| The Medical Literature as a Resource for Evidence Based Care | | 太极医疗保健网 来源： | 字体： 放大 还原 缩小 | | | Contents
Abstract
Introduction
Medline Studies
ACP Journal Club
Systematic Overviews
Cochrane Collaboration
Evidence Based Guidelines
On-line Resources
References
--------------------------------------------------------------------------------
Abstract
Evidence-based medicine (EBM) is an approach to health care that promotes the collection, interpretation, and integration of valid, important and applicable patient-reported, clinician-observed, and research-derived evidence. The best available evidence, moderated by patient circumstances and preferences, is applied to improve the quality of clinical judgments. The Health Information Research Unit of McMaster University Faculty of Health Sciences in conjunction with others at McMaster and elsewhere has developed, evaluated, and made more accessible information tools to facilitate the practice of EBM. These include users' guides to the medical literature, strategies for improving the yield of MEDLINE searches, standardized formats for abstracts of journal articles and guidelines, new journals, systematic reviews and meta-analyses, and software tools that bring high quality information to the point of clinical decision making. This article discusses these and other EBM resources for health care professionals.
Introduction
Traditionally clinicians have favored past experience, prevailing practice, professional training, and peer opinion as guides for day to day decisions about patient care. These sources have become less reliable as the volume and complexity of medical information has grown exponentially. In the 1970s, clinicians and researchers at McMaster University began to address this clinical information overload by developing tools to help clinicians to discern the clinically valid, important, and applicable details. "Critical appraisal" of the medical literature was introduced as an approach to reading that would help practitioners sift clinically relevant and methodologically sound studies from the countless articles appearing in medical journals. The original critical appraisal series was published in the Canadian Medical Association Journal, then translated into many other languages, and disseminated widely. A new series of "users guides to the medical literature", appears in the Journal of the American Medical Association (Guyatt, 1993a, 1993b, 1994; Oxman, 1993, 1994; Jaeschke, 1994a, 1994b; Levine, 1994; Laupacis, 1994; Hayward, 1995), and emphasizes the perspective of busy clinicians who need quick and simple ways to make sense of a burgeoning medical literature.
The "evidence-based medicine" (EBM) movement (Evidence-Based Medicine Working Group, 1992) asserts that potential advances in health care must be tested and proven to do more good than harm before they are incorporated into medical practice. EBM is an approach to patient care that promotes the collection, interpretation, and integration of valid, important and applicable patient-reported, clinician-observed, and research-derived evidence. The best available evidence, moderated by patient circumstances and preferences, is applied to improve the quality of clinical judgments. The EBM movement has grown in parallel with the introduction of problem-based curricula into health sciences training programs and has spread to many other institutions, including the University of New Mexico and Harvard in the United States, the Suez Canal University in Egypt, and Maastricht in the Netherlands.
The medical literature contains evidence that can be used to improve patient care, but only a small portion of the medical literature describes solid advances in the diagnosis, prevention, treatment, cause or prognosis of illness. Finding and understanding the important and valid studies is tough for busy clinicians, and an impediment to the wide adoption of EBM. Efficient, effective information retrieval tools, on the other hand, could ease the information overload of practitioners, and help them apply evidence to clinical practice. In this article, we review the rationale for EBM and describe information tools to facilitate the practice of EBM, emphasizing the research done in the Health Information Research Unit (HIRU) and the Department of Clinical Epidemiology and Biostatistics at McMaster University.
MEDLINE studies
Much of the medical literature, including editorials, letters, case reports, reviews, laboratory and animal studies, is interesting and informative. A relatively small fraction of the literature, however, reports specific, scientifically sound advances that can and should change how clinicians care for patients. Such information is most often found in reports of experiments in people, where groups of persons are systematically exposed to alternative interventions to evaluate the effectiveness of prevention, diagnosis, and treatment of specific health conditions. EBM practitioners need fast and efficient access to subsets of the medical literature enriched with this kind of clinical research. Fortunately, the most trustworthy reports of the effectiveness of health interventions bear common characteristics that can be used to identify them among the huge number of clinical studies and to enable their selective retrieval and synthesis.
