2Schritte eines Cochrane Reviews Fragestellung festlegenAuswahlkriterien definierenMethoden definierenStudien suchenAuswahlkriterien anwendenDaten extrahierenBias-Riskio der Studien bewertenErgebnisse analysieren und darstellenErgebnisse interpretieren und Schlussfolgerungen ziehenReview optimieren und aktualisierenDefining your review question is the first step in starting your Cochrane systematic review. You begin this process at the title registration stage, but there’s often more work to be done in really thinking through your question in detail.
3Übersicht Bedeutung einer klar definierten Review-Fragestellung Komponenten einer FragestellungWas sollte das Protokoll beinhalten?Siehe Kapitel 5 im Handbuch
4Fragestellung definieren Erster wichtiger Schritt eines ReviewsBeeinflusst viele methodische AspekteAuswahlkriterienSuchstrategieDatensammlung und -analyseÜberlegen Sie sorgfältig welche Implikationen die Forschungsfrage für Ihre weitere Arbeit hatKontaktieren Sie die Review Gruppe falls die Fragestellung geändert werden sollA well-defined review question is essential to your review. It’s important that you’re clear about what your review will cover, as the question will define many of the subsequent steps of the review:it will determine your eligibility criteria – that is, which studies are included in the review, and which are excludedit will determine how you go about your search strategy, and what kinds of studies you find. If you’re not clear enough about your question at this stage, you may miss papers that are really of interest to you, or find lots of paper that’s not what you wanted.your question will also determine your analysis of the results of the studies – which outcomes do you want to measure, are there specific issues you want to explore, what information do you need to find in the included studies?It’s worth spending time to think this through in some detail at the beginning of the process. Not only can it help you plan your work, but a clear idea of the scope of your review will help you avoid bias later on. By laying down your parameters objectively in advance, you can reduce the risk of making decisions or changing your mind later, on the fly, in a way that might be influenced by the results of particular studies.Your question will be discussed and agreed with your CRG at the title registration stage. It’s not impossible to make changes to the scope of your review later on, but make sure you speak to your CRG if you plan to do so.
5Themengebiet und Umfang planen Wählen Sie eine Fragestellung die wichtig und relevant istRelevanz des Gesundheitsproblems– auf Bevölkerungs- und individueller EbeneMögliche Auswirkungen der InterventionDenken Sie an alle wichtigen InteressensvertreterInnen: KonsumentInnen, GesundheitsexpertInnen, und politische EntscheidungsträgerInnenAdressieren Sie relevante HandlungsalternativenNehmen Sie eine internationale Sichtweise einTake some time to think about the importance of your question: who is it relevant to? Does it address an important burden of disease? What is the possible impact of your intervention on that burden? Try to select a question of real importance to those who will be affected by the intervention, including not only issues of interest to health professionals, but also consumers and policy makers.It’s also important to select a question that addresses the real choices faced in decision-making. What are the intervention options available? What are the outcomes that influence those choices? For example, when considering a new intervention, is it most useful to test it against no intervention or a placebo, or is it more useful to test it against the currently available treatment options?Cochrane reviews should always consider an international perspective. The burden of specific diseases may vary greatly in different countries or different populations. The intervention options available and the way health systems operate may also be different, as well as the outcomes of importance. Cochrane reviews may be used by people anywhere the world, in contexts very different from yours, so it’s important not to make assumptions when planning or interpreting the results of your review.
