scholarly journals Factors underpinning discrepant findings from reviews on the same topic: A systematic analysis of Cochrane and non-Cochrane reviews

2019 ◽  
Author(s):  
Claudia Hacke ◽  
David Nunan
Keyword(s):  
Systematic Reviews ◽  
Methodological Quality ◽  
Data Extraction ◽  
Meta Analysis ◽  
List Type ◽  
Eligibility Criteria ◽  
Cochrane Reviews ◽  
And Performance ◽  
Meta Analyses

AbstractObjectiveTo explore factors underpinning discrepancies in reported pooled effect estimates from Cochrane and non-Cochrane systematic reviews answering the same question.Study Design and SettingWe observed discrepant pooled effects in 23 out of 24 pairs of meta-analyses from Cochrane and non-Cochrane systematic reviews answering the same question. Here we present the results of a systematic assessment of methodological quality and factors that explain the observed quantitative discrepancies. Methodological quality of each review was assessed using AMSTAR (Assessing the Methodological Quality of Systematic Reviews). Matched pairs were contrasted at the macro- (review methodology), meso- (application of methodology) and micro- (data extraction) level and reasons for differences were derived.ResultsAll Cochrane reviews had high methodological quality (AMSTAR 8-11), whereas the majority (87.5%) of non-Cochrane reviews were classified as moderate (AMSTAR 4-7). Only one pair included exactly the same studies for their respective meta-analyses but there was still a discrepancy in the pooled estimate due to differences in data extraction. One pair did not include any study of its match and for one pair the same effect estimates were reported despite inclusion of different studies. The remaining pairs included at least one study in their match. Due to insufficient reporting (predominantly affecting non-Cochrane reviews) we were only able to completely ascertain the reasons for discrepancies in all included studies for 9/24 (37.5%) pairs. Across all pairs, differences in pre-defined methods (macro-level) including search strategy, eligibility criteria and performance of dual screening could possibly explain mismatches in included studies. Study selection procedures (meso-level) including disagreements in the interpretation of pre-defined eligibility criteria (14 matches) were identified as reasons underpinning discrepant review findings. Comparison of data extraction from primary studies (micro-level) was not possible in 13/24 pairs as a result of the non-Cochrane review providing insufficient details of the studies included in their meta-analyses. Two out of 24 pairs completely agreed on the numerical data presented for the same studies in their respective meta-analysis. Both review types provided sufficient information to check the accuracy of data extraction for 8 pairs (45 studies) where there were discrepancies. An assessment of 50% (22 studies) of these showed that reasons for differences in extracted data could be identified in 15 studies. We found examples for both types of review where data presented were discrepant from that given in the source study without a plausible explanation.ConclusionMethodological and author judgements and performance are key aspects underpinning poor overlap of included studies and discrepancies in reported pooled effect estimates between topic-matched reviews. Though caution must be taken when extrapolating, our findings raise the question as to what extent the entire meta-analysis evidence-base accurately reflects the available primary research both in terms of volume and data. Reinforcing awareness of the application of guidelines for systematic reviews and meta-analyses may help mitigate some of the key issues identified in our analysis.What is new?Key findings Non-Cochrane reviews were of a lower overall methodological quality compared with Cochrane reviews. Discrepant results of meta-analyses on the same topic can be attributed to differences in included studies based on review author decision, judgements and performance at different stages of the review process.What this adds to what was known?This study provides the most robust analysis to date of the potential methodological factors underpinning discrepant review findings between matched meta-analyses answering the same question. Assessing differences between reviews at the macro-, meso-, and micro-levels is a useful method to identify reasons for discrepant meta-analyses at key stages of the review process.What is the implication and what should change now?There is a need for a standardised approach to performing matched-pair analysis of meta-analyses and systematic reviews answering the same question. Our paper provides a base for this that can be refined by replication and expert consensus.

scholarly journals Systematic Reviews and Meta-Analysis in Spine Surgery—How Good Are They in Methodological Quality? A Systematic Review

2020 ◽  
pp. 219256822090681 ◽  
Author(s):  
Muthu Sathish ◽  
Ramakrishnan Eswar
Keyword(s):  
Systematic Review ◽  
Spine Surgery ◽  
Systematic Reviews ◽  
Methodological Quality ◽  
Meta Analysis ◽  
Eligibility Criteria ◽  
Cochrane Database ◽  
Critical Flaw ◽  
Meta Analyses

