A critical appraisal of the risk of bias in systematic reviews and metaanalyses pertaining to COVID-19

Background: We critically evaluated the risk of bias in published systematic reviews (SRs) and meta-analyses (MAs) pertaining to COVID-19 using ROBIS tool. Materials And Methods: Medline and Cochrane Central Library were searched for SRs/MAs on 14th May 2020, including studies of all designs describing various facets of COVID-19 in humans; no restrictions were applied for interventions, comparators, and outcomes. Two reviewers independently assessed all the SRs/MAs with ROBIS. Results: Out of 204 identified records, 48 SRs/MAs were included. The most frequently reviewed topics were therapy outcomes, diagnosis, and comorbidities (15, 8, and 6 papers respectively). Only 29/48(60.41%) papers had made a mention of using PRISMA or other guidelines for drafting the SR/MA. Only 5/48(10.42%) of all included SRs/MAs had low overall risk of bias as per ROBIS tool; 41/48(85.42%) had high risk of bias, 2/48(4.17%) had unclear risk of bias. The highest proportion of bias was found in data synthesis and findings (30/48, 62.50% of studies had high risk of bias), followed by study identification and selection (29/48, 60.42%). The IRR for methodological quality assessment was substantial, with the Cohen’s kappa values being 0.64, 0.68, 0.62, and 0.75 for domains 1-4 of ROBIS tool, and 0.66 for overall risk of bias assessment. Conclusion: There are serious concerns about the methodology employed to generate the results of the SRs/ MAs pertaining to COVID-19, with ‘quantity’ seemingly being given more importance than ‘quality’ of the paper.

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Evaluation of Industry Relationships Among Authors of Systematic Reviews and Meta-analyses Regarding Ménières Disease

Annals of Otology Rhinology & Laryngology ◽

10.1177/00034894211051822 ◽

2021 ◽

pp. 000348942110518

Author(s):

David Wenger ◽

Ross Nowlin ◽

Austin L. Johnson ◽

Michael Anderson ◽

Michael Weaver ◽

...

Keyword(s):

High Risk ◽

Systematic Reviews ◽

Conflicts Of Interest ◽

Cochrane Collaboration ◽

Risk Of Bias ◽

Inclusion Criteria ◽

Disease Treatment ◽

Bias Assessment ◽

Meta Analyses ◽

The Cochrane Collaboration

Objectives: To quantify the presence of conflicts of interest (COI) in SRs and MAs of Ménières disease treatment and identify any related secondary characteristics of these articles. Methods: A search was conducted on May 28, 2020 to search MEDLINE and Embase databases for SRs or MAs pertaining to Ménières disease published between September 1, 2016 and June 2, 2020. A risk of bias assessment was performed using the Cochrane Collaboration risk of bias assessment criteria. Results: A total of 13 systematic reviews conducted by 49 authors met the inclusion criteria. Of the 49 authors, 7 (14.3%) were found to have some form of COI. Of these 7 authors, 1 (14.3%) completely disclosed all COI within the SR, 1 (14.3%) disclosed one or more COI but were found to have an additional undisclosed COI, and 5 (71.4%) were found to have only undisclosed COI. One of 2 industry funded SRs (50%) had a high risk of bias, and 1 (50%) of the non-industry sponsored SRs were found to have a high risk of bias. Conclusions: Overall authors of SRs pertaining to Ménières disease appear to be properly disclosing COI at higher rates than other fields of medicine; however, further room for improvement has been noted.