6Enge oder breite Fragestellung? VorteileEinfach zu schreibenEinfach zu lesenUmfangreichVerallgemeinerbarNachteileNotwendigkeit mehrerer ReviewsKann zu selektiven Fragestellungen führenKomplexSubgruppeneffekte können übersehen werdenÜbersicht von Reviews ist eventuell vorzuziehenConsider whether you wish to answer a narrow question, e.g. looking at one specific intervention in a specific patient group, or a broader question, e.g. looking at all interventions to address a particular health condition, or something more complex like health system or community interventions.A well-focussed systematic review question will be broad enough to answer a useful question, allowing for some of the variations that will always be observed in a field, but not so broad that it doesn’t make sense to consider all those studies together in one review. Narrower reviews are easier to write and easier to read, but you may need to have multiple reviews to answer all the questions relating to a condition or type of intervention. Broad reviews are more comprehensive, but they can be complex, more difficult for authors to write, and can miss some of the detail possible in a narrower review.In some cases what’s most appropriate can change over time. There was once a Cochrane review, ‘Interventions for shoulder pain’, that looked at all possible interventions – steroid injections, physiotherapy, exercise, pain killers. Over time, however, as more and more studies were published, it became unmanageable, and has now been split into a set of reviews looking at one specific intervention.One way that the Cochrane Collaboration manages sets of narrow reviews is to publish Overviews of Reviews – these are brief papers that summarise the findings of multiple related reviews. More information about these Overviews is available in Chapter 22 of the Handbook, if you’re interested in reading more.There’s no right or wrong answer to this - it depends on what you’re interested in. Your Review Group may have a preference based on their experience and how your review fits with other similar reviews already published.Siehe Kapitel 22 im Handbuch
7Übersicht Bedeutung einer klar definierten Review-Fragestellung Komponenten einer FragestellungWas sollte das Protokoll beinhalten?
8Komponenten einer Fragestellung Beschreiben Sie folgende Komponenten im DetailÜberlegen Sie sich Variationen, die Sie im Rahmen des Reviews untersuchen möchtenP PatientInnen/PopulationI InterventionC Vergleichsintervention (Comparison)O Endpunkte (Outcomes)You will need to define each aspect of your question very clearly.ASK: Who has seen this PICO format before?It can be used to design a study, or a literature search, and it’s also useful for thinking through the question for your systematic review.You will need to think about each of these components and define in detail: who are you interested in studying in your review? What is the intervention or group of interventions you want to test? What will the interventions be compared to? What outcomes will tell you which intervention is the most effective?Think about what you’re interested in, and what you’re not interested in. Within each component, it’s also important to think about the variations that you would like to explore further, such as different populations for whom the intervention might work differently, or variations on the way the intervention can be applied.
9AuswahlkriterienLegen fest welche Studien in den Review eingeschlossen werdenBasierend auf:Einigen oder allen PICO-KomponentenplusFestlegung der zuberücksichtigenden StudiendesignsJegliche Änderung der Auswahlkriterien nach Veröffentlichung des Protokolls sollte im Review begründet werdenWhen you have clearly defined your question, and identified in detail the components you would like to investigate, you can then define the eligibility criteria for your review. Eligibility criteria are the essential components, the boundaries, that determine whether a study is included and discussed in the review, or whether it is excluded.Remember that the eligibility criteria for a review may be different from the ideal criteria you might set if you were designing a primary study yourself. For example, you may wish to look specifically at the impact on people with a certain stage of disease, or you might have a preferred model for implementing a complex intervention. However, the body of studies you find in the literature might show considerable variation from your ideal model, or might incorporate a mixture of participants with different stages of disease. If these studies are included in your eligibility criteria, you can explore the effect of these differences within the review. If you rule them out, they will be excluded altogether.It’s important to articulate each component carefully, so that when you come to making decisions about including studies in the review, you are doing so as objectively as possible. Having clear criteria to refer to will help you avoid ad hoc decisions that may introduce bias.Following pre-specified eligibility criteria is a fundamental attribute of a systematic review. However, unanticipated issues may arise, and it is possible to change your mind about eligibility criteria if needed. Review authors should make sensible post hoc decisions about exclusion of studies. You should be careful to apply any new eligibility rules consistently across all potentially eligible studies. To ensure transparency, any changes to your eligibility criteria should be reported in the review, possibly accompanied by sensitivity analyses (that is, repeating your analysis to test whether your post hoc decision had an important impact on the results of your review). Changes to the protocol must not be made on the basis of the findings of the studies or the review, as this can introduce bias.
