Database selection in systematic reviews: an insight through clinical neurology

The Relationship Between Dissociation and Complex Post-Traumatic Stress Disorder: A Scoping Review

Complex post-traumatic stress disorder (CPTSD) has recently been recognized as an official psychiatric diagnosis in ICD-11, after years of research and advocacy in the field. It has been suggested that dissociative symptoms are a major feature of CPTSD. This scoping review aimed to summarize the existing knowledge base on the relationship between dissociation and CPTSD, and to identify relevant research gaps. We searched the two largest and most widely used academic databases (i.e., the Web of Science and Scopus databases) and the ProQuest database and identified original studies published in English relevant to our research questions, namely: (1) Would CPTSD be associated with dissociative symptoms? 2) How common are dissociative symptoms among people with CPTSD? (3) What are the correlates of dissociative symptoms among people with CPTSD? In all, 26 studies were included. We found 10 studies which reported that people with CPTSD scored significantly higher on a dissociation measure than those without CPTSD, and 11 studies reported a positive correlation between CPTSD symptoms and psychoform/somatoform dissociation scores. While very few studies reported the prevalence and correlates of dissociative symptoms among people with CPTSD, there may be a considerable subgroup of people with CPTSD who have clinically significant levels of dissociative symptoms (e.g., 28.6-76.9%). Dissociation may also be associated with other comorbidities (e.g., DSM-IV Axis II features, shame, somatic symptoms) in people with CPTSD. We recommend that more studies are needed to investigate the prevalence of dissociative symptoms among people with CPTSD and examine how these symptoms are associated with other comorbid conditions and clinical needs in this vulnerable group.

Chemsex and Psychosis: A Systematic Review

Chemsex is presented as a major challenge in public health, with numerous physical and mental consequences. The general objective of this review was to analyze the relationship between the practice of chemsex and the development of psychosis. A mixed systematic review model was chosen. PubMed, PsycINFO, and Web of Science databases were searched following a predetermined search strategy. The studies were selected, and their information was extracted following a systematic method. A total of 10 articles were included. Psychotic symptoms ranged from 6.7% to 37.2%, being one of the most frequent psychiatric diagnoses. Slamsex, polydrug use and smoked methamphetamine posed up to a 3-fold increased risk of psychosis within this practice. The risk factors found were foreign or ethnic minority status, location in large cities, stress and anxiety, trauma, loneliness, sexually transmitted infections (STIs), hepatitis, and previous psychotic history. In conclusion, chemsex is associated with psychosis development; we found numerous converging risk factors and a clear mediating role of drugs. It is important, in approaching the prevention and treatment of this addiction, to take into account motivations and psychosocial circumstances.

Searching two or more databases decreased the risk of missing relevant studies: a metaresearch study

OBJECTIVE

Assessing changes in coverage, recall, review conclusions and references not found when searching fewer databases.

STUDY DESIGN AND SETTING

In 60 randomly selected Cochrane reviews, we checked included study publications' coverage (indexation) and recall (findability) using different search approaches with MEDLINE, Embase, and CENTRAL and related them to authors' conclusions and certainty. We assessed characteristics of unfound references.

RESULTS

1989/2080 included references, were indexed in ≥1 database (coverage=96%). In reviews where using one of our search approaches would not change conclusions and certainty (n=44-54), median coverage and recall were highest (range 87.9-100.0% and 78.2-93.3%, respectively). Here, searching ≥2 databases reached >95% coverage and ≥87.9% recall. In reviews with unchanged conclusions but less certainty (n=2-8): 63.3-79.3% coverage and 45.0-75.0% recall. In reviews with opposite conclusions (n=1-3): 63.3-96.6% and 52.1-78.7%. In reviews where a conclusion was no longer possible (n=3-7): 60.6%-86.0% and 20.0-53.8%. The 265 references that were indexed but unfound were more often abstractless (30% vs 11%) and older (28% vs. 17% published before 1991) than found references.

