Use Of Systematic Reviews Research Articles

A review of the systematic review process and its applicability for use in evaluating evidence for health claims on probiotic foods in the European Union.

This paper addresses the use of systematic review and meta-analysis to evaluate the strength of evidence for health benefits of probiotic foods, especially relating to health claim substantiation in the European Union. A systematic review is a protocol-driven, transparent and replicable approach, widely accepted in a number of scientific fields, and used by many policy-setting organizations to evaluate the strength of evidence to answer a focused research question. Many systematic reviews have been published on the broad category of probiotics for many different outcomes. Some of these reviews have been criticized for including poor quality studies, pooling heterogeneous study results, and not considering publication bias. Well-designed and -conducted systematic reviews should address such issues. Systematic reviews of probiotics have an additional challenge – rarely addressed in published reviews - in that there must be a scientifically sound basis for combining evidence on different strains, species or genera. The European Food Safety Authority (EFSA) is increasingly adopting the systematic review methodology. It remains to be seen how health claims supported by systematic reviews are evaluated within the EFSA approval process. The EFSA Panel on Dietetic Products, Nutrition and Allergies deems randomized trials to be the best approach to generating evidence about the effects of foods on health outcomes. They also acknowledge that systematic reviews (with or without meta-analyses) are the best approach to assess the totality of the evidence. It is reasonable to use these well-established methods to assess objectively the strength of evidence for a probiotic health claim. Use of the methods to combine results on more than a single strain or defined blend of strains will require a rationale that the different probiotics are substantively similar, either in identity or in their mode of action.

Is the Naming of Herpes Simplex Gladiatorum Correct?

Herpes Gladiatorum (HG) outbreaks should be regarded as serious long term infections that can have negative consequences on the health of individual athletes and the athletic community as a whole. Purpose: The main goal of this analysis was to provide a scientific basis and evidence that the herpes infections in athletes caused by Herpes Simplex Virus type I (HSV-1), might not be appropriately called Herpes Gladiatorum (HG), but should be renamed as Herpes Luctatorum (HL). Methods: The methodology of the current study was included the use of systematic review of the writings in the ancient Greek and the modern literature. Results: From literature review and careful consideration of sports scenes, we found that the sport in which there was extensive physical contact in antiquity is wrestling, and this is not a mono- Mini-review Article

Systematic Review and Meta-Analysis of Studies Evaluating Diagnostic Test Accuracy: A Practical Review for Clinical Researchers-Part I. General Guidance and Tips.

In the field of diagnostic test accuracy (DTA), the use of systematic review and meta-analyses is steadily increasing. By means of objective evaluation of all available primary studies, these two processes generate an evidence-based systematic summary regarding a specific research topic. The methodology for systematic review and meta-analysis in DTA studies differs from that in therapeutic/interventional studies, and its content is still evolving. Here we review the overall process from a practical standpoint, which may serve as a reference for those who implement these methods.

The usefulness of systematic reviews of animal experiments for the design of preclinical and clinical studies.

The question of how animal studies should be designed, conducted, and analyzed remains underexposed in societal debates on animal experimentation. This is not only a scientific but also a moral question. After all, if animal experiments are not appropriately designed, conducted, and analyzed, the results produced are unlikely to be reliable and the animals have in effect been wasted. In this article, we focus on one particular method to address this moral question, namely systematic reviews of previously performed animal experiments. We discuss how the design, conduct, and analysis of future (animal and human) experiments may be optimized through such systematic reviews. In particular, we illustrate how these reviews can help improve the methodological quality of animal experiments, make the choice of an animal model and the translation of animal data to the clinic more evidence-based, and implement the 3Rs. Moreover, we discuss which measures are being taken and which need to be taken in the future to ensure that systematic reviews will actually contribute to optimizing experimental design and thereby to meeting a necessary condition for making the use of animals in these experiments justified.

