Communicating cardiovascular risk: Systematic review of qualitative evidence.

INTRODUCTION: Cardiovascular risk prediction models are widely used to help individuals understand risk and make decisions. METHODS: Systematic review of qualitative evidence. We searched MEDLINE, Embase, PsycINFO and CINAHL. We included English-language qualitative studies on the communication of cardiovascular risk. We assessed study quality using Hawker et al.'s tool and synthesised data thematically. RESULTS: Thirty-seven studies were included. Many patients think that risk scores are of limited practical value. Other sources of information feed into informal estimates of risk, which may lead patients to reject the results of clinical risk assessment when the two conflict. Clinicians identify a number of barriers to risk communication, including patients' limited understanding of risk and excessive anxiety. They use a range of strategies for adapting risk communication. Both clinicians and individuals express specific preferences for risk communication formats. DISCUSSION: Ways of communicating risk that provide some comparison or reference point seem more promising. The broader context of communication around risk may be more important than the risk scoring instrument. Risk communication interventions, in practice, may be more about appeals to emotion than a rationalistic model of decision-making.

Can Peer-based Interventions Improve Adolescent Sexual and Reproductive Health Outcomes? An Overview of Reviews.

PURPOSE: An overview of reviews was conducted to summarize the evidence and synthesize the results from systematic reviews. METHODS: The Cochrane and Preferred Reporting Items for Overviews of Reviews reporting guidelines were followed and the protocol was registered. Electronic and manual searches were conducted to identify systematic reviews, published between January 1990 and July 2022. Studies with outcomes relating to all areas of adolescent sexual and reproductive health (SRH) (changes in knowledge, attitudes, beliefs, skills, and practices) were considered. The ROBIS (Risk of Bias in Systematic Reviews) tool was used to assess quality. RESULTS: A total 1849 articles were retrieved, and eight reviews met the inclusion criteria. Three of the eight reviews included meta-analyses. All three of these reviews demonstrated a significant improvement in HIV knowledge. One reported improved attitudes toward people living with HIV but none found any statistically significant effect on condom use or other SRH behaviors. The remaining five reviews included reports of positive individual study outcomes related to knowledge and attitudes and provided narrative syntheses with regard to recruitment, training, support, and participation of peers. Five of the eight reviews were judged to have a low risk of bias. DISCUSSION: Our overview demonstrates that peer-based interventions can improve SRH knowledge and attitudes. Evidence of their effectiveness in promoting healthier SRH behaviors is less certain. Any future studies need to investigate which adolescent health outcomes peer-based programs could reasonably be expected to improve using robust methodologies. Additionally, peers need to be meaningfully engaged and acknowledged as experience-based experts.

Comparison of national surveillance systems for Lyme disease in humans in Europe and North America: a policy review.

BACKGROUND: Lyme disease incidence is increasing in Europe, the USA, and Canada. In 2010, a comparison of surveillance systems for Lyme disease (LD) in humans in 28 European countries showed that systems highly varied, making epidemiological comparisons difficult. Details by country were not published. In 2018, one of LD clinical manifestations, neuroborreliosis, was added under European Union (EU) surveillance to standardise definitions. In this study, we identified and compared, 10 years after the European inventory, the characteristics of national surveillance systems and policies for LD in humans, with additional countries. METHODS: Thirty-four European and North American countries were included. Information on national "traditional" systems (which compile data reported by clinicians and laboratories) and "public participatory" websites and mobile applications (which collect information directly from the public) were searched in MEDLINE, a systematic evidence map, and Google. An existing framework on LD surveillance was adapted to capture information on the administration level, indicators, reporting entities, coverage, and obligation to report. RESULTS: A surveillance system was found for 29 (85%) countries. Twenty-four had a traditional system alone, one had a public participatory system alone, and the remaining had both. Among countries with traditional systems, 23 (82%) administered them at the national level. Nineteen (68%) required mandatory reporting. Sixteen (57%) used both clinicians and laboratories as reporting entities. Eighteen (64%) employed case definitions, most of which considered both neuroborreliosis and erythema migrans (n = 14). Others monitored the number of positive laboratory tests and/or patient consultations. Public participatory systems were only implemented in countries employing either also sentinels or voluntary surveys, or no traditional system, suggesting their use as a complementary tool. Only 56% of EU countries had neuroborreliosis as an indicator. CONCLUSION: The situation remains similar to 2010 with persisting heterogeneity between systems, suggesting that countries prioritise different surveillance objectives for LD. Without a common indicator in Europe, it is difficult to get a clear epidemiological picture. We discuss four factors that potentially influence LD surveillance strategies: perceptions of severity, burden on resources, two-way communication, and the medical conflicts about LD. Addressing these with countries might help moving towards the adoption of common practices.