10PatientInnen/Population Eindeutige Definition der ZielpopulationZwei Aspekte sind dabei zu berücksichtigenGesundheitsproblemWie und von wem diagnostiziert?Charakteristika der Population und SettingJegliche Einschränkung sollte klar begründet seinAlternativ kann man breitere Auswahlkriterien wählen und später Subgruppenanalysen durchführenFirst: the population (sometimes also called the participants, or people). What are the most important characteristics that describe the people you are interested in?The level of precision you need will depend on the topic of your review, but should always be detailed enough to identify which studies you wish to exclude from the review. For example, if you are interested in a specific population with defined diagnostic criteria, e.g. a particular stage of breast cancer, or a particular genetic marker, you will need to describe the criteria in some detail. Keep in mind that your ideal diagnostic criteria may not be universally used, or even available, and older studies may not have access to the newest available tests.Alternatively, if you are looking at a broader group of people with a health condition, e.g. any stage of breast cancer, or even a healthy population with no health condition, less detail will be needed.Whatever limits you place around the group of people should have a clear rationale: if you are limiting to a specific stage of disease, or to a specific age group, is this because you expect this group to react differently to an intervention than other people?Remember: once you have defined your eligibility criteria, you can also identify other differences of interest that you would like to explore in the review.
11Gemischte Populationen Studien, in denen nur ein Teil der TeilnehmerInnen die Auswahlkriterien erfülltz.B.: Sie wollen Kinder bis zu 16 Jahren einschließen, finden aber eine Studie die Kinder bis zu 18 Jahren eingeschlossen hatWas entspricht am ehesten den Zielen des Reviews?Gesamte Studie inkludierenEin Grenzwert kann bestimmt werden (z.B. 80%, oder die Mehrheit)Nur diejenigen StudienteilnehmerInnen miteinbeziehen, die Einschlusskriterien erfüllenSeparate Daten sind in der Publikation vielleicht nicht angegebenGesamte Studie ausschließenBereits in der Protokollphase überlegen und angeben wie mit solchen Studien umgegangen wirdSometimes a study includes some ‘eligible’ participants and some ‘ineligible’ participants, for example when an age cut-off is used in the review’s eligibility criteria. In this situation, how will you apply your eligibility criteria? Should the study be included or excluded?You have several options for how to treat populations where only a subset meets your criteria: 1. You could include the whole study – although this will mean some participants who don’t meet your criteria will be excluded, it means you won’t lose all the information about those participants who do meet your criteria. You may wish to select a threshold or cut-off point for this – for example, you could decide to include any study in which at least half, or at least 80% of the population meets your criteria.2. You could decide to only include information on those participants who meet your criteria. This ensures that you don’t include any information from ineligible participants. However, detailed information on which participants met your inclusion criteria and separate results for those participants may not be available. You can try asking the authors of the study for separate information, but you may not be able to obtain it.3. Finally, you can decide to exclude the whole study. That is, you can decide that the risk of including some inaccurate information from ineligible participants outweighs the benefit of including the study at all.If possible, it is good practice to specify in your protocol how you plan to manage studies where only some of the participants meet your eligibility criteria, particularly where you know there are many mixed studies in your field (such as reviews of joint replacements that often combine kip and knee replacements), or where you have given a cut-off point (such as an age group) that you know will not always match the cut-off points of your included studies. A rationale should be given for why you have chosen a particular approach.Remember that it’s not always possible to predict when this situation will arise, and that in some cases, although post hoc decisions should be avoided, it may be better to consider studies on a case by case basis, rather than stick to an arbitrary rule. When making post hoc decisions, you should consider the overall aims and rationale for defining the scope of your review, and your decisions should be documented in your review. You may wish to conduct a sensitivity analysis on your results to assess the impact of your decisions on the review’s findings.
12Gleichstellung und spezielle Populationen Überlegen Sie, ob Fragen der Gleichstellung (equity) und unterschiedlicher Relevanz für spezielle Populationen für Ihren Review wichtig sindz.B. Geschlecht, Alter, Ethnizität, geographische Herkunft, ökonomischer Status, Ausbildung, etc.Warum?unterschiedliche Prävalenz, Fortschreiten und Auswirkungen der Erkrankungunterschiedliche Wirksamkeit oder Sicherheit der Interventionunterschiedliche Wichtigkeit von EndpunktenCochrane reviews seek to be relevant internationally and across contexts, and it’s important to consider your question in relation to all the different types of people who may be affected. You may need to plan additional methods in your review to ensure these questions are addressed.Prevalence and progress – e.g. antibiotics for sore throat – may not be useful in high-income settings, where impact of the disease is not great. In some low-income countries there is a greater likelihood of progression to rheumatic fever, with very serious consequences, such that you might come to a different conclusion about the importance of intervention.Different effects or safety – e.g. some interventions may work differently in different cultural settings (e.g. communication and education interventions), or there may be biological differences in the way interventions work among different ethnic groups, in women compared to men, or in children compared to adults.Different outcomes of importance – e.g. for interventions in children, developmental milestones or attendance at school may be important outcomes that don’t apply to adults. You may need to measure outcomes differently in some populations, e.g. measuring pain in newborn babies. The cost of an intervention may be very important for people without health insurance, or for policy makers planning implementation in resource-poor settings. The duration of treatment required may be important for participants in rural settings who travel long distances to access treatment.Although these may not form part of your eligibility criteria, they will assist you in considering other aspects of your question as you plan your review.