The use of systematic review to develop a self-management program for CKD

Chronic kidney disease (CKD) has become a public health issue of international concern due to its high prevalence. The concept of self-management has been comprehensively applied in education programs that address chronic diseases. In recent years, many studies have used self-management programs in CKD interventions and have investigated the pre- and post-intervention physiological and psychological effectiveness of this approach. However, a complete clinical application program in the self-management model has yet to be developed for use in clinical renal care settings. A systematic review is used to develop a self-management program for CKD. Three implementation steps were used in this study. These steps include: (1) A systematic literature search and review using databases including CEPS (Chinese Electronic Periodical Services) of Airiti, National Digital Library of Theses and Dissertations in Taiwan, CINAHL, Pubmed, Medline, Cochrane Library, and Joanna Briggs Institute. A total of 22 studies were identified as valid and submitted to rigorous analysis. Of these, 4 were systematic literature reviews, 10 were randomized experimental studies, and 8 were non-randomized experimental studies. (2) Empirical evidence then was used to draft relevant guidelines on clinical application. (3) Finally, expert panels tested the validity of the draft to ensure the final version was valid for application in practice. This study designed a self-management program for CKD based on the findings of empirical studies. The content of this program included: design principles, categories, elements, and the intervention measures used in the self-management program. This program and then was assessed using the content validity index (CVI) and a four-point Liker's scale. The content validity score was .98. The guideline of self-management program to CKD was thus developed. This study developed a self-management program applicable to local care of CKD. It is hoped that the guidelines developed in this study offer a reference for clinical caregivers to improve their healthcare practices.

Conflicts of interest and critiques of the use of systematic reviews in policymaking: an analysis of opinion articles.

BackgroundStrong opinions for or against the use of systematic reviews to inform policymaking have been published in the medical literature. The purpose of this paper was to examine whether funding sources and author financial conflicts of interest were associated with whether an opinion article was supportive or critical of the use of systematic reviews for policymaking. We examined the nature of the arguments within each article, the types of disclosures present, and whether these articles are being cited in the academic literature.MethodsWe searched for articles that expressed opinions about the use of systematic reviews for policymaking. We included articles that presented opinions about the use of systematic reviews for policymaking and categorized each article as supportive or critical of such use. We extracted all arguments regarding the use of systematic reviews from each article and inductively coded each as internal or external validity argument, categorized disclosed funding sources, conflicts of interest, and article types, and systematically searched for undisclosed financial ties. We counted the number of times each article has been cited in the “Web of Science.” We report descriptive statistics.ResultsArticles that were critical of the use of systematic reviews (n = 25) for policymaking had disclosed or undisclosed industry ties 2.3 times more often than articles that were supportive of the use (n = 34). We found that editorials, comments, letters, and perspectives lacked published disclosures nearly twice as often (60% v. 33%) as other types of articles. We also found that editorials, comments, letters, and perspectives were less frequently cited in the academic literature than other article types (median number of citations = 5 v. 19).ConclusionsIt is important to consider whether an article has industry ties when evaluating the strength of the argument for or against the use of systematic reviews for policymaking. We found that journal conflict of interest disclosures are often inadequate, particularly for editorials, comments, letters, and perspectives and that these articles are being cited as evidence in the academic literature. Our results further suggest the need for more consistent and complete disclosure for all article types.

Some notes on critical appraisal of prevalence studies: Comment on: "The development of a critical appraisal tool for use in systematic reviews addressing questions of prevalence".

Decisions in healthcare should be based on information obtained according to the principles of Evidence-Based Medicine (EBM). An increasing number of systematic reviews are published which summarize the results of prevalence studies. Interpretation of the results of these reviews should be accompanied by an appraisal of the methodological quality of the included data and studies. The critical appraisal tool for prevalence studies developed and tested by Munn et al. comprises 10 items and aims at targeting all kinds of prevalence studies. This comment discusses the pros and cons of different designs of quality appraisal tools and highlights their importance for systematic reviews of prevalence studies. Beyond piloting, which has been performed in the study by Munn et al., it is suggested here that the validity of the tool should be tested, including reproducibility and inter-rater reliability. It is concluded that studies as the one by Munn et al. will help to establish a critical understanding of methodological quality and will support the use of systematic reviews of non-intervention studies for health policy making.

Scientific hypotheses can be tested by comparing the effects of one treatment over many diseases in a systematic review

ObjectivesTo describe the use of systematic reviews or overviews (systematic reviews of systematic reviews) to synthesize quantitative evidence of intervention effects across multiple indications (multiple-indication reviews) and to highlight issues pertaining to such reviews. Study Design and SettingMEDLINE was searched from 2003 to January 2014. We selected multiple-indication reviews of interventions of allopathic medicine that included evidence from randomized controlled trials. We categorized the subject areas evaluated by these reviews and examined their methodology. Utilities and caveats of multiple-indication reviews are illustrated with examples drawn from published literature. ResultsWe retrieved 52 multiple-indication reviews covering a wide range of interventions. The method has been used to detect unintended effects, improve precision by pooling results across indications, and examine scientific hypotheses across disease classes. ConclusionSystematic reviews of interventions are typically used to evaluate the effects of treatments, one indication at a time. Here, we argue that, with due attention to methodological caveats, much can be learned by comparing the effects of a given treatment across many related indications.