What you see depends on where you sit: The effect of geographical location on web-searching for systematic reviews: A case study.

There is limited guidance on how to web-search in systematic reviews and concern relates to the reproducibility of searches using search engines such as Google. The aim of this paper is to address one potential source of variation in Google searches: does the geographical location of a researcher affect Google search returns? Using a virtual private network, we ran the same web-search for the medical technology Dasatinib in 12 different countries. Two researchers independently extracted the search returns by country organised by page rank. We compared: C1. any difference in the items returned by Google searches between countries and C2. any difference in the page rank of items returned between countries. Searches were undertaken on Monday September 28th 2020. From 12 countries, 43 items were identified. For C1: 19 items were common to all 12 countries. Twenty-four items were missed by searches in some countries. This means that there were differences in search returns between countries. For C2: a randomised trial reported by Raddich et al was the first search return for all countries. All other items, common to all countries, varied in their page-rank. We find that geographic location would appear to influence Google search returns based on the findings of this case study. The findings suggest that recording the location of the researcher undertaking web-searching may now be an important factor to report alongside detail on steps taken to minimise personalisation of web-searches covered by recent guidance. This finding also has implications for stopping-rules.

Cost-effectiveness of Microsoft Academic Graph with machine learning for automated study identification in a living map of coronavirus disease 2019 (COVID-19) research.

Background: Identifying new, eligible studies for integration into living systematic reviews and maps usually relies on conventional Boolean updating searches of multiple databases and manual processing of the updated results. Automated searches of one, comprehensive, continuously updated source, with adjunctive machine learning, could enable more efficient searching, selection and prioritisation workflows for updating (living) reviews and maps, though research is needed to establish this. Microsoft Academic Graph (MAG) is a potentially comprehensive single source which also contains metadata that can be used in machine learning to help efficiently identify eligible studies. This study sought to establish whether: (a) MAG was a sufficiently sensitive single source to maintain our living map of COVID-19 research; and (b) eligible records could be identified with an acceptably high level of specificity. Methods: We conducted an eight-arm cost-effectiveness analysis to assess the costs, recall and precision of semi-automated workflows, incorporating MAG with adjunctive machine learning, for continually updating our living map. Resource use data (time use) were collected from information specialists and other researchers involved in map production. Our systematic review software, EPPI-Reviewer, was adapted to incorporate MAG and associated machine learning workflows, and also used to collect data on recall, precision, and manual screening workload. Results: The semi-automated MAG-enabled workflow dominated conventional workflows in both the base case and sensitivity analyses. At one month our MAG-enabled workflow with machine learning, active learning and fixed screening targets identified 469 additional, eligible articles for inclusion in our living map, and cost £3,179 GBP per week less, compared with conventional methods relying on Boolean searches of Medline and Embase. Conclusions: We were able to increase recall and coverage of a large living map, whilst reducing its production costs. This finding is likely to be transferrable to OpenAlex, MAG's successor database platform.

Use and value of systematic reviews in English local authority public health: a qualitative study.

BACKGROUND: Responsibility for public health in England transferred from the National Health Service to local authorities in 2013, representing a different decision-making environment. Systematic reviews are considered the gold standard of evidence for clinical decision-making but little is known about their use in local government public health. This study aimed to explore the extent to which public health decision-makers in local authorities engage with systematic reviews and how they do so. METHODS: Semi-structured interviews were conducted with senior public health practitioners (n = 14) in Yorkshire and the Humber local authorities. Sampling was purposive and involved contacting Directors of Public Health directly and snowballing through key contacts. Face-to-face or telephone interviews were digitally recorded, transcribed verbatim and analysed using the Framework Method. RESULTS: Public health practitioners described using systematic reviews directly in decision-making and engaging with them more widely in a range of ways, often through a personal commitment to professional development. They saw themselves as having a role to advocate for the use of rigorous evidence, including systematic reviews, in the wider local authority. Systematic reviews were highly valued in principle and public health practitioners had relevant skills to find and appraise them. However, the extent of use varied by individual and local authority and was limited by the complexity of decision-making and various barriers. Barriers included that there were a limited number of systematic reviews available on certain public health topics, such as the wider determinants of health, and that the narrow focus of reviews was not reflective of complex public health decisions facing local authorities. Reviews were used alongside a range of other evidence types, including grey literature. The source of evidence was often considered an indicator of quality, with specific organisations, such as Public Health England, NICE and Cochrane, particularly trusted. CONCLUSIONS: Research use varies and should be considered within the specific decision-making and political context. There is a need for systematic reviews to be more reflective of the decisions facing local authority public health teams.