CONCLUSION

Searching ≥2 databases improves coverage and recall and decreases the risk of missing eligible studies. If researchers suspect that relevant articles are difficult to find, supplementary search methods should be used.

Literature searching methods or guidance and their application to public health topics: A narrative review

Background

Information specialists conducting searches for systematic reviews need to consider key questions around which and how many sources to search. This is particularly important for public health topics where evidence may be found in diverse sources.

Objectives

The objective of this review is to give an overview of recent studies on information retrieval guidance and methods that could be applied to public health evidence and used to guide future searches.

Methods

A literature search was performed in core databases and supplemented by browsing health information journals and citation searching. Results were sifted and reviewed.

Results

Seventy‐two papers were found and grouped into themes covering sources and search techniques. Public health topics were poorly covered in this literature.

Discussion

Many researchers follow the recommendations to search multiple databases. The review topic influences decisions about sources. Additional sources covering grey literature eliminate bias but are time‐consuming and difficult to search systematically. Public health searching is complex, often requiring searches in multidisciplinary sources and using additional methods.

Conclusions

Search planning is advisable to enable decisions about which and how many sources to search. This could improve with more work on modelling search scenarios, particularly in public health topics, to examine where publications were found and guide future research.

Development of an efficient search filter to retrieve systematic reviews from PubMed

Objective:

Locating systematic reviews is essential for clinicians and researchers when creating or updating reviews and for decision-making in health care. This study aimed to develop a search filter for retrieving systematic reviews that improves upon the performance of the PubMed systematic review search filter.

Methods:

Search terms were identified from abstracts of reviews published in Cochrane Database of Systematic Reviews and the titles of articles indexed as systematic reviews in PubMed. Both the precision of the candidate terms and the number of systematic reviews retrieved from PubMed were evaluated after excluding the subset of articles retrieved by the PubMed systematic review filter. Terms that achieved a precision greater than 70% and relevant publication types indexed with MeSH terms were included in the filter search strategy.

Results:

The search strategy used in our filter added specific terms not included in PubMed's systematic review filter and achieved a 61.3% increase in the number of retrieved articles that are potential systematic reviews. Moreover, it achieved an average precision that is likely greater than 80%.

Conclusions:

The developed search filter will enable users to identify more systematic reviews from PubMed than the PubMed systematic review filter with high precision.

Databases Selection in a Systematic Review of the Association between Anthropometric Measurements and Dental Caries among Children in Asia

A comprehensive search for primary studies using a sufficient number and relevant databases is critical to minimise bias and increase the validity of a systematic review. We examined the frequency and choices of databases commonly used to provide an efficient search of primary studies for a systematic review of anthropometric measurements and dental caries among children in Asia. Twelve previous systematic reviews on a similar topic were retrieved from six databases. The frequency and choice of databases used by reviewers were determined from the methods sections. We also identified the lists of other databases usually searched in other reviews. Eligibility criteria for final databases selection were the database's scope, the topic of interest, design of the study, type of article, and the accessibility of the databases. Of the 77 databases identified, previous reviews on this topic used 21 databases, ranging from 2 to 12 databases in each review. Medline, Cochrane Library, Web of Science, and PubMed were employed most frequently. Twenty-six databases were eligible and selected for the present review. Twelve were regional databases to provide comprehensive coverage of primary studies. A systematic approach in selecting appropriate databases for searching primary studies is paramount to reduce errors, ensure coverage, and increase the validity of systematic reviews' conclusions.

