Development of a highly sensitive search strategy for the retrieval of reports of controlled trials using PubMed

OBJECTIVE: To develop, through revision of the Cochrane Collaboration search strategy for OVID-MEDLINE, a highly sensitive search strategy to retrieve reports of controlled trials using PubMed. METHODS: The original highly sensitive Cochrane strategy was revised to take into account additional Medical Subject Headings (MeSH) and other terminology as well as the current unique features of PubMed. We compared the retrieval of the revised strategy with that of the original Cochrane strategy before and after translation of the strategies into PubMed format. Finally, we used a gold standard database of reports of controlled trials identified by electronic and hand search of selected journals to test the revised strategy in PubMed format. RESULTS: The revised strategy included a search statement modified for increased precision, and added 'Cross-over Studies' as a MeSH term and the term 'latin square' as a text word. Compared to the original Cochrane strategy, the revised strategy identified 53 additional reports of controlled trials accessing MEDLINE through OVID. When the revised strategy and original Cochrane strategy were translated into PubMed format, the revised strategy retrieved 90 reports of controlled trials not identified by the original strategy. Finally, the revised strategy in PubMed format retrieved all of the reports of controlled trials in the gold standard database. Ninety-eight per cent of the gold standard reports of controlled trials were retrieved by Phase 1 of the optimal PubMed search strategy. CONCLUSIONS: Failure to identify all relevant trials for systematic review could result in bias. We developed a highly sensitive search strategy for the retrieval of reports of controlled trials for use with PubMed that retrieves more relevant citations (greater sensitivity) and fewer non-relevant citations (greater precision) than the original Cochrane search strategy.     

Demystifying the Search Button

A thorough review of the literature is the basis of all research and evidence‐based practice. A gold‐standard efficient and exhaustive search strategy is needed to ensure all relevant citations have been captured and that the search performed is reproducible. The PubMed database comprises both the MEDLINE and non‐MEDLINE databases. MEDLINE‐based search strategies are robust but capture only 89% of the total available citations in PubMed. The remaining 11% include the most recent and possibly relevant citations but are only searchable through less efficient techniques. An effective search strategy must employ both the MEDLINE and the non‐MEDLINE portion of PubMed to ensure all studies have been identified. The robust MEDLINE search strategies are used for the MEDLINE portion of the search. Usage of the less robust strategies is then efficiently confined to search only the remaining 11% of PubMed citations that have not been indexed for MEDLINE. The current article offers step‐by‐step instructions for building such a search exploring methods for the discovery of medical subject heading (MeSH) terms to search MEDLINE, text‐based methods for exploring the non‐MEDLINE database, information on the limitations of convenience algorithms such as the “related citations feature,” the strengths and pitfalls associated with commonly used filters, the proper usage of Boolean operators to organize a master search strategy, and instructions for automating that search through “MyNCBI” to receive search query updates by email as new citations become available.     

The pitfalls of a systematic MEDLINE review in palliative medicine: symptom assessment instruments

The Medical Literature Analysis and Retrieval System Online (MEDLINE) database provides many references for reviews, but many relevant articles are missed, especially when the topic is complex. Reported here is the detailed methodology of a PubMed search of MEDLINE augmented by a related articles link search. Of 1181 citations identified, through a PubMed search, 10 articles met the inclusion criteria. Fifty-one were identified through the related articles link; of which 43 were not detected by standard searches using medical subject heading terms. More than 50% were identified using the related articles link. Only 14% of relevant articles were identified using the standard PubMed MEDLINE search. The related articles link is not included in methodologic recommendations for systematic literature reviews but this experience suggests that it is a useful tool in PubMed for reviewing complex evidence. Related links searches are proposed in any systematic PubMed MEDLINE literature review in palliative medicine.     