Interventions to support people exposed to adverse childhood experiences: systematic review of systematic reviews.

BACKGROUND: Adverse Childhood Experiences (ACEs) such as abuse, neglect or household adversity may have a range of serious negative impacts. There is a need to understand what interventions are effective to improve outcomes for people who have experienced ACEs. METHODS: Systematic review of systematic reviews. We searched 18 database sources from 2007 to 2018 for systematic reviews of effectiveness data on people who experienced ACEs aged 3-18, on any intervention and any outcome except incidence of ACEs. We included reviews with a summary quality score (AMSTAR) of 5.5 or above. RESULTS: Twenty-five reviews were included. Most reviews focus on psychological interventions and mental health outcomes. The strongest evidence is for cognitive-behavioural therapy for people exposed to abuse. For other interventions - including psychological therapies, parent training, and broader support interventions - the findings overall are inconclusive, although there are some positive results. CONCLUSIONS: There are significant gaps in the evidence on interventions for ACEs. Most approaches focus on mitigating individual psychological harms, and do not address the social pathways which may mediate the negative impacts of ACEs. Many negative impacts of ACEs (e.g. on health behaviours, social relationships and life circumstances) have also not been widely addressed by intervention studies.

Understanding the unintended consequences of public health policies: the views of policymakers and evaluators.

BACKGROUND: Public health policies sometimes have unexpected effects. Understanding how policies and interventions lead to outcomes is essential if policymakers and researchers are to intervene effectively and reduce harmful and other unintended consequences (UCs) of their actions. Yet, evaluating complex mechanisms and outcomes is challenging, even before considering how to predict assess and understand outcomes and UCs when interventions are scaled up. We aimed to explore with UK policymakers why some policies have UCs, and how researchers and policymakers should respond. METHODS: We convened a one-day workshop with 14 people involved in developing, implementing or evaluating social and public health policies, and/or evaluating possible unintended effects. This included senior evaluators, policymakers from government and associated agencies, and researchers, covering policy domains from public health, social policy, poverty, and international development. RESULTS: Policymakers suggested UCs happen for a range of reasons: poor policy design, unclear articulation of policy mechanisms or goals, or unclear or inappropriate evidence use, including evaluation techniques. While not always avoidable, it was felt that UCs could be partially mitigated by better use of theory and evidence, better involvement of stakeholders in concurrent design and evaluation of policies, and appropriate evaluation systems. CONCLUSIONS: UCs can be used to explore the mechanisms underpinning social change caused by public health policies. Articulating these mechanisms is essential for truly evidence-informed decision-making, to enable informed debate about policy options, and to develop evaluation techniques. Future work includes trying to develop a holistic stakeholder-led evaluation process.

Just how plain are plain tobacco packs: re-analysis of a systematic review using multilevel meta-analysis suggests lessons about the comparative benefits of synthesis methods.

BACKGROUND: Comparisons between narrative synthesis and meta-analysis as synthesis methods in systematic reviews are uncommon within the same systematic review. We re-analysed a systematic review on the effects of plain packaging of tobacco on attractiveness. We sought to compare different synthesis approaches within the same systematic review and shed light on the comparative benefits of each approach. METHODS: In our re-analysis, we included results relating to attractiveness in included reports. We extracted findings from studies and converted all estimates of differences in attractiveness to Cohen's d. We used multilevel meta-analysis to account for clustering of effect sizes within studies. RESULTS: Of the 19 studies reporting results on attractiveness, seven studies that included between-subjects analyses could be included in the meta-analysis. Plain packs were less attractive than branded packs (d = - 0.59, 95% CI [- 0.71, - 0.47]), with negligible but uncertain between-studies heterogeneity (I2 = 0%, 95% CI [0.00, 70.81]) and high within-study heterogeneity (I2 = 92.6%, 95% CI [91.04, 93.90]). CONCLUSIONS: The meta-analysis found, similar to the narrative synthesis, that respondents typically rated plain packaging as less attractive than alternative (e.g. branded) tobacco packs. However, there were several trade-offs between analysis methods in the types and bodies of evidence each one contained and in the difference between partial precision and breadth of conclusions. Analysis methods were different in respect of the role of judgement and contextual variation and in terms of estimation and unexpected effect modification. In addition, we noted that analysis methods were different in how they accounted for heterogeneity and consistency.

