Maintaining relevance in HIV systematic reviews: an evaluation of Cochrane reviews.
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ABSTRACT:
SUBMITTER: Eshun-Wilson I
PROVIDER: S-EPMC6366015 | biostudies-literature | 2019 Feb
REPOSITORIES: biostudies-literature
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Project description:Systematic reviews (SRs) are considered an important tool for decision-making. There has been no recent comprehensive identification or description of child-relevant SRs. A description of existing child-relevant SRs would help to identify the extent of available child-relevant evidence available in SRs and gaps in the evidence base where SRs are required. The objective of this study was to describe child-relevant SRs from the Cochrane Database of Systematic Reviews (CDSR, Issue 2, 2009).SRs were assessed for relevance using pre-defined criteria. Data were extracted and entered into an electronic form. Univariate analyses were performed to describe the SRs overall and by topic area.The search yielded 1666 SRs; 793 met the inclusion criteria. 38% of SRs were last assessed as up-to-date prior to 2007. Corresponding authors were most often from the UK (41%). Most SRs (59%) examined pharmacological interventions. 53% had at least one external source of funding. SRs included a median of 7 studies (IQR 3, 15) and 679 participants (IQR 179, 2833). Of all studies, 48% included only children, and 27% only adults. 94% of studies were published in peer-reviewed journals. Primary outcomes were specified in 72% of SRs. Allocation concealment and the Jadad scale were used in 97% and 25% of SRs, respectively. Adults and children were analyzed separately in 12% of SRs and as a subgroup analysis in 14%. Publication bias was assessed in only 14% of SRs. A meta-analysis was conducted in 68% of SRs with a median of 5 trials (IQR 3, 9) each. Variations in these characteristics were observed across topic areas.We described the methodological characteristics and rigour of child-relevant reviews in the CDSR. Many SRs are not up-to-date according to Cochrane criteria. Our study describes variation in conduct and reporting across SRs and reveals clinicians' ability to access child-specific data.
| S-EPMC2881081 | biostudies-other
Project description:BackgroundSystematic reviews with meta-analyses often contain many statistical tests. This multiplicity may increase the risk of type I error. Few attempts have been made to address the problem of statistical multiplicity in systematic reviews. Before the implications are properly considered, the size of the issue deserves clarification. Because of the emphasis on bias evaluation and because of the editorial processes involved, Cochrane reviews may contain more multiplicity than their non-Cochrane counterparts. This study measured the quantity of statistical multiplicity present in a population of systematic reviews and aimed to assess whether this quantity is different in Cochrane and non-Cochrane reviews.Methods/principal findingsWe selected all the systematic reviews published by the Cochrane Anaesthesia Review Group containing a meta-analysis and matched them with comparable non-Cochrane reviews. We counted the number of statistical tests done in each systematic review. The median number of tests overall was 10 (interquartile range (IQR) 6 to 18). The median was 12 in Cochrane and 8 in non-Cochrane reviews (difference in medians 4 (95% confidence interval (CI) 2.0-19.0). The proportion that used an assessment of risk of bias as a reason for doing extra analyses was 42% in Cochrane and 28% in non-Cochrane reviews (difference in proportions 14% (95% CI -8 to 36). The issue of multiplicity was addressed in 6% of all the reviews.Conclusion/significanceStatistical multiplicity in systematic reviews requires attention. We found more multiplicity in Cochrane reviews than in non-Cochrane reviews. Many of the reasons for the increase in multiplicity may well represent improved methodological approaches and greater transparency, but multiplicity may also cause an increased risk of spurious conclusions. Few systematic reviews, whether Cochrane or non-Cochrane, address the issue of multiplicity.
| S-EPMC3229598 | biostudies-literature
Project description:Objectivesour study had two objectives: a) to systematically identify all existing systematic reviews of Chinese herbal medicines (CHM) published in Cochrane Library; b) to assess the methodological quality of included reviews.Methodology/principal findingsWe performed a systematic search of the Cochrane Database of Systematic Reviews (CDSR, Issue 5, 2010) to identify all reviews of CHM. A total of fifty-eight reviews were eligible for our study. Twenty-one of the included reviews had at least one Traditional Chinese Medicine (TCM) practitioner as its co-author. 7 reviews didn't include any primary study, the remaining reviews (n = 51) included a median of 9 studies and 936 participants. 50% of reviews were last assessed as up-to-date prior to 2008. The questions addressed by 39 reviews were broad in scope, in which 9 reviews combined studies with different herbal medicines. For OQAQ, the mean of overall quality score (item 10) was 5.05 (95% CI; 4.58-5.52). All reviews assessed the methodological quality of primary studies, 16% of included primary studies used adequate sequence generation and 7% used adequate allocation concealment. Of the 51 nonempty reviews, 23 reviews were reported as being inconclusive, while 27 concluded that there might be benefit of CHM, which was limited by the poor quality or inadequate quantity of included studies. 58 reviews reported searching a median of seven electronic databases, while 10 reviews did not search any Chinese database.ConclusionsNow CDSR has included large numbers of CHM reviews, our study identified some areas which could be improved, such as almost half of included reviews did not have the participation of TCM practitioners and were not up-to-date according to Cochrane criteria, some reviews pooled the results of different herbal medicines and ignored the searching of Chinese databases.