What does systematic review and meta-analysis offer, and what does it not?

In the rapidly evolving field of health sciences, systematic reviews and meta-analyses have been increasingly used to inform health care practices and to provide an evidence base for policy making. Despite their increasing popularity, the findings and conclusions of systematic reviews and meta-analyses should be read, interpreted and applied with caution. Here we provide an example of incompatible conclusions from two recent systematic reviews and meta-analyses on indoor air pollution (IAP) and tuberculosis (TB) to illustrate the challenge of such an approach. In the first systematic review, Sumpter and Chandramohan identified 10 case-control studies and 3 cross-sectional studies.1 They applied the fix-effect model and reported that the pooled odds ratio from the 10 case-control studies was 1.30 (95% confidence interval [CI] 1.04–1.62). They concluded that ‘there is increasingly strong evidence for an association between IAP and TB.’ In the other systematic review, Lin and colleagues identified 10 case-control studies and 5 cross-sectional studies.2 They found a high risk of bias in control selection and exposure assessment and substantial between-study heterogeneity, implying that the true association between IAP and TB was likely to be different across studies. They applied the statistical model that accounted for between-study heterogeneity (the random-effects model), and reported a pooled odds ratio of 1.17 (95%CI 0.83–1.65) for the 10 case-control studies. Based on the quality of the included studies and the quantitative results, the authors concluded that the level of evidence for a positive association between IAP and TB was low. Although systematic reviews can be a useful tool for summarising available evidence and to ‘see the forest’, it may not always offer unbiased estimates of interest, as study selection, data extraction or statistical analysis might be inadequate, resulting in biases. In addition, the reviewers might have different (and often subjective) interpretations of the studies. It is thus not rare to see two meta-analyses conducted in the same period that report different or even inconsistent results. Finally, meta-analysis should be more than just a mechanistic procedure for reducing multiple studies into one single summary effect estimate. The objective of a systematic review and meta-analysis is not to pool all included studies. In the presence of substantial between-study heterogeneity, the exploration and explanations of the heterogeneity observed will be more informative than the mechanical pooling itself. To make the best use of systematic review and meta-analysis in the synthesis of public health evidence, peer-reviewed journals should advise researchers to follow reporting guidelines for systematic reviews and meta-analyses, such as the now widely accepted PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guideline.3 For the readers, users' guides are available to help appraise this type of literature and apply results to daily practice.4 In sum, systematic reviews and meta-analyses can be a valuable tool for evidence synthesis in health sciences, but to achieve the anticipated value both reviewers and readers need to be fully aware of their limitations.

Ability of a meta-analysis to prevent redundant research: systematic review of studies on pain from propofol injection

Objective To examine whether, according to the conclusions of a 2000 systematic review with meta-analysis on interventions to prevent pain from propofol injection that provided a research agenda to guide...

Systematic reviews addressing identified health policy priorities in Eastern Mediterranean countries: a situational analysis.

BackgroundSystematic reviews can offer policymakers and stakeholders concise, transparent, and relevant evidence pertaining to pressing policy priorities to help inform the decision-making process. The production and the use of systematic reviews are specifically limited in the Eastern Mediterranean region. The extent to which published systematic reviews address policy priorities in the region is still unknown. This situational analysis exercise aims at assessing the extent to which published systematic reviews address policy priorities identified by policymakers and stakeholders in Eastern Mediterranean region countries. It also provides an overview about the state of systematic review production in the region and identifies knowledge gaps.MethodsWe conducted a systematic search of the Health System Evidence database to identify published systematic reviews on policy-relevant priorities pertaining to the following themes: human resources for health, health financing, the role of the non-state sector, and access to medicine. Priorities were identified from two priority-setting exercises conducted in the region. We described the distribution of these systematic reviews across themes, sub-themes, authors’ affiliations, and countries where included primary studies were conducted.ResultsOut of the 1,045 systematic reviews identified in Health System Evidence on selected themes, a total of 200 systematic reviews (19.1%) addressed the priorities from the Eastern Mediterranean region. The theme with the largest number of systematic reviews included was human resources for health (115) followed by health financing (33), access to medicine (27), and role of the non-state sector (25). Authors based in the region produced only three systematic reviews addressing regional priorities (1.5%). Furthermore, no systematic review focused on the Eastern Mediterranean region. Primary studies from the region had limited contribution to systematic reviews; 17 systematic reviews (8.5%) included primary studies conducted in the region.ConclusionsThere are still gaps in the production of systematic reviews addressing policymakers’ and stakeholders’ priorities in the Eastern Mediterranean region. Efforts should be directed towards better aligning systematic review production with policy needs and priorities. Study findings can inform the agendas of researchers, research institutions, and international funding agencies of priority areas where systematic reviews are required.