Sex-Specific Changes in Physical Performance Following Military Training: A Systematic Review.

INTRODUCTION: Men and women joining the military undergo the same training, often in mixed-sex platoons. Given the inherent physiological and physical performance differences between men and women, it is reasonable to question whether sex differences exist in the adaptation to military training and, therefore, whether sex-specific training should be employed to optimise training adaptations. OBJECTIVE: To systematically review the literature evaluating changes in the physical performance of men and women following military training. METHODS: Six database sources were searched in addition to extensive secondary searching. Primary prospective intervention studies (all designs) evaluating physical training interventions in military populations, reporting pre- to post-training changes in physical fitness outcomes for both women and men, were included. RESULTS: We screened 3966 unique records. Twenty-nine studies (n = 37 study reports) were included, most of which were conducted in the USA and evaluated initial training for military recruits. Positive changes were more consistently observed in aerobic fitness and muscle strength (whole body and upper body) outcomes than lower body strength, muscle power or muscle endurance outcomes, following physical training. Relative pre- to post-training changes for all outcome measures tended to be greater in women than men although few statistically significant sex by outcome/time interactions were observed. CONCLUSION: Improvements in some, but not all, performance components were observed following a period of military training. Largely, these improvements were not significantly different between sexes. Further prospective research is needed to evaluate sex-specific differences in the response to physical training in controlled conditions to improve military physical training outcomes for both sexes.

Support for adults with autism spectrum disorder without intellectual impairment: Systematic review.

Adults with autism spectrum disorder without intellectual impairment may benefit from a range of support services. This article presents the results of a systematic review assessing the effectiveness of supportive interventions for adults with autism spectrum disorder without intellectual impairment. A total of 32 studies were included; most focused on younger male participants. Although evidence was lacking for most types of intervention, employment programmes and social skills training were found to be effective for more proximal outcomes such as social skills. Evidence that any intervention improves mental health or well-being was very limited. Most interventions focused on mitigating specific deficits, rather than on providing broader support. Further research is needed on the effectiveness of supportive interventions such as advocacy and mentoring.

Seasonal influenza vaccination of healthcare workers: systematic review of qualitative evidence.

BACKGROUND: Most countries recommend that healthcare workers (HCWs) are vaccinated seasonally against influenza in order to protect themselves and patients. However, in many cases coverage remains low. A range of strategies have been implemented to increase uptake. Qualitative evidence can help in understanding the context of interventions, including why interventions may fail to achieve the desired effect. This study aimed to synthesise evidence on HCWs' perceptions and experiences of vaccination for seasonal influenza. METHODS: Systematic review of qualitative evidence. We searched MEDLINE, EMBASE and CINAHL and included English-language studies which reported substantive qualitative data on the vaccination of HCWs for seasonal influenza. Findings were synthesised thematically. RESULTS: Twenty-five studies were included in the review. HCWs may be motivated to accept vaccination to protect themselves and their patients against infection. However, a range of beliefs may act as barriers to vaccine uptake, including concerns about side-effects, scepticism about vaccine effectiveness, and the belief that influenza is not a serious illness. HCWs value their autonomy and professional responsibility in making decisions about vaccination. The implementation of interventions to promote vaccination uptake may face barriers both from HCWs' personal beliefs and from the relationships between management and employees within the targeted organisations. CONCLUSIONS: HCWs' vaccination behaviour needs to be understood in the context of HCWs' relationships with each other, with management and with patients. Interventions to promote vaccination should take into account both the individual beliefs of targeted HCWs and the organisational context within which they are implemented.

Meta-analysis, complexity, and heterogeneity: a qualitative interview study of researchers' methodological values and practices.

BACKGROUND: Complex or heterogeneous data pose challenges for systematic review and meta-analysis. In recent years, a number of new methods have been developed to meet these challenges. This qualitative interview study aimed to understand researchers' understanding of complexity and heterogeneity and the factors which may influence the choices researchers make in synthesising complex data. METHODS: We conducted interviews with a purposive sample of researchers (N = 19) working in systematic review or meta-analysis across a range of disciplines. We analysed data thematically using a framework approach. RESULTS: Participants reported using a broader range of methods and data types in complex reviews than in traditional reviews. A range of techniques are used to explore heterogeneity, but there is some debate about their validity, particularly when applied post hoc. CONCLUSIONS: Technical considerations of how to synthesise complex evidence cannot be isolated from questions of the goals and contexts of research. However, decisions about how to analyse data appear to be made in a largely informal way, drawing on tacit expertise, and their relation to these broader questions remains unclear.