| S-EPMC3235143 | biostudies-literature
Project description:BackgroundIn contemporary medical research, randomised controlled trials are seen as the gold standard for establishing treatment effects where it is ethical and practical to conduct them. In palliative care such trials are often impractical, unethical, or extremely difficult, with multiple methodological problems. We review the utility of Cochrane reviews in informing palliative care practice.MethodsPublished reviews in palliative care registered with the Cochrane Pain, Palliative and Supportive Care Group as of December 2007 were obtained from the Cochrane Database of Systematic Reviews, issue 1, 2008. We reviewed the quality and quantity of primary studies available for each review, assessed the quality of the review process, and judged the strength of the evidence presented. There was no prior intention to perform any statistical analyses.Results25 published systematic reviews were identified. Numbers of included trials ranged from none to 54. Within each review, included trials were heterogeneous with respect to patients, interventions, and outcomes, and the number of patients contributing to any single analysis was generally much lower than the total included in the review. A variety of tools were used to assess trial quality; seven reviews did not use this information to exclude low quality studies, weight analyses, or perform sensitivity analysis for effect of low quality. Authors indicated that there were frequently major problems with the primary studies, individually or in aggregate. Our judgment was that the reviewing process was generally good in these reviews, and that conclusions were limited by the number, size, quality and validity of the primary studies.We judged the evidence about 23 of the 25 interventions to be weak. Two reviews had stronger evidence, but with limitations due to methodological heterogeneity or definition of outcomes. No review provided strong evidence of no effect.ConclusionCochrane reviews in palliative care are well performed, but fail to provide good evidence for clinical practice because the primary studies are few in number, small, clinically heterogeneous, and of poor quality and external validity. They are useful in highlighting the weakness of the evidence base and problems in performing trials in palliative care.
| S-EPMC2532992 | biostudies-literature
Project description:BACKGROUND:Despite the growing reputation and subject coverage of the Cochrane Database of Systematic Reviews, many systematic reviews continue to be published solely in paper-based health care journals. This study was designed to determine why authors choose to publish their systematic reviews outside of the Cochrane Collaboration and if they might be interested in converting their reviews to Cochrane format for publication in the Cochrane Database of Systematic Reviews. METHODS:Cross-sectional survey of Australian primary authors of systematic reviews not published on the Cochrane Database of Systematic Reviews identified from the Database of Abstracts of Reviews of Effectiveness. RESULTS:We identified 88 systematic reviews from the Database of Abstracts of Reviews of Effectiveness with an Australian as the primary author. We surveyed 52 authors for whom valid contact information was available. The response rate was 88 per cent (46/52). Ten authors replied without completing the survey, leaving 36 valid surveys for analysis. The most frequently cited reasons for not undertaking a Cochrane review were: lack of time (78%), the need to undergo specific Cochrane training (46%), unwillingness to update reviews (36%), difficulties with the Cochrane process (26%) and the review topic already registered with the Cochrane Collaboration (21%). (Percentages based on completed responses to individual questions.) Nearly half the respondents would consider converting their review to Cochrane format. Dedicated time emerged as the most important factor in facilitating the potential conversion process. Other factors included navigating the Cochrane system, assistance with updating and financial support. Eighty-six per cent were willing to have their review converted to Cochrane format by another author. CONCLUSION:Time required to complete a Cochrane review and the need for specific training are the primary reasons why some authors publish systematic reviews outside of the Cochrane Collaboration. Encouragingly, almost half of the authors would consider converting their review to Cochrane format. Based on the current number of reviews in the Database of Abstracts of Reviews of Effectiveness, this could result in more than 700 additional Cochrane reviews. Ways of supporting these authors and how to provide dedicated time to convert systematic reviews needs further consideration.