The best evaluations of health care result from preplanned, time-limited trials in large numbers of humans, with criterion standard, sensitivity and specificity measurements for diagnostic studies; randomized controlled trials for therapy, prevention, quality of care, and economics; randomized controlled trials, cohort studies, or case-control studies for harm or etiology evaluations; cohort studies for prognosis; and meta-analyses or systematic overviews for reviews of the results of many primary studies. The results of the best evaluations of health care are first published as journal articles, then registered in bibliographic databases maintained at the National Library of Medicine (NLM). Indexers apply medical subject headings (MeSH) to each entry in NLM databases (MEDLARS), and some of these index terms describe how studies were designed and executed. The quality and consistency of methodological indexing was given a boost in 1990 and 1991 when the MeSH vocabulary was expanded to include specific tags for different types of studies (e.g., controlled trial) and publications (e.g. meta-analysis). By including methodologic terms in their search strategies, users of the NLM databases now can look for studies that avoid the most common threats to the validity and applicability of their results.
With the proliferation of personal computers, modems, CD-ROM products, wide-area networks and Internet, MEDLINE searches have become more accessible to clinicians, who are the fastest growing population of MEDLINE users. MEDLINE-derived databases, interfaces and search software packages have steadily improved, further easing the way for clinicians. Indeed, different systems no longer differ substantially for price and performance (Haynes, 1994c, 1995). Some interfaces to MEDLINE, however, may work better for particular subgroups of users. In one study librarians' strategies produced more rewarding MEDLINE searches using on-line systems and clinicians' strategies produced better results with CD-ROM systems (Haynes, 1994c). This suggests that software interfaces and search engines should be selected based on personal preferences, available support and training opportunities.
When MEDLINE access was provided on the wards and clinics of a hospital, experienced clinicians retrieved relevant citations, enjoyed searching, and felt that their searches enhanced patient care outcomes (Haynes, 1990b, 1993; McKibbon, 1990). After experiences with approximately 8 searches, clinicians also retrieved just as many relevant citations as librarian searchers although they also captured more irrelevant citations. New medical trainees may be more familiar with computers and more likely to acquire MEDLINE skills. A survey of first-year medical students at McMaster University after 3 months in school showed that MEDLINE use was 65% in 1987 and had risen to 99% by 1991 (Haynes, 1994b).
Recent enhancements to MEDLINE have allowed for more sophisticated search techniques and HIRU has developed and tested strategies for improving the yield of clinically important and valid information from MEDLINE. First, the wider use of more informative on-line abstracts has been promoted. Most clinicians draw conclusions about the applicability of study results directly from the on-line abstract. More informative abstracts of original research (Ad Hoc, 1987; Haynes, 1990a), review articles (Mulrow, 1988), and practice guidelines (Hayward, 1993) give key information about the study purpose, patients, settings, methods, interventions, results, and conclusions. The structured summaries provide more information than conventional abstracts (Taddio, 1994; Narine, 1991; Counams, 1990), highlight methodologic considerations and facilitate more effective textword searching.
