Planetary health in medical guidelines - A workshop report from the conference of the evidence-based medicine network 2023.

INTRODUCTION: Guidelines may play an important role in the process of adopting a planetary health perspective in clinical medicine. Current issues relating to the integration of planetary health aspects in guidelines were discussed during a workshop at the German Network for Evidence-Based Medicine conference in 2023. METHODS: In a multidisciplinary workshop, 25 persons with an interest in guideline development selected important planetary health dimensions that could be promptly included in guidelines. Group discussions addressed the challenges of integrating planetary health aspects in guidelines and feasible solutions. RESULTS: Participants recommended to first integrate the dimensions Environmental impacts, Prevention & co-benefits and Choosing wisely and provided corresponding rationales. Updating evidence to decision frameworks and including relevant climate outcomes (e.g., CO2 equivalents) in clinical trials were regarded as crucial. Pragmatic steps to integrate planetary health aspects such as an adapted guideline layout and prioritization of recommendations were proposed. DISCUSSION: Changes in the guideline development processes are necessary to incorporate the planetary health perspective into guidelines. Capacity building for guideline developers and modifications to frameworks are important next steps. Public discussion and cooperation between guideline developing bodies are therefore essential to move beyond the results of this workshop. CONCLUSION: The aforementioned workshop underpins the strong interest to integrate planetary health aspects into guideline frameworks to eventually promote planetary health in clinical medicine.

S2k guideline for diving accidents.

For the purposes of this guideline, a diving accident is defined as an event that is either potentially life-threatening or hazardous to health as a result of a reduction in ambient pressure while diving or in other hyperbaric atmospheres with and without diving equipment. This national consensus-based guideline (development grade S2k) presents the current state of knowledge and recommendations on the diagnosis and treatment of diving accident victims. The treatment of a breath-hold diver as well as children and adolescents does not differ in principle. In this regard only unusual tiredness and itching without visible skin changes are mild symptoms. The key action statements: on-site 100% oxygen first aid treatment, immobilization/no unnecessary movement, fluid administration and telephone consultation with a diving medicine specialist are recommended. Hyperbaric oxygen therapy (HBOT) remains unchanged as the established treatment in severe cases, as there are no therapeutic alternatives. The basic treatment scheme recommended for diving accidents is hyperbaric oxygenation at 280 kPa.

S3 guideline Allergy Prevention.

