RESEARCHUniversityofPittsburgh的研究匹兹堡大学课件

1、EVIDENCE BASED MEDICINEfor BeginnersMaria Fidelis Manalo, MD, Msc EpidemiologyDepartment of Community & Family MedicineFEU-NRMF Medical CenterPhilippines 第1页，共29页。Evidence-Based Medicine Definition“the conscientious, explicit and judicious use of current best evidence in making decisions about the c

2、are of the individual patient” David Sackett第2页，共29页。EBMHistorical EvolutionHas roots going back to 19th c. Recently broadened interest due to information explosion that increased dramatically in the last decade. Has become more formalized that have enabled practitioners to approach medical problems

3、 and evaluate medical literature with greater consistency and to deal with massive amounts of medical information via a qualitative approach.第3页，共29页。EBMUsefulnessInstead of routinely reviewing the contents of dozens of journals for interesting articles, EBM suggests that you target your reading to

4、issues related to specific patient problems as encountered. This makes EBM a life-long self-directed and problem-based learning process.第4页，共29页。Misapprehensions & Misinterpretations about EBM 1) Evidence-based medicine ignores clinical experience and clinical intuition.2) Understanding of basic inv

5、estigation and pathophysiology plays no part in evidence-based medicine. 3) Evidence-based medicine ignores standard aspects of clinical training such as the physical examination. 第5页，共29页。Types of Questions第6页，共29页。Asked for general knowledge about a disorder Has two essentials components:a questio

6、n root ( who, what, where, how, why) with a verba disorder(1) Background Questions第7页，共29页。Background QuestionsTextbooks answer background questions, they contain collected & synthesized wisdom for topics that do not change often. Not all topics are covered, easy to use, relatively inexpensive and c

7、an be opinion-based rather than evidence-based, written by experts in their fields.第8页，共29页。(2) Foreground QuestionsAsked for specific knowledge about managing patients with a disorder It has 4 components (PICO analysis):P - Patient/PopulationI - InterventionC - ComparisonO - Outcome 第9页，共29页。Basis

8、of Evidence-based care involves the integration of the best research evidence with clinical expertise and patient values. Patients Needs/PreferencesClinical ExperienceBest Clinical Evidence第10页，共29页。 Novice Expert Searcher Searcher At all stages you ask both kinds of questions, but as experience inc

9、reases the foreground questions increase.It is essential that you understand the background question before attempting to answer the foreground ones.Background InformationForeground Information第11页，共29页。EBM Principles 1. Construct a well-built clinical question and classify it into one category (the

10、rapy, diagnosis, etiology or prognosis)2. Find the evidence in health care literature 3. Critically appraise or formally evaluate for validity and usefulness 4. Integrate the evidence with patient factors to carry out the decision 5. Evaluate the whole process 第12页，共29页。PICO ANALYSISBefore attemptin

11、g to search for the evidence in the literature, construct a well-built or clearly structured question that could be broken into the following four parts第13页，共29页。(1) Patient /Population What is the primary problem, disease or co-existing conditions? On what groups do you want information? How would

12、you describe a group of patients similar to the one in question? Sometimes age or sex of a patient may be relevant and should be included. Example: post-menopausal women with hypertension第14页，共29页。(2) Intervention What medical event do you want to study the effect of? Which main intervention are you

13、 considering, prescribing a drug, ordering a test, ordering surgery?. . . . Example: ERT第15页，共29页。What medical event do you want to study the effect of? Which main intervention are you considering, prescribing a drug, ordering a test, ordering surgery. . . . Example: ERT.(3) Comparison Compared to w

14、hat? Better or worse than no intervention at all or than another intervention? What is the main alternative to compare with the intervention, are you trying to decide between two drugs, a drug and a placebo, or two diagnostic tests? Sometimes there is no comparison. - Example: no ERT第16页，共29页。(4) Ou

15、tcome What is the effect of the intervention? What do you hope to accomplish, measure, improve, or affect with this intervention?What are you trying to do for the patient, relieve or eliminate the symptoms, reduce side effects, reduce cost? . . Example: improve quality of life 第17页，共29页。What makes a

16、 clinical question well built?Question should be directly relevant to the problem at hand. Question should be phrased to facilitate searching for a precise answer.Asking a well-built question, like many clinical skills, needs practice. 第18页，共29页。After constructing the PICO analysis, determine the ca

17、tegory of the question. There are the four categories of EBM questionsCategories of EBM Questions第19页，共29页。Solves questions about which treatment to administer, and what might be the outcome of different treatment options. For most therapyquestions one may want to look for the best evidence namely a

18、 randomized controlled study, and if the study can be a double blind, so much the better. - Example: find the evidence for the use of anticoagulants in patients with atrial fibrillation 1) Therapy第20页，共29页。Solves questions about degree to which a test is reliable and clinically useful, to decide whe

19、ther the patient would benefit from it Most articles compare result of a certain diagnostic test with that of a standard test regarded as being a gold standard. - Example: search for the best diagnostic test for Alzheimers disease 2) Diagnosis第21页，共29页。Solves problems about the relationship between

20、a disease and a possible cause - Example: find out if a diet rich in saturated fats increases the risk of heart disease, and if so by how much3) Etiology第22页，共29页。Answers questions about a patients future health, life span and quality of life in the event one chooses a particular treatment option -

21、Example: find how would the quality of life change for a patient who undergoes surgery for prostate cancerThe next step would be to determine the best study design needed to answer the clinical question.4) Prognosis第23页，共29页。Types of Research StudiesCertain study designs are superior to others when

22、answering particular questions. RCT are considered the best for addressing questions about therapy. Etiology questions may be addressed by case-control & cohort studies. Other aspects relevant to study design include placebo comparison group and follow-up. 第24页，共29页。 Answers therapy, prevention ques

23、tionsRandomization avoids selection bias1) Randomized Controlled Trial (RCT)第25页，共29页。2) Cohort studyAnswers prognosis, etiology, prevention questionsCohorts are defined populations that, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics. Researchers identif