Study Design: Systematic review. Objectives: To assess the methodological quality of systematic reviews and meta-analyses in spine surgery over the past 2 decades. Materials and Methods: We conducted independent and in duplicate systematic review of the published systematic reviews and meta-analyses between 2000 and 2019 from PubMed Central and Cochrane Database pertaining to spine surgery involving surgical intervention. We searched bibliographies to identify additional relevant studies. Methodological quality was evaluated with AMSTAR score and graded with AMSTAR 2 criteria. Results: A total of 96 reviews met the eligibility criteria, with mean AMSTAR score of 7.51 (SD = 1.98). Based on AMSTAR 2 criteria, 13.5% (n = 13) and 18.7% (n = 18) of the studies had high and moderate level of confidence of results, respectively, without any critical flaws. A total of 29.1% (n = 28) of the studies had at least 1 critical flaw and 38.5% (n = 37) of the studies had more than 1 critical flaw, so that their results have low and critically low confidence, respectively. Failure to analyze the conflict of interest of authors of primary studies included in review and lack of list of excluded studies with justification were the most common critical flaw. Regression analysis demonstrated that studies with funding and studies published in recent years were significantly associated with higher methodological quality. Conclusion: Despite improvement in methodological quality of systematic reviews and meta-analyses in spine surgery in current decade, a substantial proportion continue to show critical flaws. With increasing number of review articles in spine surgery, stringent measures must be taken to adhere to methodological quality by following PRISMA and AMSTAR guidelines to attain higher standards of evidence in published literature.

scholarly journals Methodological Quality Assessment of Systematic Review or Meta-Analysis Using AMSTAR-2: the Long-Term Effectiveness or Efficacy of Opioids for Chronic Non-Cancer Pain

2019 ◽  
Author(s):  
Qian Li ◽  
Ke Deng ◽  
Xiaoyuan Jiang ◽  
Huan Tao ◽  
Hui Liu ◽  
...  
Keyword(s):  
Cancer Pain ◽  
Systematic Reviews ◽  
Methodological Quality ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Cochrane Central Register ◽  
Cochrane Reviews ◽  
Meta Analyses

Abstract Background：Systematic review or meta-analysis, the strong study design of high quality evidence, give inconsistent conclusion of long-term effectiveness or efficacy of opioids for chronic non-cancer pain. We appraised the methodological quality of systematic reviews or meta-analyses. Methods: We found the relevant systematic reviews or meta-analyses by searching Medline, EMBASE, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, the International prospective register of systematic reviews, Psyc ARTICLES/OVID, the Chinese Bio-Medical Literature Database, the China National Knowledge Infrastructure, and the Wan Fang Data and VIP Database on March 1st, 2019. The methodological quality was assessed by A Measurement Tool to Assess Systematic Reviews-2(AMSTAR-2). Spearman correlation analysis and non-parametric tests were used to assess the association between quality and factors. Results: Twenty-one systematic reviews or meta-analyses were included in our study. One has no individual study. In terms of methodological quality, twelve reviews were critically low in overall confidence, four reviews were low, two reviews were moderate, two reviews were high. When referring to the systematic reviews or meta-analyses of relatively better methodological quality with more credible results and conclusions, the effectiveness or efficacy of opioids was small to questionable. Cochrane reviews performed better than non-Cochrane reviews in establishing prior protocol (100% vs 17%, P<0.05), providing an excluded studies list (100% vs 50%, P<0.05) and taking risk of bias into account when interpreting the results of the review (100% vs 75%, P<0.05). There was a strong correlation (ρ=0.526, P<0.05) between the impact factor of systematic reviews or meta-analyses in published journals and methodological quality. Conclusion The methodological quality of the included systematic reviews or meta-analyses is far from satisfactory and needs improvement, especially in establishing prior protocol and justifying significant deviations from the protocol, providing an excluded primary studies list, reporting the funding information of primary studies, and assessing the potential impact of risk of bias on individual studies.

scholarly journals Inconsistencies are common between non-Cochrane systematic reviews and their protocols registered in the International prospective register of systematic reviews (PROSPERO) but were seldom explained

