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Academia and Clinic18 August 2009Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA StatementFREEDavid Moher, PhD, Alessandro Liberati, MD, DrPH, Jennifer Tetzlaff, BSc, and Douglas G. Altman, DSc, the PRISMA Group*David Moher, PhDFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, Alessandro Liberati, MD, DrPHFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, Jennifer Tetzlaff, BScFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, and Douglas G. Altman, DScFrom Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.Search for more papers by this author, the PRISMA Group*Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-151-4-200908180-00135 SectionsSupplemental MaterialAboutVisual AbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail Editor's Note: In order to encourage dissemination of the PRISMA Statement, this article is freely accessible on the Annals of Internal Medicine Web site (www.annals.org) and will be also published in PLOS Medicine, BMJ, Journal of Clinical Epidemiology, and Open Medicine. The authors jointly hold the copyright of this article. For details on further use, see the PRISMA Web site (www.prisma-statement.org).Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field (1, 2), and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research (3), and some health care journals are moving in this direction (4). As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews.Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in four leading medical journals in 1985 and 1986 and found that none met all eight explicit scientific criteria, such as a quality assessment of included studies (5). In 1987, Sacks and colleagues (6) evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in six domains. Reporting was generally poor; between one and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement (7).In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized, controlled trials (8). In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1).Box 1. Conceptual Issues in the Evolution From QUOROM to PRISMA Download figure Download PowerPoint TerminologyThe terminology used to describe a systematic review and meta-analysis has evolved over time. One reason for changing the name from QUOROM to PRISMA was the desire to encompass both systematic reviews and meta-analyses. We have adopted the definitions used by the Cochrane Collaboration (9). A systematic review is a review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyze and summarize the results of the included studies. Meta-analysis refers to the use of statistical techniques in a systematic review to integrate the results of included studies.Developing the PRISMA StatementA three-day meeting was held in Ottawa, Ontario, Canada, in June 2005 with 29 participants, including review authors, methodologists, clinicians, medical editors, and a consumer. The objective of the Ottawa meeting was to revise and expand the QUOROM checklist and flow diagram, as needed.The executive committee completed the following tasks, prior to the meeting: a systematic review of studies examining the quality of reporting of systematic reviews, and a comprehensive literature search to identify methodological and other articles that might inform the meeting, especially in relation to modifying checklist items. An international survey of review authors, consumers, and groups commissioning or using systematic reviews and meta-analyses was completed, including the International Network of Agencies for Health Technology Assessment (INAHTA) and the Guidelines International Network (GIN). The survey aimed to ascertain views of QUOROM, including the merits of the existing checklist items. The results of these activities were presented during the meeting and are summarized on the PRISMA Web site (www.prisma-statement.org).Only items deemed essential were retained or added to the checklist. Some additional items are nevertheless desirable, and review authors should include these, if relevant (10). For example, it is useful to indicate whether the systematic review is an update (11) of a previous review, and to describe any changes in procedures from those described in the original protocol.Shortly after the meeting a draft of the PRISMA checklist was circulated to the group, including those invited to the meeting but unable to attend. A disposition file was created containing comments and revisions from each respondent, and the checklist was subsequently revised 11 times. The group approved the checklist, flow diagram, and this summary paper.Although no direct evidence was found to support retaining or adding some items, evidence from other domains was believed to be relevant. For example, Item 5 asks authors to provide registration information about the systematic review, including a registration number, if available. Although systematic review registration is not yet widely available (12, 13), the participating journals of the International Committee of Medical Journal Editors (ICMJE) (14) now require all clinical trials to be registered in an effort to increase transparency and accountability (15). Those aspects are also likely to benefit systematic reviewers, possibly reducing the risk of an excessive number of reviews addressing the same