The Potential and Limitations of Meta-Analysis

Total Page:16

File Type:pdf, Size:1020Kb

The Potential and Limitations of Meta-Analysis journal of Epidemiology and Community Health 1991; 45: 89-92 J Epidemiol Community Health: first published as 10.1136/jech.45.2.89 on 1 June 1991. Downloaded from REVIEW ARTICLE:Research methods in epidemiology, V The potential and limitations of meta-analysis Tim D Spector, Simon G Thompson We are currently wimessing an "epidemic" of numbers is particularly relevant when dealing meta-analyses and overviews in the scientific with subgroup analysis, for which very often the literature. This is a relatively new phenomenon randomised controlled trial was not designed. and this article addresses some of the important Combining the results of comparable trials or issues raised by their increasing use. In particular studies can reduce random sampling errors that the differing applications and limitations ofmeta- may predominate in any individual study. The analysis are discussed, with a review of the larger the sample size available, the more precise analytic methods used and the problems and the estimate of the effect, and the hypothesis of biases encountered. subgroup effects can be more reliably investigated. What is meta-analysis? It has been suggested by some authors that only Meta-analysis has come to refer to the combining randomised controlled trials should be subjected ofresults from a number ofexperiments or studies to meta-analysis.8 However this restriction is not examining the same question. Such a process is desirable; aetiological meta-analyses (ie, of case- not new, and some meta-analytic studies were control or prospective studies) have recently been reported as early as 1955.1 However, only since carried out, usually to clarify inconsistent the term meta-analysis was first used in 19762 has findings or to estimate the true effect of a risk the technique become recognised as an analytical factor. However the interpretation of a meta- method. Meta-analysis is a discipline that reviews analysis of randomised controlled trials is usually critically and combines statistically the results of simpler. If all relevant clinical trials are included previous research in an attempt to summarise the and these are free from bias (ie, trials are totality ofevidence relating to a particular medical randomised, all randomised individuals are issue. The term meta-analysis is now often used included in "intention to treat" analyses, and synonymously with overview. outcome assessments are objective or blinded), a meta-analysis will give an unbiased assessment of Why use meta-analysis? a treatment's efficacy.9 In observational http://jech.bmj.com/ Traditionally, when seeking advice in epidemiology, potential bias in individual studies controversial or novel areas, clinicians and (through confounding, misclassification, or other scientists have relied heavily on "informed" causes) will always remain a problem, especially editorials or narrative reviews. There is now good when effect sizes are small. If such biases are to an evidence to suggest that these traditional methods extent consistent over different studies, a meta- are subject to bias and inaccuracy.3 Reviewers analysis will reflect both the true effect and the are a using traditional methods less likely to detect biases. However the increasing use of meta- on September 27, 2021 by guest. Protected copyright. small but significant effect or difference analysis in observational studies should compared with reviewers using formal statistical encourage the more formal reporting of techniques.4 In controversial topics, such as aetiological studies, to facilitate the combining of reviews of the uses of new procedures, the such results. Indeed the direct comparison of Department of enthusiasm for the procedure may be associated results from meta-analyses of randomised Environmental and more with the specialty of the reviewer than with contfolled trials and of the related observational Preventive Medicine, the most current St Bartholomew's results of the trials.5 As medical studies is a novel and informative advance.'0 Hospital Medical reviews do not use scientific methods to assess and College, Charterhouse present data, different reviewers often reach Examples of meta-analysis Square, London different conclusions based on the same data.6 ECIM 6BQ For There are now many examples ofmeta-analysis in T D Spector these reasons some formal statistical process of a great variety of medical specialities that Medical Statistics review should replace the informal approach. demonstrate their potential usefulness. One ofthe Unit, London School Meta-analysis can be used to resolve uncertainty f of Hygiene and early important studies concerned the use of Tropical Medicine, when reports, editorials or reviews disagree. blockers in myocardial infarction'2 13 which Keppel St, London Although the randomised controlled clinical showed the efficacy of post-discharge treatment wC1 trial is now accepted as the gold standard method by combining the results of over 60 small studies. S G Thompson of assessing therapeutic regimes, individual trials It also produced a useful framework for future Correspondence to: may produce false positive or negative studies. Another meta-analysis has concluded Dr Spector conclusions. Small numbers and the consequent that steriods are of benefit in meningitis in Accepted for publication lack ofpower ofany individual study is usually the children,14 