2020 ◽  
Author(s):  
Kaiyan Hu ◽  
Ting Zhang ◽  
Weiyi Zhang ◽  
Qi Zhou ◽  
Mengyao Jiang New ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Data Extraction ◽  
Meta Analysis ◽  
Reporting Quality ◽  
Fundamental Solutions ◽  
Cochrane Reviews ◽  
Or Methodology ◽  
Retrospective Comparative Study ◽  
The Impact

Abstract Background: Protocols of systematic reviews allow for planning and documentation of review methods and thus improve the transparency of the reviews process. However, pre-registration of a protocol is not enough, the author also need to follow it. PROSPERO is an open-access online database for the registration of non-Cochrane systematic reviews. The purpose of this study is to compare published non-Cochrane reviews with their pre-registered protocols on PROSPERO to determine what changes, if any, have been made, and how likely these changes are to impact the quality of systematic review. Methods: This is a retrospective comparative study. We searched for protocols on PROSPERO platform that were registered in 2018 and then selected the protocols that full text have been published as of January 1st 2019. Published full texts were identified through the protocol's final publication citation. Two authors independently compared and identified changes between protocols and systematic reviews and then evaluated the impact (improve, reduce, or unclear) of these changes on the reporting or methodology quality of reviews. Descriptive statistics of percentage (%) and frequency (n) were conducted. Results: We identified 39 pairs, all of which exhibited changes. “Search strategy”(92%, n=36), “data extraction”(90%, n=35), “data synthesis”(77%, n=30), “outcome”(64%, n=24), and “subgroup analysis”(64%, n=24) all showed significant changes. All changes to only one review were considered to improve the reporting or methodology quality, and the remaining 97% of reviews (n=38) contained changes that were considered to reduce the methodology or reporting quality or that had an unclear impact on systematic reviews. Conclusions: Changes between the non-Cochrane systematic reviews and their protocols recorded on PROSPERO were widespread. Some of the changes reduced the methodology or reporting quality of systematic reviews or had an unclear impact. Measures should be taken to further improve the transparency of the non-Cochrane systematic reviews. Adding a new item in updated “Preferred Reporting Items for Systematic reviews and Meta-Analyses” (PRISMA) and “Meta-analysis of Observational Studies in Epidemiology” (MOOSE) to guide reporting and explaining the changes, as well as advising peer reviewers (and editors) to check the reviews against the protocols are two suggested fundamental solutions.

P14.71 An assessment of the reporting and methodological quality of meningioma systematic reviews and meta-analyses

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii51-ii52
Author(s):  
A M George ◽  
S Gupta ◽  
S M Keshwara ◽  
M A Mustafa ◽  
C S Gillespie ◽  
...  
Keyword(s):  
Systematic Review ◽  
Systematic Reviews ◽  
Methodological Quality ◽  
Meta Analysis ◽  
Neurofibromatosis Type ◽  
Risk Of Bias ◽  
Measurement Tool ◽  
High Quality ◽  
Meta Analyses

Abstract BACKGROUND Systematic reviews and meta-analyses constitute the highest level of research evidence and for a disease with limited clinical trial activity, are often relied upon to help inform clinical practice. This review of reviews evaluates both the reporting & methodological quality of meningioma evidence syntheses. MATERIAL AND METHODS Potentially eligible meningioma reviews published between 1st January 1990 and 31st December 2020 were identified from eight electronic databases. Inclusion required the study to meet the Cochrane guideline definition of a systematic review or meta-analysis. Reviews concerning neurofibromatosis type 2, spinal and pediatric meningiomas were excluded. The reporting and methodological quality of articles were assessed against the following modified guidelines: Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), A MeaSurement Tool to Assess Systematic Reviews (AMSTAR2) and the Risk of Bias in Systematic Reviews (ROBIS) guidelines. RESULTS 117 systematic reviews were identified, 57 of which included meta-analysis (48.7%). The number of meningioma systematic reviews published each year has increased with 63 studies (53.9%) published between 01/2018 and 12/2020. A median of 17 studies (IQR 9–29) were included per review. Impact factor of journals publishing a systematic review with or without a meta-analysis was similar (median 2.3 vs 1.8, P=0.397). The mean PRISMA scores for systematic reviews with a meta-analysis was 21.11 (SD 4.1, 78% adherence) and without was 13.89 (SD 3.4, 63% adherence). Twenty-nine systematic reviews with meta-analysis (51%) and 11 without meta-analysis (18%) achieved greater than 80% adherence to PRISMA recommendations. Methodological quality assessment using AMSTAR2 revealed one study (0.9%) as high quality whilst 111 (94.8%) studies were graded as critically low. One hundred and two articles (87.2%) did not utilize a comprehensive search strategy as defined by the AMSTAR2 tool. Ninety-nine studies (84.6%) obtained a high level of concern for potential bias as per the ROBIS assessment. One hundred and eight articles (92.3%) failed to present information that a protocol had been established prior to study commencement and 76 articles (65.0%) did not conduct a risk of bias assessment. Across the three tools, domains relating to the establishment of a protocol prior to review commencement and conducting appropriate risk of bias assessments were frequently low scoring. CONCLUSION Overall reporting and methodological quality of meningioma systematic reviews was sub-optimal. Established critical appraisal tools and reporting guidelines should be utilized a priori to assist in producing high-quality systematic reviews.