question (16, 17) and providing greater transparency when updating systematic reviews.The PRISMA StatementThe PRISMA Statement consists of a 27-item checklist (Table 1; see also Table S1, for a downloadable Word template for researchers to re-use) and a four-phase flow diagram (Figure 1; see also Figure S1, for a downloadable Word template for researchers to re-use). The aim of the PRISMA Statement is to help authors improve the reporting of systematic reviews and meta-analyses. We have focused on randomized trials, but PRISMA can also be used as a basis for reporting systematic reviews of other types of research, particularly evaluations of interventions. PRISMA may also be useful for critical appraisal of published systematic reviews. However, the PRISMA checklist is not a quality assessment instrument to gauge the quality of a systematic review.Table 1. Checklist of Items to Include When Reporting a Systematic Review or Meta-AnalysisFigure 1. Flow of information through the different phases of a systematic review. Download figure Download PowerPoint From QUOROM to PRISMAThe new PRISMA checklist differs in several respects from the QUOROM checklist, and the substantive specific changes are highlighted in Table 2. Generally, the PRISMA checklist “decouples” several items present in the QUOROM checklist and, where applicable, several checklist items are linked to improve consistency across the systematic review report.Table 2. Substantive Specific Changes Between the QUOROM Checklist and the PRISMA ChecklistThe flow diagram has also been modified. Before including studies and providing reasons for excluding others, the review team must first search the literature. This search results in records. Once these records have been screened and eligibility criteria applied, a smaller number of articles will remain. The number of included articles might be smaller (or larger) than the number of studies, because articles may report on multiple studies and results from a particular study may be published in several articles. To capture this information, the PRISMA flow diagram now requests information on these phases of the review process.EndorsementThe PRISMA Statement should replace the QUOROM Statement for those journals that have endorsed QUOROM. We hope that other journals will support PRISMA; they can do so by registering on the PRISMA Web site. To underscore to authors, and others, the importance of transparent reporting of systematic reviews, we encourage supporting journals to reference the PRISMA Statement and include the PRISMA Web address in their instructions to authors. We also invite editorial organizations to consider endorsing PRISMA and encourage authors to adhere to its principles.The PRISMA Explanation and Elaboration PaperIn addition to the PRISMA Statement, a supporting Explanation and Elaboration document has been produced (18) following the style used for other reporting guidelines (19–21). The process of completing this document included developing a large database of exemplars to highlight how best to report each checklist item, and identifying a comprehensive evidence base to support the inclusion of each checklist item. The Explanation and Elaboration document was completed after several face-to-face meetings and numerous iterations among several meeting participants, after which it was shared with the whole group for additional revisions and final approval. Finally, the group formed a dissemination subcommittee to help disseminate and implement PRISMA.DiscussionThe quality of reporting of systematic reviews is still not optimal (22–27). In a recent review of 300 systematic reviews, few authors reported assessing possible publication bias (22), even though there is overwhelming evidence both for its existence (28) and its impact on the results of systematic reviews (29). Even when the possibility of publication bias is assessed, there is no guarantee that systematic reviewers have assessed or interpreted it appropriately (30). Although the absence of reporting such an assessment does not necessarily indicate that it was not done, reporting an assessment of possible publication bias is likely to be a marker of the thoroughness of the conduct of the systematic review.Several approaches have been developed to conduct systematic reviews on a broader array of questions. For example, systematic reviews are now conducted to investigate cost-effectiveness (31), diagnostic (32) or prognostic questions (33), genetic associations (34), and policy making (35). The general concepts and topics covered by PRISMA are all relevant to any systematic review, not just those whose objective is to summarize the benefits and harms of a health care intervention. However, some modifications of the checklist items or flow diagram will be necessary in particular circumstances. For example, assessing the risk of bias is a key concept, but the items used to assess this in a diagnostic review are likely to focus on issues such as the spectrum of patients and the verification of disease status, which differ from reviews of interventions. The flow diagram will also need adjustments when reporting individual patient data meta-analysis (36).We have developed an explanatory document (18) to increase the usefulness of PRISMA. For each checklist item, this document