To evaluate the effectiveness of methodology-based MEDLINE searching, HIRU (Haynes, 1994a) studied the retrieval characteristics of index terms and textwords alone and in combination. We compared MEDLINE retrievals for each citation with the results of a manual review of 10 core medical and internal medicine journals (American Journal of Medicine, Annals of Internal Medicine, Archives of Internal Medicine, BMJ, Circulation, Diabetes Care, Journal of Internal Medicine, Journal of the American Medical Association, Lancet, and New England Journal of Medicine) for the years 1986 and 1991. Our results show that various combinations of index terms and textwords can be used to increase the number of relevant citations or the proportion of relevant citations retrieved. For example, in searching for studies that evaluate diagnostic procedures in adult medicine, the one-term strategy SENSITIVITY (TEXTWORD) retrieved up to 57% of relevant articles; the strategy EXPLODE SENSITIVITY AND SPECIFICITY (INDEX TERM) OR SENSITIVITY (TEXTWORD) OR DIAGNOSIS (PRE-EXPLODED SUBHEADING) OR DIAGNOSTIC USE (SUBHEADING) OR SPECIFICITY (TEXTWORD) retrieved 92% of the relevant citations with 27% irrelevant citations. To maximize the proportion of relevant citations, the strategy EXPLODE SENSITIVITY AND SPECIFICITY OR PREDICTIVE AND VALUE (TEXTWORD) retrieved 55% of the relevant citations available with less than 2% irrelevant citations. These results may be artificially high because only methodology terms were tested, content was not included in the searching strategies, and only core journals were included in the manual review.
MEDLINE, however, has three major drawbacks that limit its utility in busy patient care settings. First, high-yield searches can take as much as 30 minutes to complete --much longer than physicians have to spend with each patient. Second, individuals studies rarely offer conclusive information and so results from several studies must be combined. Finally, the patient characteristics, settings, disease severity and comorbidity featured in high quality studies may differ significantly from the sorts of patients seen in typical practice. Clinicians need digests of the clinically relevant literature. These digests serve EBM to the extent that they highlight the validity, importance and applicability of multiple studies of a particular health problem.
Textbooks are traditional sources of synthesized information. Unfortunately, textbooks are often out of date even at the time of publication. Most lack a systematic approach to evidence surveillance, summarization, and citation. A notable exception is Scientific American Medicine (Dale, 1995). Its large team of authors regularly updates chapters and its subscribers regularly receive packets of updates. An electronic version, on CD-ROM, is updated 4 times a year. Chapter authors must comply with strict editor's rules about the relevance and significance of citations to the recent medical literature. Less comprehensive evidence-based texts now serve specific areas of medicine. Examples include three monographs about screening and diagnostic tests (Sox, 1987; Eddy, 1991; Panzer, 1991). The Effective Care in Pregnancy and Childbirth (Chalmers, 1989) and the Effective Care of the Newborn Infant (Sinclair, 1992) volumes from McMaster University, Oxford University and several other institutions also emphasize critical appraisal of the best available evidence from the medical literature.
ACP Journal Club
The ACP Journal Club (1995) exemplifies a new breed of EBM publications. J Club is a bimonthly abstract journal for internists published since 1991 by the American College of Physicians (ACP) with the editorial office at HIRU. Its stated purpose is "to select published articles according to strict criteria and to abstract those studies and reviews that warrant immediate attention by physicians attempting to keep pace with important advances in treatment, prevention, diagnosis, cause, prognosis, and economics of the disorders managed by internists." J Club staff at McMaster review about 50 journals of relevance to internal medicine and select only those articles that meet explicit criteria for scientific merit and clinical importance. They then prepare a structured abstract in accordance with a detailed protocol and solicit clinical feedback from experts in the subject area of the study. The abstract and commentary are published on a single page for easy reading and use.
The selection criteria for studies abstracted in ACP Journal Club emphasize the quality of evidence that might justify changes in clinical practice. For example, a study reporting the progress and outcome of a specific disease over time (prognosis) must have recruited patients at an early and uniform stage of their disease (inception cohort). This could be at first diagnosis for persons with diabetes mellitus or rheumatoid arthritis or at first symptoms for Alzheimer disease or myocardial infarction (heart attack). The cohort must be followed long enough for the health condition to progress (e.g., five years or more for multiple sclerosis) and at least 80% of the participants must have been accounted for at the end of the study. Different criteria pertain for articles that answer different types of clinical questions. ACP Journal Club inclusion criteria for review articles require a statement of methods that describes how primary articles were defined, retrieved, and screened. Such statements must be specific enough that the search strategy could be repeated, with duplicate results. Application of strict methodological and clinical inclusion criteria for ACP Journal Club has the beneficial effect of radically reducing the number of articles that merit careful attention from practitioners, and fastidious abstraction by ACP Journal Club staff. However, the cost is a huge effort to properly screen all journal articles for potential interest to internists.