13Intervention Geben Sie so viele Details wie möglich an Zusammensetzung Dosis, IntensitätApplikationsweiseZeitablauf, Häufigkeit, DauerAusstattungPersonal (Qualifikationen, Ausbildung)Standort, Kontextalleine oder in Kombination mit anderen InterventionenJegliche Einschränkung sollte klar begründet seinAlternativ kann man breitere Einschlusskriterien wählen und später Subgruppenanalysen durchführenNext, you will need to describe the intervention in enough detail to distinguish your intervention of interest from those interventions that fall outside the scope of the review.So, if your review is looking at a very specific topic, such as a specific dose of a specific drug, you can be very narrow in your definition. If you are looking at a more general topic, such as a class of drugs, or a more complex, multi-component intervention, you can be less detailed in your criteria, allowing for expected variations in the literature. However, you must be able to clearly identify the core or common factors that determine whether each study, each variation, falls within the review, or is so different that it should be excluded – whether this is a minimum clinically effective dose or duration of drug treatment, or essential components of a complex intervention.Based on the objective of your question, think carefully about the advantages and disadvantages of including studies that test your intervention in combination with other interventions. If you are interested in the direct effects, say, of phsyiotherapy for shoulder pain, then a study that looks at physiotherapy in conjunction with painkillers will not answer that question, because the effects of physiotherapy are confounded with those of painkillers . Alternatively, you might be interested in the effects of multi-component interventions, in which case a study of physiotherapy plus painkillers might be appropriate.It is particularly important to be as clear and informative as you can when describing complex interventions, such as multi-component clinical interventions like rehabilitation programs, educational or behavioural interventions, community-based interventions, etc. These are often poorly described in the literature, which makes it difficult to make decisions about inclusion, and difficult for users of the review to implement the intervention if it is found to be effective.
14Standort und Kontext Siehe Abschnitt 12.3.3 im Handbuch Interventionen können in bestimmten Kontexten funktionieren, in anderen nichtVerfügbarkeit und ZugänglichkeitAusstattungErfahrung und fachliche Kompetenz des verfügbaren PersonalsKonkurrierende Prioritäten vor OrtVergütungssystemKulturelle und sprachliche DiversitätSozioökonomische StellungLändliches/urbanes SettingAgain, it’s important to consider your intervention and how it might be applied internationally, and in a variety of contexts. Interventions may work differently in some contexts, or need to be applied differently.Factors you may wish to consider can include:whether the intervention is available in every context, or does it depends on specialised equipment itself that may not be available, where that’s an expensive scanning machine or something simple like running water?are there specific skills or training that the staff implementing the intervention will need? Will different staff be implementing the intervention in different settings?is the intervention acceptable in all cultural contexts, and will it work the same way?is the intervention affordable to people with different incomes, or under different insurance systems?Siehe Abschnitt im Handbuch
15Vergleichsintervention Basierend auf der Zielsetzung des ReviewsBeschreiben Sie Vergleichsinterventionen genauso detailliert wie die InterventionLegen Sie detailliert fest, was Sie unter ‘keiner Intervention’ verstehenz.B. keine Intervention, Placebo, übliche Behandlung, etc.Man kann alle Vergleichsmöglichkeiten zulassen, sollte dies jedoch explizit darlegenThe comparisons you’re testing against your intervention of interest should be clearly based on the objective of your review question.If you review is comparing the intervention against a specific active alternative (or more than one), e.g. one drug versus another, or health professional versus peer-led interventions for mental illness, the comparisons should be described in as much detail as the intervention. You may be interested in the effects of caffeine compared to any alternative intervention, or no intervention at all. In which case, you don’t need to specify a specific comparison for your eligibility criteria.Even if your objective is to test your intervention against no intervention, remember that may be important differences between inactive comparisons – such as truly doing nothing, or using a placebo, or leaving in place whatever ‘usual care’ is for this population. Remember, too, that ‘usual care’ may vary a lot from study to study, so plan to examine these differences carefully if this applies to your review.Again, remember to consider the real choices available to people making decisions in this area – what are the options currently available in different contexts? Have some intervention options become obsolete (remembering that interventions that are obsolete in high-income countries and large urban hospitals may still be in use in other places)?If your review is broad, you can choose to include studies comparing your intervention to any possible comparison – if that’s the case, make sure you state this clearly.