contains an example of good reporting, a rationale for its inclusion, and supporting evidence, including references, whenever possible. We believe this document will also serve as a useful resource for those teaching systematic review methodology. We encourage journals to include reference to the explanatory document in their Instructions to Authors.Like any evidence-based endeavor, PRISMA is a living document. To this end we invite readers to comment on the revised version, particularly the new checklist and flow diagram, through the PRISMA Web site. We will use such information to inform PRISMA's continued development.References1. Oxman AD, Cook DJ, Guyatt GH. Users' guides to the medical literature. VI. How to use an overview. Evidence-Based Medicine Working Group. JAMA. 1994;272:1367-71. [PMID: 7933399] CrossrefMedlineGoogle Scholar2. Swingler GH, Volmink J, Ioannidis JP. Number of published systematic reviews and global burden of disease: database analysis. BMJ. 2003;327:1083-4. [PMID: 14604930] CrossrefMedlineGoogle Scholar3. Canadian Institutes of Health Research. Randomized controlled trials registration/application checklist. December 2006. Accessed at www.cihr-irsc.gc.ca/e/documents/rct_reg_e.pdf on 19 May 2009. Google Scholar4. Young C, Horton R. Putting clinical trials into context. Lancet. 2005;366:107-8. [PMID: 16005318] CrossrefMedlineGoogle Scholar5. Mulrow CD. 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[PMID: CrossrefMedlineGoogle In to A Article, and Disclosure From Ottawa Methods Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada; Università di Modena e Reggio Emilia, Modena, Italy; Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy; and Centre for Statistics in Medicine, University of Oxford, Oxford, United The following to the PRISMA Altman, DSc, Centre for Statistics in Medicine United PhD, University Hospital MD, Health Research & Health PLoS Medicine United PhD, Hospital of Ontario, A. & Research and PhD, PLoS Medicine the of United PhD, Cochrane Centre United and of and MD, of Medicine, Clinical Epidemiology and University Ontario, PhD, Università di Modena e Reggio and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario J. PhD, University of United MD, PhD, of Medicine, Clinical Epidemiology and University Ontario, PhD, of Health MD, of and Medicine, University of MD, PhD, Medical United MD, The Cochrane Centre PhD, Ottawa Hospital Research Institute Ontario, MD, of Medicine, Clinical Epidemiology and University Ontario, PhD, United MD, University of MD, PhD, Systematic Reviews United and for Health and University of the and Alessandro Liberati, MD, Università di Modena e Reggio and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario MD, Centre for the of the of Health PhD, The United MD, Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Moher, PhD, Ottawa Methods Centre, Ottawa Hospital Research Institute Ontario, MD, Annals of Internal Medicine for Medical MD, Health Research Centre Health and Technology Assessment Ontario, Canada; at the of the first meeting of the group, Ontario, MD, University of Hospital of Ontario, PhD, Health International G. MD, PhD, Evidence-Based Jennifer Tetzlaff, BSc, Ottawa Methods Centre, Ottawa Hospital Research Institute Ontario, The Cochrane Cochrane Collaboration United at the of the first meeting of the group, United and MD, Institute of University of Ottawa Ontario, PRISMA was by the Canadian Institutes of Health Università di Modena e Reggio Emilia, Italy; Research Clinical Evidence The Cochrane Collaboration; and Liberati is in through of the of University and Altman is by Research Moher is by a University of Ottawa Research of the any in the or of the PRISMA no a role in the Moher, PhD, Ottawa Methods Centre, Ottawa Hospital Research Institute, The Ottawa Ottawa, Canada; Moher and Ottawa Methods Centre, Ottawa Hospital Research Institute, The Ottawa Ottawa, Università di Modena e Reggio and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Centre for Statistics in Medicine, University of Oxford, United of the PRISMA is in the PRISMA Statement for Reporting Systematic Reviews and of Studies Health Explanation and Elaboration Alessandro Liberati Douglas G. Altman Jennifer

Introduction: Chronic kidney disease as a public health problem. Chronic kidney disease is a worldwide public health problem. In the United States, there is a rising incidence and prevalence of kidney failure, with poor outcomes and high cost. There is an even higher prevalence of earlier stages of chronic kidney disease. Increasing evidence, accrued in the past decades, indicates that the adverse outcomes of chronic kidney disease, such as kidney failure, cardiovascular disease, and premature death, can be prevented or delayed. Earlier stages of chronic kidney disease can be detected through laboratory testing. Treatment of earlier stages of chronic kidney disease is effective in slowing the progression toward kidney failure. Initiation of treatment for cardiovascular risk factors at earlier stages of chronic kidney disease should be effective in reducing cardiovascular disease events both before and after the onset of kidney failure. Unfortunately, chronic kidney disease is "under-diagnosed" and "under-treated" in the United States, resulting in lost opportunities for prevention. One