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RobotReviewer: evaluation of a system for automatically assessing bias in clinical trials

Journal of the American Medical Informatics Association ◽

10.1093/jamia/ocv044 ◽

2015 ◽

Vol 23 (1) ◽

pp. 193-201 ◽

Cited By ~ 61

Author(s):

Iain J Marshall ◽

Joël Kuiper ◽

Byron C Wallace

Keyword(s):

Machine Learning ◽

Clinical Trials ◽

Systematic Reviews ◽

Risk Of Bias ◽

Reasonable Accuracy ◽

Bias Assessment ◽

Cochrane Database ◽

The Difference ◽

Using Data ◽

Unclear Risk

Abstract Objective To develop and evaluate RobotReviewer, a machine learning (ML) system that automatically assesses bias in clinical trials. From a (PDF-formatted) trial report, the system should determine risks of bias for the domains defined by the Cochrane Risk of Bias (RoB) tool, and extract supporting text for these judgments. Methods We algorithmically annotated 12,808 trial PDFs using data from the Cochrane Database of Systematic Reviews (CDSR). Trials were labeled as being at low or high/unclear risk of bias for each domain, and sentences were labeled as being informative or not. This dataset was used to train a multi-task ML model. We estimated the accuracy of ML judgments versus humans by comparing trials with two or more independent RoB assessments in the CDSR. Twenty blinded experienced reviewers rated the relevance of supporting text, comparing ML output with equivalent (human-extracted) text from the CDSR. Results By retrieving the top 3 candidate sentences per document (top3 recall), the best ML text was rated more relevant than text from the CDSR, but not significantly (60.4% ML text rated ‘highly relevant' v 56.5% of text from reviews; difference +3.9%, [−3.2% to +10.9%]). Model RoB judgments were less accurate than those from published reviews, though the difference was <10% (overall accuracy 71.0% with ML v 78.3% with CDSR). Conclusion Risk of bias assessment may be automated with reasonable accuracy. Automatically identified text supporting bias assessment is of equal quality to the manually identified text in the CDSR. This technology could substantially reduce reviewer workload and expedite evidence syntheses.

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

Neuro-Oncology ◽

10.1093/neuonc/noab180.178 ◽

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.

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A Reporting Quality Assessment of Systematic Reviews and Meta-Analyses in Sports Physical Therapy: A Review of Reviews

Healthcare ◽

10.3390/healthcare9101368 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1368

Author(s):

Sung-Hyoun Cho ◽

In-Soo Shin

Keyword(s):

Physical Therapy ◽

Systematic Reviews ◽

Literature Search ◽

Reporting Quality ◽

Risk Of Bias ◽

Evidence Based ◽

Reporting Practices ◽

Review Of Reviews ◽

Meta Analyses

This review of reviews aimed to evaluate the reporting quality of published systematic reviews and meta-analyses in the field of sports physical therapy using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This review of reviews included a literature search; in total, 2047 studies published between January 2015 and December 2020 in the top three journals related to sports physical therapy were screened. Among the 125 identified articles, 47 studies on sports physical therapy were included in the analysis (2 systematic reviews and 45 meta-analyses). There were several problems areas, including a lack of reporting for key components of the structured summary (10/47, 21.3%), protocol and registration (18/47, 38.3%), risk of bias in individual studies (28/47, 59.6%), risk of bias across studies (24/47, 51.1%), effect size and variance calculations (5/47, 10.6%), additional analyses (25/47, 53.2%), and funding (10/47, 21.3%). The quality of the reporting of systematic reviews and meta-analyses of studies on sports physical therapy was low to moderate. For better evidence-based practice in sports physical therapy, both authors and readers should examine assumptions in more detail, and report valid and adequate results. The PRISMA guideline should be used more extensively to improve reporting practices in sports physical therapy.

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Similarities, reliability and gaps in assessing the quality of conduct of systematic reviews using AMSTAR-2 and ROBIS: systematic survey of nutrition reviews

BMC Medical Research Methodology ◽

10.1186/s12874-021-01457-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Mateusz J. Swierz ◽

Dawid Storman ◽

Joanna Zajac ◽

Magdalena Koperny ◽

Paulina Weglarz ◽

...