Health system decision makers’ feedback on summaries and tools supporting the use of systematic reviews: a qualitative study

Health system managers and policy makers need timely access to high quality, policy-relevant systematic reviews. Our objectives were to obtain managers’ and policy makers’ feedback about user-friendly summaries of systematic reviews and about tools related to supporting or assessing their use. Our interviews identified that participants prefer key messages up front, such as details regarding background, methods, and applicability, appreciate quality ratings, and prefer bullets and tables to paragraphs. There were mixed views about the relevance-assessment tool and positive views about the use-assessment tool. The findings can be used to support evidence-informed decision making among managers and policy makers.

Commentary: towards a definite coherent heterogeneity in meta-analyses.

‘Meta-analysis’, coined by Gene Glass in 1976, is the ‘analysis of analyses’, denoting a systematic approach to summarizing the available peer-reviewed literature using statistical techniques.1 Most readers view a meta-analysis as a definitive summary of the state of the evidence, and meta-analyses have become an essential element in evidence-based decision making. Because meta-analysis involves a quantitative summary of the published data, it is sometimes interpreted as less biased and more objective than qualitative reviews of the literature or even individual studies. Over the past two decades the use of systematic reviews has exploded, with over 4000 published on human data in 2013 alone (as inventoried by PubMed).

On the use of systematic reviews to inform environmental policies

Environmental research varies in its methodological quality, degree of bias, and relevance to policy questions. Using this heterogeneous, and sometimes polarised, research to inform environmental policies can be challenging. Policy-making in the healthcare field sometimes uses systematic reviews (SRs) to tackle these issues and present a comprehensive, policy-neutral, transparent and reproducible synthesis of the evidence. However, there is less familiarity with SRs in the environmental field. The aim of this article is to: (1) summarise the process of conducting SRs, using best practice methods from the healthcare field as an example, (2) explain the rationale behind each stage of conducting a SR, and (3) examine the prospects and challenges of using SRs to inform environmental policy. We conclude that existing SR protocols from healthcare can be, and have been, applied successfully to environmental research but some adaptations could improve the process. The literature search stage could be expedited by standardising the reporting and indexing of environmental studies, equivalent to that in the healthcare field. The consistency of the study appraisal stage of SRs could be augmented by refining the existing quality assessment tools used in the healthcare field, enhancing their ability to discriminate quality and risk of bias in non-randomised studies. Ultimately, the strength of evidence within SRs on environmental topics could be improved through more widespread use of randomised controlled trials as a research method, owing to their inherently lower risk of bias when conducted according to best practice.

An introduction to systematic reviews in animal health, animal welfare, and food safety.

In this paper, we provide an introduction to systematic reviews and discuss the process for conducting systematic reviews in animal health, animal welfare, and food safety. The research synthesis need that can be addressed by a systematic review is discussed. The use of systematic reviews to address questions about intervention effects, etiology, diagnostic tests evaluation and disease burden are discussed. The steps included in a systematic review are described.

Study designs and systematic reviews of interventions: building evidence across study designs.

This article is the second article in a series of six focusing on systematic reviews in animal agriculture and veterinary medicine. This article addresses the strengths and limitations of study designs commonly used in animal agriculture and veterinary research to assess interventions (preventive or therapeutic treatments) and discusses the appropriateness of their use in systematic reviews of interventions. Different study designs provide different evidentiary value for addressing questions about the efficacy of interventions. Experimental study designs range from in vivo proof of concept experiments to randomized controlled trials (RCTs) under real-world conditions. The key characteristic of experimental design in intervention studies is that the investigator controls the allocation of individuals or groups to different intervention strategies. The RCT is considered the gold standard for evaluating the efficacy of interventions and, if there are well-executed RCTs available for inclusion in a systematic review, that review may be restricted to only this design. In some instances, RCTs may not be feasible or ethical to perform, and there are fewer RCTs published in the veterinary literature compared to the human healthcare literature. Therefore, observational study designs, where the investigator does not control intervention allocation, may provide the only available evidence of intervention efficacy. While observational studies tend to be relevant to real-world use of an intervention, they are more prone to bias. Human healthcare researchers use a pyramid of evidence diagram to describe the evidentiary value of different study designs for assessing interventions. Modifications for veterinary medicine are presented in this article.

Conducting systematic reviews of intervention questions I: Writing the review protocol, formulating the question and searching the literature.