reason is the lack of agreement on a definition and classification of stages in the progression of chronic kidney disease. A clinically applicable classification would be based on laboratory evaluation of the severity of kidney disease, association of level of kidney function with complications, and stratification of risks for loss of kidney function and development of cardiovascular disease. Charge to the K/DOQI work group on chronic kidney disease. In 2000, the National Kidney Foundation (NKF) Kidney Disease Outcome Quality Initiative (K/DOQI) Advisory Board approved development of clinical practice guidelines to define chronic kidney disease and to classify stages in the progression of chronic kidney disease. The Work Group charged with developing the guidelines consisted of experts in nephrology, pediatric nephrology, epidemiology, laboratory medicine, nutrition, social work, gerontology, and family medicine. An Evidence Review Team, consisting of nephrologists and methodologists, was responsible for assembling the evidence. Defining chronic kidney disease and classifying the stages of severity would provide a common language for communication among providers, patients and their families, investigators, and policy-makers and a framework for developing a public health approach to affect care and improve outcomes of chronic kidney disease. A uniform terminology would permit: 1. More reliable estimates of the prevalence of earlier stages of disease and of the population at increased risk for development of chronic kidney disease 2. Recommendations for laboratory testing to detect earlier stages and progression to later stages 3. Associations of stages with clinical manifestations of disease 4. Evaluation of factors associated with a high risk of progression from one stage to the next or of development of other adverse outcomes 5. Evaluation of treatments to slow progression or prevent other adverse outcomes. Clinical practice guidelines, clinical performance measures, and continuous quality improvement efforts could then be directed to stages of chronic kidney disease. The Work Group did not specifically address evaluation and treatment for chronic kidney disease. However, this guideline contains brief reference to diagnosis and clinical interventions and can serve as a "road map" linking other clinical practice guidelines and pointing out where other guidelines need to be developed. Eventually, K/DOQI will include interventional guidelines. The first three of these, on bone disease, dyslipidemia, and blood pressure management are currently under development. Other guidelines on cardiovascular disease in dialysis patients and kidney biopsy will be initiated in the Winter of 2001. This report contains a summary of background information available at the time the Work Group began its deliberations, the 15 guidelines and the accompanying rationale, suggestions for clinical performance measures, a clinical approach to chronic kidney disease using these guidelines, and appendices to describe methods for the review of evidence. The guidelines are based on a systematic review of the literature and the consensus of the Work Group. The guidelines have been reviewed by the K/DOQI Advisory Board, a large number of professional organizations and societies, selected experts, and interested members of the public and have been approved by the Board of Directors of the NKF. Framework. The Work Group defined "chronic kidney disease" to include conditions that affect the kidney, with the potential to cause either progressive loss of kidney function or complications resulting from decreased kidney function. Chronic kidney disease was thus defined as the presence of kidney damage or decreased level of kidney function for three months or more, irrespective of diagnosis. The target population includes individuals with chronic kidney disease or at increased risk of developing chronic kidney disease. The majority of topics focus on adults (age ≥18 years). Many of the same principles apply to children as well. In particular, the classification of stages of disease and principles of diagnostic testing are similar. A subcommittee of the Work Group examined issues related to children and participated in development of the first six guidelines of the present document. However, there are sufficient differences between adults and children in the association of GFR with signs and symptoms of uremia and in stratification of risk for adverse outcomes that these latter issues are addressed only for adults. A separate set of guidelines for children will have to be developed by a later Work Group. The target audience includes a wide range of individuals: those who have or are at increased risk of developing chronic kidney disease (the target population) and their families; health care professionals caring for the target population; manufacturers of instruments and diagnostic laboratories performing measurements of kidney function; agencies and institutions planning, providing or paying for the health care needs of the target population; and investigators studying chronic kidney disease. There will be only brief reference to clinical interventions, sufficient to provide a basis for other clinical practice guidelines relevant to the evaluation and management of chronic kidney disease. Subsequent