scholarly journals Overview of systematic reviews - a new type of study. Part II

2014 ◽  
Vol 133 (3) ◽  
pp. 206-217 ◽  
Author(s):  
Valter Silva ◽  
Antonio Jose Grande ◽  
Alan Pedrosa Viegas de Carvalho ◽  
Ana Luiza Cabrera Martimbianco ◽  
Rachel Riera
Keyword(s):  
Systematic Reviews ◽  
Methodological Quality ◽  
Meta Analysis ◽  
Quality Of Evidence ◽  
Overview Of Systematic Reviews ◽  
New Type ◽  
The Mean ◽  
Meta Analyses ◽  
General Profile

CONTEXT AND OBJECTIVE: Overviews of Systematic Reviews (OoRs) are a new type of study in which multiple evidence from systematic reviews (SRs) is compiled into an accessible and useful document. The aim here was to describe the state of the art and critically assess Cochrane OoRs that have been published.DESIGN AND SETTING: Descriptive study conducted at a research center.METHODS: The OoRs identified through the filter developed in Part I of this study were evaluated in five domains: methodological quality; quality of evidence; implications for practice; general profile of OoRs; and length of work.RESULTS: All 13 OoRs included had high methodological quality. Some OoRs did not present sufficient data to judge the quality of evidence; using sensitivity analysis, the quality of evidence of the OoRs increased. Regarding implications for practice, 64% of the interventions were judged as beneficial or harmful, while 36% of them showed insufficient evidence for judgment. It is expected (with 95% confidence interval) that one OoR will include 9,462 to 64,469 patients, 9 to 29 systematic reviews and 80 to 344 primary studies, and assess 6 to 21 interventions; and that 50 to 92% of OoRs will produce meta-analysis. The OoRs generated 2 to 26 meta-analyses over a period of 18 to 31 months.CONCLUSION: The OoRs presented high methodological quality; the quality of evidence tended to be moderate/high; most interventions were judged to be beneficial/harmful; the mean length of work was 24 months. The OoR profile adds power to decision-making.

Evaluation of Spin in the Abstracts of Systematic Reviews and Meta-Analyses of Atopic Dermatitis Treatments and Interventions

Dermatology ◽  
2021 ◽  
pp. 1-10
Author(s):  
Vanessa Lin ◽  
Raahi Patel ◽  
Alexis Wirtz ◽  
Deepika Mannem ◽  
Ryan Ottwell ◽  
...  
Keyword(s):  
Atopic Dermatitis ◽  
Systematic Reviews ◽  
Methodological Quality ◽  
Data Extraction ◽  
Included Study ◽  
Primary Objective ◽  
Quality Of Reporting ◽  
Study Characteristics ◽  
Meta Analyses

