Real Doctors (Life Makers)
Welcome, Guest. Please login or register.
/October/ 23, 2017, 06:28:05 PM
6115 Posts in 1589 Topics by 6180 Members
Latest Member: kz7tfriex4b
Latest Forum Topics: Basic Gunshot Wound Care First Aid  :-:-:-:-:-:-:-:  Ultimate USMLE Collection: Steps 1, 2 & 3 Videos, Books & Audiobooks  :-:-:-:-:-:-:-:  THE POST GRADUATE STUDY  :-:-:-:-:-:-:-:  Surgical Examination Videos  :-:-:-:-:-:-:-:  Pathoma for step 1  :-:-:-:-:-:-:-:  Huge Collection of Dental Videos, Books & applications !  :-:-:-:-:-:-:-:  Psychology Books Collection: 300+ Books  :-:-:-:-:-:-:-:   Vaccines: are they really safe & effective? [Video Collection]  :-:-:-:-:-:-:-:  The Ultimate Massage Thread: Huge Collection of Videos & Books about Massage  :-:-:-:-:-:-:-:  Manteca Chia - Full course of Taoist practice [1986-2007, DVDRip]  :-:-:-:-:-:-:-:  Natural Health - The Longevity Conference 2010 DVD Set  :-:-:-:-:-:-:-:  
Home Help Login Register

   * Clinical examination videos for Free

Doctors and medical students

Real Doctors (Life Makers)  |  Clinical  |  Tools of the trade  |  Evidence Based Medicine more detailed - please check the made easy section first « previous next »
Pages: [1] Print
Author Topic: Evidence Based Medicine more detailed - please check the made easy section first  (Read 7128 times)
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Evidence Based Medicine more detailed - please check the made easy section first
« on: /November/ 15, 2005, 05:11:31 PM »

Evidence-based medicine is the care of patients using the best available evidence from the results of research to guide clinical decision making [1-3]. It has become a popular movement in medicine in recent years. Critics of the term ask, "Is that not what good doctors - Osler, included - have always practiced, at least to the best standards of their day?" But several aspects of the present situation make the term more meaningful:

? ?A vast and growing volume of evidence to guide clinical decisions

? ?A rapidly increasing understanding of how to produce valid clinical research related to the development of scientifically strong research designs (such as randomized trials), clinically relevant measurements, and powerful statistical analyses made possible by modern computers

? ?Users who have become more sophisticated in their ability to distinguish credible from trivial research results

? ?More general awareness that many physicians, even those in good standing, do not practice medicine according to the best current research evidence.


Alternatives to evidence-based medicine, all too common in day-to-day information management, include reliance on the eminence, vehemence, eloquence, or confidence of the source, or practicing defensive medicine [4].

The basic elements of evidence-based medicine will be reviewed here. The focus will be upon applying the results of research involving patients and clinical outcomes such as death, symptoms, and loss of function. Other kinds of evidence, such as that obtained by personal experience and laboratory studies of the pathogenesis of disease, are also useful in the care of patients but are not usually included under "evidence-based medicine."

DEFINING THE QUESTION ? Clinicians need answers to several general kinds of questions (show table 1). As examples, what is the diagnosis and what are the effects of treatment? The question must be defined before searching for the answer [5]. These general kinds of questions are applied to countless specific diseases.

Research can only answer specific questions, one at a time. "How effective is amitriptyline for the symptoms of diabetic neuropathy?" can be answered by research studies, while "what is the best way to manage diabetic neuropathy?" cannot. The latter requires synthesis of information from many different sources, including clinical research, as is done in a traditional review article. Similarly, "does use of amitriptyline do more good than harm for patients with diabetic neuropathy?" involves a value judgment about the good and bad effects of the drug in this situation and is not determined by research alone. Thus, the search for the best research answers to clinical questions begins with tight definition of the question.

ACCESS TO INFORMATION
? Until recently physicians had to depend on printed information and colleagues, resources that have been, and remain, familiar and convenient but limited [6,7]. Books are out of date (in fast moving fields) when printed and become progressively more so; reading several journals offers only a limited sample of new developments and journals can be searched only by physicians with an elaborate filing system or a magnificent memory; and colleagues and consultants may not be available just when they are needed and may have hidden biases.