K/DOQI clinical practice guidelines will be based on the framework developed here. Definition of chronic kidney disease. Why "Kidney"? The word "kidney" is of Middle English origin and is immediately understood by patients, their families, providers, health care professionals, and the lay public of native English speakers. On the other hand, "renal" and "nephrology," derived from Latin and Greek roots, respectively, commonly require interpretation and explanation. The Work Group and the NKF are committed to communicating in language that can be widely understood, hence the preferential use of "kidney" throughout these guidelines. The term "End-Stage Renal Disease" (ESRD) has been retained because of its administrative usage in the United States referring to patients treated by dialysis or transplantation, irrespective of their level of kidney function. Why Develop a New Classification? Currently, there is no uniform classification of the stages of chronic kidney disease. A review of textbooks and journal articles clearly demonstrates ambiguity and overlap in the meaning of current terms. The Work Group concluded that uniform definitions of terms and stages would improve communication between patients and providers, enhance public education, and promote dissemination of research results. In addition, it was believed that uniform definitions would enhance conduct of clinical research. Why Base a New Classification System on Severity of Disease? Adverse outcomes of kidney disease are based on the level of kidney function and risk of loss of function in the future. Chronic kidney disease tends to worsen over time. Therefore, the risk of adverse outcomes increases over time with disease severity. Many disciplines in medicine, including related specialties of hypertension, cardiovascular disease, diabetes, and transplantation, have adopted classification systems based on severity to guide clinical interventions, research, and professional and public education. Such a model is essential for any public health approach to disease. Why Classify Severity as the Level of GFR? The level of glomerular filtration rate (GFR) is widely accepted as the best overall measure of kidney function in health and disease. Providers and patients are familiar with the concept that "the kidney is like a filter." GFR is the best measure of the kidneys' ability to filter blood. In addition, expressing the level of kidney function on a continuous scale allows development of patient and public education programs that encourage individuals to "Know your number!" The term "GFR" is not intuitively evident to anyone. Rather, it is a learned term, which allows the ultimate expression of the complex functions of the kidney in one single numerical expression. Conversely, numbers are an intuitive concept and easily understandable by everyone.

Prediction models are developed to aid health care providers in estimating the probability or risk that a specific disease or condition is present (diagnostic models) or that a specific event will occur in the future (prognostic models), to inform their decision making. However, the overwhelming evidence shows that the quality of reporting of prediction model studies is poor. Only with full and clear reporting of information on all aspects of a prediction model can risk of bias and potential usefulness of prediction models be adequately assessed. The Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) Initiative developed a set of recommendations for the reporting of studies developing, validating, or updating a prediction model, whether for diagnostic or prognostic purposes. This article describes how the TRIPOD Statement was developed. An extensive list of items based on a review of the literature was created, which was reduced after a Web based survey and revised during a three day meeting in June 2011 with methodologists, health care professionals, and journal editors. The list was refined during several meetings of the steering group and in e-mail discussions with the wider group of TRIPOD contributors. The resulting TRIPOD Statement is a checklist of 22 items, deemed essential for transparent reporting of a prediction model study. The TRIPOD Statement aims to improve the transparency of the reporting of a prediction model study regardless of the study methods used. The TRIPOD Statement is best used in conjunction with the TRIPOD explanation and elaboration document. To aid the editorial process and readers of prediction model studies, it is recommended that authors include a completed checklist in their submission (also available at www.tripod-statement.org). To encourage dissemination of the TRIPOD Statement, this article is freely accessible on the <i>Annals of Internal Medicine</i> Web site (www.annals.org) and will be also published in <i>BJOG</i>, <i>British Journal of Cancer</i>, <i>British Journal of Surgery</i>, <i>BMC Medicine</i>, <i>The BMJ</i>, <i>Circulation</i>, <i>Diabetic Medicine</i>, <i>European Journal of Clinical Investigation</i>, <i>European Urology</i>, and <i>Journal of Clinical Epidemiology</i>. The authors jointly hold the copyright of this article. An accompanying explanation and elaboration article is freely available only on www.annals.org; <i>Annals of Internal Medicine</i> holds copyright for that article.

