Study design
This systematic review will apply both aggregative and configurative approaches[9]. Aggregative reviews are seeking evidence to inform decisions and make statements by collecting empirical data. The interest of configurative reviews is more in examining the complexity and range of different concepts than “in seeking a single correct answer”[9]. To examine the variation in and complexity of different research approaches (objectives 1 and 3), we will mainly use configurative methods. The information, attained from included studies, will serve to consolidate existing concepts and develop new insights about the health situation of asylum seekers. The review contains aggregative elements for analyzing collected data in a realist synthesis, which answers objective 2. An evidence map will be created with the aim of describing the research field and to structure and interpret the following synthesis.
The development of the protocol was informed and guided by the “EPPI-Centre guidelines”[10], the “Cochrane Guidelines for Systematic Reviews of Health Promotion and Public Health Interventions”[11], the “CRD’s Guidance for Undertaking Reviews in Health Care”[12], and “Systematic Reviews in the Social Sciences. A Practical Guide”[13].
The report of our systematic review will adhere to “PRISMA-Equity 2012 Extension: Reporting Guidelines for Systematic Reviews with a Focus on Health Equity”[14] as far as applicable to give special consideration to the aspect of equity.
Search method for identification of studies
In the first step we will search in databases for relevant articles fulfilling pre-defined inclusion criteria. Following that, we will perform a screening of the citing and cited references of all included articles.
Strategy 1: search databases
We developed the search strategy according to “Cochrane Handbook for Systematic Reviews of Interventions”[15]. The following electronic databases will be searched for studies and reviews:
The search terms (refugee* OR asylum*) AND (health* OR access OR utilization OR use) AND german* are searched for in the articles’ title, abstract, and key words. For databases providing publications in German language, we will use the search terms (Asyl* OR Flüchtling*) AND Gesundheit*.
Further searches will be conducted by using web search engines (Google) to include grey literature articles, which give essential information but are not published in journals. To limit the number of hits to the relevant ones, we will search for (Asyl* ODER Flüchtling*) UND (Gesundheit ODER Gesundheitsversorgung) UND (Studie ODER qual* ODER quant*) and (refugee* OR asylum*) AND (health* OR access OR utilization OR use) AND german*. The Google search will be conducted in three steps: first, screening all hits; second, we will search for .pdf files only, followed by a search for .doc files only.
Additional searches will be performed on websites of NGOs to increase the sensitivity of our search strategy.
An overview of the final search term combinations which will be applied for searching each database is available in Additional file1
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Strategy 2: searching in the selected articles
We will view the reference lists of all included publications. Moreover, we will use backward and forward citations for Web of Knowledge for all publications included at the end of the screening process.
Strategy 3: contacting experts, individuals, and non-governmental organizations
We will contact experts, authors of identified studies, and non-governmental organizations to identify grey literature.
Selection of studies-eligibility criteria
Broadly spoken, all empirical studies that use a sample of asylum seekers will be included regardless of the research question as long as they report a health outcome or an outcome measure related to health-care provision.
Inclusion criteria
More specifically, we will include studies which fulfill the following criteria:
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Type of population: refugees and asylum seekers (studies on “migrants” will be included only if a clear distinction is made between “refugees and asylum seekers” and other forms of migration in analysis and reporting of data).
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Types of studies: we will include all published empirical materials, including qualitative studies (in-depth interviews, semi-structured interviews, focus groups, ethnographies, participatory action research) and quantitative studies (cohort and case-control studies, cross-sectional studies, descriptive surveys, studies using routine/secondary data as long as health outcomes or health-care provision aspects are addressed), as well as mixed-methods studies. Unpublished material will only feed into the review if the review team is granted full access to the reports. Since many studies might not be analytical in nature, we explicitly consider descriptive surveys for inclusion provided that sufficient information on data collection and analysis is provided.
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Types of articles: original articles and review articles, including systematic and narrative reviews (of qualitative and/or quantitative research). Authors of relevant conference abstracts will be contacted for full research reports. If available, they will be included in the review.
