Comparison of search strategies in systematic reviews of adverse effects to other systematic reviews

Digital accessibility in the era of artificial intelligence-Bibliometric analysis and systematic review

Introduction

Digital accessibility involves designing digital systems and services to enable access for individuals, including those with disabilities, including visual, auditory, motor, or cognitive impairments. Artificial intelligence (AI) has the potential to enhance accessibility for people with disabilities and improve their overall quality of life.

Methods

This systematic review, covering academic articles from 2018 to 2023, focuses on AI applications for digital accessibility. Initially, 3,706 articles were screened from five scholarly databases-ACM Digital Library, IEEE Xplore, ScienceDirect, Scopus, and Springer.

Results

The analysis narrowed down to 43 articles, presenting a classification framework based on applications, challenges, AI methodologies, and accessibility standards.

Discussion

This research emphasizes the predominant focus on AI-driven digital accessibility for visual impairments, revealing a critical gap in addressing speech and hearing impairments, autism spectrum disorder, neurological disorders, and motor impairments. This highlights the need for a more balanced research distribution to ensure equitable support for all communities with disabilities. The study also pointed out a lack of adherence to accessibility standards in existing systems, stressing the urgency for a fundamental shift in designing solutions for people with disabilities. Overall, this research underscores the vital role of accessible AI in preventing exclusion and discrimination, urging a comprehensive approach to digital accessibility to cater to diverse disability needs.

Comprehensive review for healthcare data quality challenges in blockchain technology

There are several features inherent in blockchain, including decentralized storage, distributed ledger, immutability, security and authentication, and it has shifted away from the hype to be used practically in different industries, such as in the healthcare sector. The use of blockchain technology has allowed the provision of improved services to industries. The objective of this paper is to demonstrate how the use of blockchain is influenced by data quality issues in the healthcare industry. The article is structured as a systematic literature review study that uses several articles issued in various databases from 2016 onwards. In this review study, 65 articles were chosen and grouped into a single key aspect of the challenge in the healthcare sector. The findings obtained were analyzed based on factors in three domains, classified as issues pertinent to the adoption, operational and technological domains. This review study aims to use the findings to provide support to the practitioners, stakeholders and professionals, whose purpose is to carry out and manage transformation projects pertinent to blockchain in the field of healthcare. In addition, the organizations would be facilitated in their decision-making processes when the potential blockchain users are made to comprehend the implicit factors related to blockchain.

A review of advanced technologies available to improve the healthcare performance during COVID-19 pandemic

Information technology (IT) has enabled the initiation of an innovative healthcare system. An innovative healthcare system integrates new technologies such as cloud computing, the internet of things, and artificial intelligence (AI), to transform the healthcare to be more efficient, more convenient and more personalized. This review aims to identify the key technologies that will help to support an innovative healthcare system. A case study approach was used in this research analysis to enable a researcher to closely analyze the data in a particular context. It presents a case study of the coronavirus (COVID-19) as a means of exploring the use of advanced technologies in an innovative healthcare system to help address a worldwide health crisis. An innovative healthcare system can help to promote better patient self-management, reduce costs, relieve staff pressures, help with resource and knowledge management, and improve the patient experience. An innovative healthcare system can reduce the expense and time for research, and increase the overall efficacy of the research. Overall, this research identifies how innovative technologies can improve the performance of the healthcare system. Advanced technologies can assist with pandemic control and can help in the recognition of the virus, clinical treatment, medical protection, intelligent diagnosis, and outbreak analysis. The review provides an analysis of the future prospects of an innovative healthcare system.

CLUSTER searching approach to inform evidence syntheses: A methodological review

BACKGROUND

The CLUSTER model of searching was proposed as a systematic method of searching for studies for reviews of complex interventions.

AIM

The method has not been evaluated before. This methodological review identified and evaluated a sample of evidence syntheses that have used CLUSTER.

METHODS

A forward citation search on the seed CLUSTER publication was conducted on Web of Science Core Collection using six journal citation indexes and Google Scholar in December 2020. Reviews which used the CLUSTER method were eligible for inclusion. A narrative synthesis was used to describe the types of evidence syntheses that used CLUSTER searching, the extent to which the CLUSTER approach has been operationalised within evidence syntheses and whether the value, benefits and limitations of CLUSTER were assessed by the reviewers.