Provenance: Not commissioned; externally peer reviewed by European Journal of Clinical Investigation, Journal of Clinical Epidemiology, Preventive Medicine, Mutagenesis, Journal of Epidemiology and Community Health, European Journal of Epidemiology. In order to encourage dissemination of this extension to the STROBE Statement, this article has also been published by European Journal of Clinical Investigation, Journal of Clinical Epidemiology, Preventive Medicine, Mutagenesis, Journal of Epidemiology and Community Health, European Journal of Epidemiology.

BACKGROUND: The coronavirus disease (COVID-19) has been identified as the cause of an outbreak of respiratory illness in Wuhan, Hubei Province, China beginning in December 2019. As of 31 January 2020, this epidemic had spread to 19 countries with 11 791 confirmed cases, including 213 deaths. The World Health Organization has declared it a Public Health Emergency of International Concern. METHODS: A scoping review was conducted following the methodological framework suggested by Arksey and O'Malley. In this scoping review, 65 research articles published before 31 January 2020 were analyzed and discussed to better understand the epidemiology, causes, clinical diagnosis, prevention and control of this virus. The research domains, dates of publication, journal language, authors' affiliations, and methodological characteristics were included in the analysis. All the findings and statements in this review regarding the outbreak are based on published information as listed in the references. RESULTS: Most of the publications were written using the English language (89.2%). The largest proportion of published articles were related to causes (38.5%) and a majority (67.7%) were published by Chinese scholars. Research articles initially focused on causes, but over time there was an increase of the articles related to prevention and control. Studies thus far have shown that the virus' origination is in connection to a seafood market in Wuhan, but specific animal associations have not been confirmed. Reported symptoms include fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis, and dyspnea. Preventive measures such as masks, hand hygiene practices, avoidance of public contact, case detection, contact tracing, and quarantines have been discussed as ways to reduce transmission. To date, no specific antiviral treatment has proven effective; hence, infected people primarily rely on symptomatic treatment and supportive care. CONCLUSIONS: There has been a rapid surge in research in response to the outbreak of COVID-19. During this early period, published research primarily explored the epidemiology, causes, clinical manifestation and diagnosis, as well as prevention and control of the novel coronavirus. Although these studies are relevant to control the current public emergency, more high-quality research is needed to provide valid and reliable ways to manage this kind of public health emergency in both the short- and long-term.

CONTEXT: Editors, authors, and reviewers are influential in shaping science. The careers of women in public health have received less scrutiny than those of women in medicine and other branches of science. The performance of women as editors, authors, and reviewers in epidemiology has not been previously studied. OBJECTIVE: To examine changes over time in the representation of women at the editorial level in US epidemiology journals compared with the proportion of women authors and reviewers. DESIGN AND SETTING: Cross-sectional study of 4 US epidemiology journals, American Journal of Epidemiology, Annals of Epidemiology, Epidemiology, and the Journal of Clinical Epidemiology (formerly the Journal of Chronic Diseases), for 1982, 1987, 1992, and 1994. SUBJECTS: Editors, authors, and reviewers for the selected years. MAIN OUTCOME MEASURES: Sex of editors, authors, and reviewers. RESULTS: We identified 2415 reports associated with 8005 authors. One of 7 editors in chief was a woman, a position she shared with a man. For all journals, the proportion of editors who were women ranged from 5 (6.5%) of 77 in 1982 to 42 (16.3%) of 258 in 1994. Over all journals and all years, women comprised a higher proportion of authors (28.7% [2225/7743]) compared with reviewers (26.7% [796/2982]) or editors (12.8% [89/696]). CONCLUSIONS: Fewer women in public health hold editorial positions than are authors and reviewers. The reasons for this important discrepancy, including the possibility of a selection bias favoring men, should be further investigated.