This article is the fourth of six articles addressing systematic reviews in animal agriculture and veterinary medicine. Previous articles in the series have introduced systematic reviews, discussed study designs and hierarchies of evidence, and provided details on conducting randomized controlled trials, a common design for use in systematic reviews. This article describes development of a review protocol and the first two steps in a systematic review: formulating a review question, and searching the literature for relevant research. The emphasis is on systematic reviews of questions related to interventions. The review protocol is developed prior to conducting the review and specifies the plan for the conduct of the review, identifies the roles and responsibilities of the review team and provides structured definitions related to the review question. For intervention questions, the review question should be defined by the PICO components: population, intervention, comparison and outcome(s). The literature search is designed to identify all potentially relevant original research that may address the question. Search terms related to some or all of the PICO components are entered into literature databases, and searches for unpublished literature also are conducted. All steps of the literature search are documented to provide transparent reporting of the process.

The Use of Systematic Reviews in Clinical Trials and Narrative Reviews in Dermatology: Is the Best Evidence Being Used?

Introduction and objectivesSystematic reviews —the most comprehensive type of literature review—should be taken into account before a clinical trial or a narrative review on a topic is undertaken. The objective of this study was to describe the use of systematic reviews in clinical trials and narrative reviews in dermatology. Material and methodsThis was a descriptive cross-sectional study. We selected randomized clinical trials and narrative reviews from the dermatological clinical research journals identified as most important (according to impact factor) and from Actas Dermosifiliográficas, and studied the bibliographies to ascertain whether the authors made reference to existing systematic reviews and Cochrane reviews. ResultsOf the 72 clinical trials for which a systematic review was available, 24 (33.3%) cited at least 1 review; reference was made to relevant Cochrane reviews in 15.6% of cases and to non-Cochrane reviews in 32%. In the case of the 24 narrative reviews for which a review was available, 10 (41.7%) cited at least 1 review; Cochrane reviews were cited in 20% and non-Cochrane reviews in 35.3%.In the case of Actas Dermosifiliográficas, very few clinical trials were found and the findings for narrative review articles were similar to those observed for the other journals. ConclusionsSystematic reviews are not often taken into account by the authors of clinical trials and narrative reviews and this may lead to redundant studies and publications. Authors appear to use Cochrane reviews even less than non-Cochrane reviews and are therefore ignoring one of the main sources of available evidence.

Systematic reviews and meta-analysis of preclinical studies: why perform them and how to appraise them critically.

The use of systematic review and meta-analysis of preclinical studies has become more common, including those of studies describing the modeling of cerebrovascular diseases. Empirical evidence suggests that too many preclinical experiments lack methodological rigor, and this leads to inflated treatment effects. The aim of this review is to describe the concepts of systematic review and meta-analysis and consider how these tools may be used to provide empirical evidence to spur the field to improve the rigor of the conduct and reporting of preclinical research akin to their use in improving the conduct and reporting of randomized controlled trials in clinical research. As with other research domains, systematic reviews are subject to bias. Therefore, we have also suggested guidance for their conduct, reporting, and critical appraisal.

Empleo de las revisiones sistemáticas en ensayos clínicos y revisiones narrativas en dermatología: ¿se usa la mejor evidencia disponible?

Introduction and objectivesSystematic reviews —the most comprehensive type of literature review— should be taken into account before a clinical trial or a narrative review on a topic is undertaken. The objective of this study was to describe the use of systematic reviews in clinical trials and narrative reviews in dermatology. Material and methodsThis was a descriptive cross-sectional study. We selected randomized clinical trials and narrative reviews from the dermatological clinical research journals identified as most important (according to impact factor) and from Actas Dermosifiliográficas, and studied the bibliographies to ascertain whether the authors made reference to existing systematic reviews and Cochrane reviews. ResultsOf the 72 clinical trials for which a systematic review was available, 24 (33.3%) cited at least 1 review; reference was made to relevant Cochrane reviews in 15.6% of cases and to non-Cochrane reviews in 32%. In the case of the 24 narrative reviews for which a review was available, 10 (41.7%) cited at least 1 review; Cochrane reviews were cited in 20% and non-Cochrane reviews in 35.3%.In the case of Actas Dermosifiliográficas, very few clinical trials were found and the findings for narrative review articles were similar to those observed for the other journals. ConclusionsSystematic reviews are not often taken into account by the authors of clinical trials and narrative reviews and this may lead to redundant studies and publications. Authors appear to use Cochrane reviews even less than non-Cochrane reviews and are therefore ignoring one of the main sources of available evidence.