| S-EPMC149345 | biostudies-literature
Project description:BackgroundChinese herbal medicines (CHMs) are the major interventions of traditional Chinese medicine (TCM), which are typically administered as either single herbs or formulas. The Cochrane systematic reviews (SRs) of CHMs are essential references for evaluating the efficacy and safety of CHMs interventions; they are expected to be accurate and reliable. This study aimed to assess the reporting quality of these SRs, particularly whether necessary information related to CHM was adequately reported.MethodsThe Cochrane Database was systematically searched for all SRs of CHM that were published up to 31 December 2017. The primary analysis was to assess their reporting quality based on 27-item of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and 9-item of CHM-related information designed according to TCM theory. Descriptive statistics were additionally used to analyze their baseline characteristics.ResultsA total of 109 Cochrane SRs of CHM were identified from 1999 to 2017. For 27-item of PRISMA, 26 had the reporting compliances higher than 50%, of which 11 were fully reporting (100%). However, for CHM-related information, 65 (59.6%) SRs did not report the specific name of the CHM in the title, 42 (38.5%) lacked TCM-related rationales in the introduction, 62 (56.9%) did not include CHM-related characteristics in the additional analyses, and 77 (70.6%) did not analyze CHM results in terms of TCM-related theories in the discussion. Of 97 SRs that included clinical trials, 38 (39.2%) did not provide the details of composition and dosage of CHMs, 85 (87.6%) did not report the CHM sources, 13 (13.4%) did not provide the dosage form, 95 (97.9%) lacked CHM quality control information, and 57 (58.8%) did not describe details of the controls. For 62 (72.9%) of 85 SRs that included meta-analysis, it was impossible to assess whether meta-analysis had been properly conducted due to inadequate reporting of CHM interventions.ConclusionAlthough the Cochrane SRs of CHM showed reporting compliance with PRISMA checklist, their reporting quality needs improvement, especially about full reporting of CHM interventions and of TCM-related rationales. Reporting guideline of "PRISMA extension for CHM interventions" should be developed thus to improve their quality.
| S-EPMC6892158 | biostudies-literature
Project description:BackgroundMany systematic reviews of clinical trials on acupuncture were performed within the Cochrane Collaboration, the evidence-based medicine (EBM) most recognized organization. Objective of the article was to systematically collect and identify systematic reviews of acupuncture published in the Cochrane Library and assess their quality from a methodological perspective.MethodsA comprehensive literature search was performed in the Cochrane Database of Systematic Reviews to identify the reviews of acupuncture conducted until June 2019. The methodological quality of the included reviews was assessed using the AMSTAR 2 checklist, an evaluation tool for systematic reviews.ResultsOut of a total of 126 eligible reviews, 50 systematic reviews were included. According to the AMSTAR 2, 52% of Cochrane Systematic Reviews (CSRs) were of low quality, due to the presence of one or more weaknesses in at least one of the domains defined as critical for the methodological quality assessment. The less satisfied critical domain was inadequate investigation and discussion of publication bias. Declaration of potential sources of conflict of interest, and funding of the authors of the review and of the included studies were other important weaknesses.ConclusionsThe main methodological flaws in the included CSRs were related to topics of relatively new concern in the conduction of systematic reviews of the literature. However, both, lack of attention about retrieval of negative studies, and statements about conflict of interests are crucial point for the evaluation of therapeutic interventions according to EBM methodology.
| S-EPMC7556594 | biostudies-literature
Project description:ObjectiveTo compare cancer-related systematic reviews (SRs) published in the Cochrane Database of SRs (CDSR) and high-impact journals, with respect to type, content, quality and citation rates.DesignMethodological SR with assessment and comparison of SRs and meta-analyses. Two authors independently assessed methodological quality using an Assessment of Multiple Systematic Reviews (AMSTAR)-based extraction form. Both authors independently screened search results, extracted content-relevant characteristics and retrieved citation numbers of the included reviews using the Clarivate Analytics Web of Science database.Data sourcesCancer-related SRs were retrieved from the CDSR, as well as from the 10 journals which publish oncological SRs and had the highest impact factors, using a comprehensive search in both the CDSR and MEDLINE.Eligibility criteria for selecting studiesWe included all cancer-related SRs and meta-analyses published from January 2011 to May 2016. Methodological SRs were excluded.ResultsWe included 346 applicable Cochrane reviews and 215 SRs from high-impact journals. Cochrane reviews consistently met more individual AMSTAR criteria, notably with regard to an a priori design (risk ratio (RR) 3.89; 95%?CI 3.10 to 4.88), inclusion of the grey literature and trial registries (RR 3.52; 95%?CI 2.84 to 4.37) in their searches, and the reporting of excluded studies (RR 8.80; 95%?CI 6.06 to 12.78). Cochrane reviews were less likely to address questions of prognosis (RR 0.04; 95%?CI 0.02 to 0.09), use individual patient data (RR 0.03; 95%?CI 0.01 to 0.09) or be based on non-randomised controlled trials (RR 0.04; 95%?CI 0.02 to 0.09). Citation rates of Cochrane reviews were notably lower than those for high-impact journals (Cochrane reviews: mean number of citations 6.52 (range 0-143); high-impact journal SRs: 74.45 (0-652)).ConclusionsWhen comparing cancer-related SRs published in the CDSR versus those published in high-impact medical journals, Cochrane reviews were consistently of higher methodological quality, but cited less frequently.
