Systematic Reviews and Meta-Analyses：系统综述和Meta分析
系统评价与Meta分析
限性。纳入研究的局限性是指单个研究在各个研究设计、
实施等方法学质量方面的局限性。系统评价的局限性是指 系统评价在研究过程中可能存在的资料收集是否全面、纳 入研究的多少、研究过程中哪些问题没有解决等。
2 系统评价的实用性
meta分析的结果在推广利用时要考虑到个体对象的特征
系统评价与Meta分析、传统综述的主要区别
第二节 系统评价的基本步骤
确定题目、制定研究计划 数据整理、统计分析 检索文献 数据整理、统计分析
数据整理、统计分析 筛选文献
Байду номын сангаас文献质量评价
资料提取
定性分析 资料分析 定量分析
同质性好 同质性不好
固定效应模型
解释结果，撰写报告 亚组分析 更新系统评价 随机效应模型 敏感性分析
格； 3 与原作者联系。
四、对证据进行严格的质量评价
证据的评价即证据的批判性评估，是循证医学实践中 最重要和最关键的一步 。单个研究的设计和实施质量影 响研究结果的真实性。 评价纳入研究的质量是指单独评 估每篇纳入文献在其科研设计、实施和分析过程中是否采 用了防止或减少偏倚的措施，以保证其试验结果的真实性。 文献的严格评鉴主要包括对研究的内在真实性和外在真 是性进行评价。 1 内在真实性即研究在设计和实施中防止偏倚和误差的 程度。 2 外在真实性是指研究结果的实用性如何，是否可以推 广利用。
及生物学或文化背景、患者病情、干预措施、患者依从性
的差异。
3 系统评价结果的时效性 系统评价的结果不是一成不变的，只是对现有资料综合 分析的结果，随着新的研究资料的不断充实，其结果可以 进行更新。
系统评价与meta分析的关系
系统评价和Meta分析 Systematic review and Meta-analysis
合并
解释
固定效应 模型
有异质性 不合并
随机效应 模型
亚组分析
Meta回归
八、敏感性分析
检查一定假设条件下结果稳定性的方法 目的：
发现影响meta分析研究结果的主要因素； 解决不同研究结果的矛盾性； 发现产生不同结论的原因。
分层分析：
按不同研究特征，将各独立研究分为不同组 按Mental-Haenszel法进行合并分析 比较各组及其与合并效应间有无显著性差异
三、收集资料
原则：多途径、多渠道、最大限度 途径：利用多途径广泛收集资料
多种电子资源数据库 参考文献的追溯
注意未正式发表“灰色文献”（grey literature） 的收集：这些文献中可能包含阴性研究结果：
会议专题论文 未发表的学位论文 其他原因未发表的文献
临床试验注册登记系统 手工检索
专著内的章节 制药工业的报告
综述
Meta-分析
系统评价
几个概念的范围包含关系
系统评价的重要性：
应对信息时代的挑战：海量信息需要整合、避免“只见 树木不见森林”。专业人员定期对相关临床研究进行严 格总结，临床医师能更快、更准确、更方便地了解最新 医疗措施，指导临床实践，提高医疗质量； 促进成果转化： 结论更真实、可靠：被推荐为疗效评价的金标准，为临 床治疗实践提供可靠依据 节约研究成本，提高统计效能： 为临床科研提供立题依据：避免重复研究 克服传统文献综述的缺陷： 连接新旧知识的桥梁：
用meta分析软件（RevMan）中的MetaView或
SPSS、SAS、EXCEL等建立数据库；
注意对计量资料必须注明单位； 双重录入。
提取的内容：
Systematic Reviews and MetaAnalyses系统综述和Meta分析
Statistical Quality of Medical Research gets low marks!
• Founded 1993
CC built on 10 Principles
Canadian Cochrane Network & Centre
• • • • • • • • • •
collaboration building on the enthusiasm of individuals avoiding duplication minimizing bias keeping up to date striving for relevance promoting access ensuring quality continuity enabling wide participation
RESULTS???