BACKGROUND: The persistently high prevalence of allergic diseases in Western industrial nations and the limited possibilities of causal therapy make evidence-based recommendations for primary prevention necessary. METHODS: The recommendations of the S3 guideline Allergy Prevention, published in its last version in 2014, were revised and consulted on the basis of a current systematic literature search. The evidence search was conducted for the period 06/2013 - 11/2020 in the electronic databases Cochrane and MEDLINE, as well as in the reference lists of current reviews and through references from experts. The literature found was screened in two filtering processes, first by title and abstract, and the remaining papers were screened in the full text for relevance. The studies included after this were sorted by level of evidence, and the study quality was indicated in terms of potential bias (low/high). The revised recommendations were formally agreed and consented upon with the participation of representatives of the relevant professional societies and (self-help) organizations (nominal group process). Of 5,681 hits, 286 studies were included and assessed. RESULTS: Recommendations on maternal nutrition during pregnancy and breastfeeding as well as on infant nutrition in the first months of life again play an important role in the updated guideline: Many of the previous recommendations were confirmed by the current data. It was specified that breastfeeding should be exclusive for the first 4 - 6 months after birth, if possible, and that breastfeeding should continue with the introduction of complementary foods. A new recommendation is that supplementary feeding of cow's milk-based formula should be avoided in the first days of life if the mother wishes to breastfeed. Furthermore, it was determined that the evidence for a clear recommendation for hydrolyzed infant formula in non-breastfed infants at risk is currently no longer sufficient. It is therefore currently recommended to check whether an infant formula with proven efficacy in allergy prevention studies is available until the introduction of complementary feeding. Finally, based on the EAACI guideline, recommendations were made for the prevention of chicken egg allergy by introducing and regularly giving thoroughly heated (e.g., baked or hard-boiled) but not "raw" chicken egg (also no scrambled egg) with the complementary food. The recommendation to introduce peanut in complementary feeding was formulated cautiously for the German-speaking countries: In families who usually consume peanut, the regular administration of peanut-containing foods in age-appropriate form (e.g., peanut butter) with the complementary diet can be considered for the primary prevention of peanut allergy in infants with atopic dermatitis (AD). Before introduction, a clinically relevant peanut allergy must be ruled out, especially in infants with moderate to severe AD. There is still insufficient evidence for an allergy-preventive efficacy of prebiotics or probiotics, vitamin D, or other vitamins in the form of supplements so that recommendations against their supplementation were adopted for the first time in the current guideline. Biodiversity plays an important role in the development of immunological tolerance to environmental and food allergens: there is clear evidence that growing up on a farm is associated with a lower risk of developing asthma and allergic diseases. This is associated with early non-specific immune stimulation due to, among other things, the greater microbial biodiversity of house dust in this habitat. This aspect is also reflected in the recommendations on animal husbandry, on which a differentiated statement was made: In families without a recognizable increased allergy risk, pet keeping with cats or dogs should not generally be restricted. Families with an increased allergy risk or with children with already existing AD should not acquire a new cat - in contrast, however, dog ownership should not be discouraged. Interventions to reduce exposure to dust mite allergens in the home, such as the use of mite allergen-proof mattress covers ("encasings"), should be restricted to patients with already proven specific sensitization against house dust mite allergen. Children born by caesarean section have a slightly increased risk of asthma - this should be taken into account when advising on mode of delivery outside of emergency situations. Recent work also supports the recommendations on air pollutants: Active and passive exposure to tobacco smoke increase the risk of allergies, especially asthma, and should therefore be avoided. Exposure to nitrogen oxides, ozone, and small particles (PM 2.5) is associated with an increased risk, especially for asthma. Therefore, exposure to emissions of nitrogen oxides, ozone, and small particles (PM 2.5) should be kept low. The authors of this guideline are unanimously in favor of enacting appropriate regulations to minimize these air pollutants. There is no evidence that vaccinations increase the risk of allergies, but conversely there is evidence that vaccinations can reduce the risk of allergies. All children, including children at risk, should be vaccinated according to the current recommendations of the national public health institutes, also for reasons of allergy prevention. CONCLUSION: The consensus of recommendations in this guideline is based on an extensive evidence base. The update of the guideline enables evidence-based and up-to-date recommendations for the prevention of allergic diseases including asthma and atopic dermatitis.

S2k guideline diagnosis and treatment of carbon monoxide poisoning.

Carbon monoxide (CO) can occur in numerous situations and ambient conditions, such as fire smoke, indoor fireplaces, silos containing large quantities of wood pellets, engine exhaust fumes, and when using hookahs. Symptoms of CO poisoning are nonspecific and can range from dizziness, headache, and angina pectoris to unconsciousness and death. This guideline presents the current state of knowledge and national recommendations on the diagnosis and treatment of patients with CO poisoning. The diagnosis of CO poisoning is based on clinical symptoms and proven or probable exposure to CO. Negative carboxyhemoglobin (COHb) levels should not rule out CO poisoning if the history and symptoms are consistent with this phenomenon. Reduced oxygen-carrying capacity, impairment of the cellular respiratory chain, and immunomodulatory processes may result in myocardial and central nervous tissue damage even after a reduction in COHb. If CO poisoning is suspected, 100% oxygen breathing should be immediately initiated in the prehospital setting. Clinical symptoms do not correlate with COHb elimination from the blood; therefore, COHb monitoring alone is unsuitable for treatment management. Especially in the absence of improvement despite treatment, a reevaluation for other possible differential diagnoses ought to be performed. Evidence regarding the benefit of hyperbaric oxygen therapy (HBOT) is scant and the subject of controversy due to the heterogeneity of studies. If required, HBOT should be initiated within 6 h. All patients with CO poisoning should be informed about the risk of delayed neurological sequelae (DNS).