FINDINGS

A total of 16 reviews were identified and eligible for synthesis. Six different review types that used CLUSTER were identified with realist reviews being the most prominent. The evaluation of complex interventions was the most common review topic area. The use of CLUSTER varied among reviews with the retrieval of sibling studies being the most common reason. 'Citations' and 'Lead authors' were the most followed elements of CLUSTER.

CONCLUSIONS

Evidence suggests that CLUSTER has been adopted for use in reviews of complex interventions. Its usage varied among the included reviews. It is imperative that future reviewers diligently report the elements and steps of CLUSTER that were utilised in order to provide a reproducible and transparent search strategy that can be reported with similar transparency to bibliographic database searches.

Quality of Literature Searches Published in Leading Neurosurgical Journals: A Review of Reviews

BACKGROUND

There is mounting evidence that the search strategies upon which systematic reviews (SRs) are based frequently contain errors are incompletely reported or insensitive.

OBJECTIVE

To appraise the quality of search strategies in the 10 leading specialty neurosurgical journals and identify factors associated with superior searches.

METHODS

This research-on-research study systematically surveyed SRs published in the 10 leading neurosurgical journals between 01/10/2017 and 31/10/2019. All SRs were eligible for assessment using a predefined coding manual that was adapted from the preferred reporting items for systematic reviews and meta-analyses (PRISMA), a measurement tool to assess systematic reviews (AMSTAR), and Cochrane Collaboration guidelines. The PubMed interface was used to search the MEDLINE database, which was supplemented by individual journal searches. Descriptive statistics were utilized to identify factors associated with improved search strategies.

RESULTS

A total of 633 articles were included and contained a median of 19.00 (2.00-1654.00) studies. Less than half (45.97%) of included search strategies were considered to be reproducible. Aggregated reporting score was positively associated with in-text reference to reporting guideline adherence (τb = 0.156, P < .01). The number of articles retrieved by a search (τb = 0.11, P < .01) was also associated with the reporting of a reproducible search strategy.

CONCLUSION

This study demonstrates that the search strategies used in neurosurgical SRs require improvement. In addition to increasing awareness of reporting standards, we propose that this be achieved by the incorporation of PRISMA and other guidelines into article submission and peer-review processes. This may lead to the conduct of more informative SRs, which may result in improved clinician decision-making and patient outcomes.

Methodological Considerations for Auditory Training Interventions for Adults With Hearing Loss: A Rapid Review

Purpose The aim of this study was to evaluate literature on auditory training published since 2013. Method A rapid review or a streamlined approach to systematically identify and summarize relevant studies was performed. Selected health sciences databases were searched using a search strategy developed with the PICO (population, intervention, comparison, and outcome) framework. Studies eligible for inclusion had older adult participants with hearing loss and utilized technology-based auditory training in laboratory or home settings. Results The study quality of most studies was found to be low to moderate, with concentrations between low and moderate. Major issues were related to study design and reporting, such as the need for blinding and a control group, larger sample sizes, and a follow-up for long-term outcomes of auditory training interventions. Wide variability in training approaches, participant backgrounds (e.g., audiograms, hearing aid use), and outcome measures are also noted. Conclusions Evidence on the effectiveness of auditory training is mixed. Future research should include high-quality randomized controlled trials with representative populations; follow-up periods to study long-term effects; and exploration of behavioral, electrophysiological, and self-reported outcome measures. Recommendations for study designs and methodologies are also discussed.

Risk of Adverse Outcomes in Females Taking Oral Creatine Monohydrate: A Systematic Review and Meta-Analysis

Creatine Monohydrate (CrM) is a dietary supplement routinely used as an ergogenic aid for sport and training, and as a potential therapeutic aid to augment different disease processes. Despite its increased use in recent years, studies reporting potential adverse outcomes of CrM have been mostly derived from male or mixed sex populations. A systematic search was conducted, which included female participants on CrM, where adverse outcomes were reported, with meta-analysis performed where appropriate. Six hundred and fifty-six studies were identified where creatine supplementation was the primary intervention; fifty-eight were female only studies (9%). Twenty-nine studies monitored for adverse outcomes, with 951 participants. There were no deaths or serious adverse outcomes reported. There were no significant differences in total adverse events, (risk ratio (RR) 1.24 (95% CI 0.51, 2.98)), gastrointestinal events, (RR 1.09 (95% CI 0.53, 2.24)), or weight gain, (mean difference (MD) 1.24 kg pre-intervention, (95% CI -0.34, 2.82)) to 1.37 kg post-intervention (95% CI -0.50, 3.23)), in CrM supplemented females, when stratified by dosing regimen and subject to meta-analysis. No statistically significant difference was reported in measures of renal or hepatic function. In conclusion, mortality and serious adverse events are not associated with CrM supplementation in females. Nor does the use of creatine supplementation increase the risk of total adverse outcomes, weight gain or renal and hepatic complications in females. However, all future studies of creatine supplementation in females should consider surveillance and comprehensive reporting of adverse outcomes to better inform participants and health professionals involved in future trials.

