CAHTA of Catalonia and the ISCIII it was agreed to develop a CPG for eating disorders: anorexia nervosa (AN), bulimia nervosa (BN) and atypical or unspecified eating disorders (EDNOS), based on the best scientific evidence available, which would address the most important areas for the NHS, in a coordinated manner and with shared methodology which would be determined by a group of NHS professionals experienced in CPG development. These professionals have comprised the methodological group and the panel of collaborators of the CPG development programme ¹.

Justification

In the last decades, eating disorders have gained increasing sociosanitary relevance due to their severity, complexity and difficulty in establishing a diagnosis and specific treatment. Eating disorders are pathologies of multifactorial ethiology where genetic, biological, personality, family and sociocultural factors converge, affecting mainly children, adolescents and young adults.

There are is no data available in Spain that analyses the economic burden of eating disorder treatments nor studies that assess the cost-effectiveness of different treatments. However, different studies conducted in countries of the European Union^2-7 indicate that direct costs (diagnosis, treatment and monitoring or follow-up) and especially indirect costs (economic losses derived from the disease that impact the patient and his/her social setting) entail a high economic burden and considerably decrease the quality of life of patients with eating disorders. According to a German study that was carried out in 2002, in the case of AN, average hospitalisation cost is 3.5 times higher than the general hospitalisation average ⁴.

In 2002, Gowers SG, et al.⁸ published the results of a survey conducted in 12 countries that were participating in the European project COST Action B6, which aimed to explore consensus and differences in the therapeutic approaches indicated for adolescents with AN (several different Spanish hospitals participated in this project). Results demonstrated significant agreement between the interviewed countries regarding the need to offer a wide array of services at the different levels of care. However, considerable differences were detected in terms of strategies, especially in hospital admission criteria, use of day centres/day hospitals, etc.

In the case of AN¹, according to the Atlas of Variations in medical practice of the NHS, where the variability in admissions into acute care public or publicly funded⁹ hospitals, are described and mapped, a low hospitalisation incidence is observed in AN with, 0.32 admissions per 10,000 inhabitants and year. Hospitalisation rates for AN ranged between 0.08 –practically nil- and 1.47 admissions per 10,000 inhabitants and year. In terms of the weighted variation coefficient, the figures confirmed the wide variation among the different health areas in 70% of AN cases. After consideration of the variation randomised effect, the systematic component of variation of the health areas included in the percentiles 5 to 95 shows high variability (SCV5-95 = 0,26). The ample variation found may be related either to demand factors (different morbidity, socio-economic differences of the cities and towns) or to offer factors (practice style, healthcare resources, different policies for the development of mental care procedures, etc. The variability observed in hospitalisation rates among Spanish provinces is significant and accounts for a 40% of the variability in hospitalisation rates in cases of AN. Upon multilevel analysis, provincial level accounts for a larger variance proportion than in the region (regional level), reinforcing the hypothesis that the different provincial development of psychiatric models and services is behind the variations found. The remaining studied factors (age, gender, available income, educational level, predisposition to hospitalisation) do not appear to exert an influence upon the variability observed in hospitalisation rates in AN, save for the recorded unemployment that works in the opposite way: in areas with more recorded unemployment, the probability of hospitalisation is lower. No data are available for BN or eating disorder not otherwise specified (EDNOS-atypical eating disorders).

Different governmental Spanish and foreign institutions have published guides, recommendations and protocols on EDs in the last years, of which the following stand out:

1. Osona (2008)¹⁰ and the Gerona health region (2006)¹¹ from the Department of Health-Catalan Health Service
2. semFYC (prevention activities and health promotion group) (2007)¹², (2005)¹³.
3. American Psychiatric Association (2006)¹⁴.
4. Action Manual of the Ministry of Health and Consumer Affairs on the scientific evidence regarding specialised nutritional support (2006)¹⁵.
5. General subdirectorate of Mental Health- Health Service of Murcia (2005)¹⁶.
6. Official College and Board of Physicians of Barcelona (2005)¹⁷.
7. Royal Australian and New Zealand College of Psychiatrists (2004)¹⁸.
8. National Health Institute (INSALUD, 2000)¹⁹, (1995)²⁰.

However, there is a need for a guide adapted to the Spanish population using the best possible methodology and based on the best available evidence.

Recently, other important actions related with eating disorders have been carried out in our context, such as: NAOS and PAOS programme for the prevention of obesity in children and a healthy diet; the Social Pact of the Madrid for the prevention of eating disorders; Image and Self-Esteem Foundation, and pacts between user federations (FEACAB and ADANER) and the MSC.

Magnitude of the problem

Estimations on the incidence and prevalence of eating disorders vary depending on the studied population and assessment tools employed. Therefore, in order to compare data from different national and international sources it is essential that the study design be the same. The study in “two phases” is the most appropriate methodology for the detection of cases in the community. The first phase consists of screening using self-report symptom questionnaires. In the second phase, assessment is carried out by means of clinical interviews that are conducted with individuals who obtained scores above the cut-off point in the screening questionnaire (“at risk” subjects), meaning only a subsample of the total initially screened sample is interviewed.