<b><i>Background:</i></b> Spin – the misrepresentation of a study’s results – has been identified in abstracts of studies focused on a variety of disorders from multiple fields of medicine. <b><i>Objectives:</i></b> This study’s primary objective was to evaluate the abstracts of systematic reviews and meta-analyses focused on the treatment of atopic dermatitis for the nine most severe forms of spin. <b><i>Methods:</i></b> We systematically searched Embase and MEDLINE for systematic reviews of atopic dermatitis therapies. Screening and data extraction occurred in a masked, duplicate fashion. Each included study was evaluated for the nine most severe types of spin and other study characteristics. <b><i>Results:</i></b> Our searches retrieved 2,456 studies, of which 113 were included for data extraction. Spin was found in 74.3% of our included studies (84/113). Spin type 6 occurred most frequently (68/113, 60.2%). Spin types 1, 2, and 9 were not identified. All industry-funded systematic reviews contained spin in their abstract. The presence of spin was not associated with any specific study characteristics, including the methodological quality of the study. <b><i>Conclusions:</i></b> Severe forms of spin were found in the majority of abstracts for systematic reviews of atopic dermatitis treatments. Steps should be taken to prevent spin to improve the quality of reporting in abstracts.

scholarly journals Evaluating the Quality of the Iranian Systematic Reviews, Meta-Analyses, and Economic Evaluations in Healthcare from 2005 to 2015

2021 ◽  
Author(s):  
Morteza Arab-Zozani ◽  
Zahra Heidarifard ◽  
Efat Jabarpour
Keyword(s):  
Systematic Review ◽  
Systematic Reviews ◽  
Methodological Quality ◽  
Time Horizon ◽  
Meta Analysis ◽  
Economic Evaluations ◽  
Evidence Based ◽  
Economic Perspective ◽  
Meta Analyses

Context: The number of studies on health is increasing rapidly worldwide and in Iran. Systematic review studies, meta-analyses, and economic evaluation are of great importance in evidence-based decision making because of their standing in the evidence-based pyramid. The purpose of this study was to evaluate the reporting and methodological quality of Iranian systematic reviews, meta-analysis studies and economic evaluations on healthcare. Evidence Acquisition: PubMed and Scopus databases were searched to find considered studies, including systematic reviews, meta analyses and economic evaluations published from 2005 to 2015. Because of the high volume of review studies, 10% of all systematic reviews and meta-analyses were selected as a random sample. Also, all economic evaluations were included. Articles were evaluated using checklists, including PRISMA, AMSTAR and QHES with a maximum score of 27, 11 and 100, respectively. The quality score for each criterion as well as the epidemiological and descriptive characteristics of all articles was determined. Data were analyzed using SPSS V. 16 software. Results: After searching the databases, 1084 systematic reviews and meta-analyses were obtained, 10% of which were included in the study. A total of 41 economic evaluations were also included. The mean scores of systematic reviews and meta-analyses based on PRISMA and AMSTAR checklists were 17.04 (5.35) and 5.42 (1.97), respectively, and 68.21 (12.44) for economic evaluations based on QHES. Only three systematic reviews and meta-analysis articles had recorded protocols and 85% of the studies included the terms “systematic review” and “meta-analysis” in their titles. Only one study had been updated. In addition, 81% of the systematic reviews and meta-analyses were published in specialized journals and 47% in Iranian journals. Financial resources and conflict of interests had been mentioned in 33% and 66% of the studies, respectively. Of the selected studies, 60% had evaluated the quality of the articles and 35% of the studies had assessed publication bias. In economic evaluations, 56% had used CEA analysis, 22% CUA analysis, 12% CBA analysis, and one study had used CMA analysis. Of these studies, 54% were model-based health economic studies and 12% were trial-based. The economic perspective was the health care system in most studies. Forty-four percent of the studies had a short time horizon of one year or less, whereas 33% had a lifetime horizon. Moreover, 68% of the studies showed sensitivity analysis and only 5 included the magnitude and direction of the bias. Conclusions: Overall, the reporting and methodological quality of the selected studies were estimated at a moderate level. Based on these results, it is recommended to adopt strategies to reduce preventable errors in studies. Having a primary plan and protocol and registering it as a systematic review can be an important factor in improving the quality of studies. Economic evaluations should also focus on issues, such as economic perspective, time horizon, available bias, and sensitivity analysis.

scholarly journals Low Methodological Quality of Systematic Reviews on Acupuncture: A Cross- Sectional Study