Construction of a User-Led Resource for People Transitioning to Secondary Progressive Multiple Sclerosis: Results of an International Nominal Group Study.

Background: ManTra is a mixed-methods, co-production research project for developing an intervention (resource) for people with newly diagnosed secondary progressive multiple sclerosis (pwSPMS) in Italy and Germany. In previous project actions, six resources were outlined, meeting the needs prioritized by pwSPMS. Aims: This study aims to achieve multiple-stakeholder consensus on the most suitable resource and to refine the consensus resource. Methods: Two nominal group technique (NGT) meetings were held, one in Milan and one in Hamburg. Participants were pwSPMS (five in Italy/six in Germany), pwSPMS significant others (SOs, four/five), healthcare professionals (HPs, seven/four), and health service researchers/patient and citizen organizations representatives (HPCORs, five/five). Two of the four resources discussed in each meeting were the same in Italy and Germany: "Promoting the engagement of pwSPMS: a program for the patients and the HPs" and "Enriched physiotherapy program for pwSPMS." The other two were "A personalized care plan for pwSPMS" and "Roadmap for social and economic benefits" in Italy and "Metacognitive and everyday life training for pwSPMS" and "Psychological support for pwSPMS" in Germany. Each meeting consisted of two plenary sessions and a parallel group session (four stakeholder groups: pwSPMS, SOs, HPs, and HPCORs) in between. Meetings' narratives were analyzed thematically. Results: The two meetings were rich in participation and discussion. In Italy, the consensus resource was "A personalized care plan for pwSPMS." Refinements included enrichment with pwSPMS engagement, inclusion of additional HPs, improved definition of the MS nurse's role within the interdisciplinary panel, and community care integration. In Germany, the consensus resource was "Psychological support for pwSPMS." Refinements included reshaping this resource into a more comprehensive and adaptive rehabilitation intervention and training the psychologist in recognizing client's rehabilitative needs and enhancing his/her autonomy. Conclusions: The NGT eased multiple-stakeholder deliberation and resource fine-tuning in both countries.

[Patients with chronic diseases in emergency rooms in Germany : Cross-sectional analysis of consultations, reasons for use, and discharge diagnosis]. / Chronisch Kranke in deutschen Notaufnahmen : Querschnittsanalysen zu Konsultationsanlässen, Gründen für die Inanspruchnahme und Entlassungsdiagnosen.

BACKGROUND: The number of patients in emergency rooms without a medical emergency is increasing. Outpatient services for mutual support and relief between the in-patient and out-patient sector are not yet fully established. AIM OF THE WORK: The aim was to determine the extent to which patients in emergency rooms have real medical emergencies by comparing patients with at least two and those with a maximum of one chronic illness. An additional aim was to identify factors influencing the previous use of outpatient structures. MATERIAL AND METHODS: The study participants included emergency room patients from the cross-sectional study "PiNo-Nord." All persons in five emergency rooms in northern Germany between October 2015 and July 2016 who were not treated as "immediate" or "very urgent" were interviewed. An exploratory data analysis and multivariate logistic regression were performed. RESULTS: The 293 patients with ≥2 chronic diseases were just as often a medical emergency compared to the 847 patients with a maximum of 1 chronic disease. The most frequent occasions for consultation were musculoskeletal trauma (33%, n = 293 vs. 42%, n = 847) or trauma of the skin (11%, n = 293 vs. 13%, n = 847). In both groups, the general practitioner or specialist caregiver, as well as diagnostic or treatment options, rarely played a role in visiting the emergency department. The strongest predictors of previous outpatient treatment were the duration of the appeal in the last six months, a high subjective treatment urgency, the presence of at least two chronic conditions, and a consultation event concerning the musculoskeletal injuries. CONCLUSIONS: In both patient groups, no evidence of unnecessary visits to the emergency room was found. For the most part, outpatient structures are used in advance and the emergency department is only visited in the event of an actual medical emergency.