Information is relatively easy to come by in the electronic age; in principle, nearly all of the world's information is available instantly. The opportunities are almost limitless: the full contents of some journals and the table of contents for others; vendors offering the full text for a large selection of journals; databases of articles, reviews, guidelines, drug interactions; and access to web sites for governmental organizations such as the National Institutes of Health, Centers for Disease Control and Prevention, and professional organizations such as the American College of Physicians and American Society of Internal Medicine. Physicians who want to keep up with the medical literature and look up the best information must invest time in developing their electronic capabilities and finding print publications that cull and synthesize the best evidence.

The sheer volume of easily accessed information creates a new challenge: keeping up with new information and finding the best available answers to specific questions amidst all the other information. "Knowledge management" is a term for finding effective and efficient ways of finding and organizing the best available information.

SURVEILLANCE ON NEW INFORMATION ? It is not possible for a clinician to keep up with all important new developments simply by reading a few journals. An internist reading five of the most high-yield journals (eg, New England Journal of Medicine, Annals of Internal Medicine, Journal of the American Medical Association, Lancet, and leading subspecialty journals) would encounter only one-half of the most scientifically strong, clinically relevant articles in internal medicine ( figure 1) [8]. To maintain a comprehensive surveillance on new developments in internal medicine, the searching and sorting must be delegated to someone else. Among the options are:

? ?UpToDate editors and authors revise the program continually. New information is highlighted in each new edition of the CD-ROM and internet versions, and the date when the topic was last updated is noted at the beginning of each topic review. Other textbooks are finding ways to update regularly, but readers should be aware of how often each part of the information base is updated and when the last update of each section they are depending on was done.

? ?ACP Journal Club is published every two months by the American College of Physicians/American Society of Internal Medicine. It reviews the world's English-language medical journals in internal medicine, selects scientifically strong articles by explicit criteria, and summarizes those meeting these criteria as structured abstracts with commentary by an expert, one article per page. (ACP Journal Club, ACP-ASIM, 190 North Independence Mall West, Philadelphia, PA 19106-1572, USA; 800-523-1546)

? ?The Medical Letter, a four-page, biweekly, evidence-based review of drugs, including effectiveness, mechanism of action, side effects and interactions, and cost ? for new drugs in relation to older alternatives. (The Medical Letter, Inc., 1000 Main Street, New Rochelle, NY 10801; 800-211-2769).

? ?Evidence-Based Medicine is similar to ACP Journal Club but with a wider scope, including articles of interest to family medicine, pediatrics, obstetrics and gynecology, surgery, and psychiatry. (Evidence-Based Medicine, ACP-ASIM, 190 N. Independence Mall West, Philadelphia, PA 19106-1572; 800-523-1546)

? ?The Family Practice Newsletter is a four-page, "biweekly update and commentary on new and practical clinical information for the primary care practitioner," written by a family physician with public health and law degrees. (Primary Care Press, 5423 Monocracy Drive, Bethlehem, PA 18017; 888-399-7442; fax 631-474-5390; cpkerr@nni.com).

? ?Evidence-Based Practice, "patient-oriented evidence that matters," from the publishers of The Journal of Family Practice. (Dowden Health Media, 110 Summitt Ave., Montvale, NJ 07645-9894; 800-707-7040; ebp@dowdenhealth.com)

? ?Journal Watch is a monthly publication of the Massachusetts Medical Society that summarizes recent articles with commentary. (Massachusetts Medical Society. 860 Winter St. Waltham, MA 02451.1411. 781-893-4610).


LOOKING UP THE ANSWERS TO CLINICAL QUESTIONS ? Requirements for truly useful information sources for clinicians include:

? ?Rapid access (within minutes) so the information can guide clinical decisions as they arise, and learning is promoted by the answers coming soon after the questions ("just in time learning").

? ?Targeted to the specific clinical question

? ?The best and most current research information

? ?Mobile, because many clinicians move from place to place ? such as from office to ward - as they see patients

? ?In a medium that is simple to use.


Some sources meeting many of these criteria include:

? ?UpToDate meets all of these criteria including mobility for those who use the hand-held version released in 2003.

? ?ACP Journal Club online is a web-based compendium of abstracts reviewed in ACP Journal Club and is easily searched. (www.acpjc.org).

? ?The Cochrane Database. This is a collection of systematic reviews of clinical interventions, each including the articles that meet methodologic criteria, a meta-analysis of their results (when appropriate), and a commentary [9]. Teams of scholars all over the world agree to search the world's literature, in English and other languages, not just by Medline but also by hand, to find the best articles about specific therapeutic questions. Abstracts of these reviews are made available on the Web at www.cochrane.org. So far only a fraction of all clinically important questions have been reviewed, but the number is growing every day.