another that H2 antagonists are ofonly October 1990 main problem area.7 The problem of small minor benefit in the treatment of gastrointestinal 90 Tim D Spector, Simon G Thompson haemorrhage, and only in gastric ulcers.'5 independently assessed "quality", derived from a J Epidemiol Community Health: first published as 10.1136/jech.45.2.89 on 1 June 1991. Downloaded from Although the vast majority of meta-analyses large number of predetermined "quality" concern the assessment of therapies in criteria.26 The pooled estimate can then be randomised controlled trials, a few studies have adjusted accordingly, or else the quality* score addressed contentious aetiological issues such as used to exclude studies. A simpler method for the quantification ofthe effect ofpassive smoking trials has been proposed which concentrates on on the risk of lung cancer,'6 alcohol in breast three areas of potential bias, namely treatment cancer,"7 the oral contraceptive pill in rheumatoid allocation by randomisation, inclusion of all arthritis,'8 and leukaemia in refinery workers.'9 randomised individuals in analysis, and the blindness of the outcome assessments.27 Quality Study design in meta-analysis assessments have also been used in With the proliferation of meta-analyses, it has epidemiological studies.'7 28 The major problem become apparent that their design, methods and with quality weighting is that it must remain publication should be conducted in a rigorous arbitrary and to an extent subjective. A single scientific manner, akin to that currently expected choice of weights is difficult to justify; for of randomised controlled trials. This is to allow example, is it worse to have poor blinding or poor critical appraisal of each individual meta-analysis randomisation? Moreover the procedure goes in terms of its methodology and therefore the against the general purpose of meta-analysis, that validity ofits conclusions. A meta-analysis should is to obtain an objective summary of the available be a research study in its own right. Specific a evidence. Because of the time and resources priori aims should be set out and a working needed to undertake full quality assessment, its protocol established. routine use cannot be recommended unless its Having defined the aims of the study, a true worth becomes established. thorough search of relevant publications needs to be performed. Computer searches have aided the Publication bias inclusion of large numbers of trials in published Publication bias is a potential problem in all meta-analyses. However, several studies have meta-analyses.29 30 It arises from the fact that shown that less than two thirds of relevant trials unpublished papers may contradict the findings are uncovered by computer searches.20 Therefore of the overview due to the overrepresentation of computer searches should be supplemented by published "positive" (ie, statistically significant) the bibliographies of textbooks, reviews, and the studies. There is now good evidence that negative studies themselves, and information from studies in medicine are less likely to be published specialists in the field. Where possible databases than positive ones.3' 32The likelihood ofthis bias of ongoing clinical trials should be consulted. altering the conclusions will depend on the In order to reduce bias, the inclusion of studies chances of the existence of important numbers of should be based on predetermined criteria. For unpublished papers. This is less likely to occur example in clinical trials, evidence of when the result is of considerable importance (eg, randomisation is usually regarded as crucial2"; in vitamin supplementation and neural tube some situations a minimum study size might be defects)33 or when the questions can only be desirable. Ideally all studies should be assessed in answered by large costly studies which are likely a blinded fashion by independent observers, to reach publication (eg, trials ofthrombolytics on although this is often difficult and impractical to cardiovascular mortality). http://jech.bmj.com/ perform. The decision to include studies should The question of publication bias needs to be consider whether treatments,
Recommended publications
  • The Statistical Significance of Randomized Controlled Trial Results Is Frequently Fragile: a Case for a Fragility Index
    The statistical significance of randomized controlled trial results is frequently fragile: A case for a Fragility Index Walsh, M., Srinathan, S. K., McAuley, D. F., Mrkobrada, M., Levine, O., Ribic, C., Molnar, A. O., Dattani, N. D., Burke, A., Guyatt, G., Thabane, L., Walter, S. D., Pogue, J., & Devereaux, P. J. (2014). The statistical significance of randomized controlled trial results is frequently fragile: A case for a Fragility Index. Journal of Clinical Epidemiology, 67(6), 622-628. https://doi.org/10.1016/j.jclinepi.2013.10.019 Published in: Journal of Clinical Epidemiology Document Version: Publisher's PDF, also known as Version of record Queen's University Belfast - Research Portal: Link to publication record in Queen's University Belfast Research Portal Publisher rights 2014 The Authors. Published by Elsevier Inc. This is an open access article published under a Creative Commons Attribution-NonCommercial-NoDerivs License (https://creativecommons.org/licenses/by-nc-nd/3.0/), which permits distribution and reproduction for non-commercial purposes, provided the author and source are cited. General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws.