MEDLINE search retrieval issues: A longitudinal query analysis of five vendor platforms

This study compared the results of data collected from a longitudinal query analysis of the MEDLINE database hosted on multiple platforms that include PubMed, EBSCOHost, Ovid, ProQuest, and Web of Science. The goal was to identify variations among the search results on the platforms after controlling for search query syntax. We devised twenty-nine cases of search queries comprised of five semantically equivalent queries per case to search against the five MEDLINE database platforms. We ran our queries monthly for a year and collected search result count data to observe changes. We found that search results varied considerably depending on MEDLINE platform. Reasons for variations were due to trends in scholarly publication such as publishing individual papers online first versus complete issues. Some other reasons were metadata differences in bibliographic records; differences in the levels of specificity of search fields provided by the platforms and large fluctuations in monthly search results based on the same query. Database integrity and currency issues were observed as each platform updated its MEDLINE data throughout the year. Specific biomedical bibliographic databases are used to inform clinical decision-making, create systematic reviews, and construct knowledge bases for clinical decision support systems. They serve as essential information retrieval and discovery tools to help identify and collect research data and are used in a broad range of fields and as the basis of multiple research designs. This study should help clinicians, researchers, librarians, informationists, and others understand how these platforms differ and inform future work in their standardization.

Database selection and data gathering methods in systematic reviews of qualitative research regarding diabetes mellitus - an explorative study

BACKGROUND

Systematic reviews (SRs) are considered one of the most reliable types of studies in evidence-based medicine. SRs rely on a comprehensive and systematic data gathering, including the search of academic literature databases. This study aimed to investigate which combination of databases would result in the highest overall recall rate of references when conducting SRs of qualitative research regarding diabetes mellitus. Furthermore, we aimed to investigate the current use of databases and other sources for data collection.

METHODS

Twenty-six SRs (published between 2010 and 2020) of qualitative research regarding diabetes mellitus, located through PubMed, met the inclusion criteria. References of the SRs were systematically hand searched in the six academic literature databases CINAHL, MEDLINE/PubMed, PsycINFO, Embase, Web of Science, and Scopus and the academic search engine Google Scholar. Recall rates were calculated using the total number of included references retrieved by the database or database combination divided by the total number of included references, given in percentage.

RESULTS

The SRs searched five databases on average (range two to nine). MEDLINE/PubMed was the most commonly searched database (100% of SRs). In addition to academic databases, 18 of the 26 (69%) SRs hand searched the reference lists of included articles. This technique resulted in a median (IQR) of 2.5 (one to six) more references being included per SR than by database searches alone. 27 (5.4%) references were found only in one of six databases (when Google Scholar was excluded), with CINAHL retrieving the highest number of unique references (n = 15). The combinations of MEDLINE/PubMed and CINAHL (96.4%) and MEDLINE/PubMed, CINAHL, and Embase (98.8%) yielded the highest overall recall rates, with Google Scholar excluded.

CONCLUSIONS

We found that the combinations of MEDLINE/PubMed and CINAHL and MEDLINE/PubMed, CINAHL, and Embase yielded the highest overall recall rates of references included in SRs of qualitative research regarding diabetes mellitus. However, other combinations of databases yielded corresponding recall rates and are expected to perform comparably. Google Scholar can be a useful supplement to traditional scientific databases to ensure an optimal and comprehensive retrieval of relevant references.

Overlaps of multiple database retrieval and citation tracking in dementia care research: a methodological study

OBJECTIVE

We aimed to determine overlaps and optimal combination of multiple database retrieval and citation tracking for evidence synthesis, based on a previously conducted scoping review on facilitators and barriers to implementing nurse-led interventions in dementia care.

METHODS

In our 2019 scoping review, we performed a comprehensive literature search in eight databases (CENTRAL, CINAHL, Embase, Emcare, MEDLINE, Ovid Nursing Database, PsycINFO, and Web of Science Core Collection) and used citation tracking. We retrospectively analyzed the coverage and overlap of 10,527 retrieved studies published between 2015 and 2019. To analyze database overlap, we used cross tables and multiple correspondence analysis (MCA).

RESULTS

Of the retrieved studies, 6,944 were duplicates and 3,583 were unique references. Using our search strategies, considerable overlaps can be found in some databases, such as between MEDLINE and Web of Science Core Collection or between CINAHL, Emcare, and PsycINFO. Searching MEDLINE, CINAHL, and Web of Science Core Collection and using citation tracking were necessary to retrieve all included studies of our scoping review.