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Type of outcome measure:
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○ Health: including all criteria of WHO definition [16]: physical, mental, and social well-being
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○ All aspects of health-care provision (i.e., accessibility, availability, affordability, and quality of health care)
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Geographical area: studies conducted in Germany or studies giving account of asylum seekers’ experiences in Germany (even if they do not reside anymore in Germany during the conduct of the study)
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Date of publication: initial search without limitation, mapping, and synthesis will be performed by distinguishing between studies pre-1993 and post-1993 due to major changes in legislation in 1993.
Exclusion criteria
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Type of population: migrants without clear reference to asylum seeker status/refugee status
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Types of articles: commentaries, discussion papers, journalistic interviews, policy reports, books, conference proceedings, abstracts
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Type of outcome measure: studies assessing social situation without clear link to health understood as physical, mental, and social well-being
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Geographical area: studies conducted on asylum seekers outside Germany and/or where the primary focus is not their situation while they resided in Germany
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Articles not published in German or English
Screening process
The screening process will be conducted in two steps:
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1.
Screening titles and abstracts
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2.
Screening full texts
Title and abstract screening
Two reviewers will independently screen 10% of the articles by title and abstract resulting from the search process (after exclusion of duplicates) and assess them for inclusion using the a priori defined criteria. If necessary, inclusion and exclusion criteria will be re-defined based on this initial screening before screening all articles. Subsequently, all article titles and abstract will be screened in duplicate using the (potentially re-defined) inclusion/exclusion criteria. Eligibility for inclusion from both the initial and subsequent screening process will be recorded in an Excel File/EndNote database. Discrepancies in judgements on eligibility will be solved by discussion in the review team. If discrepancies in judgement on eligibility exist in absence of clear exclusion criteria, we will obtain all publications as full text that are deemed relevant by at least one reviewer.
Full text screening
We will obtain the full text of all the references included after title and abstract screening. All files will be incorporated to a bibliographic database (EndNote). Two reviewers will independently read the full text of the previously selected articles and assess eligibility for inclusion. Disagreements will be discussed in the review team and only references judged as eligible by all will be included.
Screening of citations
Finally, for the publications included after the screening process (i.e., for all publications meeting the inclusion criteria), we will review the references which are cited by and cite our “relevant articles”. Furthermore we will screen all articles received by experts, authors of identified studies, and non-governmental organizations. They will also be screened by using the stages described above (title, abstract, and full text) with the same inclusion and exclusion criteria.
Sensitivity and specificity of search strategy and selection process
We will assess the specificity (false-positives: excluded articles divided by all identified hits from the search results) and sensitivity (false-negatives: eligible articles not identified by our search strategies) using a test set of articles at hand of the authors prior to conducting the systematic review (Additional file2).
Data extraction and critical appraisal
Data extraction and critical appraisal will be conducted simultaneously and be piloted against a random sample of the included articles by two reviewers.
Data extraction
We have designed preliminary data extraction forms based on the STROBE and QOREC checklists for quantitative and qualitative studies, respectively, adapted to the specific characteristics of this review (Additional file3 and Additional file4). The data extraction forms include the following items:
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Generic bibliographic information (author, year published)
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Study characteristics (year of study/study period/research method)
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Study objectives/research questions
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Population and context characteristics
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Health condition (physical and mental health/social well-being) and/or health-care provision domain analyzed or explored
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For quantitative studies: exposures and co-variables on individual and/or contextual level, as well as measures of frequency/association for the analyzed outcomes
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For qualitative studies: major themes/minor themes as reported
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Results of the critical appraisal
Further details on the type of data we seek to extract from quantitative/qualitative studies are provided in Additional file3 and Additional file4. The preliminary data extraction form for reviews can be found in Additional file5. Modifications in the data extraction forms are expected after the pilot study. Given the broad research questions, an iterative approach in developing and refining the data extraction form will be more adequate than a pre-defined fixed approach. All the reviewers will participate in the data extraction. Of the selected articles, 50% will be extracted by AM, the other 50% will be extracted by CS. All articles will be checked vice versa and will be checked by random sampling by SJ and KB. Disagreement will be resolved by discussion until consensus is reached. All extracted data will be recorded in a transparent and systematic way which will be detailed in the review report.