Keyword(s):

Systematic Reviews ◽

Nutritional Intervention ◽

Risk Of Bias ◽

Cochrane Library ◽

Measurement Tool ◽

Eligibility Criteria ◽

Systematic Survey ◽

Meta Analyses ◽

The Cochrane Library

Abstract Background AMSTAR-2 (‘A Measurement Tool to Assess Systematic Reviews, version 2’) and ROBIS (‘Risk of Bias in Systematic Reviews’) are independent instruments used to assess the quality of conduct of systematic reviews/meta-analyses (SR/MAs). The degree of overlap in methodological constructs together with the reliability and any methodological gaps have not been systematically assessed and summarized in the field of nutrition. Methods We performed a systematic survey of MEDLINE, EMBASE, and the Cochrane Library for SR/MAs published between January 2010 and November 2018 that examined the effects of any nutritional intervention/exposure for cancer prevention. We followed a systematic review approach including two independent reviewers at each step of the process. For AMSTAR-2 (16 items) and ROBIS (21 items), we assessed the similarities, the inter-rater reliability (IRR) and any methodological limitations of the instruments. Our protocol for the survey was registered in PROSPERO (CRD42019121116). Results We found 4 similar domain constructs based on 11 comparisons from a total of 12 AMSTAR-2 and 14 ROBIS items. Ten comparisons were considered fully overlapping. Based on Gwet’s agreement coefficients, six comparisons provided almost perfect (> 0.8), three substantial (> 0.6), and one a moderate level of agreement (> 0.4). While there is considerable overlap in constructs, AMSTAR-2 uniquely addresses explaining the selection of study designs for inclusion, reporting on excluded studies with justification, sources of funding of primary studies, and reviewers’ conflict of interest. By contrast, ROBIS uniquely addresses appropriateness and restrictions within eligibility criteria, reducing risk of error in risk of bias (RoB) assessments, completeness of data extracted for analyses, the inclusion of all necessary studies for analyses, and adherence to predefined analysis plan. Conclusions Among the questions on AMSTAR-2 and ROBIS, 70.3% (26/37 items) address the same or similar methodological constructs. While the IRR of these constructs was moderate to perfect, there are unique methodological constructs that each instrument independently addresses. Notably, both instruments do not address the reporting of absolute estimates of effect or the overall certainty of the evidence, items that are crucial for users’ wishing to interpret the importance of SR/MA results.

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A Methodological and Reporting Quality Assessment of Systematic Reviews/Meta-Analyses about Chinese Medical Treatment for Gastroesophageal Reflux Disease

Gastroenterology Research and Practice ◽

10.1155/2020/3868057 ◽

2020 ◽

Vol 2020 ◽

pp. 1-19

Author(s):

Zipan Lyu ◽

Zhongyu Huang ◽

Fengbin Liu ◽

Zhengkun Hou

Keyword(s):

Medical Treatment ◽

Systematic Reviews ◽

Methodological Quality ◽

Reporting Quality ◽

Risk Of Bias ◽

Selection Methods ◽

Study Selection ◽

Protocol Registration ◽

Meta Analyses

Objective. To access the methodological and reporting quality of systematic reviews (SRs)/meta-analyses (MAs) about Chinese medical treatment for gastroesophageal reflux disease (GERD). Methods. The PubMed, Wanfang Data, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), Chinese Biomedical (CBM), Web of Science, and Cochrane Library databases were searched from inception to June 2020. Two researchers independently screened the literature considering the eligibility criteria. Overview Quality Assessment Questionnaire (OQAQ), Assessment of Multiple Systematic Reviews 2 (AMSTAR 2), and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to assess the methodological and reporting quality of the included reports. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to evaluate the level of evidence in each report. Results. Thirty-three SRs/MAs met the inclusion criteria. The OQAQ results showed that defects in the methodological quality of 17/32 reports were major, with scores of 3 points. Analyzing a single item as the object, search strategies (item 2), and risk of bias in individual studies (item 4) was considered poor. The AMSTAR 2 results showed that 25.4% of the items were not reported, and 7.8% of the items were only partially reported. The overall assessment of AMSTAR 2 showed the majority of systematic reviews and meta-analyses were of low/very low (31/33, 93.9%) methodological quality, with a lack of protocol registration and excluded study list. The PRISMA results showed that 19.9% of items were not reported, and 15.2% of items were only partially reported, due to a lack of protocol registration and study selection methods. The methodological and reporting quality of the included studies was generally poor. Evidence evaluation with GRADE showed that most (31/33) of the included studies had low or very low levels of evidence. Conclusion. The methodological and reporting quality of SRs/MAs about Chinese medical treatment for GERD is generally poor. The main problems included incomplete search strategies, risk of bias in individual studies, the lack of protocol registration and excluded study list, and incorrect study selection methods.