Problems with Standard Reviews
Lack of scientific purpose (question) Undocumented methods of literature search Unstated criteria for selecting studies No methodological assessment of selected
Over 345,000 trials
published to date
Over 20,000 new trials
系统评价与meta分析的区别【最新】
1.什么是系统评价系统评价（systematic review，SR）“A summary of the medical literature that uses explicit methods to perform a thorough literature search and critical appraisal of individual studies and that uses appropriate statistical techniques to combine these valid studies.”——这是David Sackett等2000下的定义。
翻译成中文来说，系统评价就是全面收集全世界所有有关研究，对所有纳入的研究逐个进行严格评价，联合所有研究结果进行综合分析和评价，必要时进行Meta分析（一种定量合成的统计方法），得出综合结论（有效、无效、应进一步研究），提供尽可能减少偏倚，接近真实的科学证据。
2.什么是meta分析Meta-分析是由心理学家Glass1976年首次提出的统计学方法，并首次将其运用于教育学研究领域中对多个研究结果的综合定量，后来，这一研究方法被应用于医学领域，并日益受到重视。
80年代国际上即有50种杂志发表各种介绍或应用Meta分析方法的论文。
90年代以来，已发表数以千计的有关Meta分析的论文，涉及医学研究的各个领域，包括病因研究、诊断性试验、防治评价、预后研究等等。
Meta分析的基础是建立在全面、系统的对文献研究质量评价基础上，因此，学术界也把对于医学文献的全面系统的评价称之为“系统分析”，当应用特定的统计方法定量地进行系统分析时称之为Meta分析。
Meta分析（Meta-analysis）的定义目前尚有不同意见：可分为狭义和广义狭义——《The Cochrane Library》将其定义为：Meta-analysis is statistical technique for assembling the results of several studies in a single numerical estimate.即Meta分析是将系统评价中的多个不同结果的同类研究合并为一个量化指标的统计学方法。
循证评价方法与工具在临床实践指南制定中的应用
循证评价方法与工具在临床实践指南制定中的应用引言：临床实践指南是指医疗卫生机构或专业学会为指导临床医生制定的一系列指南，旨在提供可靠的、基于最新研究证据的医疗决策支持。
为确保指南的可靠性和有效性，循证评价方法和工具被广泛应用于临床实践指南的制定过程中。
本文将探讨循证评价在临床实践指南制定中的应用，并介绍一些常用的循证评价方法和工具。
一、循证评价方法的应用1. 问题制定：在制定临床实践指南之前，需要首先确定所要解决的医学问题。
循证评价方法可以帮助明确问题的范围、关键点和研究目标，以确保指南的焦点和可行性。
2. 文献搜索与筛选：循证评价的关键步骤是进行系统性文献搜索和筛选。
通过搜索相关数据库和文献，收集与指南目标相关的研究证据。
然后，根据预定的纳入和排除标准对文献进行筛选，筛选出与指南目标最相关的研究。
3. 研究质量评估：循证评价的另一个重要步骤是对研究质量进行评估。
通过使用特定的评估工具，如Cochrane协作网络的Risk of Bias工具，可以对纳入指南制定的研究进行质量评估。
这有助于评估研究的可靠性和结果的可靠性。
4. 数据分析和综合：一旦符合标准的研究被纳入评价，就需要对数据进行统计分析和综合。
常用的方法包括Meta分析和系统性综述。
这些方法可以将不同研究的结果进行汇总，并提供可靠性较高的结论。
二、循证评价工具的应用1. GRADE工具：GRADE（Grading of Recommendations Assessment, Development, and Evaluation）工具是用于评估指南推荐证据质量和制定推荐等级的重要工具。
它通过考虑研究质量、一致性、效果大小、结果的重要性和偏倚等因素来评估证据的质量。