Reactions to the J Club have been very favorable; a recent survey conducted by the ACP suggests that it is one of the few medical journals read by near 100% of its recipients. In addition, the NLM now indexes J Club commentaries, facilitating access to J Club resources through MEDLINE. An electronic ACP Journal Club will be released in 1995 and promises to optimize this evidence-based information tool for searching, in addition to browsing for important advances in medical practice. After five years of steady growth, the accumulated database of structured abstracts is now large enough to afford useful answers to a wide range of clinical questions with over 750 studies abstracted. Other medical disciplines such as pediatrics (Current, 1995) and sports medicine (Mohtadi, 1994) have developed their own abstracting sections. The ACP is working with the British Medical Association (BMA) to publish a companion product for all areas of medicine. The new journal, called EBM, will supplement a core of J Club articles with abstracts of studies from psychiatry, surgery, obstetrics and gynecology, family medicine, public health, and pediatrics. A sample issue will appear in September, 1995 and full production begins in January 1996.
Systematic Overviews
Another rapidly maturing subset of the medical literature is secondary publications that summarize original research appearing in primary journal articles. Good quality overviews help clinicians by doing much of the work of critical appraisal pertaining to specific health conditions. The NLM helps clinicians by publishing its Bibliography of Review Articles at in the front of each volume of Index Medicus and by indexing different types of reviews with specific "publication type" tags in MEDLINE.
Standards are emerging for evidence-based systematic overviews of evidence and meta-analyses of data from multiple studies (Mulrow, 1987). Meta-analysis was developed in the humanities and education fields in the early 1970s (Glass, 1981) and has been embraced by medicine as a strategy for extending the power and applicability of results from large numbers of primary studies. Overviews and meta-analyses start with a clearly articulated question then gather and appraise all relevant published and unpublished evidence before combining and analyzing data and exploring the experience of subsets of patients. For example, the Antiplatelet Trialists' Collaboration group's (1994a, 1994b, 1994c) study of antiplatelet agents (aspirin and other similar drugs) identified and analyzed data from 145 studies with 70 000 high-risk and 30 000 low-risk patients. They found that patients with unstable angina, myocardial infarction, stroke, transient ischemic attack, peripheral vascular disease and patients scheduled for vascular procedures had substantially decreased risks for death, stroke, myocardial infarction, leg and lung clots, and arterial occlusion if they were receiving antiplatelet agents.
Properly conducted and reported, evidence-based overviews provide readers with the information they need to ascertain biases that might have distorted the selection and analysis of evidence from multiple sources. One of the most important features of a good meta-analysis is the description of how primary data sources were identified. Many journal editors now insist that the search strategies (including databases searched, search terms used, and other information gathering processes such as contact with important authors and drug manufacturers) and the assessment of evidence quality appear in the abstract with full description in the methods section of the report. HIRU has promoted structured abstracts for review articles (systematic and meta-analyses) (Mulrow, 1988) and guides to using them effectively (Oxman, 1994).
Cochrane Collaboration
The Cochrane Collaboration represents an international effort to build, gather, catalogue and disseminate systematic overviews and meta-analyses about the effects of health interventions in man. Archie Cochrane (1972), an inspirational epidemiologist in the United Kingdom, lamented: "it is surely a great criticism of our profession that we have not organized a critical summary, by specialty or subspecialty, adapted periodically of all relevant randomized controlled trials". The Cochrane Collaboration is now a world-wide network of over 1000 health care professionals working together in disease and methods-focused groups to meet Archie Cochrane's challenge. HIRU is the home to the Canadian Cochrane Centre (email: cochrane@mcmaster.ca), with special interests in the dissemination of Cochrane Collaboration reviews in print, on-line, and CD-ROM format (the Cochrane Database of Systematic Reviews, CDSR).