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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

10.21203/rs.2.12469/v1 ◽

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.

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The Effects of Tai Chi Exercise Among Adults With Chronic Heart Failure: An Overview of Systematic Review and Meta-Analysis

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2021.589267 ◽

2021 ◽

Vol 8 ◽

Author(s):

Jinke Huang ◽

Xiaohui Qin ◽

Min Shen ◽

Yanjuan Xu ◽

Yong Huang

Keyword(s):

Systematic Reviews ◽

Methodological Quality ◽

Tai Chi ◽

Meta Analysis ◽

Reporting Quality ◽

Risk Of Bias ◽

Quality Reporting ◽

Evidence Quality ◽

Meta Analyses

Background: Tai chi (TC) is a popular form of exercise among adults with chronic heart failure (CHF), yet services are greatly underutilized. The aim of the current study was to identify and summarize the existing evidence and to systematically determine the clinical effectiveness of Tai Chi in the management of CHF using a systematic overview.Methods: Both English and Chinese databases were searched for systematic reviews (SRs)/meta-analyses (MAs) on TC for CHF from their inception to June 2020. The methodological quality, reporting quality, and risk of bias of SRs/MAs were assessed using Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR-2), the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist, and Risk of Bias in Systematic reviews (ROBIS), respectively. The evidence quality of outcome measures was assessed by the Grades of Recommendations, Assessment, Development and Evaluation (GRADE).Results: Six SRs/MAs using a quantitative synthesis to assess various outcomes of TC in CHF were included in this overview. The methodological quality, reporting quality and risk of bias of the SRs/MAs and the evidence quality of the outcome measures are generally unsatisfactory. The limitations of the past SRs/MAs included the lack of either the protocol or registration, the list of excluded studies, and the computational details of meta-analysis were inadequately reported. The critical problems were that qualitative data synthesis relied on trials with small sample sizes and critical low quality.Conclusions: TC may be a promising complementary treatment for CHF. However, further rigorous and comprehensive SRs/MAs and RCTs are required to provide robust evidence for definitive conclusions.

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Evaluation of Spin in the Abstracts of Systematic Reviews and Meta-Analyses Focused on the Treatment of Acne Vulgaris: Cross-Sectional Analysis

JMIR Dermatology ◽

10.2196/16978 ◽

2020 ◽

Vol 3 (1) ◽

pp. e16978 ◽

Cited By ~ 1

Author(s):

Ryan Ottwell ◽

Taylor C Rogers ◽

J Michael Anderson ◽

Austin Johnson ◽

Matt Vassar

Keyword(s):