Evaluating the factors that influence cloud technology adoption-comparative case analysis of health and non-health sectors: A systematic review

Cloud technology has brought great benefits to the health industry, including enabling improvement in the quality of services. The objective of this review study is to investigate the reported factors affecting the adoption of cloud in the health sector by comparing studies in the health and non-health sectors. This article is a systematized review of studies conducted in 2018. From 541 articles, 47 final articles were selected and classified into two categories: health and non-health studies; conclusions were drawn from the two sectors by comparing their effective factors. Based on the results of this review, the factors were categorized as technological, organizational, environmental, and individual. The results of this review study could be a beneficial guide to the health empirical research on cloud adoption. Individual domains have not been examined in health sector studies. Since the process of adoption of new technologies in organizations is time-consuming, due to the lack of managerial knowledge about the efficient factors, recognition of these factors by decision-makers while planning for cloud adoption becomes of great importance. The findings of this review study aim to help health decision-makers by increasing their awareness of the cloud and of the factors that impact decisions at both the organizational and individual levels.

Overview: comprehensive and carefully constructed strategies are required when conducting searches for adverse effects data

OBJECTIVES

Methodological research has been undertaken to investigate the many challenges in searching for adverse effects data. It is imperative that the search approach adopted in systematic reviews is based on the best available evidence. We provide a detailed summary of the results and implications of the current evidence base to assist future searches for adverse effects.

STUDY DESIGN AND SETTING

This article is a narrative review from the authors of the Cochrane Handbook chapter on adverse effects.

RESULTS

The specified search strategy must be based on the population, intervention, comparator, outcome(s) format for question formulation and appropriate study designs for adverse effects data. Search filters and suggested search terms are available for the adverse effects of drug, medical devices, and surgical interventions. The use of generic adverse effects terms (such as harms and complications) as text words and indexing terms and specific adverse effects terms (such as rash and wound infection) are warranted. Searching databases beyond MEDLINE has proven useful, as well as the use of nondatabase sources.

CONCLUSION

This article provides the most up-to-date evidence-based guidance in identifying adverse effects data in the literature. It will support searchers and researchers evaluating the potential for harm of medical interventions in systematic reviews.

The development of search filters for adverse effects of surgical interventions in medline and Embase

Background

Search filter development for adverse effects has tended to focus on retrieving studies of drug interventions. However, a different approach is required for surgical interventions.

Objective

To develop and validate search filters for medline and Embase for the adverse effects of surgical interventions.

Methods

Systematic reviews of surgical interventions where the primary focus was to evaluate adverse effect(s) were sought. The included studies within these reviews were divided randomly into a development set, evaluation set and validation set. Using word frequency analysis we constructed a sensitivity maximising search strategy and this was tested in the evaluation and validation set.

Results

Three hundred and fifty eight papers were included from 19 surgical intervention reviews. Three hundred and fifty two papers were available on medline and 348 were available on Embase. Generic adverse effects search strategies in medline and Embase could achieve approximately 90% relative recall. Recall could be further improved with the addition of specific adverse effects terms to the search strategies.

Conclusion

We have derived and validated a novel search filter that has reasonable performance for identifying adverse effects of surgical interventions in medline and Embase. However, we appreciate the limitations of our methods, and recommend further research on larger sample sizes and prospective systematic reviews.

Roles for librarians in systematic reviews: a scoping review

OBJECTIVE

What roles do librarians and information professionals play in conducting systematic reviews? Librarians are increasingly called upon to be involved in systematic reviews, but no study has considered all the roles librarians can perform. This inventory of existing and emerging roles aids in defining librarians' systematic reviews services.

METHODS

For this scoping review, the authors conducted controlled vocabulary and text-word searches in the PubMed; Library, Information Science & Technology Abstracts; and CINAHL databases. We separately searched for articles published in the Journal of the European Association for Health Information and Libraries, Evidence Based Library and Information Practice, the Journal of the Canadian Heath Libraries Association, and Hypothesis. We also text-word searched Medical Library Association annual meeting poster and paper abstracts.