Evaluating the effect of HIV prevention strategies on uptake of HIV counselling and testing among male most-at-risk-populations in Nigeria; a cross-sectional analysis.

OBJECTIVE: The aim of this study was to evaluate the effects of three strategies in increasing uptake of HIV counselling and testing (HCT) among male most-at-risk-population (M-MARPs) using programmatic data. DESIGN: HIV prevention strategies were evaluated in a cross-sectional analysis. METHODS: Three HCT strategies were implemented between July 2009 and July 2012 among men who have sex with men (MSM) and people who inject drugs (PWIDs) in four states in Nigeria. The first strategy (S1), involved key opinion leaders (KOLs) who referred M-MARPs to health facilities for HCT. The second strategy (S2) involved KOLs referring M-MARPs to nearby mobile HCT teams while the third (S3) involved mobile M-MARPs peers conducting the HCT. χ(2) statistics were used to test for differences in the distribution of categorical variables across groups while logistic regression was used to measure the effect of the different strategies while controlling for confounding factors. RESULTS: A total of 1988, 14 726 and 14 895 M-MARPs were offered HCT through S1, S2 and S3 strategies, respectively. Overall, S3 (13%) identified the highest proportion of HIV-positive M-MARPs compared with S1 (9%) and S2 (3%), p≤0.001. Also S3 (13%) identified the highest proportion of new HIV diagnosis compared with S1 (8%) and S2 (3%), respectively, p≤0.001. When controlled for age, marital status and occupation, MSM reached via S3 were 9 times (AOR: 9.21; 95% CI 5.57 to 15.23) more likely to uptake HCT when compared with S1 while PWIDs were 21 times (AOR: 20.90; 95% CI 17.33 to 25.21) more likely to uptake to HCT compared with those reached via S1. CONCLUSIONS: Peer-led HCT delivered by S3 had the highest impact on the total number of M-MARPs reached and in identifying HIV-positive M-MARPs and new testers. Training M-MARPs peers to provide HCT is a high impact approach in delivering HCT to M-MARPs.

The social ecology of girls' bullying practices: exploratory research in two London schools.

This exploratory study adopts a socio-ecological approach to examine the context of school bullying. It asks: (1) what are students' accounts of bullying practices?; (2) how are these enabled and constrained by the school-environment?; (3) how is gender implicated? Qualitative data were collected from girls in two schools in London via focus groups (one in each school; students aged 12-15) and seven semi-structured interviews (in one school; students aged 16-18); and from school policy documents. Our interpretation of girls' accounts, informed by Giddens' structuration theory, suggests that bullying practices were spatially patterned in the schools and often characterised by the regulation of girls' sexuality and sexual-harassment. Repeated acts of aggression were fluid with regard to the bully and victim role, challenging the dominant view of bullying as characterised by consistent disparities in power between individuals. Schools structured bullying behaviour via policies and practices that ignored these forms of abuse and which focused on and may have been complicit in the making of stable 'bully' and 'victim' roles, thus indirectly contributing to the reproduction of unhealthy relationships between students. In terms of gender, traditional gendered and sexual discourses appear to structure the identities of the schools and girls in our study.

A qualitative study into the development of a physical activity legacy from the London 2012 Olympic Games.

Olympic Games have sometimes been considered as public health interventions capable of improving population health by encouraging increased physical activity levels. However, the evidence base does not appear to support this and is of poor quality, focussing on population level outcomes, usually related only to participation in organised sports. A new approach to research into the effects of such events is required focussing on the processes and mechanisms by which population physical activity levels might be increased enabling more effective use of such events in the future. Two separate processes, the 'demonstration effect' and 'festival effect,' have been proposed in Government guidance and are explored using qualitative methods in eight inactive people and four physical activity promotion specialists in Brighton & Hove. The findings appear to support the idea that watching elite athletes compete is unlikely to inspire participation among inactive people and may even discourage it by reducing self-efficacy as a result of the perceived competence gap. Despite this, positive attitudes towards the London Olympics were observed among inactive members of the public and a desire to become actively involved in the event. Examples of intention to continue participating in community events and physical activities as a result of positive experiences of Olympic related events were also observed.