? ?Clinical practice guidelines. At their best, guidelines are comprehensive syntheses of the best evidence, from which the guidelines themselves follow. Standards for credible guidelines have been proposed (show table 2) [10], but there is great variation in how well existing guidelines meet these standards. An effort is being made to establish a comprehensive database of all existing guidelines, which can be found at www.guideline.gov. The collection is incomplete, and listing in the database does not imply that the guidelines are well done.

? ?Systematic reviews. These kinds of reviews are best for answering single questions (eg, the effectiveness of tight glucose control of microvascular complications of diabetes). They are more scientifically structured than traditional reviews, making explicit how the authors attempted to find all relevant articles, judge the scientific quality of each study, and weigh evidence from multiple studies with conflicting results. They pay particular attention to including all strong research, whether or not it has been published, to avoid publication bias whereby positive studies are more likely to be published. They require that studies included in the review meet explicit criteria for scientific validity. They typically present a figure summarizing all studies that meet stringent scientific criteria, their effect sizes, and their confidence intervals.

? ?Meta-analysis. Results of strong studies can be pooled, in a process called "meta-analysis," to yield a summary measure of effect. Meta-analysis is especially informative if enough strong studies of a question are available and come to different conclusions (perhaps because they are small and so represent imprecise estimates of effect), and if the studies are similar enough to each other in patients, intervention, and outcomes measured to make a pooled measure of effect meaningful. Some databases, such as the Cochrane Database, include cumulative meta-analyses in which the summary measure of effect is updated every time new study results become available [11].

« Last Edit: /November/ 22, 2005, 08:21:54 PM by cleo_md » Logged


 
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Re: Evidence Based Medicine
« Reply #1 on: /November/ 15, 2005, 05:11:50 PM »

   Medline. Searching Medline is especially useful for rare events such as case reports or rare drug side effects or interactions. This approach is cumbersome for day-to-day questions because searches typically turn up many articles that are not strong enough to be clinically useful and because searches miss many relevant articles. Searching can be made more sensitive and specific by using specific strategies [12,13]. Searching is now free and relatively easy to accomplish for anyone who is connected to the Internet (PubMed at www.ncbi.nlm.nih.gov/PubMed; or Grateful Med at the same address).

   Books. Printed textbooks are familiar, easy-to-use sources of information, especially for issues where the information base is not changing rapidly (eg, diagnosis of the acute abdomen). However, for time-sensitive questions, few of us have a current, comprehensive collection and even newly published textbooks are several months out of date, at a minimum, when they are first published.

   Journal reviews. Reviews published in journals are relatively current at the time of publication; a typical time lag between acceptance and publication is six months. Traditional narrative reviews are most suitable for multifaceted questions (eg, modern management of diabetes mellitus). Disadvantages are that they tend to lag behind the best research evidence at the time they are written [14] and may reflect the biases of the author(s) but not make them explicit.

   Web Sites. The world wide web includes credible, up-to-date sources of medical information in fast-moving fields. Some especially useful ones are: Health advice for international travelers: www.cdc.gov; National Guideline Clearinghouse: www.guideline.gov; Patient Support Organizations: healthhotlines.nlm.nih.gov/subserch.html.


JUDGING THE CREDIBILITY OF RESEARCH RESULTS ? Clinicians should have the ability to do an in-depth analysis of research articles that are especially important to their practice and are controversial. They should be in a position to experience the power, independence, and enjoyment of critically analyzing articles on their own or with colleagues in a local journal club.

The basic elements of critical reading are:

   Internal validity ? Are the results of clinical research correct for the patients in the study? Internal validity is threatened by two processes, bias and chance. Bias is any systematic error (eg, in assembling patients for study, allocating them to comparison groups, following them up, and measuring outcomes) that might distort the observed result relative to the true situation. Chance is random error, inherent in all observations. The probability of chance effects can be minimized by studying a large number of patients and is described by p-values (the probability of a false-positive result), power (the probability of a false-negative result) and by confidence intervals (for the range that is likely to include the true effect size) (show figure 2).

   Generalizability ? Do the results of the study apply to my patients? Study patients are typically highly selected relative to patients in usual practice. They are referred to academic medical centers, have classic disease, do not have other diseases, and are willing to cooperate. As a result, they may be systematically different from the patients most doctors see from day to day. The user of research results must make a well informed judgment about whether the study patients are similar enough to be a guide to their care, or how the guidance should be modified to suit individual patients.