    [Show full text]
  • Why Do You Need a Biostatistician? Antonia Zapf1* , Geraldine Rauch2 and Meinhard Kieser3
    Zapf et al. BMC Medical Research Methodology (2020) 20:23 https://doi.org/10.1186/s12874-020-0916-4 DEBATE Open Access Why do you need a biostatistician? Antonia Zapf1* , Geraldine Rauch2 and Meinhard Kieser3 Abstract The quality of medical research importantly depends, among other aspects, on a valid statistical planning of the study, analysis of the data, and reporting of the results, which is usually guaranteed by a biostatistician. However, there are several related professions next to the biostatistician, for example epidemiologists, medical informaticians and bioinformaticians. For medical experts, it is often not clear what the differences between these professions are and how the specific role of a biostatistician can be described. For physicians involved in medical research, this is problematic because false expectations often lead to frustration on both sides. Therefore, the aim of this article is to outline the tasks and responsibilities of biostatisticians in clinical trials as well as in other fields of application in medical research. Keywords: Medical research, Biostatistician, Tasks, Responsibilities Background Biometric Society (IBS) provides a definition of biomet- What is a biostatistician, what does he or she actually do rics as a ‘field of development of statistical and mathem- and what distinguishes him or her from, for example, an atical methods applicable in the biological sciences’ [2]. epidemiologist? If we would ask this our main cooper- In here, we will focus on (human) medicine as area of ation partners like physicians or biologists, they probably application, but the results can be easily transferred to could not give a satisfying answer. This is problematic the other biological sciences like, for example, agricul- because false expectations often lead to frustration on ture or ecology.
    [Show full text]
  • Observational Clinical Research
    E REVIEW ARTICLE Clinical Research Methodology 2: Observational Clinical Research Daniel I. Sessler, MD, and Peter B. Imrey, PhD * † Case-control and cohort studies are invaluable research tools and provide the strongest fea- sible research designs for addressing some questions. Case-control studies usually involve retrospective data collection. Cohort studies can involve retrospective, ambidirectional, or prospective data collection. Observational studies are subject to errors attributable to selec- tion bias, confounding, measurement bias, and reverse causation—in addition to errors of chance. Confounding can be statistically controlled to the extent that potential factors are known and accurately measured, but, in practice, bias and unknown confounders usually remain additional potential sources of error, often of unknown magnitude and clinical impact. Causality—the most clinically useful relation between exposure and outcome—can rarely be defnitively determined from observational studies because intentional, controlled manipu- lations of exposures are not involved. In this article, we review several types of observa- tional clinical research: case series, comparative case-control and cohort studies, and hybrid designs in which case-control analyses are performed on selected members of cohorts. We also discuss the analytic issues that arise when groups to be compared in an observational study, such as patients receiving different therapies, are not comparable in other respects. (Anesth Analg 2015;121:1043–51) bservational clinical studies are attractive because Group, and the American Society of Anesthesiologists they are relatively inexpensive and, perhaps more Anesthesia Quality Institute. importantly, can be performed quickly if the required Recent retrospective perioperative studies include data O 1,2 data are already available.