Use of epidemiology in medical specialties: an examination by citation analysis

Epidemiologic methods have been applied unevenly among medical specialties. Identifying current uses and areas of potential research helps clarify and define the field. Using citation analysis of published data, the patterns of references to and by the American Journal of Epidemiology were examined for 1974-1982; 17,574 citations to and 15,872 citations by that Journal were classified according to the subject category of the referencing or referenced journal. Internal medicine and public health/epidemiology journals accounted for the largest proportion of all citations, followed by journals of immunology, cancer, microbiology, pediatrics, cardiovascular system, virology, tropical medicine, statistics, and obstetrics/gynecology. Few citations to or by the Journal were found in the allergy, anesthesiology, dermatology, geriatrics, hematology, nephrology, orthopedics, otorhinolaryngology, radiology, rheumatology, and urology journals. Examination of citations between clinical and epidemiologic literature suggests that adequate interchange between clinicians and epidemiologists is occurring. Citation analysis results for the American Journal of Epidemiology were significantly correlated (p less than 0.05) with those from a MEDLINE search on epidemiologic methods used in research in 22 clinical specialties. Despite inherent limitations, citation analysis appears to be a useful tool for examining interactions and trends in epidemiology and for identifying fields which may be ripe for new epidemiologic studies.     

Evaluation of social relevance of applied health research: a rough indicator may be the significance of publishing in national professional journals

Evaluation of health research output can have important implications for departments, institutes and individual careers. Typically, a peer review of the scientific quality of the output is central in this evaluation, increasingly with a bibliometric analysis at its core. Such an analysis is based on counting publications and citations from journals included in the (Social) Science Citation Index. Although the methodology is still far from perfect, there seems to be consensus on how to evaluate the scientific quality. This is in contrast to the evaluation of the social relevance of health research output, as there is no agreement on its importance, the dimensions involved, or the relevant methods of assessment. There is a need for the assessment of the social impact of applied health research, next to its scientific quality. As an initial rough approximation, counting publications in national professional journals may provide a suitable indicator of the social relevance of the research output.     

The growth of health-related meta-analyses published from 1980 to 2000

A MEDLINE search was conducted to estimate trends in the growth of health-related meta-analyses published during the past two decades. Employing a more specific than sensitive search strategy, and not supplementing these results with known sources of published meta-analyses or manual search strategies, 3,025 probable meta-analyses were selected from the 5,128 citations identified. The data showed a definitive upward (and generally linear) trend across time with no evidence for this genre of research either leveling off or decreasing.     

A nursing qualitative systematic review required MEDLINE and CINAHL for study identification

OBJECTIVE: Analyze the number and the relevance of references retrieved from CINAHL, MEDLINE, and EMBASE to perform a nursing systematic review. STUDY DESIGN: A search strategy for the review topic was designed according to thesaurus terms. The study analyzes (1) references with abstract, (2) overlap between databases, (3) reference relevance, (4) relevance agreement between experts, and (5) reference accessibility. RESULTS: Bibliographic search retrieved 232 references: 16% (37) in CINAHL, 68% (157) in MEDLINE, and 16% (38) in EMBASE. Of these, 72% (164) were references retrieved with an abstract: 14% (23) in CINAHL, 70% (115) in MEDLINE, and 16% (26) in EMBASE. Overlap was observed in 2% (5) of the references. Relevance assessment reduced the number of references to 43 (19%): 12 (34.3%) in CINAHL, 31 (19.7%) in MEDLINE, and none in EMBASE (Z=-1.97; P=.048). Agreement between experts achieved a maximum Cohen's kappa of 0.76 (P < .005). References identified in CINAHL were the most difficult to obtain (chi(2)=3.9; df=1; P=.048). CONCLUSIONS: To perform a quality bibliographic search for a systematic review on nursing topics, CINAHL and MEDLINE are essential databases for consultation to maximize the accuracy of the search.     

