循证医学证据检索 Searching for Best Evidence 韦焘 昆明医学院图书馆 Library of Kunming Medical University 2015/4/13 Outline 1.Introduction to EBM 2.Category & Pyramid of Evidence 3.Sources of Evidence 4.Searching for Evidence 2015/4/13 1. Introduction to Evidence-Based Medicine 1.1 Definition 1.2 Three key points of EBM 1.3 Basic steps to practice EBM 2015/4/13 1.1 What is EBM? The conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients based on doctors’ clinical expertise, patients’ values and expectations. 3 Key Points: – evidence – doctor – patient Dr. Sackett 2015/4/13 1.1.1 Evidence • validity • importance • applicability 1.1.1.1 Validity 1) RANDOMIZED? 2) METHODOLOGY? 3) RESULTS? 1.1.1.2 Importance 1) TREATMENT EFFECT? 2) PRECISION? 1.1.1.3 Applicability 1) STUDY OBJECTS VS PATIENT 2) TREATMENT FEASIBLE? 3) BENEFIT & HARM 4) PATIENT’S VALUES & PREFERENCES 1.1.2 Doctor • Expertise • Experience 1.1.3 Patient • Value • Expectation 1.2 Origin & Development of EBM • Spectrum of Disease • Cost of Researches • Effectiveness and Efficiency – Random Reflections on Health Services • Resources: RCT, SR, MA … 2015/4/13 Dr. Archie Cochrane British physician and epidemiologist 1.3 Steps for Evidence-based practice (1) Ask Questions (5) Assess effectiveness, efficiency of EBM process (2) Acquire the evidence 5A’s (4) Apply the evidence 2015/4/13 (3) Appraise the evidence 1.3.1 Step 1 Ask questions 1) Causes, Diagnosis, Treatment, Prevention, Prognosis… 2) PICO Population/patient Intervention/issue of interest Comparison intervention/comparison group Outcome 3) Example: Liver Cancer 2015/4/13 1.3.2 Step 2 Acquire the evidence Databases: 1 Clinical Queries, PubMed 2 Cochrane Library 3 SinoMed 4 CNKI 5 VIP 6 WANFANG … 2015/4/13 1.3.2.1 PubMed Clinical Queries 2015/4/13 1.3.2.2 Homepage of Cochrane Library 2015/4/13 1.3.3 Step 3 Appraise the evidence Category of Evidence e.g., systematic review, meta analysis, randomized controlled trials… Pyramid of Evidence e.g., SR is a priority… NNT (Number needed to treat) NNH (Number needed to harm) 2015/4/13 1.3.4 Step 4 Apply the evidence Develop a relevant program to use the evidence. 2015/4/13 1.3.5 Step 5 Assess effectiveness, efficiency of EBM process What were implemented well? What could be implemented better next time? 2015/4/13 2. Category & Pyramid of Evidence • What kinds of evidence are there in EBM? • What is the pyramid of evidence? • 8 major categories • 5 major levels 2015/4/13 2.1 Category of Evidence(1) 2.1.1 Systematic Review also Cochrane review, a literature review focused on a single question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. 2015/4/13 2.1 Category of Evidence(2) 2.1.2 Meta Analysis uses statistical techniques for combining results from different studies to obtain a quantitative estimate of the overall effect of a particular intervention or variable on a defined outcome, producing a stronger conclusion than any individual study. (http://medicaldictionary.thefreedictionary.com/meta-analysis) 2015/4/13 2.1 Category of Evidence(3) 2.1.3 Clinical Practice Guideline (CPG) A Clinical Practice Guideline is a systematically developed statement/document to assist practitioner and patient make decisions about appropriate health care for specific clinical circumstances. (http://www.cvh.on.ca/pro/cpg.php) 2.1 Category of Evidence(4) 2.1.4 Health Technology Assessment (HTA) HTA is an innovative program that determines if health services used are safe and effective. (http://www.hta.hca.wa.gov/) 2.1 Category of Evidence(5) • 2.1.3 Randomized Controlled Trial A study in which patients are randomly assigned to the treatment or control group and are followed prospectively. (www.orthobullets.com/basic-science/9080/clinicaltrials) 2015/4/13 2.1 Category of Evidence(6) • Cohort Study A Cohort Study is a study in which patients who presently have a certain condition and/or receive a particular treatment are followed over time and compared with another group who are not affected by the condition under investigation. (http://library.downstate.edu/EBM2/2400.htm) 2.1 Category of Evidence(7) • Case-Control Study Case control studies are studies in which patients who already have a certain condition are compared with people who do not. 2.1 Category of Evidence(8) • Case Series and Case Report Case series and case reports consist either of collections of reports on the treatment of individual patients, or of reports on a single patient. (http://library.downstate.edu/EBM2/2600.htm) 2.2 Pyramid of Evidence(1) • Consideration – Which kind of evidence have you got? – How do you know it is good or not? To what extent? 2015/4/13 2.2 Pyramid of Evidence(2) Ⅰ SR, MA, CPG, HTA Ⅱ Randomized Controlled Trial Ⅲ Cohort Study Ⅳ Case-Control Study Ⅴ Case Report, Case Series, and Personal Opinion 2015/4/13 3.Sources of Evidence 1) Information in Chinese 2) Information in English 3) Information in Other Languages 2015/4/13 3.1Information in Chinese 2015/4/13 2) 1)3) Wanfang SinoMed 4)CNKI VIP 3.2 Information in English 1) 2)PubMed COCHRANE Clinical LIBRARY Queries 2015/4/13 4.Searching for Evidence • Case Study – There is a patient with hypertension, who has been taking Irbesartan and Amlodipine for more than two years. • Question – He would like to know if the side effects of the two drugs are serious. 2015/4/13 4.1 Searching Strategy • Searching words: – Irbesartan 厄贝沙坦 – Amlodipine 氨氯地平 – High blood pressure / hypertension 高血压/高血压病 • Sources of evidence – 中文数据库:CBM, CNKI, etc. – English databases: PubMed, Cochrane Library, etc. 2015/4/13 4.2.1 Searching Steps (CBM) 基本检索 厄贝沙坦 厄贝沙坦主题检索 AND 高血压 AND 多中心研究 记录数:0 系统评价 AND 厄贝沙坦 更多限定 记录数:1 记录总数:7 Meta分析 记录数:0 记录数:1055 2015/4/13 4.2.2 Searching Steps (CNKI) “主题=厄贝沙坦” AND “主题=厄贝沙坦” AND“主题=系统评价” “主题=Meta” “主题=厄贝沙坦” AND “主题=系统回顾” 6篇关于Meta分析的文章 厄贝沙坦氢氯噻嗪治疗老年原 发性高血压的汇总分析 厄贝沙坦治疗轻、中度高血压 的疗效和安全性Meta分析 4.2.3 Searching Steps (PubMed) Irbesartan PubMed Clinical Queries Systematic Reviews: 32 Clinical Queries 2015/4/13 4.2.4 Searching Steps (Cochrane Library) The Cochrane Library Cochrane Review (1) Title, Abstract or Keywords = irbesartan Title of Review Wrap-up 1. Definition of EBM 2. Three key points of EBM 3. Five steps to practice EBM 4. Categories of evidence 5. Pyramid of evidence 6. Sources of evidence 7. Ways to search for evidence 2015/4/13 Thanks a lot. 2015/4/13