    [Show full text]
  • Certification Accredited Schools List
    = Academic Clinical Research Programs Which Currently Meet Waiver Requirements for the Academy of Clinical Research Professional (Updated October 15, 2015) This list includes academic clinical research programs which, as of the above date, have been evaluated and found to meet the current waiver requirements established by the Academy of Clinical Research Professionals (Academy) Board of Trustees. Programs that meet the waiver requirements allow a candidate to waive 1,500 hours of hands-on experience performing the Essential Duties of the program to which the candidate has made application. This list is not to be considered exhaustive and is not designed to represent all the academic offerings available. Appearance on this list is not to be construed as an endorsement of its content or format by the Academy or a guarantee that a candidate will be eligible for certification. All individuals interested in enrolling in a program of study should evaluate any program on the basis of his or her personal needs. (* - programs marked with an asterisk MAY be accepted but acceptance will be dependent on the complete listing of courses completed) Individuals seeking additional information about each program should contact the institution directly. Academic Institution Program Name ( Click Title for Web Navigation) Academy of Applied Pharmaceutical Sciences Clinical Research Diploma Program American University of Health Sciences Master of Science in Clinical Research Anoka-Ramsey Community College Clinical Research Professional - Certificate Graduate
    [Show full text]
  • Placebo-Controlled Trials of New Drugs: Ethical Considerations
    Reviews/Commentaries/Position Statements COMMENTARY Placebo-Controlled Trials of New Drugs: Ethical Considerations DAVID ORENTLICHER, MD, JD als, placebo controls are not appropriate when patients’ health would be placed at significant risk (8–10). A placebo- controlled study for a new hair- uch controversy exists regarding sufficiently more effective than placebo to thickening agent could be justified; a the ethics of placebo-controlled justify its use. Finally, not all established placebo-controlled study for patients M trials in which an experimental therapies have been shown to be superior with moderate or severe hypertension therapy will compete with an already es- to placebo. If newer drugs are compared would not be acceptable (11). Similarly, if tablished treatment (or treatments). In with the unproven existing therapies, an illness causes problems when it goes such cases, argue critics, patients in the then patients may continue to receive untreated for a long period of time, a 52- control arm of the study should receive an drugs that are harmful without being week study with a placebo control is accepted therapy rather than a placebo. helpful. much more difficult to justify than a By using an active and effective drug, the Moreover, say proponents of placebo 6-week study (12). control patients would not be placed at controls, patients can be protected from When David S.H. Bell (13) explains risk for deterioration of their disease, and harm by “escape” criteria, which call for why placebo controls are unacceptable the study would generate more meaning- withdrawal from the trial if the patient for new drugs to treat type 2 diabetes, he ful results for physicians.
    [Show full text]
  • NIH Definition of a Clinical Trial
    UNIVERSITY OF CALIFORNIA, SAN DIEGO HUMAN RESEARCH PROTECTIONS PROGRAM NIH Definition of a Clinical Trial The NIH has recently changed their definition of clinical trial. This Fact Sheet provides information regarding this change and what it means to investigators. NIH guidelines include the following: “Correctly identifying whether a study is considered to by NIH to be a clinical trial is crucial to how [the investigator] will: Select the right NIH funding opportunity announcement for [the investigator’s] research…Write the research strategy and human subjects section of the [investigator’s] grant application and contact proposal…Comply with appropriate policies and regulations, including registration and reporting in ClinicalTrials.gov.” NIH defines a clinical trial as “A research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.” NIH notes, “The term “prospectively assigned” refers to a pre-defined process (e.g., randomization) specified in an approved protocol that stipulates the assignment of research subjects (individually or in clusters) to one or more arms (e.g., intervention, placebo, or other control) of a clinical trial. And, “An ‘intervention’ is defined as a manipulation of the subject or subject’s environment for the purpose of modifying one or more health-related biomedical or behavioral processes and/or endpoints. Examples include:
    [Show full text]
  • Generating Real-World Evidence by Strengthening Real-World Data Sources
    Generating Real-World Evidence by Strengthening Real-World Data Sources Using “real-world evidence” to bring new “Every day, health care professionals are updating patients’ treatments to patients as part of the 21st electronic health records with data on clinical outcomes Century Cures Act (the “Cures Act”) is a key resulting from medical interventions used in routine clinical priority for the Department of Health and practice. As our experience with new medical products Human Services (HHS). Specifically, the Cures expands, our knowledge about how to best maximize their Act places focus on the use of real-world data benefits and minimize potential risks sharpens with each data to support regulatory decision-making, including point we gather. Every clinical use of a product produces data the approval of new indications for existing that can help better inform us about its safety and efficacy.” drugs in order to make drug development faster jacqueline corrigan-curay, md, jd and more efficient. As such, the Cures Act director of the office of medical policy in fda’s center for drug evaluation and research has tasked the Food and Drug Administration (FDA) to develop a framework and guidance for evaluating real-world evidence in the context of drug regulation.1 Under the FDA’s framework, real-world evidence (RWE) is generated by different study designs or analyses, including but not limited to, randomized trials like large simple trials, pragmatic trials, and observational studies. RWE is the clinical evidence about the use, potential benefits, and potential risks of a medical product based on an analysis of real-world data (RWD).