Protection against the overuse and underuse of health care - methodological considerations for establishing prioritization criteria and recommendations in general practice.

BACKGROUND: Initiatives such as "Choosing Wisely" in the USA and "Smarter Medicine" in Switzerland have published lists of widely overused health care services. The German initiative "Choosing Wisely Together (Gemeinsam Klug Entscheiden)" follows this example. The goal of our study was to prioritize important recommendations against the overuse and underuse of health care services. The final list of recommendations will be published in the German guideline "Protection against the overuse and underuse of health care". METHODS: First, a multidisciplinary expert panel established a catalogue of prioritization criteria. Second, we extracted all the recommendations from evidence- and consensus-based German College of General Practice and Family Medicine (DEGAM) guidelines and National Health Care Guidelines (NVL). Third, the recommendations were rated by two independent panels (general practitioners and other health care professionals involved/not involved in guideline development). The prioritization process was finalized in a consensus conference held by DEGAM's Standing Guideline Committee (SLK). RESULTS: Eleven prioritization criteria were established. A total of 782 recommendations were extracted and rated by 98 physicians and other health care professionals in a survey. In the voting process, more than 80% of the recommendations were eliminated. After the final consensus conference, twelve recommendations from DEGAM guidelines, nine DEGAM addenda and 17 NVL recommendations were chosen for inclusion in the guideline, for a total of 38 recommendations. CONCLUSION: The selection procedure proved helpful in identifying the highest priority recommendations with which to combat the overuse and underuse of health care services. To date, in Germany there has been no attempt to compile such a list by using a systematic and transparent methodology. Hence, the guideline that results from this process can fill an important gap.

Development of a meta-algorithm for guiding primary care encounters for patients with multimorbidity using evidence-based and case-based guideline development methodology.

OBJECTIVE: The study aimed to develop a comprehensive algorithm (meta-algorithm) for primary care encounters of patients with multimorbidity. We used a novel, case-based and evidence-based procedure to overcome methodological difficulties in guideline development for patients with complex care needs. STUDY DESIGN: Systematic guideline development methodology including systematic evidence retrieval (guideline synopses), expert opinions and informal and formal consensus procedures. SETTING: Primary care. INTERVENTION: The meta-algorithm was developed in six steps:1. Designing 10 case vignettes of patients with multimorbidity (common, epidemiologically confirmed disease patterns and/or particularly challenging health care needs) in a multidisciplinary workshop.2. Based on the main diagnoses, a systematic guideline synopsis of evidence-based and consensus-based clinical practice guidelines was prepared. The recommendations were prioritised according to the clinical and psychosocial characteristics of the case vignettes.3. Case vignettes along with the respective guideline recommendations were validated and specifically commented on by an external panel of practicing general practitioners (GPs).4. Guideline recommendations and experts' opinions were summarised as case specific management recommendations (N-of-one guidelines).5. Healthcare preferences of patients with multimorbidity were elicited from a systematic literature review and supplemented with information from qualitative interviews.6. All N-of-one guidelines were analysed using pattern recognition to identify common decision nodes and care elements. These elements were put together to form a generic meta-algorithm. RESULTS: The resulting meta-algorithm reflects the logic of a GP's encounter of a patient with multimorbidity regarding decision-making situations, communication needs and priorities. It can be filled with the complex problems of individual patients and hereby offer guidance to the practitioner. Contrary to simple, symptom-oriented algorithms, the meta-algorithm illustrates a superordinate process that permanently keeps the entire patient in view. CONCLUSION: The meta-algorithm represents the back bone of the multimorbidity guideline of the German College of General Practitioners and Family Physicians. This article presents solely the development phase; the meta-algorithm needs to be piloted before it can be implemented.