CONCLUSIONS

Our results can contribute to enhancing future search practice related to database selection in dementia care research. However, due to limited generalizability, researchers and librarians should carefully choose databases based on the research question. More research on optimal database retrieval in dementia care research is required for the development of methodological standards.

Sample Selection in Systematic Literature Reviews of Management Research

Systematic review techniques are about to become the “new normal” in reviews of management research. However, there is not yet much advice on how to organize the sample selection process as part of such reviews. This article addresses this void and analyzes this vital part of systematic reviews in more detail. In particular, it offers a critical review of systematic literature reviews published in the Academy of Management Annals and the International Journal of Management Reviews between 2004 and 2018. Based on this methodological literature review, the article presents issues to consider in the most critical choices during the sample selection process. Furthermore, this review identifies several descriptive features such as the mean number of research items included in systematic reviews, the mean number of databases used, and the mean coverage period of such reviews. These numbers may be used as benchmark figures in future reviews.

Using Embase as a supplement to PubMed in Cochrane reviews differed across fields

OBJECTIVE

Medline/PubMed is often first choice for health science researchers when doing literature searches. However, Medline/PubMed does not cover the health science research literature equally well across specialties. Embase is often considered an important supplement to Medline/PubMed in health sciences. The present study analyzes the coverage of Embase as a supplement to PubMed, and the aim of the study is to investigate if searching Embase can compensate for low PubMed retrieval.

STUDY DESIGN AND SETTING

The population in this study is all the included studies in all Cochrane reviews from 2012 to 2016 across the 53 Cochrane groups. The analyses were performed using two units of analysis (study and publication). We are examining the coverage in Embase of publications and studies not covered by PubMed (25,119 publications and 9,420 studies).

RESULTS

The results showed that using Embase as a supplement to PubMed resulted in a coverage of 66,994 publications out of 86,167 and a coverage rate of 77.7, 95% CI [75.05, 80.45] of all the included publications. Embase combined with PubMed covered 48,326 out of 54,901 studies and thus had a coverage rate of 88.0%, 95% CI [86.2, 89.9] of studies. The results also showed that supplementing PubMed with Embase increased coverage of included publications by 6.8 percentage points, and the coverage of studies increased by 5.5 percentage points. Substantial differences were found across and within review groups over time.

CONCLUSION

The included publications and studies in some groups are covered considerably better by supplementing with Embase, whereas in other groups, the difference in coverage is negligible. However, due to the variation over time, one should be careful predicting the benefit from supplementing PubMed with Embase to retrieve relevant publications to include in a review.

Sodium and Potassium Intake and Cardiovascular Disease in Older People: A Systematic Review

This review aims to examine the relationship of sodium and potassium intake and cardiovascular disease (CVD) among older people. Methods: We performed a literature search using PubMed and Web of Science (January 2015 to July 2020) without language restriction. Observational and experimental studies that reported the relationship between sodium, potassium, or sodium-to-potassium ratio with CVD among older adults aged higher than 60 years were included. The authors independently screened all identified studies, extracted information, and assessed the quality of included studies. Risk of bias was assessed using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS) for observational studies and the revised Cochrane risk-of-bias tool (RoB 2 tool) for randomized trials. Results: We included 12 studies (6 prospective cohort studies, 5 cross-sectional studies, and 1 experimental study). Five of the studies reported on sodium-to-potassium ratio (n = 5), and the others on potassium and/or sodium intake. Cardiovascular events (e.g., stroke and heart failure) were the most reported outcome (n = 9). Of the 12 studies included, five observational studies had low bias risk and the randomized controlled trial was judged as uncertain risk of bias. We found inconsistent results for the effect of the reduction of sodium intake in this population for lower risk of CVD. We found that both the increase of potassium intake and the decrease of sodium-to-potassium ratio were associated with lower risk of hypertension and CVD, particularly stroke. Conclusion: The present review suggests that both higher potassium and lower sodium-to-potassium ratio are associated with lower risk of CVD.