RESULTS

We identified 18 different roles filled by librarians and other information professionals in conducting systematic reviews from 310 different articles, book chapters, and presented papers and posters. Some roles were well known such as searching, source selection, and teaching. Other less documented roles included planning, question formulation, and peer review. We summarize these different roles and provide an accompanying bibliography of references for in-depth descriptions of these roles.

CONCLUSION

Librarians play central roles in systematic review teams, including roles that go beyond searching. This scoping review should encourage librarians who are fulfilling roles that are not captured here to document their roles in journal articles and poster and paper presentations.

Ten years of reviews

The March 2017 issue of the Health Information and Libraries Journal marks the 10 year anniversary of the inaugural review published in the journal's review series. The review series was conceived to meet the growing appetite of health library and information workers to access synthesised evidence to inform their practice; something we'd already been doing to support medics in their practice. This editorial looks back on the 10 years and the inspiration which saw the development of a typology of review types and associated methodologies to address the lack of consistent guidelines on the features a review should incorporate.

SYSTEMATIC REVIEWS OF ECONOMIC EVALUATIONS: HOW EXTENSIVE ARE THEIR SEARCHES?

Objectives: Economic evaluation (EE) is an accepted element of decision making and priority setting in healthcare. As the number of published EEs grows, so does the number of systematic reviews (SRs) of EEs. Although search methodology makes an important contribution to SR quality, search methods in reviews of EEs have not been evaluated in detail. We investigated the resources used to identify studies in recent, published SRs of EEs, and assessed whether the resources reflected recommendations.

Methods: We searched MEDLINE for SRs of EEs published since January 2013 and extracted the following from eligible reviews: databases searched, health technology assessment (HTA) sources searched, supplementary search techniques used. Results were compared against the minimum search resources recommended by National Institute for Health and Care Excellence (NICE) (MEDLINE, Embase, NHS EED, EconLit) for economic evidence for single technology appraisals, and resource types suggested in the summary of current best evidence from SuRe Info (economic databases, general databases, HTA databases, HTA agency Web pages, gray literature).

Results: Sixty-five SRs met the inclusion criteria; data were extracted from forty-two. Five reviews (12 percent) met or exceeded the NICE recommended resources. Nine reviews (21 percent) searched at least four of the five types of resource recommended by SuRe Info. Five reviews (12 percent) searched all five. Twenty-three reviews (55 percent) did not meet the NICE recommendations or four of five of the SuRe Info recommended resource types. Search reporting was frequently unclear or incorrect.

Conclusions: Searches conducted for the majority of recently published SRs of EEs do not meet two published approaches.

Reporting of Adverse Events in Published and Unpublished Studies of Health Care Interventions: A Systematic Review

BACKGROUND

We performed a systematic review to assess whether we can quantify the underreporting of adverse events (AEs) in the published medical literature documenting the results of clinical trials as compared with other nonpublished sources, and whether we can measure the impact this underreporting has on systematic reviews of adverse events.

METHODS AND FINDINGS

Studies were identified from 15 databases (including MEDLINE and Embase) and by handsearching, reference checking, internet searches, and contacting experts. The last database searches were conducted in July 2016. There were 28 methodological evaluations that met the inclusion criteria. Of these, 9 studies compared the proportion of trials reporting adverse events by publication status. The median percentage of published documents with adverse events information was 46% compared to 95% in the corresponding unpublished documents. There was a similar pattern with unmatched studies, for which 43% of published studies contained adverse events information compared to 83% of unpublished studies. A total of 11 studies compared the numbers of adverse events in matched published and unpublished documents. The percentage of adverse events that would have been missed had each analysis relied only on the published versions varied between 43% and 100%, with a median of 64%. Within these 11 studies, 24 comparisons of named adverse events such as death, suicide, or respiratory adverse events were undertaken. In 18 of the 24 comparisons, the number of named adverse events was higher in unpublished than published documents. Additionally, 2 other studies demonstrated that there are substantially more types of adverse events reported in matched unpublished than published documents. There were 20 meta-analyses that reported the odds ratios (ORs) and/or risk ratios (RRs) for adverse events with and without unpublished data. Inclusion of unpublished data increased the precision of the pooled estimates (narrower 95% confidence intervals) in 15 of the 20 pooled analyses, but did not markedly change the direction or statistical significance of the risk in most cases. The main limitations of this review are that the included case examples represent only a small number amongst thousands of meta-analyses of harms and that the included studies may suffer from publication bias, whereby substantial differences between published and unpublished data are more likely to be published.