Critical appraisal
Different types of included studies need to be critically appraised with appropriate appraisal tools for the study design. Critical appraisal of selected quantitative studies will be conducted by means of the Quality Assessment Tool for Quantitative Studies of the Effective Public Health Practice Project (EPHPP) (see Additional file6). Mixed-methods studies will be judged by the McGill Mixed-Methods Appraisal Tool for Mixed-Methods Studies[8] (see Additional file7). The quality of reviews will be appraised using the AMSTAR tool, a validated 11-item tool to assess the quality of systematic reviews[17]. The tool will also be applied to non-systematic reviews in order to assess the quality of included reviews against the ‘gold standard’ of a systematic review. Non-applicable items will not be weighted in order to avoid undue judgements on the quality of non-systematic reviews raised by the (potential) non-applicability of AMSTAR items.
There is currently no consensus among qualitative researchers on the role of quality criteria and how they should be applied, and there is ongoing debate about how study quality should be assessed for the purposes of systematic reviews[13, 18]. Prior to the review process, a selective literature review has been conducted by the review team to identify the most suitable assessment tool for the quality appraisal of qualitative studies, which will be included in our systematic review. We followed the Cochrane guidance for “Critical Appraisal of Qualitative Research”[19, 20] and agreed on the use of the Critical Appraisal Skills Programme (CASP) for qualitative studies (see Additional file8 for CASP Screening Questions). The reasons for applying CASP are as follows:
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It is widely used in similar reviews and recommended by Cochrane guidance and the guidance of the Center for Reviews and Dissemination (CRD).
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It contains only 10 items for rapid evaluation.
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It is suitable for different types of qualitative studies.
The critical appraisal process will not lead to exclusion of papers, but rather serves as one of several other criteria to evaluate the body of evidence.
Analysis of findings
Summary table
One or more tables will be drawn up containing condensed information from the data extraction forms (i.e., a description of included studies, study populations, methods, analyzed health outcomes/health-care domains, results, and quality).
Evidence map
In the next step, we will create a thematic and conceptual evidence map to illustrate the research landscape and identify research gaps. To this end, all included articles will be grouped and categorized by year of data collection (pre- vs. post-1993), research design (quantitative/qualitative/mixed methods), and the analyzed health conditions and/or health-care domains. In its descriptive way, this map will address objectives 1 and 3 by providing a systematic description of available research. The body of evidence (in particular, related to objective 3) will be evaluated by the following criteria: the number of studies analyzing the same outcome(s) (quantitative studies) or exploring the same topic (qualitative studies), overall quality and risk of bias (quantitative studies)/credibility (qualitative studies), external validity (quantitative studies)/saturation and transferability (qualitative studies), and consistency of findings across studies. Any modifications to this protocol will be made transparent and documented in the final review report.
Evidence synthesis
As our review question dictates the inclusion of many different research designs, we will follow the recommendation to use a primarily “narrative synthesis”[21] to answer review question 2. Despite the absence of procedures and standards, the narrative synthesis allows flexibility and coping with large evidence base, comprising diverse evidence types. Beginning with a quantitative analysis, the included studies will be organized and presented in logical categories by study design. We decided to apply a multi-level approach (according to Cochrane Handbook for Systematic Reviews of Interventions[20]), where quantitative evidence (synthesis 1) and qualitative evidence (synthesis 2) are synthesized as separate streams and the product of each synthesis is then combined (synthesis 3).
If possible, we will conduct a meta-analysis to summarize the findings of quantitative studies which analyze the same outcome.
As there are no standard approaches for the synthesis of qualitative data[13], we will combine a descriptive synthesis with a narrative elaboration of the patterns identified in qualitative studies. Narrative descriptions of each included article will provide a short, clear summary of information on a range of process and outcome measures. We will then combine separate elements to form a coherent whole, a synthesized finding of qualitative research (interpretative synthesis).
In the third synthesis, we will integrate the findings of all primary studies (quantitative and qualitative ones), taking into account variations in study design, context, and study quality.
This final configuration of synthesized findings will be a summary of knowledge about the health status of and health-care provision to asylum seekers in Germany, as generated by empirical studies.The overall design and process of this review is shown in Figure 1.