Surgery for adult spondylolisthesis: a systematic review of the evidence.

Surgery for isthmic and degenerative spondylolisthesis (SL) in adults is carried out very frequently in everyday practice. However, it is still unclear whether the results of surgery are better than those of conservative treatment and whether decompression alone or instrumented fusion with decompression should be recommended. In addition, the role of reduction is unclear. Four clinically relevant key questions were addressed in this study: (1) Is surgery more successful than conservative treatment in relation to pain and function in adult patients with isthmic SL? (2) Is surgery more successful than conservative treatment in relation to pain and function in adult patients with degenerative SL? (3) Is instrumented fusion with decompression more successful in relation to pain and function than decompression alone in adult patients with degenerative SL and spinal canal stenosis? (4) Is instrumented fusion with reduction more successful in relation to pain and function than instrumented fusion without reduction in adult patients with isthmic or degenerative SL? A systematic PubMed search was carried out to identify randomized and nonrandomized controlled trials on these topics. Papers were analyzed systematically in a search for the best evidence. A total of 18 studies was identified and analyzed: two for question 1, eight for question 2, four for question 3, and four for question 4. Surgery appears to be better than conservative treatment in adults with isthmic SL (poor evidence) and also in adults with degenerative SL (good evidence). Instrumented fusion with decompression appears to be more successful than decompression alone in adults with degenerative SL and spinal stenosis (poor evidence). Reduction and instrumented fusion does not appear to be more successful than instrumented fusion without reduction in adults with isthmic or degenerative SL (moderate evidence).

[Implementation of clinical practice guidelines: how can we close the evidence-practice gap?]. / Leitlinienimplementierung : Wie schließen wir die Lücke zwischen Evidenz und Anwender?

Guidelines are intended as instruments of knowledge transfer to support decision-making by physicians, other health professionals and patients in clinical practice and thereby contribute to quality improvements in healthcare. To date they are an indispensable tool for healthcare. Their benefit for patients can only be seen in application, i.e. the implementation of guideline recommendations. For successful implementation, implementability and practicability play a crucial role and these characteristics can be influenced and should be promoted by the guideline development group. In addition, a force field analysis to identify barriers against and facilitators for the implementation of specific guideline recommendations from the perspective of physicians and patients is recommended to guide the development of an individual implementation strategy and the selection of appropriate interventions. However, implementation cannot be achieved by the guideline development group alone and a universal implementation strategy does not exist. Therefore, a process using theory, analysis, experience and shared responsibility of stakeholders in healthcare is recommended, with the aim to achieve sustainable behavioral change and improve the quality of care by guideline-oriented behavior.

[Reflections on 20 years of clinical practice guideline programmes in Germany: what is their impact?]. / 20 Jahre ärztliche Leitlinien in Deutschland - was haben sie bewirkt?

Following a recommendation of the National Advisory Council for the Concerted Action in Health Care, the Association of the Scientific Medical Societies (AWMF) have promoted, supported and coordinated the development of clinical practice guidelines in Germany since 1995. The allocation of the responsibility for guideline development in the scientific societies corresponded to the principle of subsidiarity, in contrast to other countries counting on government-organised guideline programmes. To fulfil internationally consented criteria of high-quality guidelines, a quality improvement system was established relying on frequent assessments of the current state. Today, high-quality clinical practice guidelines developed by the scientific societies organised under the umbrella of the AWMF are an indispensable tool for various initiatives to improve healthcare in the German healthcare system. The next challenging goal is to establish a theory-driven framework allowing for a systematic implementation and evaluation of guidelines in Germany on the basis of existing approaches. However, success in this endeavour will require further research and funding.