16Endpunkte Selten Teil der Auswahlkriterien Auschluss von Studien aufgrund nicht-berichteter Endpunkte kann zu Bias führenStudienautorInnen könnten Endpunkte selektiv berichtet habenZusätzliche Informationen sind eventuell erhältlichAls Auswahlkriterien angemessen, wenn Endpunkte wichtig im Hinblick auf die Definition der Fragestellung sindz.B. Prävention vs Behandlung; Interventionen, die bei mehreren Gesundheitsproblemen angewendet werdenLegen Sie Ihr Vorgehen eindeutig im Protokoll festMoving on to outcomes, note that it is not always expected that outcomes will form part of the eligibility criteria for a review. Commonly, studies that do not measure your outcomes of interest are still included and noted in the review, although they cannot contribute to your analysis of those outcomes. It is important to include these studies so that you are presenting a complete picture of the literature.It’s particularly important to consider the possibility of outcome reporting bias.ASK: Can anyone explain the meaning of outcome reporting bias?You are probably familiar with the concept of publication bias – that is, studies with positive or significant findings are more likely to be published than non-significant studies. That also applies within studies to the reporting of results for individual outcomes - outcomes with positive or significant findings are more likely to be fully reported in a paper, which means they’re more available to be included in your review. Given that, it’s important to consider the possibility that your outcomes of interest may have been measured by a study, even if they were not reported. By excluding these studies without exploring further, you run the risk of introducing bias to your review. Don’t forget, also, that it may be possible to contact the authors of a trial and obtain additional information for these studies.In some cases it is appropriate to include the outcomes in your eligibility criteria – for example, if you are interested in prevention, then your included studies must measure prevention, and not only treatment outcomes. For interventions with many applications, you may wish to define your review to cover one particular field – the Cochrane Library currently has separate reviews looking at hormone replacement therapy for menopausal symptoms, for cardiovascular outcomes, and cognitive outcomes.Whether your outcomes are part of the eligibility criteria or not should be clearly stated in your protocol.Quelle: Dwan K, Gamble C, Kolamunnage-Dona R, Mohammed S, Powell C, Williamson PR. (2010) Assessing the potential for outcome reporting bias in a review: a tutorial. Trials. 11:52
17Endpunkte Legen Sie aussagekräftige Endpunkte fest Für KonsumentInnen, GesundheitsexpertInnen, und politische EntscheidungsträgerInnenNebenwirkungen berücksichtigenRelevanz für verschiedene PopulationenWichtige ErhebungszeitpunkteAkzeptable Messinstrumente für Endpunkte (z.B. Definitionen, Skalen)Triviale Endpunkte vermeiden (z.B. biochemische, Surrogatendpunkte)Berücksichtigen Sie standardisierte Endpunkte (core outcome sets) und Endpunkte, die in ähnlichen Reviews verwendet wurdenGegebenenfalls Auswahl eines Endpunktes aus mehreren ähnlichen EndpunktenWichtige Endpunkte sollten im Protokoll und Review enthalten sein, unabhängig davon ob später Daten dazu gefunden werdenEven if outcomes are not part of your eligibility criteria, you should identify the outcomes you plan to assess in your review. Plan to report outcomes of importance to people making decisions, starting with those people who are affected by the condition, and those who are making decisions about care. It’s important that you plan in advance which outcomes you will report, to minimise bias in the selection of outcomes when you come to complete the review. Some fields have articulated key outcomes, such as the work done by OMERACT for rheumatology studies – if so, take advantage of these standards. If not, you may wish to look at other reviews in similar areas to see the outcomes they report.Don’t forget to always include possible adverse effects.You might consider how outcomes might be measured – for example, are there published, validated measurement instruments for your outcomes? Consider the variety of ways in which an outcome may be measured and reported in the studies you find, and only be restrictive if you have a good rationale – for example, the latest validated test might be the best, but if it was only released last year, or has not been widely adopted internationally, it may exclude the majority of studies.You may also specify important time points for the measurement of outcomes. Is there a minimum period of time before you could expect the intervention to have an effect? e.g. interventions to improve bone density will take longer than a few weeks. Also, systematic reviews authors are often confronted with a variety of measurement time points in their included studies. One study may have measured at 2 weeks, another at 3, a few at 5, and