CONCLUSIONS

There is strong evidence that much of the information on adverse events remains unpublished and that the number and range of adverse events is higher in unpublished than in published versions of the same study. The inclusion of unpublished data can also reduce the imprecision of pooled effect estimates during meta-analysis of adverse events.

Most systematic reviews of adverse effects did not include unpublished data

OBJECTIVES

We sought to identify the proportion of systematic reviews of adverse effects which search for unpublished data and the success rates of identifying unpublished data for inclusion in a systematic review.

STUDY DESIGN AND SETTING

Two reviewers independently screened all records published in 2014 in the Database of Abstracts of Reviews of Effects (DARE) for systematic reviews where the primary aim was to evaluate an adverse effect or effects. Data were extracted on the types of adverse effects and interventions evaluated, sources searched, how many unpublished studies were included, and source or type of unpublished data included.

RESULTS

From 9,129 DARE abstracts, 348 met our inclusion criteria. Most of these reviews evaluated a drug intervention (237/348, 68%) with specified adverse effects (250/348, 72%). Over a third (136/348, 39%) of all the reviews searched, a specific source for unpublished data, such as conference abstracts or trial registries, and nearly half of these reviews (65/136, 48%) included unpublished data. An additional 13 reviews included unpublished data despite not searching specific sources for unpublished studies. Overall, 22% (78/348) of reviews included unpublished data/studies.

CONCLUSION

Most reviews of adverse effects do not search specifically for unpublished data but, of those that do, nearly half are successful.

Prospective comparison of search strategies for systematic reviews: an objective approach yielded higher sensitivity than a conceptual one

BACKGROUND

In the development of search strategies for systematic reviews, "conceptual approaches" are generally recommended to identify appropriate search terms for those parts of the strategies for which no validated search filters exist. However, "objective approaches" based on search terms identified by text analysis are increasingly being applied.

OBJECTIVES

To prospectively compare an objective with a conceptual approach for the development of search strategies.

METHODS

Two different MEDLINE search strategies were developed in parallel for five systematic reviews covering a range of topics and study designs. The Institute for Quality and Efficiency in Health Care (IQWiG) applied an objective approach, and external experts applied a conceptual approach for the same research questions. For each systematic review, the citations retrieved were combined and the overall pool of citations screened to determine sensitivity and precision.

RESULTS

The objective approach yielded a weighted mean sensitivity and precision of 97% and 5%. The corresponding values for the conceptual approach were 75% and 4%.

CONCLUSION

Our findings indicate that the objective approach applied by IQWiG for search strategy development yields higher sensitivity than and similar precision to a conceptual approach. The main advantage of the objective approach is that it produces consistent results across searches.

Use of recommended search strategies in systematic reviews and the impact of librarian involvement: a cross-sectional survey of recent authors

Background

Previous research looking at published systematic reviews has shown that their search strategies are often suboptimal and that librarian involvement, though recommended, is low. Confidence in the results, however, is limited due to poor reporting of search strategies the published articles.

Objectives

To more accurately measure the use of recommended search methods in systematic reviews, the levels of librarian involvement, and whether librarian involvement predicts the use of recommended methods.

Methods

A survey was sent to all authors of English-language systematic reviews indexed in the Database of Abstracts of Reviews of Effects (DARE) from January 2012 through January 2014. The survey asked about their use of search methods recommended by the Institute of Medicine, Cochrane Collaboration, and the Agency for Healthcare Research and Quality and if and how a librarian was involved in the systematic review. Rates of use of recommended methods and librarian involvement were summarized. The impact of librarian involvement on use of recommended methods was examined using a multivariate logistic regression.

Results

1560 authors completed the survey. Use of recommended search methods ranged widely from 98% for use of keywords to 9% for registration in PROSPERO and were generally higher than in previous studies. 51% of studies involved a librarian, but only 64% acknowledge their assistance. Librarian involvement was significantly associated with the use of 65% of recommended search methods after controlling for other potential predictors. Odds ratios ranged from 1.36 (95% CI 1.06 to 1.75) for including multiple languages to 3.07 (95% CI 2.06 to 4.58) for using controlled vocabulary.