[Measuring quality in the German Guideline Programme in Oncology (GGPO)­methodology and implementation]. / Methodik und Umsetzung der Qualitätsmessung im Leitlinienprogramm Onkologie.

The German Guideline Programme in Oncology (GGPO) is a joint initiative between the German Cancer Society, the Association of the Scientific Medical Societies in Germany and German Cancer Aid. In accordance with the aims of the German National Cancer Plan, the GGPO supports the systematic development of high-quality guidelines. To enhance implementation and evaluation, the suggestion of performance measures (PMs) derived from guideline recommendations following a standardised methodology is obligatory within the GGPO. For this purpose, PM teams are convened representing the multidisciplinary guideline development groups including clinical experts, methodologists and patient representatives as well as those organisations that take an active part in and share responsibility for documentation and quality improvement, i.e., clinical cancer registries, certified cancer centres and, if appropriate, the institution responsible for external quality assurance according to the German Social Code (SGB). The primary selection criteria for PMs include strength of the underlying recommendation (strong, grade A), existing potential for improvement of care and measurability. The premises of data economy and standardised documentation are taken into account. Between May 2008 and July 2014, 12 guidelines with suggestions for 100 PMs have been published. The majority of the suggested performance measures is captured by the specific documentation requirements of the clinical cancer registries and certified cancer centres. This creates a solid basis for an active quality management and re-evaluation of the suggested PMs. In addition, the suspension of measures should be considered if improvement has been achieved on a broad scale and for a longer period in order to concentrate on a quality-oriented, economic documentation.

S3-Guideline on allergy prevention: 2014 update: Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) and the German Society for Pediatric and Adolescent Medicine (DGKJ).

The continued high prevalence of allergic diseases in Western industrialized nations combined with the limited options for causal therapy make evidence-based primary prevention necessary. The recommendations last published in the S3-guideline on allergy prevention in 2009 have been revised and a consensus reached on the basis of an up-to-date systematic literature search. Evidence was sought for the period between May 2008 and May 2013 in the Cochrane and MEDLINE electronic databases, as well as in the reference lists of recent review articles. In addition, experts were surveyed for their opinions. The relevance of retrieved literature was checked by means of two filter processes: firstly according to title and abstract, and secondly based on the full text of the articles. Included studies were given an evidence grade, and a bias potential (low/high) was specified for study quality. A formal consensus on the revised recommendations was reached by representatives of the relevant specialist societies and (self-help) organizations (nominal group process). Of 3,284 hits, 165 studies (one meta-analysis, 15 systematic reviews, 31 randomized controlled trials, 65 cohort studies, 12 case-control studies and 41 cross-sectional studies) were included and evaluated. Recommendations on the following remain largely unaltered: full breastfeeding for 4 months as a means of allergy prevention (hypoallergenic infant formula in the case of infants at risk); avoidance of overweight; fish consumption (during pregnancy/lactation and in the introduction of solid foods for infants); vaccination according to the recommendations of the German Standing Committee on Vaccination (Ständige Impfkommission, STIKO); avoidance of air pollutants and tobacco exposure and avoidance of indoor conditions conducive to the development of mold. The assertion that a reduction in house-dust mite allergen content as a primary preventive measure is not recommended also remains unchanged. The introduction of solid foods into infant diet should not be delayed. In the case of children at risk cats should not be acquired as domestic pets. Keeping dogs is not associated with an increased risk of allergy. The updated guideline includes a new recommendation to consider the increased risk of asthma following delivery by cesarean section. Additional statements have been formulated on pre- and probiotic agents, psychosocial factors, medications, and various nutritional components. Revising the guideline by using an extensive evidence base has resulted not only in an endorsement of the existing recommendations, but also in modifications and in the addition of new recommendations. The updated guideline enables evidence-based and up-to-date recommendations to be made on allergy prevention. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s40629-014-0022-4 and is accessible for authorized users.