《中国寄生虫学与寄生虫病杂志》5年引文分析

目的 通过对《中国寄生虫学与寄生虫病杂志》2000-2004年30期载文的引文进行统计分析,以了解本刊著者的引用文献规律及吸收利用信息的能力.方法 用文献计量学方法对该刊2000-2004年30期833篇论文的引文量、引文类型、引文半衰期和普赖斯指数进行统计分析,用布拉德福定律找出引文核心区域期刊.结果 833篇论文的总引文量6 385条,引文率从2000年的84.4%上升至2004年的90.5%.5年中篇均引文平均为7.7条.引文以期刊为主占88.3%,其中中、外文期刊分别占34.8%和65.2%.引用中、外文期刊的平均半衰期分别为4.8年和6.4年,平均普赖斯指数分别为51.8%和40.3%.所引中、外文期刊的核心区域期刊：中文4种,其引文量占所引中文期刊的48.1%;外文12种,其引文量占所引外文期刊的36.9%.结论 该刊作者的引文范围广泛,吸收和利用本领域国内外最新研究动态信息的能力较强.但利用外文文献的新颖性有待于提高.     

Citation analysis of the field of medical decision making: update, 1959-1985

This article updates a prior citation analysis of medical decision making, published in this journal in 1984. Building on the original core list, decision making papers were added based on any of three criteria: citation of three papers already on the list, identification by a MEDLINE search (CATLINE for books) as relevant to the topic, or mention in a recent review article on decision analysis. The revised core list contains 105 articles and five books. The changes in the field of medical decision making from 1978 to 1981 are reviewed, and key areas of development are identified by co-citation clustering.     

PubMed perspective of family medicine research: where does it stand?

OBJECTIVE: The aim of this study was to obtain a view of family medicine research by analyzing PubMed citations from 1960-2003. METHOD: Family practice (FP) citations in PubMed from 1960 to 2003 were downloaded in MEDLINE format. This was written into relation database using 'PubMed Grabber/Analyzer' software developed at University of Kelaniya, Sri Lanka. Search Query Language (SQL) and online PubMed queries were used for further analysis. RESULTS: There were 50288 FP citations from 80 countries. Of these, 33712 (67%) citations were from 15 FP journals. United Kingdom (18760), United States (13584), Australia (3262), Canada (1848), Germany-west (1340) were the five countries which had the most citations and 22 countries had less than 5 citations. Van Weel C (118), Geyman JP (116), Olesen F (87), Jones R (83) and Knottnerus JA (82) were numerically, the top five authors. Only 921 authors had more than 10 citations and the vast majority of authors had only one citation. Letters (5121), review (2715), editorial (2259), randomized controlled trials-RCT (1585) and Meta-analysis (44) were the top publication types. 40 citations found under 'qualitative research'. Discussion. The relatively few PubMed FP citations (50288) are by a small number of academics in developed countries. Citations showed an upsurge from the mid 1980s to the late 1990's but reached a plateau in the new millennium. Compared to PubMed citations from 1960-2003 in other specialties such as 2737655 for public health, 1151194 for cardiology & cardiovascular diseases and 318538 for medical informatics, the 50288 FP citations were paltry. Paucity of RCT (1585) and meta-analysis (44) was noted. The low 'qualitative research' citations (44) could have been due to the late introduction of the MeSH concept in 2003. CONCLUSIONS: Priority should be given to increase FP research and also to ensure the indexing of FP journals that are not currently indexed in PubMed. Efforts to increase citations in Medline may not give the desired results because of low priority given primary care specialties such as family medicine in the USA. Alternative solution of a separate bibliographic database for FP similar to PsycInfo may be too costly.     

Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Pediatric Critically Ill Patient: Society of Critical Care Medicine and American Society for Parenteral and Enteral Nutrition

This document represents the first collaboration between 2 organizations—the American Society for Parenteral and Enteral Nutrition and the Society of Critical Care Medicine—to describe best practices in nutrition therapy in critically ill children. The target of these guidelines is intended to be the pediatric critically ill patient (>1 month and <18 years) expected to require a length of stay >2–3 days in a PICU admitting medical, surgical, and cardiac patients. In total, 2032 citations were scanned for relevance. The PubMed/MEDLINE search resulted in 960 citations for clinical trials and 925 citations for cohort studies. The EMBASE search for clinical trials culled 1661 citations. In total, the search for clinical trials yielded 1107 citations, whereas the cohort search yielded 925. After careful review, 16 randomized controlled trials and 37 cohort studies appeared to answer 1 of the 8 preidentified question groups for this guideline. We used the GRADE criteria (Grading of Recommendations, Assessment, Development, and Evaluation) to adjust the evidence grade based on assessment of the quality of study design and execution. These guidelines are not intended for neonates or adult patients. The guidelines reiterate the importance of nutrition assessment—particularly, the detection of malnourished patients who are most vulnerable and therefore may benefit from timely intervention. There is a need for renewed focus on accurate estimation of energy needs and attention to optimizing protein intake. Indirect calorimetry, where feasible, and cautious use of estimating equations and increased surveillance for unintended caloric underfeeding and overfeeding are recommended. Optimal protein intake and its correlation with clinical outcomes are areas of great interest. The optimal route and timing of nutrient delivery are areas of intense debate and investigations. Enteral nutrition remains the preferred route for nutrient delivery. Several strategies to optimize enteral nutrition during critical illness have emerged. The role of supplemental parenteral nutrition has been highlighted, and a delayed approach appears to be beneficial. Immunonutrition cannot be currently recommended. Overall, the pediatric critical care population is heterogeneous, and a nuanced approach to individualizing nutrition support with the aim of improving clinical outcomes is necessary.     

Citation bias of hepato-biliary randomized clinical trials

The objective of this study was to assess whether trials with a positive (i.e., statistically significant) outcome are cited more often than negative trials. We reviewed 530 randomized clinical trials on hepato-biliary diseases published in 11 English-language journals indexed in MEDLINE from 1985-1996. From each trial, we extracted the statistical significance of the primary study outcome (positive or negative), the disease area, and methodological quality (randomization and double blinding). The number of citations during two calendar years after publication was obtained from Science Citation Index. There was a significant positive association between a statistically significant study outcome and the citation frequency (beta, 0.55, 95% confidence interval, 0.39-0.72). The disease area and adequate generation of the allocation sequence were also significant predictors of the citation frequency. We concluded that positive trials are cited significantly more often than negative trials. The association was not explained by disease area or methodological quality.     

利用论文被引频次基准线遴选学者代表作的方法——以河南省学者论文为例

【目的】根据论文被引频次百分位创建不同学科论文被引频次基准线,探讨基于被引频次基准线遴选论文代表作的方法。【方法】以河南省科学技术领域学者为研究对象,以WoS数据库的学科分类为依据,建立不同学科论文被引频次基准线。依据该基准线对河南省各学科学者2009—2018年发表的每篇研究论文确定PR8分值,PR8分值≥3为论文代表作遴选的最低标准,其中PR8分值≥6者为第Ⅰ层次代表作,PR8分值≥5者为第Ⅱ层次代表作,PR8分值≥3者为第Ⅲ层次代表作。对不同层次代表作遴选的优秀学者进行比较。【结果】创建了177个学科论文被引频次基准线,根据代表作遴选标准确定了河南省学者7707篇代表作。采用代表作论文和全部论文以及采用不同层次代表作论文遴选优秀学者的结果明显不同。【结论】论文被引频次基准线在跨学科学术评价中具有重要意义,可以简单、明确地界定不同学科论文代表作;代表作评价制度的推行势在必行。     

Citation networks of related trials are often disconnected: implications for bidirectional citation searches