| S-EPMC5875625 | biostudies-literature
Project description:BackgroundDiscrepancies in outcome reporting (DOR) between protocol and published studies include inclusions of new outcomes, omission of prespecified outcomes, upgrade and downgrade of secondary and primary outcomes, and changes in definitions of prespecified outcomes. DOR can result in outcome reporting bias (ORB) when changes in outcomes occur after knowledge of results. This has potential to overestimate treatment effects and underestimate harms. This can also occur at the level of systematic reviews when changes in outcomes occur after knowledge of results of included studies. The prevalence of DOR and ORB in systematic reviews is unknown in systematic reviews published post-2007.ObjectiveTo estimate the prevalence of DOR and risk of ORB in all Cochrane reviews between the years 2007 and 2014.MethodsA stratified random sampling approach was applied to collect a representative sample of Cochrane systematic reviews from each Cochrane review group. DOR was assessed by matching outcomes in each systematic review with their respective protocol. When DOR occurred, reviews were further assessed if there was a risk of ORB (unclear, low or high risk). We classified DOR as a high risk for ORB if the discrepancy occurred after knowledge of results in the systematic review.Results150 of 350 (43%) review and protocol pairings contained DOR. When reviews were further scrutinised, 23% (35 of 150) of reviews with DOR contained a high risk of ORB, with changes being made after knowledge of results from individual trials.ConclusionsIn our study, we identified just under a half of Cochrane reviews with at least one DOR. Of these, a fifth were at high risk of ORB. The presence of DOR and ORB in Cochrane reviews is of great concern; however, a solution is relatively simple. Authors are encouraged to be transparent where outcomes change and to describe the legitimacy of changing outcomes in order to prevent suspicion of bias.
| S-EPMC7076244 | biostudies-literature
Project description:BackgroundThere has been a growing emphasis on evidence-informed decision-making in health care. Systematic reviews, such as those produced by the Cochrane Collaboration, have been a key component of this movement. The UK National Institute for Health Research (NIHR) Systematic Review Programme currently supports 20 Cochrane Review Groups (CRGs). The aim of this study was to identify the impacts of Cochrane reviews published by NIHR-funded CRGs during the years 2007-2011.MethodsWe sent questionnaires to CRGs and review authors, interviewed guideline developers and used bibliometrics and documentary review to get an overview of CRG impact and to evaluate the impact of a sample of 60 Cochrane reviews. We used a framework with four categories (knowledge production, research targeting, informing policy development and impact on practice/services).ResultsA total of 1,502 new and updated reviews were produced by the 20 NIHR-funded CRGs between 2007 and 2011. The clearest impacts were on policy with a total of 483 systematic reviews cited in 247 sets of guidance: 62 were international, 175 national (87 from the UK) and 10 local. Review authors and CRGs provided some examples of impact on practice or services, for example, safer use of medication, the identification of new effective drugs or treatments and potential economic benefits through the reduction in the use of unproven or unnecessary procedures. However, such impacts are difficult to objectively document, and the majority of reviewers were unsure if their review had produced specific impacts. Qualitative data suggested that Cochrane reviews often play an instrumental role in informing guidance, although a poor fit with guideline scope or methods, reviews being out of date and a lack of communication between CRGs and guideline developers were barriers to their use.ConclusionsHealth and economic impacts of research are generally difficult to measure. We found that to be the case with this evaluation. Impacts on knowledge production and clinical guidance were easier to identify and substantiate than those on clinical practice. Questions remain about how we define and measure impact, and more work is needed to develop suitable methods for impact analysis.
| S-EPMC4238314 | biostudies-literature