[On the attractiveness, implementation and evaluation of guidelines]. / Leitlinien - Attraktivität, Implementierung und Evaluation.

Principles and conditions for guideline implementation and evaluation were the subject of a workshop organised by the German Association of the Scientific Medical Societies (AWMF) and the German Network for Health Services Research (DNVF). This report reflects contents and discussions and suggests possible future activities. The workshop highlighted the need for conceptual frameworks, theory-driven research and concerted strategies. The reinforcement of strategic partnerships within the health care organisations is an indispensable prerequisite for successful guideline implementation and evaluation.(As supplied by author).

Allergy prevention.

The further increase of allergies in industrialized countries demands evidence-based measures of primary prevention. The recommendations as published in the guideline of 2004 were updated and consented on the basis of a systematic literature search. Evidence from the period February 2003-May 2008 was searched in the electronic databases Cochrane and MEDLINE as well as in reference lists of recent reviews and by contacting experts. The retrieved citations were screened for relevance first by title and abstract and in a second step as full paper. Levels of evidence were assigned to each included study and the methodological quality of the studies was assessed as high or low. Finally the revised recommendations were formally consented (nominal group process) by representatives of relevant societies and organizations including a self-help group. Of originally 4556 hits, 217 studies (4 Cochrane Reviews, 14 meta-analyses, 19 randomized controlled trials, 135 cohort and 45 case-control studies) were included and critically appraised. Grossly unchanged remained the recommendations on avoiding environmental tobacco smoke, breast-feeding over 4 months (alternatively hypoallergenic formulas for children at risk), avoiding a mold-promoting indoor climate, vaccination according to current recommendations, and avoidance of furry pets (especially cats) in children at risk. The recommendation on reducing the house dust mite allergen exposure as a measure of primary prevention was omitted and the impact of a delayed introduction of supplementary food was reduced. New recommendations were adopted concerning fish consumption (during pregnancy / breast-feeding and as supplementary food in the first year), avoidance of overweight, and reducing the exposure to indoor and outdoor air pollutants. The revision of this guideline on a profound evidence basis led to (1) a confirmation of existing recommendations, (2) substantial revisions, and (3) new recommendations. Thereby it is possible to give evidence-based and up-to-date recommendations on primary prevention of allergies.

Allergy prevention.

BACKGROUND: Evidence-based primary prevention of allergic conditions is important in view of their increasing prevalence in Western industrialized countries. METHODS: The Cochrane and Medline databases were searched for relevant scientific publications that appeared from February 2003 to May 2008. Articles in the reference lists of recent reviews were also considered, and experts were directly asked for their opinions. The retrieved publications were screened for relevance by evaluation of the title and abstract, and then by evaluation of the entire text. Each study chosen for inclusion was assigned an evidence grade as well as a grade for study quality relating to its potential for bias (low or high). The revised recommendations were then formally accepted by a consensus of representatives of medical specialist societies and other organizations, including a patient self-help group. RESULTS: The search initially yielded 4556 results out of which 217 articles (4 Cochrane reviews, 14 meta-analyses, 19 randomized clinical trials, 135 cohort studies, and 45 case-control studies) were chosen for inclusion and critical appraisal. No major changes ensued in the existing recommendations to avoid exposure to tobacco smoke, breast-feed for 4 months (or use hypoallergenic formulas), avoid a mould-promoting indoor climate, avoid exposure to furry pets (particularly cats), and vaccinate according to the current recommendations of the Standing Committee on Vaccination of the Robert Koch Institute (Ständige Impfkommission, STIKO). Neither the delayed introduction of solid food nor the avoidance of potent dietary allergens is recommended as a means of primary prevention. New recommendations were issued regarding fish consumption (by the mother while breastfeeding and nursing, and by the infant as solid food), avoidance of overweight, and reduction of exposure to air pollutants. CONCLUSIONS: This updated guideline serves as an aid in giving patients current, evidence-based recommendations for allergy prevention.