2. AGREE工具：AGREE（Appraisal of Guidelines for Research and Evaluation）工具是用于评估指南质量的工具。
它包括一系列域，如范围和目的、参与者和利益相关者的参与、方法的明确性和透明度以及推荐的明确性等，通过评估这些域来评估指南的质量水平。
系统评价_Meta分析方法学质量的评价工具AMSTAR
பைடு நூலகம்
中国循证医学杂志 2011, 11(9): 1084～1089
临床流行病学专家们在英国医学委员会期刊《医 学 研 究 方 法 学》上 发 表 了 名 为“Development of AMSTAR：A Measurement Tool to Assess Systematic Reviews”的专论，标志着 AMSTAR 的正式形成 。 [15] 研发小组认为，系统评价在跟进医学专业最新知识 和信息、形成有价值的临床证据以及影响医疗卫生 决策方面扮演着难以替代的重要角色。但系统评价 制作过程是一项复杂、需要谨慎进行的工作，研究 者和使用者都必须检查其真实性。研究如何评价系 统 评 价 /Meta 分 析 的 质 量 已 逾 10 年，如 Oxman、 Guyatt 以及 Sacks 研制的测量工具。已有超过 24 种 测量工具被报道使用过。然而，它们绝大多数运用 不广泛，有些测量工具要么条目非常冗长，要么使 用过程很复杂、不便于把握。尤其是在不断的运用 过程中，许多实证性证据发现了系统评价诸多偏倚 来源。比如，最近的方法学研究强调发表文种和出 版偏倚是系统评价的重要潜在偏倚[16-18]。所以，研 发小组基于以上认识，把有参考价值的代表性评价 工具、长期使用过程中形成的实证性证据以及专家 共识作为研发 AMSTAR 的科学来源。
2 评价条目
实践与交流
AMSTAR 是用于衡量系统评价 /Meta 分析的 避免或减少偏倚的程度，即方法学质量的一种量 表。它 的 条 目 形 成 基 础 有 OQAQ 的 10 个 条 目、 SQAC 的 24 个条目以及另外 3 个考虑文种偏倚、发 表偏倚和灰色文献的条目。研发组采用探索性因素 分析和名义群体技术保证了量表的表面效度和内 容效度 [15]。在后续研究中，该研发组进一步考验了 AMSTAR 的信度、结构效度和实用性 [19]。还专门委 托加拿大药物卫生技术评估中心评估其科学性，评 估结果也十分令人满意 [20]。在上述工作的基础上， 研发小组正式提出了 AMSTAR 的标准条目，共 11 个 条 款，其 英 文 版 可 从 http://www.biomedcentral. com/content/supplementary/1471-2288-7-10-S1.doc 上免费获取，开放使用。本文把 AMSTAR 用中文表 述成表 1。每个条款的评语选项有“是”、“否”、“不 清楚”以及“未采用”。
Meta分析与系统评价
统计量的选择
MD mean difference 均数差
包括方法学异质性和生物学效应异质性； 根据统计学原理，只有同质的资料才能合并，比较，分析； 如果异质性分析发现异质性较大，尽可能找到导致异质的原
因； 亚组分析或者meta回归； Q检验及I2检验（P>0.1且I2≤50%时选用固定效应模型）
结果分析
制定统计分析方案； 选择适当的效应指标。连续变量一般用均数差（MD）表示效
统计量的选择
深刻理解Meta分析中各种常用效应尺度指标的意义，对正确 选择效应指标、理解和应用统计结果至关重要。
RR rate ratio or risk ratio or relative risk的缩写，国内翻译为 “相对危险度”，其意义为两组的事件率之比。RR是反映暴露 （干预）与事件关联强度的最有用的指标。
敏感性分析/STATA
累计分析/STATA
发表偏倚/STATA
Egger’s test Begg’s test
序贯分析
反复的期中分析会增加Ⅰ类错误的概率； 系统综述存在重复测量的问题，目前发表的系统综述中18%的
meta分析都有更新，并且所有的cochrane的meta分析每两 年均需要更新，此外由于阴性结果而未发表的meta分析有可 能反复的分析直至出现阳性结果
THE COCHRANE COLLABORATION
氢化可的松治疗先兆早产是否有效，能否降低早产儿死亡率？
系统评价
系统评价(Systematic Review)的要素?
4）应用纳入标准并说明排除的理由
– 列表说明排除的研究及其理由
5）收集最完整的资料 6）对纳入研究的结果进行汇总分析 如有可能使用统计学的资料合成方法 (meta分析) 即使不做meta-分析也应对结果进行概括
系统评价(Systematic Review)的要素?