Journal Article TEST OF THE NATIONAL DEATH INDEX Get access MEIR J. STAMPFER, MEIR J. STAMPFER 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA3Department of Epidemiology, Harvard School of Public HealthBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar WALTER C. WILLETT, WALTER C. WILLETT 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA3Department of Epidemiology, Harvard School of Public HealthBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar FRANK E. SPEIZER, FRANK E. SPEIZER 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar DAVID C. DYSERT, DAVID C. DYSERT 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar ROBERT LIPNICK, ROBERT LIPNICK 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA3Department of Epidemiology, Harvard School of Public HealthBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar BERNARD ROSNER, BERNARD ROSNER 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA2Department of Preventive Medicine and Clinical Epidemiology, Harvard Medical SchoolBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar CHARLES H. HENNEKENS CHARLES H. HENNEKENS 1Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA Search for other works by this author on: Oxford Academic PubMed Google Scholar American Journal of Epidemiology, Volume 119, Issue 5, May 1984, Pages 837–839, https://doi.org/10.1093/oxfordjournals.aje.a113804 Published: 01 May 1984

Journal Article EPIDEMIOLOGY OF OSTEOPOROSIS AND OSTEOPOROTIC FRACTURES Get access STEVEN R. CUMMINGS, STEVEN R. CUMMINGS 1Division of General Internal Medicine and the Clinical Epidemiology Program, University of CaliforniaSan Francisco, CA Reprint requests to Dr. Steven R. Cummings, Division of General Internal Medicine, University of California Medical Center, 400 Parnassus Avenue, Room A-405, San Francisco, CA 94143 Search for other works by this author on: Oxford Academic PubMed Google Scholar JENNIFER L. KELSEY, JENNIFER L. KELSEY 2Division of Epidemiology, Columbia University, School of Public HealthNew York, NY Search for other works by this author on: Oxford Academic PubMed Google Scholar MICHAEL C. NEVITT, MICHAEL C. NEVITT 3Robert Wood Johnson Clinical Scholars Program and the Multipurpose Arthritis Center, University of CaliforniaSan Francisco, CA Search for other works by this author on: Oxford Academic PubMed Google Scholar KENNETH J. O'DOWD KENNETH J. O'DOWD 2Division of Epidemiology, Columbia University, School of Public HealthNew York, NY Search for other works by this author on: Oxford Academic PubMed Google Scholar Epidemiologic Reviews, Volume 7, Issue 1, 1985, Pages 178–208, https://doi.org/10.1093/oxfordjournals.epirev.a036281 Published: 01 March 1985

The NC3Rs gratefully acknowledges the expertise and advice that all the contributors have given to developing the guidelines. We would particularly like to acknowledge the contribution of the NC3Rs Reporting Guidelines Working Group-– Professor Doug Altman, Centre for Statistics in Medicine, University of Oxford UK, Professor David Balding, Department of Epidemiology & Public Health, Imperial College, London UK, Professor William Browne, Department of Clinical Veterinary Science, University of Bristol UK, Professor Innes Cuthill, School of Biological Sciences, University of Bristol UK, Dr Colin Dunn, Editor Laboratory Animals (Royal Society of Medicine press), Dr Michael Emerson, National Heart and Lung Institute, Imperial College, London UK, Dr Stella Hurtley, Senior Editor Science, Professor Ian McGrath, Editor-in-Chief British Journal of Pharmacology (Wiley Blackwell Publishers) and Dr Clare Stanford, Department of Psychopharmacology, University College, London UK. We would also like to thank NC3Rs grant holders, the Medical Research Council, Biotechnology and Biological Sciences Research Council (BBSRC), Wellcome Trust, Parkinson's Disease Society, British Heart Foundation and their grant holders and funding committee members who provided feedback on the guidelines; and Kathryn Chapman and Vicky Robinson (both NC3Rs) for their help with the manuscript. -Please note: that the working group members who contributed to these guidelines were advising in their personal capacity and their input does not necessarily represent the policy of the organisations they are associated with. The reporting guidelines project was funded by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs). These guidelines are excerpted (as permitted under the Creative Commons Attribution License [CCAL], with the knowledge and approval of PLoS Biology and the authors) from Kilkenny C, Browne WJ, Cuthill IC, Emerson M, Altman DG. Animal research: reporting in vivo experiments: ARRIVE guidelines. PLoS Biol 2010; 8(6): e1000412. doi: 10.1371/journal.pbio.1000412. These guidelines are licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA.