Within the studies that use correct two-phase methodology, very few perform random sampling of participants who score below the cut-off point of the screening questionnaire to interviews, which leads to a subestimation of the prevalence of eating disorders by not taking false negatives into account^21-23. An additional problem is the use of different cut-off points in screening questionnaires.

In spite of these methodological difficulties, the increased prevalence of eating disorders is significant, especially in developed or developing countries, while it is nearly inexistent in third-world countries. Increased prevalence is attributable to increased incidence and duration and chronicity of these clinical pictures.

Based on two-phase studies conducted in Spain (Tables 1 and 2) on the highest risk population, women ranging from 12 to 21 years of age, a prevalence of 0.14% to 0.9% is obtained for AN, 0.41% to 2.9% for BN and 2.76% to 5.3% in the case of EDNOS. In total, we would be looking at an eating disorder prevalence of 4.1% to 6.41%. In the case of male adolescents, even though there are fewer studies available, a prevalence of 0% for AN, 0% to 0.36% for BN and 0.18% to 0.77% for EDNOS is obtained, with a total prevalence of 0.27% to 0.90%^21-29.

These numbers are similar to those presented in the NICE CPG (2004), where prevalence in of EDNOS, BN and AN in women ranges from 1% to 3.3%, 0.5% to 1.0% and 0.7%, respectively, and also to those in the Systematic Review of Scientific Evidence (SRSE) (2006) which reports prevalence in Western Europe and the United States (0.7% to 3% of EDNOS in the community, 1% of BN in women and 0.3% of AN in young women).

Several studies on the incidence of eating disorders that have been published in North America and Europe present a 5- to 6-fold increase in incidence between 1960 and 1970. In 1998, a review presented by Pawluck, et al. on the general population of the United States reported that annual incidence of AN was 19 per 100,000 in women and 2 per 100,000 in males³⁰. In the review presented by Hoek in 2003, incidence was 8 cases per 100,000 inhabitants for AN and 12 cases per 100,000 inhabitants for BN³².

In a recent study in the United Kingdom (UK), incidence for AN in 2000 was 4.7 per 100,000 inhabitants (95% CI: 3.6 to 5.8) and 4.2 per 100,000 inhabitants in 1993 (95% CI: 3.4 to 5.0). In Holland, incidence of AN was 7.7 (95% CI: 5.9 to 10.0) per 100,000 inhabitants/year between 1995-1999 and 7.4 between 1985 and 1989³³. In Navarra, a population survey in 1,076 13-year old girls was used to estimate an eating disorder incidence of 4.8% (95% CI: 2.84 to 6.82) in a period of 18 months, corresponding to: 0.3% AN (95% CI: 0.16 to 0.48): 0.3% BN (95% CI: 0.15 to 0.49) and 4.2% EDNOS (95% CI: 2.04 to 6.34) ³⁴.

Incidence was greater in women aged 15 to 19 years: they constitute approximately 40% of identified cases in studies both in the US and Europe^{30, 31, 33}. There are very few studies that report data on AN in prepubertal children or in adults³¹. There are also scarce studies that present incidence data of AN in men. Of all the aforementioned studies, we can conclude that incidence is lower than 1 per 100,000 inhabitants/year³³. All these sources establish an eating disorder prevalence ratio of 1 to 9 in males versus women.

Table 1. Studies on the prevalence of eating disorders in adolescent females in Spain

Study	N	Age (years)	AN (%)	BN %	EDNOS %	EDs %
Madrid, 199724 Morandé G and Casas J.	723	15	0,69	1,24	2,76	4,69
Zaragoza, 199826 Ruiz P et al.	2.193	12-18	0,14	0,55	3,83	4,52
Navarra, 200027 Pérez-Gaspar M et al.	2.862	12-21	0,31	0,77	3,07	4,15
Reus, 200829 Olesti M et al.	551	12-21	0,9	2,9	5,3	9,1

Table 2. Studies on the prevalence of eating disorders in adolescent males and females in Spain

Study	N	Age (years)	AN (%)	BN %	EDNOS %	EDs %
Madrid, 199925 Morandé G et al.	1.314	15	0,00 a 0,69	0,36 a 1,24	0,54 a 2,76	3,04 4,70 0,90
Valencia, 200321 Rojo L et al.	544	12-18	0,00 a 0,45	0,00 a 0,41	0,77 a 4,71	2,91 5,56 0,77
Ciudad Real, 200522 Rodríguez-Cano T et al.	1.766	12-15	0,00 a 0,17	0,00 a 1,38	0,60 a 4,86	3,71 6,41 0,60
Osona (Barcelona), 200628 Arrufat F	2.280	14-16	0,00 a 0,35	0,09 a 0,44	0,18 a 2,70	1,90 3,49 0,27
Madrid, 200723 Peláez MA et al.	1.545	12-21	0,00 a 0,33	0,16 a 2,29	0,48 a 2,72	3,43 5,34 0,64