文献有效性分析

1、医学文献的有效应用医学文献的有效应用 Prepare students to make independent, balanced clinical decisions that contribute to optimal patient outcomes.Clinical Reasoning 的纵向目标:Clinical Reasoning 的纵向目标By end of Year 2, students should be able to: Understand patient-centered outcomes and shared medical decision-making Syst

2、ematically analyze any clinical problem Make independent judgments on tests and treatments, based on published evidence Habitually seek and apply new knowledge from reliable sourcesCore Competencies Heath Professions Education: A Bridge to Quality Institute of Medicine 2003Provide patient-centered c

3、are Work in interdisciplinary teamsEmploy evidence-based practiceApply quality improvementUtilize informatics AAMC-HHMI 2009 Competency M8 Apply quantitative knowledge and reasoningincluding integration of data, modeling, computation, and analysisand informatics tools to diagnostic and therapeutic c

4、linical decision making.本次课的目标本次课的目标理解从文献样例中获得的两个关键概念：理解从文献样例中获得的两个关键概念：关注结果从病人角度考虑医学, （6 “requests” ） 理解医学文献及其有效性的评价标准理解医学文献及其有效性的评价标准 What is it? Whats in it? Who creates it, how and why? What is clinical “evidence”? What are the criteria for validity of medical literature? Where to find the medic

5、al literature. Matching information sources to question types: what should an MS1 read? What are the best sources for PBL? PBL Learning issue sourcing matrix: how to use it医学结果医学结果 广义定义广义定义：results that matter to someone Patient-centered, clinical, satisfaction, cost, safety Individual and populatio

6、n outcomes 着眼于结果的各种器官系统及其相关状况的方法。着眼于结果的各种器官系统及其相关状况的方法。 “Input” focus: “How are iron chelating（螯合）agents used to treat complications of thalassemia(地中海贫血 ) ?” Outcome focus: “What outcomes do patients with thalassemia experience under different treatment approaches?”病人参照框病人参照框Dont kill me Do help me

7、Dont hurt meDont make me feel helplessDont keep me waitingDont waste resources, mine or anyone elsesProfessionalismOur duty to patientsKnow what to doDo what is knownUnderstand what is doneProvide ALL and ONLY the care patients needKnow what to do:3 sources of medical knowledge What we hear What we

8、see What we readThe Medical Literature: what is it?Definition: Experts systematically recorded observations relating to human illness and how to relieve it, published in generally accessible locations and forms Media: journals, books, web sites, audio, video Range: from single case reports to system

9、atic syntheses of large trials VERY LARGE!The Medical Literature: What kinds do clinicians use? 作为临床医生, 我们是 “信息不偏食者” We “consume” all different types of published information that help us care for patients But: we prefer some types to others, when available e.g., we prefer large clinical trials to c

10、ase series to guide choice of therapyWhat kinds of information does the medical literature contain? 用三条用三条“轴轴”简单分类简单分类 Biology (mechanism) vs. Outcomes Primary vs. Secondary Observational vs. Experimental Major clinical knowledge “Domains”: Biological knowledge: normal human biology and disease mech

11、anisms Outcomes knowledge: how tests and treatments perform in real patients Both types necessary, and complementary Major trend: clinicians increasingly favor outcomes information (when available) as a basis for specific clinical decisions But clinicians must judge outcome data in context of known

12、biology Based on the title, is this study an example of Outcomes or Biological clinical knowledge?Tropak MB, et al. Pharmacological enhancement of beta-hexosaminidase （已糖胺酶）activity in fibroblasts（纤维原细胞） from adult Tay-Sachs and Sandhoff Patients . J Biol Chem. 2004 Apr 2;279(14):13478-87The Medical

13、 Literature: Two main article types Primary studies: initial, first-hand report of observations from a (new) data set examples: case series, clinical trial Secondary literature: summaries or syntheses of primary studies examples: review article, textbook chapterBased on the title, is this study an e

14、xample of primary or secondary literature?Khoury MJ, McCabe LL, McCabe ER. Population screening in the age of genomic medicine. N Engl J Med. 2003 Jan 2;348(1):50-8 The Outcomes Literature: Two main classes of study designObservational: examples: case series, case control, cohortExperimental: exampl

15、es: Clinical Trials, RCTs Each has advantages and weaknesses General preference for experimental designs to answer clinical questionsWhat is “Clinical Evidence”? Inclusive definition: All systematically collected knowledge relating to illness and its treatment “Evidence-based” medicine: care that re

16、flects a good-faith effort to tie clinical decisions to current knowledge EBM: a method, and a movementClinical Evidence:Orthodox definition Clinical evidence comes from patient- centered clinical research which investigates the accuracy and precision of diagnostic tests, the efficacy and safety of

17、therapeutic regimes, and the reliability of prognostic indicators. DL Sackett, Evidence-based Medicine. How to Practice & Teach EBM, 2000 “Evidence alone is never enough” Evidence-based Medicine (EBM) combines individual clinical expertise with the best available clinical evidence from systemati

18、c research in making decisions about the care of individual patients. Clinical expertise is the proficiency and judgment that individual clinicians acquire through knowledge, clinical experience, and practice.DL Sackett, Evidence-based Medicine. How to Practice & Teach EBM, 2000Obtain current best evidence -文献有效性分析文献有效性分析临床证据的质量分级临床证据的质量分级 是指各种可以导致研究结果失真的系统性误差。是指各种可以导致研究结果失真的系统性误差。选择偏倚（选择偏倚（Selection bias)志愿者偏倚（志愿者偏倚（Volunteer bias）,也称无应答偏倚（也称无应答偏倚（Non-respondent bias）检出偏