Considering methodological options for reviews of theory: illustrated by a review of theories linking income and health.

BACKGROUND: Review of theory is an area of growing methodological advancement. Theoretical reviews are particularly useful where the literature is complex, multi-discipline, or contested. It has been suggested that adopting methods from systematic reviews may help address these challenges. However, the methodological approaches to reviews of theory, including the degree to which systematic review methods can be incorporated, have received little discussion in the literature. We recently employed systematic review methods in a review of theories about the causal relationship between income and health. METHODS: This article discusses some of the methodological issues we considered in developing the review and offers lessons learnt from our experiences. It examines the stages of a systematic review in relation to how they could be adapted for a review of theory. The issues arising and the approaches taken in the review of theories in income and health are considered, drawing on the approaches of other reviews of theory. RESULTS: Different approaches to searching were required, including electronic and manual searches, and electronic citation tracking to follow the development of theories. Determining inclusion criteria was an iterative process to ensure that inclusion criteria were specific enough to make the review practical and focused, but not so narrow that key literature was excluded. Involving subject specialists was valuable in the literature searches to ensure principal papers were identified and during the inductive approaches used in synthesis of theories to provide detailed understanding of how theories related to another. Reviews of theory are likely to involve iterations and inductive processes throughout, and some of the concepts and techniques that have been developed for qualitative evidence synthesis can be usefully translated to theoretical reviews of this kind. CONCLUSIONS: It may be useful at the outset of a review of theory to consider whether the key aim of the review is to scope out theories relating to a particular issue; to conduct in-depth analysis of key theoretical works with the aim of developing new, overarching theories and interpretations; or to combine both these processes in the review. This can help decide the most appropriate methodological approach to take at particular stages of the review.

New directions in evidence-based policy research: a critical analysis of the literature.

Despite 40 years of research into evidence-based policy (EBP) and a continued drive from both policymakers and researchers to increase research uptake in policy, barriers to the use of evidence are persistently identified in the literature. However, it is not clear what explains this persistence - whether they represent real factors, or if they are artefacts of approaches used to study EBP. Based on an updated review, this paper analyses this literature to explain persistent barriers and facilitators. We critically describe the literature in terms of its theoretical underpinnings, definitions of 'evidence', methods, and underlying assumptions of research in the field, and aim to illuminate the EBP discourse by comparison with approaches from other fields. Much of the research in this area is theoretically naive, focusing primarily on the uptake of research evidence as opposed to evidence defined more broadly, and privileging academics' research priorities over those of policymakers. Little empirical data analysing the processes or impact of evidence use in policy is available to inform researchers or decision-makers. EBP research often assumes that policymakers do not use evidence and that more evidence - meaning research evidence - use would benefit policymakers and populations. We argue that these assumptions are unsupported, biasing much of EBP research. The agenda of 'getting evidence into policy' has side-lined the empirical description and analysis of how research and policy actually interact in vivo. Rather than asking how research evidence can be made more influential, academics should aim to understand what influences and constitutes policy, and produce more critically and theoretically informed studies of decision-making. We question the main assumptions made by EBP researchers, explore the implications of doing so, and propose new directions for EBP research, and health policy.

A population search filter for hard-to-reach populations increased search efficiency for a systematic review.

OBJECTIVES: This article discusses how hard-to-reach population groups were conceptualized into a search filter. The objectives of this article were to (1) discuss how the authors designed a multistranded population search filter and (2) retrospectively test the effectiveness of the search filter in capturing all relevant populations (eg, homeless people, immigrants, substance misusers) in a public health systematic review. STUDY DESIGN AND SETTING: Systematic and retrospective analysis via a case study. Retrospective analysis of the search filter was conducted by comparing the MEDLINE search results retrieved without using the search filter against those retrieved with the search filter. A total of 5,465 additional results from the unfiltered search were screened to the same criteria as the filtered search. RESULTS: No additional populations were identified in the unfiltered sample. The search filter reduced the volume of MEDLINE hits to screen by 64%, with no impact on inclusion of populations. CONCLUSIONS: The results demonstrate the effectiveness of the filter in capturing all relevant UK populations for the review. This suggests that well-planned search filters can be written for reviews that analyze imprecisely defined population groups. This filter could be used in topic areas of associated comorbidities, for rapid clinical searches, or for investigating hard-to-reach populations.