The propensity score is a subject's probability of treatment, conditional on observed baseline covariates. Conditional on the true propensity score, treated and untreated subjects have similar distributions of observed baseline covariates. Propensity-score matching is a popular method of using the propensity score in the medical literature. Using this approach, matched sets of treated and untreated subjects with similar values of the propensity score are formed. Inferences about treatment effect made using propensity-score matching are valid only if, in the matched sample, treated and untreated subjects have similar distributions of measured baseline covariates. In this paper we discuss the following methods for assessing whether the propensity score model has been correctly specified: comparing means and prevalences of baseline characteristics using standardized differences; ratios comparing the variance of continuous covariates between treated and untreated subjects; comparison of higher order moments and interactions; five-number summaries; and graphical methods such as quantile-quantile plots, side-by-side boxplots, and non-parametric density plots for comparing the distribution of baseline covariates between treatment groups. We describe methods to determine the sampling distribution of the standardized difference when the true standardized difference is equal to zero, thereby allowing one to determine the range of standardized differences that are plausible with the propensity score model having been correctly specified. We highlight the limitations of some previously used methods for assessing the adequacy of the specification of the propensity-score model. In particular, methods based on comparing the distribution of the estimated propensity score between treated and untreated subjects are uninformative.

Journal Article CLINICAL EPIDEMIOLOGY Get access DAVID L. SACKETT DAVID L. SACKETT Chairman 1Department of Clinical Epidemiology and Biostatistics, and Department of Medicine, Faculty of Medicine, MCMaster University; the St. Joseph's and Hamilton Civic HospitalsHamilton, Ontario Search for other works by this author on: Oxford Academic PubMed Google Scholar American Journal of Epidemiology, Volume 89, Issue 2, February 1969, Pages 125–128, https://doi.org/10.1093/oxfordjournals.aje.a120921 Published: 01 February 1969

Journal Article Population-Based Study of Survival after Osteoporotic Fractures Get access Cyrus Cooper, Cyrus Cooper From the Department of Health Sciences Research, Mayo Clinic and Foundation200 First Street, S W , Rochester, MN 55905 Search for other works by this author on: Oxford Academic PubMed Google Scholar Elizabeth J. Atkinson, Elizabeth J. Atkinson From the Department of Health Sciences Research, Mayo Clinic and Foundation200 First Street, S W , Rochester, MN 55905 Search for other works by this author on: Oxford Academic PubMed Google Scholar Steven J. Jacobsen, Steven J. Jacobsen From the Department of Health Sciences Research, Mayo Clinic and Foundation200 First Street, S W , Rochester, MN 55905 Search for other works by this author on: Oxford Academic PubMed Google Scholar W. Michael O’Fallon, W. Michael O’Fallon From the Department of Health Sciences Research, Mayo Clinic and Foundation200 First Street, S W , Rochester, MN 55905 Search for other works by this author on: Oxford Academic PubMed Google Scholar L. Joseph Melton, III L. Joseph Melton, III From the Department of Health Sciences Research, Mayo Clinic and Foundation200 First Street, S W , Rochester, MN 55905 From the Department of Health Sciences Research, Mayo Clinic and Foundation, 200 First Street, S W , Rochester, MN 55905 Reprint requests to Dr. L. J. Melton III, Section of Clinical Epidemiology, at this address Search for other works by this author on: Oxford Academic PubMed Google Scholar American Journal of Epidemiology, Volume 137, Issue 9, 1 May 1993, Pages 1001–1005, https://doi.org/10.1093/oxfordjournals.aje.a116756 Published: 01 May 1993 Article history Received: 14 September 1992 Revision received: 15 January 1993 Published: 01 May 1993