1、进行Cochrane系统评价的基本步骤 2、系统评价的选题和立题 3、系统评价计划书的撰写
注册和进行Cochrane系统 评价的基本步骤
• 确定题目和注册
与相关评价小组联系
• 计划书
评审，合格后发表在CL
• 系统评价
评审，合格后发表在CL
• 定期更新
1. 确定题目和注册
• 选择题目，将题目和背景情况告之 评价小组协调员，确定该题目是否 已被注册 • 等待专家评审，确定是否有必要进 行该题目的系统评价 • 如果该题目无人注册且有研究的价 值，评价小组将通知申报者填写有 关表格，确定其注册的资格
5、系统评价与传统综述的区别
传统综述
问题
涉及面常较广
系统评价
常集中于某一临床问题
文献来源和收集 不系统、全面，可能存 收集全面，有规定的步 筛选文献 质量评价 资料综合 推论(结论)
在偏倚 骤和策略 没有统一标准，常存在 根据统一标准筛选文献 偏倚 常无或随意性大 强有力的评价标准 常常为定性描述 定量综合，如 meta-分 析 有时是在证据基础上得 常常是在证据基础上得 出 出
1、系统评价的定义：
系统评价是针对某一具体的临床问题系统 、全面地收集全世界所有已发表或未发表 的相关的临床研究文章，用统一、科学的 评价标准筛选出合格的研究，进行质量评 价，用统计学方法进行定量的综合，或用 描述性方法进行定性的综合，得出可靠的 结论，并随着新的临床研究结果的出现及 时作出更新。
系统综述和meta分析(预防7版)-精品医学课件
➢ 确定研究问题
采用PICO格式将研究问题结构化：即确定研究对象（participants） 的特征、干预措施（intervention）、与什么进行比较（comparison）和 观察的结局指标（outcome）
实例
对象 P 老年人 早产儿 高脂血症者 慢性肾病患者
表19-1 如何构建一个研究问题
三、进行系统综述和meta分析的意义
海量信息需要整合 避免“只见树木不见森林” 克服传统文献综述的缺陷：？主观，无标准，不能合成，
有矛盾的结果不好处理 连接新旧知识的桥梁
四、何时进行meta分析
➢ 随机对照试验的meta分析
要做一项紧急决定，时间不允许等待新的研究 目前没有能力开展大规模的临床试验 研究结果矛盾时 各个试验在研究对象、干预措施和结局方面足够相似
清楚地表明题目和目的 采用综合检索策略 明确的研究入选和排除标准 列出所有入选的研究 清楚地表达每个入选研究的特点并对它们的方法学质量进行分析 阐明所有排除的研究的原因 如果可能使用 meta 分析合并合格的研究的结果 如果可能对合成的结果进行敏感性分析 采用统一的格式报告研究结果
标题：明确是系统综述还是Meta 分析 结构式摘要： 理论基础：背景及研究理由 目的 方案和注册 纳入标准 信息来源 检索 研究选择 资料提取 数据项目 单个研究存在的偏倚 概括效应指标 结果综合：描述结果综合的方法
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研究偏倚 其他分析：如敏感性分析等 研究选择：纳入文献数及排除原因等 研究特征：文献特征，如样本量及随访时间等 研究内部偏倚风险 单个研究的结果 结果的综合 研究间偏倚 其他分析 证据总结 局限性 结论 资金
第八章系统综述和Meta分析Systematicreviewandmeta
对潜在偏倚的控制和检测不足 统计分析不规范 缺少对原始研究的质量评价，未改变方法进行敏
感度分析 缺少对发表偏倚的检测 缺少对结果应用价值的评估
第一节 概 述
简史 基本概念 为什么要进行系统综述和Meta分析
一、简 史
系统综述的思想最早可以追溯到17世纪 瑞利勋爵（Lord Rayleigh，1842～1919）最早
RCT质量评价的Jadad 评分
条目
评分标准
随机化方法 恰当 如计算机产生的随机数字或类似的方法(2分)
不清楚 试验描述为随机试验，但没有告知随机分配产生的方 法(1分)
不恰当 如采用交替分配或类似方法的半随机化(0分)
盲法
恰当 使用完全一致的安慰剂或类似的方法(2分)
不祥 试验称为双盲法，但未交代具体的方法(1分)
发现影响meta分析研究结果的主要因素 解决不同研究结果的矛盾性 发现产生不同结论的原因
分层分析
按不同研究特征，将各独立研究分为不同组 按Mental-Haenszel法进行合并分析 比较各组及其与合并效应间有无显著性差异
九、总结报告
可以用直观的图示方法表示
研究结果点估计值,其 大小代表该研究在 Meta分析中的权重
ai
bi
ci
di
（二）一致性检验
检验的零假设为 H0 : 1 2 ... k ；
H0 成立，Q 值服从自由度 v k 1的 2分布 ；
若 P ， 则拒绝 H0，支持随机效应模型的假定，必须
用wi*计算 ORc及其95%CI；
若P ，则支持固定效应模型的假定，即使 ， wi* wi
也可令 s2 0 ，计算平均效应大小及其95%CI。
第四节 偏倚及其检查
系统综述与网状Meta分析的PRISMA扩展声明
系统综述与网状Meta分析的PRISMA扩展声明一、本文概述随着医学研究和临床实践的不断发展，越来越多的治疗方法被引入到临床实践中。
然而，这些方法之间的比较和选择一直是一个难题。
系统综述和网状Meta分析作为一种重要的统计分析方法，可以帮助我们更好地理解和比较不同治疗方法的效果，从而为临床实践提供更为科学和准确的指导。
本文旨在通过PRISMA扩展声明的方式，详细阐述系统综述和网状Meta分析的基本原理、实施步骤和注意事项，以提高读者对这一方法的理解和掌握程度。
我们将从定义和背景、研究问题和目标、文献检索和筛选、数据提取和质量评价、数据分析和解释、结果呈现和讨论等方面展开论述，以期为读者提供一份全面而深入的指南。
通过本文的阅读，读者将能够了解系统综述和网状Meta分析的基本概念、原理和实施步骤，掌握相关软件工具的使用方法，了解该方法在临床实践中的应用和限制，从而更好地利用这一方法进行医学研究和临床实践。
我们也希望通过本文的阐述，为医学研究和临床实践提供更为科学和准确的方法支持，推动医学领域的进步和发展。
二、PRISMA扩展声明概述PRISMA（Preferred Reporting Items for Systematic Reviews and Meta-Analyses）扩展声明是PRISMA声明的进一步细化和扩展，专门针对系统综述与网状Meta分析这一复杂研究领域制定的详细报告规范。
这一扩展声明在PRISMA原有27个条目的基础上，增加了针对网状Meta分析的特定要求，以确保研究者在进行系统综述和网状Meta分析时，能够全面、透明地报告其研究方法和结果，从而提高研究的可重复性和可靠性。
PRISMA扩展声明强调了以下几个关键方面的报告要求：在引言部分，研究者需要明确阐述研究的目的、研究问题和假设，以及网状Meta分析相较于传统Meta分析的适用性和优势。
在方法部分，研究者需要详细描述文献搜索策略、纳入和排除标准、数据提取和处理过程，以及网状Meta分析的具体方法和模型选择。
医学科研基本方法英文
Basic Methods in Medical ResearchIntroductionBodyMedical research plays a crucial role in advancing our understanding of diseases, developing new treatment methods, and improving patient care. Through rigorous scientific investigation, researchers are able to uncover new insights, test hypotheses, and make evidence-based recommendations. In this article, we will discuss some of the basic methods used in medical research.Observational Studies:Observational studies involve observing and analyzing the characteristics, behaviors, or outcomes of a group of individuals. These studies do not involve any intervention or manipulation by the researcher. Examples of observational studies include cohort studies, case-control studies, and cross-sectional studies. Observational studies are valuable for identifying associations between factors and diseases but cannot establish a cause-and-effect relationship.Experimental Studies:Experimental studies involve manipulating a variable or intervention and observing its effects on a group of individuals. These studies are designed to establishcause-and-effect relationships. Randomized controlled trials (RCTs) are considered the gold standard for experimental studies. In an RCT, participants are randomly assigned