Evidence Based Guidelines
Overviews can help clinicians systematically gathering, selecting and combining evidence that links practice options to health outcomes. Clinical decision analyses can help by exploring the trade-offs between competing benefits and harms. Economic analyses can help by tallying the costs associated with different options. However, none of these secondary literatures synthesizes information about evidence, values, and patient circumstances in a way that directly supports specific clinical choices. Clinical practice guidelines, which have been defined as "systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances," represent an attempt to distill a large body of medical knowledge into a convenient, readily useable format (Committee, 1980). Like overviews, they gather, appraise and combine evidence. Guidelines, however, go beyond most overviews in attempting to address all the issues relevant to a clinical decision and all the values that might sway a clinical recommendation.
Evidence based guidelines start with a sound systematic review or meta-analysis pertaining to a particular health problem. In addition, they must apply a systematic process for considering the relative importance of alternative outcomes and applying values when formulating recommendations. An example of a systematic review (Grady, 1992) with a corresponding clinical guideline comes from ACP (1992). The ACP committee concluded that for asymptomatic postmenopausal women using long-term estrogen therapy, the risks for breast cancer and endometrial cancer are increased and the risks for coronary heart disease and fracture are decreased, but individual women must take into account their family history and preferences before deciding to take postmenopausal hormones. HIRU has contributed to the development, reporting and dissemination of evidence based guidelines by studying clinician attitudes and preferences about guidelines (Tunis, 1994), developing a format for standardized abstracts of guidelines (Hayward, 1993), and promoting users' guides to practice guidelines (Hayward, 1995).
On-line Resources
Newer EBM resources increasingly are available on Internet and other networks. On-line journals are beginning to take hold and , with fewer space limitations, can include more of the evidence supporting a study or meta-analysis. For example, results from a meta-analysis of smoking cessation trials by Silagy (1994) are published in short form in Lancet and the complete data are simultaneously published in the On-line Journal of Current Clinical Trials. Although most clinicians do not currently have access to the Internet, trends indicate that they soon will have. Again, more information can be presenting in a more focused way in electronic than in paper-based media. However, it is just as likely that vast amounts of information of questionable quality will make it more difficult for clinicians to navigate a path to clinically important details. We hope that evidence-based views of the Internet (Evidence Based Medicine World Wide Web server, http://hiru.mcmaster.ca) will grow to offer selective access to high-quality, clinically focused resources. Plans are currently underway to disseminate Cochrane Collaboration overviews via Internet and such products as ACP Journal Club may soon appear there as well. As we move even more into an information-rich future we hope that it will enable the practice of evidence based medicine.
--------------------------------------------------------------------------------
References
ACP Journal Club published by the American College of Physicians, Philadelphia, Pennsylvania. (800-523-1546 for further information).
Ad Hoc Working Group for Critical Appraisal of the Medical Literature. (1987) A proposal for more informative abstracts of clinical articles. Annals of Internal Medicine, 106, 598-604.
American College of Physicians. (1992). Guidelines for counseling postmenopausal women about preventive hormone therapy. Annals of Internal Medicine, 117, 1038-1041.
Antiplatelet Trialists' Collaboration. (1994a) A collaborative overview of randomized trials of antiplatelet therapy--I: Prevention of death, myocardial infarction, and stroke by prolonged antiplatelet therapy in various category of patients. BMJ, 308, 83-108
Antiplatelet Trialists' Collaboration. (1994b). A collaborative overview of randomized trials of antiplatelet therapy-- II: Maintenance of vascular graft or arterial patency by antiplatelet therapy. BMJ, 308,159-168.