2021 ◽  
Author(s):  
Leonard TF Ho ◽  
Fiona YT Ke ◽  
Charlene HL Wong ◽  
Irene XY Wu ◽  
Andy KL Cheung ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Methodological Quality ◽  
Meta Analysis ◽  
A Priori ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Quality Ratings ◽  
Cochrane Reviews

Abstract Background: While well-conducted systematic reviews (SRs) can provide best evidence on the potential effectiveness of acupuncture, limitations on methodological rigour of SRs may impact trustworthiness of their conclusions. This cross-sectional study aimed to evaluate the methodological quality of a representative sample of SRs on acupuncture effectiveness.Methods: CDSR, MEDLINE, and EMBASE were searched for SRs on acupuncture. AMSTAR2 was applied for assessing methodological quality. Associations between bibliographical characteristics and methodological quality ratings were examined. Results: A total of 106 SRs were appraised. Only one (0.9%) SR was of high overall methodological quality, zero (0%) was of moderate-quality, six (5.7%) and 99 (93.4%) were of low-quality and critically low-quality respectively. Among appraised SRs, only ten (9.4%) provided an a priori protocol, four (3.8%) conducted a comprehensive literature search, five (4.7%) provided a list of excluded study, and six (5.7%) performed meta-analysis appropriately. Cochrane reviews, update reviews, reviews with corresponding authors from the America, and reviews that searched non-English databases had relatively higher overall quality. Conclusions: Methodological quality of SRs on acupuncture is unsatisfactory. Future reviewers should improve critical areas of publishing protocols, performing comprehensive search, providing a list of excluded studies with justifications for exclusion, and conducting meta-analysis appropriately.

Quality of meta-analyses of non-opioid, pharmacological, perioperative interventions for chronic postsurgical pain: a systematic review

2022 ◽  
pp. rapm-2021-102981
Author(s):  
Rachel H McGregor ◽  
Freda M Warner ◽  
Lukas D Linde ◽  
Jacquelyn J Cragg ◽  
Jill A Osborn ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Data Extraction ◽  
Meta Analysis ◽  
Measurement Tool ◽  
Critical Element ◽  
Postsurgical Pain ◽  
Chronic Postsurgical Pain ◽  
Registration Number ◽  
Meta Analyses

BackgroundIn an attempt to aggregate observations from clinical trials, several meta-analyses have been published examining the effectiveness of systemic, non-opioid, pharmacological interventions to reduce the incidence of chronic postsurgical pain.ObjectiveTo inform the design and reporting of future studies, the purpose of our study was to examine the quality of these meta-analyses.Evidence reviewWe conducted an electronic literature search in Embase, MEDLINE, and the Cochrane Database of Systematic Reviews. Published meta-analyses, from the years 2010 to 2020, examining the effect of perioperative, systemic, non-opioid pharmacological treatments on the incidence of chronic postsurgical pain in adult patients were identified. Data extraction focused on methodological details. Meta-analysis quality was assessed using the A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) critical appraisal tool.FindingsOur search yielded 17 published studies conducting 58 meta-analyses for gabapentinoids (gabapentin and pregabalin), ketamine, lidocaine, non-steroidal anti-inflammatory drugs, and mexiletine. According to AMSTAR 2, 88.2% of studies (or 15/17) were low or critically low in quality. The most common critical element missing was an analysis of publication bias. Trends indicated an improvement in quality over time and association with journal impact factor.ConclusionsWith few individual trials adequately powered to detect treatment effects, meta-analyses play a crucial role in informing the perioperative management of chronic postsurgical pain. In light of this inherent value and despite a number of attempts, high-quality meta-analyses are still needed.PROSPERO registration numberCRD42021230941.

scholarly journals A systematic assessment of Cochrane reviews and systematic reviews published in high-impact medical journals related to cancer

BMJ Open ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. e020869 ◽  
Author(s):  
Marius Goldkuhle ◽  
Vikram M Narayan ◽  
Aaron Weigl ◽  
Philipp Dahm ◽  
Nicole Skoetz
Keyword(s):  
Systematic Reviews ◽  
Methodological Quality ◽  
Grey Literature ◽  
High Impact ◽  
Impact Factors ◽  
High Impact Journal ◽  
Eligibility Criteria ◽  
Medical Journals ◽  
Cochrane Reviews ◽  
Meta Analyses

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.

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