    [Show full text]
  • E 8 General Considerations for Clinical Trials
    European Medicines Agency March 1998 CPMP/ICH/291/95 ICH Topic E 8 General Considerations for Clinical Trials Step 5 NOTE FOR GUIDANCE ON GENERAL CONSIDERATIONS FOR CLINICAL TRIALS (CPMP/ICH/291/95) TRANSMISSION TO CPMP November 1996 TRANSMISSION TO INTERESTED PARTIES November 1996 DEADLINE FOR COMMENTS May 1997 FINAL APPROVAL BY CPMP September 1997 DATE FOR COMING INTO OPERATION March 1998 7 Westferry Circus, Canary Wharf, London, E14 4HB, UK Tel. (44-20) 74 18 85 75 Fax (44-20) 75 23 70 40 E-mail: [email protected] http://www.emea.eu.int EMEA 2006 Reproduction and/or distribution of this document is authorised for non commercial purposes only provided the EMEA is acknowledged GENERAL CONSIDERATIONS FOR CLINICAL TRIALS ICH Harmonised Tripartite Guideline Table of Contents 1. OBJECTIVES OF THIS DOCUMENT.............................................................................3 2. GENERAL PRINCIPLES...................................................................................................3 2.1 Protection of clinical trial subjects.............................................................................3 2.2 Scientific approach in design and analysis.................................................................3 3. DEVELOPMENT METHODOLOGY...............................................................................6 3.1 Considerations for the Development Plan..................................................................6 3.1.1 Non-Clinical Studies ........................................................................................6
    [Show full text]
  • Double Blind Trials Workshop
    Double Blind Trials Workshop Introduction These activities demonstrate how double blind trials are run, explaining what a placebo is and how the placebo effect works, how bias is removed as far as possible and how participants and trial medicines are randomised. Curriculum Links KS3: Science SQA Access, Intermediate and KS4: Biology Higher: Biology Keywords Double-blind trials randomisation observer bias clinical trials placebo effect designing a fair trial placebo Contents Activities Materials Activity 1 Placebo Effect Activity Activity 2 Observer Bias Activity 3 Double Blind Trial Role Cards for the Double Blind Trial Activity Testing Layout Background Information Medicines undergo a number of trials before they are declared fit for use (see classroom activity on Clinical Research for details). In the trial in the second activity, pupils compare two potential new sunscreens. This type of trial is done with healthy volunteers to see if the there are any side effects and to provide data to suggest the dosage needed. If there were no current best treatment then this sort of trial would also be done with patients to test for the effectiveness of the new medicine. How do scientists make sure that medicines are tested fairly? One thing they need to do is to find out if their tests are free of bias. Are the medicines really working, or do they just appear to be working? One difficulty in designing fair tests for medicines is the placebo effect. When patients are prescribed a treatment, especially by a doctor or expert they trust, the patient’s own belief in the treatment can cause the patient to produce a response.
    [Show full text]
  • Studies of Staphylococcal Infections. I. Virulence of Staphy- Lococci and Characteristics of Infections in Embryonated Eggs * WILLIAM R
    Journal of Clinical Investigation Vol. 43, No. 11, 1964 Studies of Staphylococcal Infections. I. Virulence of Staphy- lococci and Characteristics of Infections in Embryonated Eggs * WILLIAM R. MCCABE t (From the Research Laboratory, West Side Veterans Administration Hospital, and the Department of Medicine, Research and Educational Hospitals, University of Illinois College of Medicine, Chicago, Ill.) Many of the determinants of the pathogenesis niques still require relatively large numbers of and course of staphylococcal infections remain staphylococci to produce infection (19). Fatal imprecisely defined (1, 2) despite their increas- systemic infections have been equally difficult to ing importance (3-10). Experimental infections produce in animals and have necessitated the in- in suitable laboratory animals have been of con- jection of 107 to 109 bacteria (20-23). A few siderable assistance in clarifying the role of host strains of staphylococci have been found that are defense mechanisms and specific bacterial virulence capable of producing lethal systemic infections factors with a variety of other infectious agents. with inocula of from 102 to 103 bacteria (24) and A sensitive experimental model would be of value have excited considerable interest (25-27). The in defining the importance of these factors in virulence of these strains apparently results from staphylococcal infections, but both humans and an unusual antigenic variation (27, 28) which, the usual laboratory animals are relatively re- despite its interest, is of doubtful significance in sistant. Extremely large numbers of staphylo- human staphylococcal infection, since such strains cocci are required to produce either local or sys- have been isolated only rarely from clinical in- temic infections experimentally.