to different groups: one group receives the intervention being tested, while the control group receives either a placebo or standard treatment. By comparing the outcomes between the two groups, researchers can determine the effectiveness of the intervention.Systematic Reviews and Meta-analysis:Systematic reviews and meta-analysis are research methods that involve synthesizing and analyzing data from multiple studies. A systematic review involves identifying and critically appraising all relevant studies on a specific topic, while meta-analysis combines the results of these studies to provide a quantitative summary of the overall effect. These methods are valuable in summarizing existing evidence and providing a comprehensive overview of a particular research question.Laboratory Studies:Laboratory studies are conducted in a controlled setting, such as a laboratory, to investigate the underlying mechanisms of diseases or test the efficacy of new treatments. In these studies, researchers manipulate variables under controlled conditions to observe the effects. Laboratory studies may involve cell cultures, animal models, or in vitro experiments. While laboratory studies provide valuable insights, it is important to validate the findings in clinical settings before drawing conclusions.Survey Studies:Survey studies involve collecting data through questionnaires or interviews to gather information about a specific population or group. This method is often used to study prevalence, risk factors, or patient satisfaction. Surveys can provide valuable data quickly and efficiently, but it is crucial to ensure the validity and reliability of the survey instrument and sampling method.In conclusion, medical research employs a variety of methods to investigate diseases, test interventions, and improve patient care. Observational studies, experimental studies, systematic reviews, laboratory studies, and survey studies each have their own strengths and limitations. Byutilizing a combination of these methods, researchers can generate robust and reliable evidence that drives advancements in medical knowledge and practice.【参考译文】基础医学研究方法【文档简介】：引言医学研究在推动我们对疾病的理解、开发新的治疗方法和改善患者护理方面起着至关重要的作用。
系统综述和Meta分析1
Meta analysis的统计分析过程
统计描述 数据来源及分类 确定效应量的表达形式 森林图 异质性检验 合并效应量的估计与统计推断 敏感性分析 固定效应与随机效应模型 Meta分析的结果评价
注意：
Meta-分析只是一个统计工具。它不可能将那些本 身有问题的研究结果，合成一个好的结果 Meta-分析仅仅是系统综述中一个部分
综述
系统评价 mቤተ መጻሕፍቲ ባይዱta-分析
第一节 概
述
为什么要进行系统综述和Meta分析
海量信息需要整合 避免“只见树木不见森林” 克服传统文献综述的缺陷 连接新旧知识的桥梁
文献资料的可靠性
系统评价与meta分析的关系
系统评价并非必须对纳入研究进行统计学合并（meta分析） 是否做Meta分析需要视纳入研究是否有足够的相似性 Meta分析也并非一定要做系统评价，因为其本质是一种统计
学方法
包含有对具同质性的多个研究进行meta分析的系统评价称为 定量系统评价 如果纳入研究不具有同质性，则不进行meta分析，而仅进行 描述性的系统评价，此类系统评价称为定性系统评价
第一节 概
述
系统评价 针对某个主题进行的二次研究 在复习、分析、整理和综合针对该主题的全 部原始文献的基础上进行 评价过程依照一定的标准化方法 是循证决策的良好依据
第一节 概
述
系统综述的主要特征
全面收集所有有关研究 对所有纳入的研究逐个进行严格评价 联合所有研究结果进行综合分析和评价 必要时进行 Meta-分析(定量合成的统计方法) 得出综合结论（有效、无效、应进一步研究) 提供尽可能减少偏倚，接近真实的科学证据
系统评价报告规范PRISMA
1Preferred Reporting Items for Systematic Reviews and Meta-Analyses:The PRISMA StatementDavid Moher1,2*,Alessandro Liberati3,4,Jennifer Tetzlaff1,Douglas G.Altman5,The PRISMA Group"1Ottawa Methods Centre,Ottawa Hospital Research Institute,Ottawa,Ontario,Canada,2Department of Epidemiology and Community Medicine,Faculty of Medicine, University of Ottawa,Ottawa,Ontario,Canada,3Universita`di Modena e Reggio Emilia,Modena,Italy,4Centro Cochrane Italiano,Istituto Ricerche Farmacologiche Mario Negri,Milan,Italy,5Centre for Statistics in Medicine,University of Oxford,Oxford,United KingdomIntroductionSystematic reviews and meta-analyses have become increasingly important in health care.Clinicians read them to keep up to date with their field[1,2],and they are often used as a starting point for developing clinical practice guidelines.Granting agencies may require a systematic review to ensure there is justification for further research[3],and some health care journals are moving in this direction[4].As with all research,the value of a systematic review depends on what was done,what was found,and the clarity of reporting.As with other publications,the reporting quality of systematic reviews varies,limiting readers’ability to assess the strengths and weaknesses of those reviews.Several early studies evaluated the quality of review reports.In 1987,Mulrow