a few more at 7. Rather than dividing the data up into so many small categories, you may wish to pre-specify some categories for your outcomes – for example, short term outcome less than one week, medium term outcomes between 1-8 weeks, and longer term outcomes. These categories should be based on your clinical judgement about meaningful groups – does it make sense to ask a broad question about these time periods, rather than splitting your results up to each individual time point?Select your outcomes based on the information you think is important, not based on what you think you will find in the literature. For example, if you’re interested in mortality, include that as an outcome, even if it’s a long-term outcome that few studies will measure. Short-term surrogate outcomes, such as biochemical markers or improvement in the regularity of heartbeat, may be easier to measure, but don’t always correspond to longer-term outcomes in the way you expect. Process outcomes should also be used with caution – those that report on the way an intervention was implemented, rather than its outcomes, but remember that information on implementation and the use of resources can be important to health professionals and policy makers in determining whether the intervention is feasible for them to use in practice.A useful resource to help you identify good outcome measures can be core outcome sets – agreed sets of useful measures that researchers are encouraged to use in particular fields, such as the OMERACT initiative in rheumatology. If your field doesn’t have an agreed set of measures, you might like to consider the outcomes that have been measured by your colleagues writing reviews on related topics.Something you will need to consider is the possibility that your included studies will report multiple similar outcomes – leaving you with a choice of which to report in your review. For example, if a study reports outcomes at 2, 4 and 6 weeks, are these all unique and useful measurements, or should you select one outcome to represent short-term effects for that study? What is a study uses several similar measurements, such as different tests for range of motion, quality of life scales, or measures of overweight, such as weight, BMI, waist circumference, etc.? It’s important to have a plan to deal with this possibility, to avoid making selective decisions later on, such as choosing the measure that gives you the largest significant effect. Principles you can use to help make your plan include some of the things we’ve mentioned already – are some outcomes more meaningful than others? Are some of them more commonly used across the literature? If these principles don’t help, you may need to give yourself a method of choosing a representative outcome that avoids selectivity, such as choosing the outcome with the median effect size of the group.Finally, you will be expected to report on all your planned outcomes in the final review, even if you don’t find any studies that measure some outcomes – picking and choosing outcomes based on those with good available data can introduce bias, and reporting that outcomes of importance have not been adequately measured is a useful finding.
18Endpunkte priorisieren Primäre Endpunkte (max 3)Sollte zumindest einen Schadensendpunkt enthaltenSekundäre EndpunkteÜbrige wesentliche EndpunkteAndere Endpunkte von geringerer PrioritätWesentliche Endpunkte (max 7)Auschlaggebened für den EntscheidungsprozessGrundlage für Analysen und ZusammenfassungenYou should specify a small number of primary outcomes, that will form the basis of the conclusions of your review, including at least one potential harm.The rest of your outcomes will be considered secondary outcomes, but keep in mind that the total number of outcomes to be addressed should be kept as small as is reasonable for your question, and focus on those outcomes that are important for decision-making.It’s important to prioritise your outcomes to help you in reporting the results of your review, particularly when it comes to summarising your results. Cochrane reviews have a range of short formats to summarise results, such as the abstract, plain language summary, or Summary of Findings table of your review. You may not be able to report against all your primary and secondary outcomes in each summary, so we recommend that you identify a group of outcomes – including your primary outcomes and perhaps a small number of your secondary outcomes – that can be designated as your main outcomes, and included in any summary of your results.These should be the outcomes that are most important for decision-making, whether or not you expect to find enough data in the literature. Also, try not to duplicate within your main outcomes – avoid including multiple variations on the same outcome (e.g. weight, BMI), or measures of the same outcome at multiple time points, without a clear rationale. Additional variations and time points can be included among your other secondary outcomes.