Antiplatelet Trialists' Collaboration. (1994c). A collaborative overview of randomized trials of antiplatelet therapy--III: Reduction in venous thrombosis and pulmonary embolism by Antiplatelet prophylaxis among surgical and medical patients. BMJ, 343, 235-246.
Chalmers, I., Enkin, M., & Kierse, M. J. N. C., eds. (1989). Effective Care in Pregnancy and Childbirth. Oxford, Oxford University Press.(22)Comans, M. L., & Overbeke, A. J. (1990). The structured summary: a tool for reader and author. Ned Tijdschr Geneeskd, 134, 2338-2343.
Cochrane, A. L. (1972). Effectiveness and Efficiency, random Thoughts in Health Services. London: Nuffield Provincial Hospital Trust.
Committee to Advise to Public Health Service on Clinical Practice Guidelines, (1980). Institute of Medicine; Field, M.J., Lohr ,K.N., eds. Clinical Practice Guidelines: Directions for a New Program. Washington, DC: National Academy Press.
Coumans, M.L., Overbeke, A.J. (1990). The structured summary: a tool for reader and author. Ned Jijdschr Geneeskd. 134, 2338-2343.
Current literature and clinical issues. Journal of Pediatrics.
Dale, D. & Federman, D. D. eds. (1995). Scientific American Medicine. New York Scientific American Inc.
Eddy, D. M., ed. (1991). Common Screening Tests. Philadelphia: American College of Physicians.
Evidence-Based Medicine Working Group. (1992). Evidence-based medicine. A new approach to teaching the practice of medicine. JAMA, 268, 2420-2425.
Glass, G. V., McGaw, B., & Smith, M. L. (1981). Meta-analysis in social research. Newbury park, California, Sage.
Grady, D, et al. (1992). Hormone therapy to prevent disease and prolong life in postmenopausal women. Annals of Internal Medicine, 117, 1016-1037.
Guyatt G. G. & Rennie, D. (1993a). Users' guides to the medical literature [editorial]. JAMA, 270, 2096-2097.
Guyatt, G. H, Sackett, D. L. & Coo
, D. C. for the Evidence-Based Medicine Working Group. (1993b). Users' guides to the medical literature. II. How to use an article about therapy or prevention. A. Are the results of the study valid? JAMA, 270, 2598-2601.
Guyatt, G. H, Sackett, D. L. & Cook, D. C. for the Evidence-Based Medicine Working Group. (1994). Users' guides to the medical literature. II. How to use an article about therapy or prevention. B. What were the results and will they help me in caring for my patients? JAMA, 271, 59-63.
Haynes, R. B. et al. (1990a). More informative abstracts revisited. Annals of Internal Medicine, 113, 169-170.
Haynes, R. B., et al. (1990b). On-line access to MEDLINE in clinical settings. A study of use and usefulness. Annals of Internal Medicine, 112, 78-84.
Haynes, R. B., Johnston, M. E., McKibbon, K. A., Walker, C. J., & Willan, A. R. (1993). A program to enhance clinical use of MEDLINE: A randomized controlled trial. On-line Journal of Current Clinical Trials. [serial on-line] (Document number 56):[4005 words; 39 paragraphs]. 6 tables.
Haynes, R.B. et al. (1994a). Developing optimal search strategies for detecting clinically sound studies in MEDLINE. Journal of the American Medical Informatics Association, 1, 447-458.(15)
Haynes, R. B., McKibbon, K. A., & Bayley, E. (1994b). Significant increase in computer access competency and use by medical students. Canadian Medical Informatics, 1, 34-39.
Haynes, R. B., Walker, C. J., McKibbon, K. A., Johnston, M. E., & Willan A. R. (1994c). Performances of 27 MEDLINE systems tested by clinical questions. Journal of the American Medical Informatics Association, 1, 285-295.
Haynes, R. B. et al. (1995). Computer searching of the medical literature: an evaluation of MEDLINE searching systems. Annals of Internal Medicine, 103, 812-816.