examined50review articles published in four leading medical journals in1985and1986and found that none met all eight explicit scientific criteria,such as a quality assessment of included studies[5].In1987,Sacks and colleagues[6]evaluated the adequacy of reporting of83meta-analyses on23characteristics in six domains. Reporting was generally poor;between one and14characteristics were adequately reported(mean=7.7;standard deviation=2.7).A 1996update of this study found little improvement[7].In1996,to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement(QU ality O f R eporting O f M eta-analyses), which focused on the reporting of meta-analyses of randomized controlled trials[8].In this article,we summarize a revision of these guidelines,renamed PRISMA(Preferred Reporting Items for Systematic reviews and Meta-Analyses),which have been updated to address several conceptual and practical advances in the science of systematic reviews(Box1).TerminologyThe terminology used to describe a systematic review and meta-analysis has evolved over time.One reason for changing the name from QUOROM to PRISMA was the desire to encompass both systematic reviews and meta-analyses.We have adopted the definitions used by the Cochrane Collaboration[9].A systematic review is a review of a clearly formulated question that uses systematic and explicit methods to identify,select,and critically appraise relevant research,and to collect and analyze data from the studies that are included in the review.Statistical methods (meta-analysis)may or may not be used to analyze and summarize the results of the included studies.Meta-analysis refers to the use of statistical techniques in a systematic review to integrate the results of included studies.Developing the PRISMA StatementA three-day meeting was held in Ottawa,Canada,in June2005 with29participants,including review authors,methodologists,clinicians,medical editors,and a consumer.The objective of the Ottawa meeting was to revise and expand the QUOROM checklist and flow diagram,as needed.The executive committee completed the following tasks,prior to the meeting:a systematic review of studies examining the quality of reporting of systematic reviews,and a comprehensive literature search to identify methodological and other articles that might inform the meeting,especially in relation to modifying checklist items.An international survey of review authors,consumers,and groups commissioning or using systematic reviews and meta-analyses was completed,including the International Network of Agencies for Health Technology Assessment(INAHTA)and the Guidelines International Network(GIN).The survey aimed to ascertain views of QUOROM,including the merits of the existing checklist items.The results of these activities were presented during the meeting and are summarized on the PRISMA Web site (/).Only items deemed essential were retained or added to the checklist.Some additional items are nevertheless desirable,and review authors should include these,if relevant[10].For example, it is useful to indicate whether the systematic review is an update [11]of a previous review,and to describe any changes in procedures from those described in the original protocol. Citation:Moher D,Liberati A,Tetzlaff J,Altman DG,The PRISMA Group(2009)Preferred Reporting Items for Systematic Reviews and Meta-Analyses:The PRISMA Statement.PLoS Med6(7):e1000097.doi:10.1371/ journal.pmed.1000097Published July21,2009Copyright:ß2009Moher et al.This is an open-access article distributed under the terms of the Creative Commons Attribution License,which permits unrestricted use,distribution,and reproduction in any medium,provided the original author and source are credited.Funding:PRISMA was funded by the Canadian Institutes of Health Research; Universita`di Modena e Reggio Emilia,Italy;Cancer Research UK;Clinical Evidence BMJ Knowledge;the Cochrane Collaboration;and GlaxoSmithKline,Canada.AL is funded,in part,through grants of the Italian Ministry of University(COFIN-PRIN 2002prot.2002061749and COFIN-PRIN2006prot.2006062298).DGA is funded by Cancer Research UK.DM is funded by a University of Ottawa Research Chair. None of the sponsors had any involvement in the planning,execution,or write-up of the PRISMA