The appropriate research design depends on the question (show figure 3) [15]. As an example, a randomized, controlled trial is best for information on the effects of a therapeutic or preventive intervention, while a cross-sectional study is best for the evaluation of diagnostic test performance.

Few physicians were taught critical appraisal skills in medical school and residency. Now there are many opportunities to learn critical reading skills from books [15-18], journal articles, courses, and special sessions of professional meetings.

Full critical appraisal, one article at a time, is time-consuming and not feasible for most practicing physicians most of the time. A variety of short-cuts, of varying effectiveness, are used to delegate critical appraisal, such as relying on a respected journal or trusted colleague. Readers should understand that these proxies are far from perfect. In a study of the effects of peer review and editing on the quality of reporting in articles published in Annals of Internal Medicine, the articles were improved but well short of perfection after careful review [19].

Critical appraisal skills, short of full, independent reviews, can be useful in day-to-day information management. These skills help clinicians make wiser choices of information sources ? for example, by looking at what they cite as evidence and how they weigh evidence from conflicting studies. These skills can also make informal reading more efficient by making it easier to spot especially strong or weak articles.

APPLYING STUDY RESULTS TO THE CARE OF PATIENTS ? Studies of the care of patients in many settings have consistently shown a gap between the recommendations of experts, based upon the best available evidence, and actual practice. Barriers include a genuine concern about applying the results of large studies to individual patients, misunderstanding of the evidence itself, not being aware of the research results, and problems with how care is organized [20].

Tailoring research results to individual patients ? The general guidance to the care of patients provided by clinical practice guidelines, algorithms, systematic reviews (including meta-analyses), and the like are meant to describe the best course of action on average, everything else being equal. To come closer to an estimate of what research results would be for an individual patient, it may be possible to find the answer in subgroups of the study patients, defined by such characteristics as age, sex, severity of disease, and presence of risk factors. Examining subgroups is worth the effort, but with two caveats. Because studies are designed to have just enough patients to detect the main effect, subgroups may include too few patients to find effects, even when they are really present; that is, subgroups are at risk for false negative results. Furthermore, when many subgroups are examined there is an increased risk that one of them will show effects by chance; that is, a false positive result.

Another way to bring rigorous research results to bear on individual patients is to do a "trial of N = 1" [21]. Alternative treatments are given to the patient in random order and the patient, who is kept unaware of which treatment he or she has taken, reports the effect. After many repetitions the pattern of results is as scientifically rigorous as a randomized controlled trial, but just for that one patient. Trials of N = 1 are a more rigorous version of therapeutic trials, or trial and error, already widely used in medicine. They can only be done for conditions such as migraine or hypertension that respond quickly to interventions, and with interventions such as some drugs to which patients can be "blinded."

Even after efforts to obtain research results that match the individual patient as closely as possible, the evidence must be interpreted in relation to the individual patient. Evidence-based medicine is not intended to replace clinical judgment [22]. Each individual patient will be cared for with the best research evidence as a benchmark, but with care tailored to their individual circumstances - genetic makeup, past and concurrent illnesses, health-related behaviors, and personal preferences.

Applying the evidence in practice ? A substantial body of research, as well as practical experience, has demonstrated that all of us, as we care for patients, engage in systematic errors of omission or commission, relative to the best available research evidence. Prominent examples are the widespread failure to prescribe beta-blockers after acute myocardial infarction or "controller" medications (eg, inhaled corticosteroids) in persistent asthma, the prescription of antibiotics for acute cough, or the use of radiologic tests for uncomplicated acute low back pain.

In some cases, failure to practice according to the best current evidence is out of ignorance. But knowledge alone rarely changes behavior [22]. The table lists the possible influences on clinicians' behavior, roughly in descending order of strength, based on a growing research literature on physician behavior change and on common sense (show table 3). Usually, no single influence is strong enough to make important changes; combinations are necessary. In general, changing clinical behavior requires not just information, but also time set aside for rethinking practice habits.