Background and ObjectivesReports of randomized controlled trials (RCTs) should set findings within the context of previous research. The resulting network of citations would also provide an alternative search method for clinicians, researchers, and systematic reviewers seeking to base decisions on all available evidence. We sought to determine the connectedness of citation networks of RCTs by examining direct (referenced trials) and indirect (through references of referenced trials, etc) citation of trials to one another.MethodsMeta-analyses were used to create citation networks of RCTs addressing the same clinical questions. The primary measure was the proportion of networks where following citation links between RCTs identifies the complete set of RCTs, forming a single connected citation group. Other measures included the number of disconnected groups (islands) within each network, the number of citations in the network relative to the maximum possible, and the maximum number of links in the path between two connected trials (a measure of indirectness of citations).ResultsWe included 259 meta-analyses with a total of 2,413 and a median of seven RCTs each. For 46% (118 of 259) of networks, the RCTs formed a single connected citation group—one island. For the other 54% of networks, where at least one RCT group was not cited by others, 39% had two citation islands and 4% (10 of 257) had 10 or more islands. On average, the citation networks had 38% of the possible citations to other trials (if each trial had cited all earlier trials). The number of citation islands and the maximum number of citation links increased with increasing numbers of trials in the network.ConclusionAvailable evidence to answer a clinical question may be identified by using network citations created with a small initial corpus of eligible trials. However, the number of islands means that citation networks cannot be relied on for evidence retrieval.     

Life course socio-economic position and quality of life in adulthood: a systematic review of life course models

ABSTRACT: BACKGROUND: A relationship between current socio-economic position and subjective quality of life has been demonstrated, using wellbeing, life and needs satisfaction approaches. Less is known regarding the influence of different life course socio-economic trajectories on later quality of life. Several conceptual models have been proposed to help explain potential life course effects on health, including accumulation, latent, pathway and social mobility models. This systematic review aimed to assess whether evidence supported an overall relationship between life course socio-economic position and quality of life during adulthood and if so, whether there was support for one or more life course models. METHODS: A review protocol was developed detailing explicit inclusion and exclusion criteria, search terms, data extraction items and quality appraisal procedures. Literature searches were performed in 12 electronic databases during January 2012 and the references and citations of included articles were checked for additional relevant articles. Narrative synthesis was used to analyze extracted data and studies were categorized based on the life course model analyzed. RESULTS: Twelve studies met the eligibility criteria and used data from 10 datasets and five countries. Study quality varied and heterogeneity between studies was high. Seven studies assessed social mobility models, five assessed the latent model, two assessed the pathway model and three tested the accumulation model. Evidence indicated an overall relationship, but mixed results were found for each life course model. Some evidence was found to support the latent model among women, but not men. Social mobility models were supported in some studies, but overall evidence suggested little to no effect. Few studies addressed accumulation and pathway effects and study heterogeneity limited synthesis. CONCLUSIONS: To improve potential for synthesis in this area, future research should aim to increase study comparability. Recommendations include testing all life course models within individual studies and the use of multiple measures of socio-economic position and quality of life. Comparable cross-national data would be beneficial to enable investigation of between-country differences.     

研究型论文中“关键引文”概念初探

【目的】 重视研究论文中引文的学术论证作用,提高引文质量。【方法】根据引文在研究型论文中所起论证作用不同,将其分为关键论证作用与非关键论证作用2大类,进而提出“关键引文”的概念和标注方法。【结果】 关键引文是指在论文中所引用的起到关键性学术论证作用并对论文核心内容具有不可或缺意义的参考文献。提出了关键引文的确定方法和标注方法。【结论】 正确认识和把握关键引文,对科学著述中参考文献的合理引用、论文审稿以及引文分析都具有参考指导意义,其有利于促进学术交流质量的提高。     

International Journal of Occupational Medicine and Environmental Health in world documentation services: the SCOPUS based analysis of citation

A high classification of scientific journals in the ranking of international transfer of knowledge is reflected by other researchers' citations. The International Journal of Occupational Medicine and Environmental Health (IJOMEH) is an international professional quarterly focused on such areas as occupational medicine, toxicology and environmental health edited in Poland. IJOMEH, published in English, is indexed in numerous world information services (MEDLINE, EMBASE, EBSCO, SCOPUS). This paper presents the contribution of IJOMEH publications to the world circulation of scientific information based on the citation analysis. The analysis, grounded on the SCOPUS database, assessed the frequency of citations in the years 1996-2005. Journals in which they have been cited were retrieved and their list is also included.     