documents.Additionally,no funder played a role in drafting the manuscript.Competing Interests:The authors have declared that no competing interests exist.Abbreviations:PRISMA,Preferred Reporting Items for Systematic reviews and Meta-Analyses;QUOROM,QU ality O f R eporting O f M eta-analyses. Provenance:Not commissioned;externally peer reviewed.In order to encourage dissemination of the PRISMA Statement,this article is freely accessible on the PLoS Medicine Web site(/)and will be also published in the Annals of Internal Medicine,BMJ,Journal of Clinical Epidemiology, and Open Medicine.The authors jointly hold the copyright of this article.For details on further use,see the PRISMA Web site(http://www.prisma-statement. org/)."Membership of the PRISMA Group is provided in the Acknowledgments.*E-mail:dmoher@ohri.caShortly after the meeting a draft of the PRISMA checklist was circulated to the group,including those invited to the meeting but unable to attend.A disposition file was created containing comments and revisions from each respondent,and the checklist was subsequently revised11times.The group approved the checklist,flow diagram,and this summary paper.Although no direct evidence was found to support retaining or adding some items,evidence from other domains was believed to be relevant.For example,Item5asks authors to provide registration information about the systematic review,including a registration number,if available.Although systematic review registration is not yet widely available[12,13],the participating journals of the International Committee of Medical Journal Editors(ICMJE)[14]now require all clinical trials to be registered in an effort to increase transparency and accountability[15]. Those aspects are also likely to benefit systematic reviewers, possibly reducing the risk of an excessive number of reviews addressing the same question[16,17]and providing greater transparency when updating systematic reviews.The PRISMA StatementThe PRISMA Statement consists of a27-item checklist(Table1; see also Text S1for a downloadable Word template for researchers to re-use)and a four-phase flow diagram(Figure1;see also Figure S1for a downloadable Word template for researchers to re-use). The aim of the PRISMA Statement is to help authors improve the reporting of systematic reviews and meta-analyses.We have focused on randomized trials,but PRISMA can also be used as a basis for reporting systematic reviews of other types of research,particularly evaluations of interventions.PRISMA may also be useful for critical appraisal of published systematic reviews.However,the PRISMA checklist is not a quality assessment instrument to gauge the quality of a systematic review.From QUOROM to PRISMAThe new PRISMA checklist differs in several respects from the QUOROM checklist,and the substantive specific changes are highlighted in Table 2.Generally,the PRISMA checklist ‘‘decouples’’several items present in the QUOROM checklist and,where applicable,several checklist items are linked to improve consistency across the systematic review report.The flow diagram has also been modified.Before including studies and providing reasons for excluding others,the review team must first search the literature.This search results in records. Once these records have been screened and eligibility criteria applied,a smaller number of articles will remain.The number of included articles might be smaller(or larger)than the number of studies,because articles may report on multiple studies and results from a particular study may be published in several articles.To capture this information,the PRISMA flow diagram now requests information on these phases of the review process. EndorsementThe PRISMA Statement should replace the QUOROM State-ment for those journals that have endorsed QUOROM.We hope that other journals will support PRISMA;they can do so by registering on the PRISMA Web site.To underscore to authors,and others,the importance of transparent reporting of systematic reviews,we encourage supporting journals to reference the PRISMA Statement and include the PRISMA Web address in their Instructions to Authors.We also invite editorial organizations to consider endorsing PRISMA and encourage authors to adhere to its principles.The PRISMA