Hayward, R. S. A. et al. (1993). More informative abstracts of articles describing clinical practice guidelines. Annals of Internal Medicine, 118, 731-7.
Hayward R. S. A., Wilson M. C., Tunis S. R., Bass E. B., Guyatt G. (1995). Users' guides to the medical literature: VIII. How to use clinical practice guidelines. Part A. Are the recommendations valid? JAMA 1995;(In Press)
Jaeschke, R., Guyatt, G. & Sackett, D. L. (1994a). Users' guides to the medical literature. III. How to use an article about a diagnostic test. A. Are the results of the study valid? JAMA, 271, 389-91.
Jaeschke, R., Guyatt, G. H. & Sackett, D. L. (1994b). Users' guides to the medical literature. III. How to use an article about a diagnostic test. B. What are the results and how will they help me in caring for my patients? JAMA, 271, 703-07.
Laupacis, A., Wells, G., Richardson, W. S., & Tugwell, P. for the Evidence-Based Medicine Working Group. (1994). Users' guides to the medical literature. V. How to use and article about prognosis. JAMA, 272, 234-237.
Levine, M., Walter, S., Lee , H., Haines , T., Holbrook, A., Moyer, V. for the Evidence-Based Medicine Working Group. (1994). Users' guides to the medical literature. IV. How to use an article about harm. JAMA, 271, 1615-1619.
McKibbon, K. A. et al. (1990). How good are clinical MEDLINE searches? A comparative study of clinical end-user and librarian searches. Computers and Biomedical Research, 23, 583-593.
Mohtadi N. G. H., & Meeuwisse W. H. (1994). Medical education: another focus for the sport medicine journal club. Clinical Journal of Sport Medicine, 4, 140.
Mulrow, C. W. (1987). The medical review article: state of the science. Annals of Internal Medicine., 106, 485-488.
Mulrow, C. D., Thacker, S. B., & Pugh J. A. (1988). A proposal for more informative abstracts of review articles. Annals of Internal Medicine, 108, 613-615.
Narine, L et al. (1991). Quality of abstracts or original research articles in CMAJ in 1989. Canadian Medical Association Journal, 144, 449-453.
Oxman, A. D., Sackett, D. L. & Guyatt, G. G. for the Evidence-Based Medicine Working Group. (1993). Users' guides to the medical literature. I. How to get started. JAMA, 270, 2093-2095.
Oxman, A. D., Cook, D. J., & Guyatt, G. H. for the Evidence-Based Medicine Working Group. (1994). Users' guides to the medical literature. VI. How to use read an overview. JAMA. 271, 1367-1371.
Panzer, R. J., Black, E. R., & Griner, P. F, eds. (1991). Diagnostic Strategies for Common Medical Problems. Philadelphia: American College of Physicians.
Silagy C. Mant D. Fowler C, Lodge M. (1994). The effectiveness of nicotine replacement therapies in smoking cessation. On-line Journal of Current Clinical Trials. 1994 Jan 14; Document Number 113: [7906 words; 110 paragraphs]. (abridged version in Lancet 1994 Jan 15;343:139-142.).
Sinclair, J. C., & Bracken M. B. , eds. (1992). Effective Care of the Newborn Infant. Oxford, Oxford University Press.
Sox, H. C. Jr, ed. (1987). Common Diagnostic tests: Use and Interpretation. Philadelphia: American College of Physicians.
Taddio, A. et al. (1994). Quality of nonstructured and structured abstracts of original research articles in the British Medical Journal, the Canadian medical Association Journal and the Journal of the American Medical Association. Canadian Medical Association Journal, 150, 1611-1615.
Tunis SR, Hayward RSA, Wilson MC, et al. (1994). Internists' attitudes about clinical practice guidelines. Ann Intern Med,120:956-963.
| | | | | | | |
|