Conclusions

Use of recommended search strategies is higher than previously reported, but many methods are still under-utilized. Librarian involvement predicts the use of most methods, but their involvement is under-reported within the published article.

Librarian co-authors correlated with higher quality reported search strategies in general internal medicine systematic reviews

OBJECTIVES

To determine whether librarian and information specialist authorship was associated with better reported systematic review (SR) search quality.

STUDY DESIGN AND SETTING

SRs from high-impact general internal medicine journals were reviewed for search quality characteristics and reporting quality by independent reviewers using three instruments, including a checklist of Institute of Medicine Recommended Standards for the Search Process and a scored modification of the Peer Review of Electronic Search Strategies instrument.

RESULTS

The level of librarian and information specialist participation was significantly associated with search reproducibility from reported search strategies (Χ(2) = 23.5; P < 0.0001). Librarian co-authored SRs had significantly higher odds of meeting 8 of 13 analyzed search standards than those with no librarian participation and six more than those with mentioned librarian participation. One-way ANOVA showed that differences in total search quality scores between all three groups were statistically significant (F2,267 = 10.1233; P < 0.0001).

CONCLUSION

Problems remain with SR search quality and reporting. SRs with librarian or information specialist co-authors are correlated with significantly higher quality reported search strategies. To minimize bias in SRs, authors and editors could encourage librarian engagement in SRs including authorship as a potential way to help improve documentation of the search strategy.

Bidirectional citation searching to completion: an exploration of literature searching methods

Literature reviews underpin the majority of research projects in the health sciences, and yet relatively little analysis has been published as to the most appropriate method to identify relevant literature, outside of specialist information journals. The method of applying keyword search queries to bibliographic databases using Boolean logic dominates literature reviews due to its easy application to the major online databases. However, it is recognised increasingly as being problematic where the research question cannot be clearly defined or requires an element of exploration, due to its reliance on author's use of titling and keywords and is unable to identify topics other than those defined in the search query. This paper discusses the relative merits of a systematic citation searching approach as both an alternative and a concurrent method to keyword searching. A method of citation searching, both forwards and backwards, which is iterated to form a closed loop solution, is discussed. An illustrative example is presented of both methods, applying them to the topic of the UK National Institute for Health and Care Excellence (NICE) cost-effectiveness threshold. The case study finds the citation searching approach dominates the traditional keyword searching approach, finding 76 papers of relevance, including all 15 found by the alternative approach. Conceptually, and in the example presented, it is demonstrated that the proposed method can represent a dominant strategy to the more traditional approach in some situations, highlighting that, wherever possible, it is preferential to employ multiple methods of searching. However, it is clear that a better understanding is required as to how we can most efficiently search the ever-growing sea of literature.

Selective reporting bias of harm outcomes within studies: findings from a cohort of systematic reviews

OBJECTIVE

To determine the extent and nature of selective non-reporting of harm outcomes in clinical studies that were eligible for inclusion in a cohort of systematic reviews.

DESIGN

Cohort study of systematic reviews from two databases.

SETTING

Outcome reporting bias in trials for harm outcomes (ORBIT II) in systematic reviews from the Cochrane Library and a separate cohort of systematic reviews of adverse events.

PARTICIPANTS

92 systematic reviews of randomised controlled trials and non-randomised studies published in the Cochrane Library between issue 9, 2012 and issue 2, 2013 (Cochrane cohort) and 230 systematic reviews published between 1 January 2007 and 31 December 2011 in other publications, synthesising data on harm outcomes (adverse event cohort).

METHODS

A 13 point classification system for missing outcome data on harm was developed and applied to the studies.

RESULTS

86% (79/92) of reviews in the Cochrane cohort did not include full data from the main harm outcome of interest of each review for all of the eligible studies included within that review; 76% (173/230) for the adverse event cohort. Overall, the single primary harm outcome was inadequately reported in 76% (705/931) of the studies included in the 92 reviews from the Cochrane cohort and not reported in 47% (4159/8837) of the 230 reviews in the adverse event cohort. In a sample of primary studies not reporting on the single primary harm outcome in the review, scrutiny of the study publication revealed that outcome reporting bias was suspected in nearly two thirds (63%, 248/393).

CONCLUSIONS

The number of reviews suspected of outcome reporting bias as a result of missing or partially reported harm related outcomes from at least one eligible study is high. The declaration of important harms and the quality of the reporting of harm outcomes must be improved in both primary studies and systematic reviews.