    [Show full text]
  • Using Real-World Evidence to Accelerate Safe and Effective Cures Advancing Medical Innovation for a Healthier America June 2016 Leadership Senator William H
    Using Real-World Evidence to Accelerate Safe and Effective Cures Advancing Medical Innovation for a Healthier America June 2016 Leadership Senator William H. Frist, MD Former U.S. Senate Majority Leader Chair, FDA: Advancing Medical Innovation Bipartisan Policy Center Representative Bart Gordon Former Member, U.S. House of Representatives Chair, FDA: Advancing Medical Innovation Bipartisan Policy Center Advisory Committee Marc M. Boutin, JD Chief Executive Officer National Health Council Mark McClellan, MD, PhD Director, Robert J. Margolis Center for Health Policy Duke University Patrick Soon-Shiong, MD Chairman and Chief Executive Officer Institute for Advanced Health Andrew von Eschenbach, MD President Samaritan Health Initiatives 1 Sta G. William Hoagland Ann Gordon Senior Vice President Writer Bipartisan Policy Center Michael Ibara, PharmD Janet M. Marchibroda Independent Consultant Director, Health Innovation Initiative and Executive Director, CEO Council on Health and Innovation Bipartisan Policy Center Tim Swope Senior Policy Analyst Bipartisan Policy Center Sam Watters Administrative Assistant Bipartisan Policy Center 2 FDA: ADVANCING MEDICAL INNOVATION EFFORT The Bipartisan Policy Center’s initiative, FDA: Advancing Medical Innovation, is developing viable policy options to advance medical innovation and reduce the time and cost associated with the discovery, development, and delivery of safe and effective drugs and devices for patients in the United States. Key areas of focus include the following: Improving the medical product development process; Increasing regulatory clarity; Strengthening the Food and Drug Administration’s (FDA) ability to carry out its mission; Using information technology to improve health and health care; and Increasing investment in medical products to address unmet and public health needs.
    [Show full text]
  • Short List of Commonly Used Acronyms in Clinical Research
    Short List of Commonly Used Acronyms in Clinical Research ACRP Association of Clinical Research Professionals AE Adverse Event ADR Adverse Drug Reaction AMA American Medical Association BAA Business Associate Agreement BIND Biological IND CA Coverage Analysis CAP College of American Pathologists CBCTN Community Based Clinical Trials Network CCRA Certified Clinical Research Associate (ACRP) CCRC Certified Clinical Research Coordinator (ACRP) CCRT Center for Clinical Research & Technology CCRP Certified Clinical Research Professional (SoCRA) CDA Confidential Disclosure Agreement CDC Center for Disease Control CFR Code of Federal Regulations CIRBI Center for IRB Intelligence CITI Collaborative Institutional Training Initiative CLIA Clinical Laboratory Improvement Amendments CME Continuing Medical Education CMS Central Management System COI Conflict of Interest CRA Clinical Research Associate CRC Clinical Research Coordinator CREC Continuing Research Education Credit CRF Case Report Form CRO Clinical Research Organization CTA Clinical Trial Agreement CTSC Clinical & Translational Science Collaborative CV Curriculum Vitae DCF Data Correction Form / Data Clarification Form DEA Drug Enforcement Agency (law enforcement division of FDA) DHHS Department of Health and Human Services DOS Date of Service DSMB or Data and Safety Monitoring Board (Plan or Committee) DSMP/C EAB Ethical Advisory Board (similar to IRB, used by other nations) EDC Electronic Data Capture FDA Food and Drug Administration FDA-482 Notice of Inspection FDA-483 Notice of Adverse
    [Show full text]