Assessment of Language and Indexing Biases Among Chinese-Sponsored Randomized Clinical Trials

IMPORTANCE

Language and indexing biases may exist among Chinese-sponsored randomized clinical trials (CS-RCTs). Such biases may threaten the validity of systematic reviews.

OBJECTIVE

To evaluate the existence of language and indexing biases among CS-RCTs on drug interventions.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective cohort study, eligible CS-RCTs were retrieved from trial registries, and bibliographic databases were searched to determine their publication status. Eligible CS-RCTs were for drug interventions conducted from January 1, 2008, to December 31, 2014. The search and analysis were conducted from March 1 to August 31, 2019. Primary trial registries were recognized by the World Health Organization and the Drug Clinical Trial Registry Platform sponsored by the China Food and Drug Administration.

EXPOSURES

Individual CS-RCTs with positive vs negative results (positive vs negative CS-RCTs).

MAIN OUTCOMES AND MEASURES

For assessing language bias, the main outcome was the language of the journal in which CS-RCTs were published (English vs Chinese). For indexing bias, the main outcome was the language of the bibliographic database where the CS-RCTs were indexed (English vs Chinese).

RESULTS

The search identified 891 eligible CS-RCTs. Four hundred seventy CS-RCTs were published by August 31, 2019, of which 368 (78.3%) were published in English. Among CS-RCTs registered in the Chinese Clinical Trial Registry (ChiCTR), positive CS-RCTs were 3.92 (95% CI, 2.20-7.00) times more likely to be published in English than negative CS-RCTs; among CS-RCTs in English-language registries, positive CS-RCTs were 3.22 (95% CI, 1.34-7.78) times more likely to be published in English than negative CS-RCTs. These findings suggest the existence of language bias. Among CS-RCTs registered in ChiCTR, positive CS-RCTs were 2.89 (95% CI, 1.55-5.40) times more likely to be indexed in English bibliographic databases than negative CS-RCTs; among CS-RCTs in English-language registries, positive CS-RCTs were 2.19 (95% CI, 0.82-5.82) times more likely to be indexed in English bibliographic databases than negative CS-RCTs. These findings support the existence of indexing bias.

CONCLUSIONS AND RELEVANCE

This study suggests the existence of language and indexing biases among registered CS-RCTs on drug interventions. These biases may distort evidence synthesis toward more positive results of drug interventions.

Sensitive Versus Specific Search Strategy to Answer Clinical Questions

BACKGROUND

Students and clinicians are challenged to locate evidence to answer clinical questions. Searching experiences include frustration with words to query databases, lack of searching skills, lack of confidence in nursing databases, and questioning how many databases to search. To implement practice change based on best available evidence, search strategies need to be efficient and effective.

METHOD

We replicated the systematic review by Stillwell, Vermeesch, and Scott, which used a specific search, with a sensitive search to compare search strategies to answer the clinical question.

RESULTS

The specific search produced 5,108 articles, with eight being relevant; whereas the sensitive search produced 11,362 articles with nine being relevant.

CONCLUSION

The sensitive search located the same eight studies and one additional study. If PubMed instead of MEDLINE had been used in the specific search, the results would have been identical. [J Nurs Educ. 2020;59(1):22-25.].

Searching for qualitative health research required several databases and alternative search strategies: a study of coverage in bibliographic databases

OBJECTIVE

Retrieving the qualitative literature can be challenging, but the number and specific choice of databases are key factors. The aim of the present study is to provide guidance for the choice of databases for retrieving qualitative health research.

STUDY DESIGN AND SETTING

Seventy-one qualitative systematic reviews, from the Cochrane Database of Systematic Reviews and JBI database of Systematic Reviews and Implementation Reports, including 927 qualitative studies, were used to analyze the coverage of the qualitative literature in nine bibliographic databases.

RESULTS

The results show that 94.4% of the qualitative studies are indexed in at least one database, with a lower coverage for publication types other than journal articles. Maximum recall with two databases is 89.1%, with three databases recall increases to 92% and maximum recall with four databases is 93.1%. The remaining 6.9% of the publications consists of 1.3% scattered across five databases and 5.6% that are not indexed in any of the nine databases used in this study.