REFERENCES
1.  Sackett, DL, Straus, SE, Richardson, WS, et al. Evidence-based medicine. How to practice and teach EBM, 2nd edition, Churchill Livingstone, Edinburgh 2000.
2.  Sackett, DL, Rosenberg, WM, Gray, JA, et al. Evidence-based medicine. What it is and what it isn't. BMJ 1996; 312:71.
3.  Geyman, JP, Deyo, RA, Ramsey, SD. Evidence-Based Clinical Practice, Butterworth-Heinemann, Woburn, MA 1999.
4.  Isaacs, D, Fitzgerald, D. Seven alternatives to evidence based medicine. BMJ 1999; 319:1618.
5.  Richardson, WS, Wilson, MC, Nishikawa, J, Hayward, RS. The well-built clinical question: a key to evidence-based decisions. ACP J Club 1995; 123:A12.
6.  Covell, DG, Uman, GC, Manning, PR. Information needs in office practice: Are they being met? Ann Intern Med 1985; 103:596.
7.  Williamson, JW, German, PS, Weiss, R, et al. Health science information management and continuing education of physicians. Ann Intern Med 1989; 110:151.
8.  Fletcher, RH, Fletcher, SW. Evidence-based approach to the medical literature. J Gen Intern Med 1997; 12 Suppl 2:S5.
9.  Godlee, F. The Cochrane Collaboration. Deserves the support of doctors and governments. BMJ 1994; 309:969.
10.  Hayward, RS, Wilson, MC, Tunis, SR, et al. More informative abstracts of articles describing clinical practice guidelines. Ann Intern Med 1993; 118:731.
11.  Lau, J, Antman, EM, Jimenez-Silva, J, et al. Cumulative meta-analyses of therapeutic trials of myocardial infarction. N Engl J Med 1992; 327:248.
12.  Haynes, RB, Wilczynski, NL, McKibbon, KA, et al. Developing optimal search strategies for detecting clinically sound studies in MEDLINE. J Am Med Inform Assoc 1994; 1:447.
13.  McKibbon, KA, Walker-Dilks, CJ. Beyond ACP Journal Club: How to Harness MEDLINE for therapy problems. [Editorial]. ACP J Club 1994 July-Aug:A-10 (Ann Intern Med vol 121, suppl 1).
14.  Antman, EM, Lau, J, Kupelnick, B, et al. A comparison of results of meta-analyses of randomized controlled trials and recommendations of clinical experts. JAMA 1992; 268:240.
15.  Fletcher, RH, Fletcher, SW, Wagner, EH. Clinical Epidemiology. The Essentials, 3rd ed, Williams and Wilkins, Baltimore 1996.
16.  Sackett, DL, Haynes, RB, Tugwell, P. Clinical Epidemiology. A Basic Science for Clinical Medicine. 2nd ed, Little, Brown Co, Boston 1991.
17.  Riegelman, RK, Hirsch, RP. Studying a study and testing a test. How to read the medical literature, Little, Brown Co, Boston 1989.
18.  Users Guide to the Medical Literature. A manual for evidence-based clinical practice. Chicago, AMA Press, 2002. www.usersguides.org (Accessed 3/7/05).
19.  Goodman, SN, Berlin, J, Fletcher, SW, Fletcher, RH. Manuscript quality before and after peer review and editing at Annals of Internal Medicine. Ann Intern Med 1994; 121:11.
20.  Haynes, B, Haines, A. Barriers and bridges to evidence based clinical practice. BMJ 1998; 317:273.
21.  Guyatt, G, Sackett, DL, Taylor, DW, et al. Determining optimal therapy randomized trials in individual patients. N Engl J Med 1986; 314:889.
22.  Davis, DA, Thomson, MA, Oxman, AD, Haynes, RB. Changing physician performance. A systematic review of the effect of continuing medical education strategies. JAMA 1995; 274:700.
Logged
 
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Re: Evidence Based Medicine
« Reply #2 on: /November/ 15, 2005, 05:15:03 PM »

table 1

* clinic31.gif (3.02 KB - downloaded 33 times.)
Logged
 
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Re: Evidence Based Medicine
« Reply #3 on: /November/ 15, 2005, 05:16:20 PM »

Figure 1

* yield_1.gif (9.06 KB - downloaded 33 times.)
Logged
 
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Re: Evidence Based Medicine
« Reply #4 on: /November/ 15, 2005, 05:17:58 PM »

Table 2

* criter15.gif (8.23 KB - downloaded 32 times.)
Logged
 
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Re: Evidence Based Medicine
« Reply #5 on: /November/ 15, 2005, 05:18:52 PM »

Figure 2

* intern3.gif (14.82 KB - downloaded 34 times.)
Logged
 
cleo_md
Administrator
*****
Offline Offline

Posts: 613



Re: Evidence Based Medicine
« Reply #6 on: /November/ 15, 2005, 05:19:28 PM »

Figure 3

* research.gif (10.92 KB - downloaded 32 times.)
Logged
 
Pages: [1] Print 
« previous next »
Jump to:  


Google
 
Web www.real-doctors.com


| Tips club library