19Besondere Endpunkte Informationen und Empfehlungen sind verfügbar Cochrane Adverse Effects Methods GroupCochrane Patient Reported Outcomes Methods GroupCampbell and Cochrane Equity Methods GroupCampbell and Cochrane Economics Methods GroupCochrane Qualitative Research Methods GroupSieheAt these early stages, it’s appropriate to consider whether the important outcomes for your review incorporate some of these outcome types. Cochrane reviews allow for more in-depth consideration of outcome types that are commonly encountered, such as adverse effects and issues of equity. Alternatively, you may wish to incorporate specialised outcome types such as economic or qualitative evidence.Consideration of these topics may require additional systematic literature searching, and more advanced analysis methods. These topics will not be covered in depth in this course, but further information is available in the Handbook, and on the websites of the Methods Groups who contribute to the Cochrane Collaboration in these areas – website details are available on the cochrane.org website.Siehe Kapitel 14,15,17,20 im Handbuch
20StudiendesignsWählen Sie das Design, das für Ihre Fragestellung am geeignetsten istBegründen Sie Ihre Entscheidung immerFür die meisten Cochrane Reviews gilt:Randomisierte kontrollierte Studienbeugt systematischen Unterschieden zwischen den Gruppen vormanchmal auch kontrollierte klinische Studien (quasi-randomisiert)ASK: who was under the impression that Cochrane reviews only include randomised trials?In fact, Cochrane reviews mostly include RCTs, but in some cases we do include other study designs. We always aim to include the most appropriate study designs to answer the review question. For straightforward questions about the effects of interventions, that will usually be RCTs. Methodological research tells us that RCTs are the best way to avoid bias introduced by systematic differences between the groups in a study. If RCTs are feasible for your intervention, then they should always be included in a Cochrane review.Usually that’s the only design you’ll need to specify in your eligibility criteria, although you should always give rationale for your choice of study design, even if you’re using standard RCTs. In some cases you might want to be specific about an aspect of study design for example if you wish to specifically exclude crossover trials from your review , or in some cases we also include quasi-randomised trials (those trials with methods of allocation that are almost random but not quite, such as alternating allocation).
21Nicht-randomisierte Studien Braucht die Zustimmung Ihrer Review-GruppeEindeutige RationaleRCTs sind ungeeignet oder kaum umsetzbar (z.B. Public Health, komplexe Gesundheitsystemfragen)Enthalten Daten zu bestimmten Endpunkten (z.B. Nebenwirkungen, ökonomische, qualitative Endpunkte)Fehlen von RCTs sollte nicht der alleinige Grund seinSpezielle Studiendesigns werden bevorzugtz.B. kontrollierte Vorher-Nachher-Studien, unterbrochene ZeitreihenBeschreiben Sie das Studiendesign anhand wichtiger Elemente anstatt es nur zu benennenMindestkriterien an das Design sollten erfüllt werdenBeachten Sie das erhöhte Bias-RisikoSome Cochrane reviews will look at non-randomised studies – usually in addition to, and occasionally instead of RCTs. You must have a clear rationale for doing this – that is, why would RCTs not be able to provide this evidence? It is not enough to say that you don’t believe there are any RCTs measuring this outcome. If an RCT is the most appropriate way to measure an effect, but there are none, then Cochrane reviews can conclude that there is no appropriate evidence, and that new studies should be conducted. Unlike a guideline or a local policy, we are not obliged to provide a recommendation if we don’t believe the evidence is sufficient.However, in some cases other study designs are appropriate to answer questions. For example, in some cases RCTs may not be appropriate, e.g. where they might be unethical, or seriously impractical, such as in the case of large-scale changes to health system structures, or public health interventions across whole communities or even countries.There are also some outcomes that RCTs are not able to measure well. RCTs are not always good at measuring adverse effects, particularly rare or long-term effects. In those cases, you might need to look for cohort or case-control studies, perhaps government monitoring data, etc. If you’re incorporating economics or qualitative data in your reviews, these have their own study designs that you