Systematic Review ◽

Systematic Reviews ◽

Acne Vulgaris ◽

Cross Sectional Study ◽

Primary Objective ◽

Risk Of Bias ◽

Selective Reporting ◽

Cross Sectional ◽

Bias Assessment ◽

Meta Analyses

Background Spin is the misrepresentation of study findings, which may positively or negatively influence the reader’s interpretation of the results. Little is known regarding the prevalence of spin in abstracts of systematic reviews, specifically systematic reviews pertaining to the management and treatment of acne vulgaris. Objective The primary objective of this study was to characterize and determine the frequency of the most severe forms of spin in systematic review abstracts and to evaluate whether various study characteristics were associated with spin. Methods Using a cross-sectional study design, we searched PubMed and EMBASE for systematic reviews focusing on the management and treatment of acne vulgaris. Our search returned 316 studies, of which 36 were included in our final sample. To be included, each systematic review must have addressed either pharmacologic or nonpharmacologic treatment of acne vulgaris. These studies were screened, and data were extracted in duplicate by two blinded investigators. We analyzed systematic review abstracts for the nine most severe types of spin. Results Spin was present in 31% (11/36) of abstracts. A total of 12 examples of spin were identified in the 11 abstracts containing spin, with one abstract containing two instances of spin. The most common type of spin, selective reporting of or overemphasis on efficacy outcomes or analysis favoring the beneficial effect of the experimental intervention, was identified five times (5/12, 42%). A total of 44% (16/36) of studies did not report a risk of bias assessment. Of the 11 abstracts containing spin, six abstracts (55%) had not reported a risk of bias assessment or performed a risk of bias assessment but did not discuss it. Spin in abstracts was not significantly associated with a specific intervention type, funding source, or journal impact factor. Conclusions Spin is present in the abstracts of systematic reviews and meta-analyses covering the treatment of acne vulgaris. This paper raises awareness of spin in abstracts and emphasizes the importance of its recognition, which may lead to fewer incidences of spin in future studies.

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Predictors of Higher Quality of Systematic Reviews Addressing Nutrition and Cancer Prevention

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph19010506 ◽

2022 ◽

Vol 19 (1) ◽

pp. 506

Author(s):

Dawid Storman ◽

Magdalena Koperny ◽

Joanna Zając ◽

Maciej Polak ◽

Paulina Weglarz ◽

...

Keyword(s):

Cancer Prevention ◽

Systematic Reviews ◽

Assessment Tool ◽

Multivariable Analysis ◽

Lower Number ◽

Risk Of Bias ◽

Assessment Instrument ◽

Bias Assessment ◽

Quality Risk

Systematic reviews/meta-analyses (SR/MAs) are considered a reliable source of information in healthcare. We aimed to explore the association of several characteristics of SR/MAs addressing nutrition in cancer prevention and their quality/risk of bias (using assessments from AMSTAR-2 and ROBIS tools). The analysis included 101 SR/MAs identified in a systematic survey. Associations of each specified characteristic (e.g., information about the protocol, publication year, reported use of GRADE, or other methods for assessing overall certainty of evidence) with the number of AMSTAR-2 not met (‘No’ responses) and the number of ROBIS items met (‘Probably Yes’ or “Yes’ responses) were examined. Poisson regression was used to identify predictors of the number of ‘No’ answers (indicating lower quality) for all AMSTAR-2 items and the number of ‘Yes’ or ‘Probably Yes’ answers (indicating higher quality/lower concern for bias) for all ROBIS items. Logistic regression was used to identify variables associated with at least one domain assessed as ‘low concern for bias’ in the ROBIS tool. In multivariable analysis, SR/MAs not reporting use of any quality/risk of bias assessment instrument for primary studies were associated with a higher number of ‘No’ answers for all AMSTAR-2 items (incidence rate ratio (IRR) 1.26, 95% confidence interval (CI) 1.09–1.45), and a lower number of ‘Yes’ or ‘Probably Yes’ answers for all ROBIS items (IRR 0.76, 95% CI 0.66–0.87). Providing information about the protocol and search for unpublished studies was associated with a lower number of ‘No’ answers (IRR 0.73, 95% CI 0.56–0.97 and IRR 0.75, 95% CI 0.59–0.95, respectively) and a higher number of ‘Yes’ or ‘Probably Yes’ answers (IRR 1.43, 95% CI 1.17–1.74 and IRR 1.28, 95% CI 1.07–1.52, respectively). Not using at least one quality/risk of bias assessment tool for primary studies within an SR/MA was associated with lower odds that a study would be assessed as ‘low concern for bias’ in at least one ROBIS domain (odds ratio 0.061, 95% CI 0.007–0.527). Adherence to methodological standards in the development of SR/MAs was associated with a higher overall quality of SR/MAs addressing nutrition for cancer prevention.

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