Citation bias favoring statistically significant studies was present in medical research

ObjectiveStatistically significant studies may be cited more than negative studies on the same topic. We aimed to assess here whether such citation bias is present across the medical literature.Study Design and SettingWe conducted a cohort study of the association between statistical significance and citations. We selected all therapeutic intervention studies included in meta-analyses published between January and March 2010 in the Cochrane database, and retrieved citation counts of all individual studies using ISI Web of Knowledge. The association between the statistical significance of each study and the number of citations it received between 2008 and 2010 was assessed in mixed Poisson models.ResultsWe identified 89 research questions addressed in 458 eligible articles. Significant studies were cited twice as often as nonsignificant studies (multiplicative effect of significance: 2.14, 95% confidence interval: 1.38–3.33). This association was partly because of the higher impact factor of journals where significant studies are published (adjusted multiplicative effect of significance: 1.14, 95% confidence interval: 0.87–1.51).ConclusionA citation bias favoring significant results occurs in medical research. As a consequence, treatments may seem more effective to the readers of medical literature than they really are.     

《医疗卫生装备》杂志1989—2008年引文分析

目的：了解《医疗卫生装备》杂志情报吸收和利用情况,客观地揭示其文献引用规律及需求特征。方法：采用引文计量分析法对《医疗卫生装备》1989—2008年所载论文的参考文献的引文量、引文语种、引文类型、普赖斯指数、半衰期、自引率及核心引用期刊等方面进行统计分析。结果：该刊引文率为43.76%;篇均引文量为2篇。主要引文类型为期刊,其中外文期刊为1481种,引文数量为3605条,占总引用频率的22.90%;中文期刊为1440种,引文数量为7059条,占总引用频率的44.84%。普赖斯指数44.67%,半衰期4.36年。期刊自引1693篇,自引率为10.75%。引用期刊共计2921种,被引30次以上的中文期刊24种;被引20次以上的外文期刊18种;共计42种,占总引用期刊引文量的39.24%。结论：该刊引文率呈逐年上升趋势。引文类型以期刊为主;文献引用较新,涉猎文献范围广,普赖斯指数较高,自引率适中。该刊可谓国内医疗卫生装备研究领域的重要信息源之一。     

Which literature retrieval method is most effective for GPs?

BACKGROUND: Evidence-based medicine requires new skills of physicians, including literature searching. OBJECTIVE: To determine which literature retrieving method is most effective for GPs: the printed Index Medicus; Medline through Grateful Med; or Medline on CD-ROM. METHODS: The design was a randomized comparative study. In a continuing medical education course, three groups of health care professionals (87 GPs and 16 other health care professionals) used one of the literature retrieval methods to retrieve citations on four search topics related to general practice. For the analysis in pairs, we used the search results of the 75 participants who completed all four assignments. As outcome measures, we used precision, recall and an overall search quality score; we also had a post-course questionnaire on personal characteristics, experience with computers, handling medical literature and satisfaction with course instruction and search results. RESULTS: The recall and overall search quality scores in the Index Medicus groups (n = 32) were higher (P = <0.001) than those in the CD-ROM groups (n = 31). In addition, the search quality scores in the Grateful Med groups (n = 12) were higher (P < 0.003) than those in the CD-ROM groups. There were no differences in precision. CONCLUSION: In the period 1994-1997, the printed Index Medicus was the most effective literature retrieval method for GPs. For inexperienced GPs, there is a need for training in electronic literature retrieval methods.