may wish to consider. These kinds of studies aren’t usually incorporated in your primary analysis of the effectiveness of the intervention, but can be used to inform and interpret the results.ASK: Is anyone planning to include non-randomised studies in their review?Whenever you plan to include non-randomised studies, you must have the agreement of your CRG – not all CRGs will be happy for you to do this. You should also specify which non-randomised designs you will include. Further advice on this is available from your CRG, including recommended minimum design criteria for non-randomised studies. Make sure when you list study designs that you are always clear and unambiguous – we recommend describing elements of the study’s design, rather than labels like ‘prospective” or “observational”. Even terms like “cohort” and “case control” can refer to a wide range of designs, and different authors will use terminology differently. Make sure you specify exactly what you mean, so that when you come to compare a published study to your eligibility criteria, you can be sure whether it meets the criteria or does not, even if the author is using labels that are unfamiliar to you or has used an unusual variation on a common study design.Whenever you’re including non-randomised studies, you must be aware of the increased risk of bias in the results. Make sure you are familiar with the risks, how to assess them, and how best to analyse the results of these studies.Siehe Kapitel 13,14,15,20,21 im Handbuch
22Von der Fragestellung zum Titel Cochrane-Titel haben Standardformate‘Intervention’ bei/gegen ‘Gesundheitsproblem’Antibiotika bei akuter BronchitisBevölkerungsbezogene Interventionen zur Steigerung der körperlichen AktivitätKann auch andere Details beinhalten:Unmittelbare versus verzögerte Behandlung von zervikaler intraepithelialer NeoplasieInhaliertes Stickstoffmonoxid bei respiratorischer Insuffizienz bei FrühgeborenenEinzäunung von Pools zur Vorbeugung von Ertrinken bei KindernThe titles of Cochrane reviews are usually based on the standard format: ‘intervention’ for ‘population’. In some cases there are variations, for example if you wish to include a specific comparison, a specific population, or if yours is a review of a prevention rather than treatment intervention. This will be agreed with your CRG at the title registration stage.
23Übersicht Bedeutung einer klar definierten Review-Fragestellung Komponenten einer FragestellungWas sollte das Protokoll beinhalten?
24Was sollte das Protokoll beinhalten? HintergrundDetaillierte Beschreibung des Gesundheitsproblems und der InterventionMethodenKriterien für die Berücksichtigung von Studien im ReviewKlare Beschreibung der AuswahlkriterienGeplanter EndpunkteDatensammlung und -analyseGeplante SubgruppenanalysenThere are several places in your protocol where the details of your question are explained. In the Background, you can give your detailed descriptions of the condition of interest, including the burden of disease, the population, and how the condition affects people.In the Methods section, your eligibility criteria are listed in the section called ‘Criteria for considering studies for this review’. Your list of outcomes to be reported is also included here, even if they are not part of your eligibility criteria.Finally, those additional factors and variations that you want to explore within your review can be planned as subgroup analyses in the section called ‘Data collection and analysis’. We’ll be talking in more detail about analysis methods in separate sessions.
29FazitÜberlegen Sie sich den thematischen Umfang Ihres Reviews genau bevor Sie beginnen (z.B. Mithilfe des PICO-Schemas)Verwenden Sie diese Information um klare und eindeutige Auswahlkriterien festzulegenDiese Information hilft Ihnen auch beim Entwickeln der richtigen Suchstrategie, Datensammlung und –analyse
30QuellenO’Connor D, Green S, Higgins JPT (editors). Chapter 5: Defining the review question and developing criteria for including studies. Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version [updated March 2011]. The Cochrane Collaboration, Available fromDanksagungZusammengestellt von Miranda CumpstonBasierend auf Unterlagen des Australasian Cochrane ZentrumsEnglische Version freigegeben vom Cochrane Methods BoardÜbersetzt in Kooperation zwischen dem Deutschen Cochrane Zentrum (Jörg Meerpohl, Laura Cabrera, Patrick Oeller), der Österreichischen Cochrane Zweigstelle (Barbara Nußbaumer, Peter Mahlknecht, Isolde Sommer, Jörg Wipplinger) und Cochrane Schweiz (Erik von Elm, Theresa Bengough)