CONCLUSION

Retrieval in one or a few-although well selected-databases does not provide all the relevant qualitative studies. The remaining studies needs to be located using several other databases and alternative search strategies.

Behavioural interventions to treat drooling in children with neurodisability: a systematic review

AIM

To review the evidence for behavioural interventions to reduce drooling in children with neurodisability.

METHOD

A detailed search in eight databases sought studies that: (1) included participants aged 0 to 18 years with neurodisability and drooling; (2) provided behavioural interventions targeting drooling or a drooling-related behaviour; and (3) used experimental designs. Two reviewers extracted data from full-text papers independently. Results were tabulated for comparison. The Risk of Bias assessment in N-of-1 Trials scale for single case experimental designs (SCEDs) and the Cochrane risk of bias assessment tool for randomized controlled trials (RCTs) were applied.

RESULTS

Of an initial yield of 763, seven SCEDs and one RCT were included. Behavioural interventions included the use of reinforcement, prompting, self-management, instruction, extinction, overcorrection, and fading. Each assessed body functions or structures' outcomes (drooling frequency and severity); three included activity outcomes (mouth drying, head control, eye contact, and vocalizations) and none assessed participation or quality of life. While each study reported positive effects of intervention, risk of bias was high.

INTERPRETATION

Low-level evidence suggests behavioural interventions may be useful for treatment of drooling in children with neurodisability. Well-designed intervention studies are urgently needed to determine effectiveness.

WHAT THIS PAPER ADDS

Behavioural interventions used to treat drooling included reinforcement, prompting, self-management, extinction, overcorrection, instruction, and fading. Interventions targeted body structures and function-level outcomes and activity-level outcomes. Low-level evidence supports the use of behavioural intervention to treat drooling.

Defining the process to literature searching in systematic reviews: a literature review of guidance and supporting studies

BACKGROUND

Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving readers clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence. Information specialists and review teams appear to work from a shared and tacit model of the literature search process. How this tacit model has developed and evolved is unclear, and it has not been explicitly examined before. The purpose of this review is to determine if a shared model of the literature searching process can be detected across systematic review guidance documents and, if so, how this process is reported in the guidance and supported by published studies.

METHOD

A literature review. Two types of literature were reviewed: guidance and published studies. Nine guidance documents were identified, including: The Cochrane and Campbell Handbooks. Published studies were identified through 'pearl growing', citation chasing, a search of PubMed using the systematic review methods filter, and the authors' topic knowledge. The relevant sections within each guidance document were then read and re-read, with the aim of determining key methodological stages. Methodological stages were identified and defined. This data was reviewed to identify agreements and areas of unique guidance between guidance documents. Consensus across multiple guidance documents was used to inform selection of 'key stages' in the process of literature searching.

RESULTS

Eight key stages were determined relating specifically to literature searching in systematic reviews. They were: who should literature search, aims and purpose of literature searching, preparation, the search strategy, searching databases, supplementary searching, managing references and reporting the search process.

CONCLUSIONS

Eight key stages to the process of literature searching in systematic reviews were identified. These key stages are consistently reported in the nine guidance documents, suggesting consensus on the key stages of literature searching, and therefore the process of literature searching as a whole, in systematic reviews. Further research to determine the suitability of using the same process of literature searching for all types of systematic review is indicated.

A plea for minimally biased naturalistic philosophy

Naturalistic philosophers rely on literature search and review in a number of ways and for different purposes. Yet this article shows how processes of literature search and review are likely to be affected by widespread and systematic biases. A solution to this problem is offered here. Whilst the tradition of systematic reviews of literature from scientific disciplines has been neglected in philosophy, systematic reviews are important tools that minimize bias in literature search and review and allow for greater reproducibility and transparency. If naturalistic philosophers wish to reduce bias in their research, they should then supplement their traditional tools for literature search and review by including systematic methodologies.