Explanation and Elaboration Paper In addition to the PRISMA Statement,a supporting Explana-tion and Elaboration document has been produced[18]following the style used for other reporting guidelines[19–21].The processBox1:Conceptual Issues in the Evolution from QUOROM to PRISMACompleting a Systematic Review Is an Iterative Process The conduct of a systematic review depends heavily on the scope and quality of included studies:thus systematic reviewers may need to modify their original review protocol during its conduct.Any systematic review reporting guideline should recommend that such changes can be reported and explained without suggesting that they are inappropriate.The PRISMA Statement(Items5,11, 16,and23)acknowledges this iterative process.Aside from Cochrane reviews,all of which should have a protocol, only about10%of systematic reviewers report working from a protocol[22].Without a protocol that is publicly accessible,it is difficult to judge between appropriate and inappropriate modifications.Conduct and Reporting Research Are Distinct Concepts This distinction is,however,less straightforward for systematic reviews than for assessments of the reporting of an individual study, because the reporting and conduct of systematic reviews are,by nature,closely intertwined.For example,the failure of a systematic review to report the assessment of the risk of bias in included studies may be seen as a marker of poor conduct,given the importance of this activity in the systematic review process[37].Study-Level Versus Outcome-Level Assessment of Risk of Bias For studies included in a systematic review,a thorough assessment of the risk of bias requires both a ‘‘study-level’’assessment(e.g.,adequacy of allocation concealment)and,for some features,a newer approach called‘‘outcome-level’’assessment.An outcome-level assessment involves evaluating the reliability and validity of the data for each important outcome by determining the methods used to assess them in each individual study [38].The quality of evidence may differ across outcomes, even within a study,such as between a primary efficacy outcome,which is likely to be very carefully and systematically measured,and the assessment of serious harms[39],which may rely on spontaneous reports by investigators.This information should be reported to allow an explicit assessment of the extent to which an estimate of effect is correct[38].Importance of Reporting Biases Different types of reporting biases may hamper the conduct and interpretation of systematic reviews.Selective reporting of complete studies(e.g.,publication bias)[28]as well as the more recently empirically demonstrated‘‘outcome reporting bias’’within individual studies[40,41]should be considered by authors when conducting a systematic review and reporting its results.Though the implications of these biases on the conduct and reporting of systematic reviews themselves are unclear,some previous research has identified that selective outcome reporting may occur also in the context of systematic reviews[42].of completing this document included developing a large database of exemplars to highlight how best to report each checklist item,and identifying a comprehensive evidence base to support the inclusion of each checklist item.The Explanation and Elaboration document was completed after several face to face meetings and numerous iterations among several meeting participants,after which it was shared with the whole group for additional revisions and final approval.Finally,the group formed a dissemination subcommittee to help disseminate and implement PRISMA.DiscussionThe quality of reporting of systematic reviews is still not optimal [22–27].In a recent review of 300systematic reviews,few authors reported assessing possible publication bias [22],even though there is overwhelming evidence both for its existence [28]and its impact on the results of systematic reviews [29].Even when the possibility of publication bias is assessed,there is no guarantee that systematic reviewers have assessed or interpreted it appropriately [30].Although the absence of reporting such an assessment does not necessarily indicate that it was not done,reporting an assessment of possible publication bias is likely to be a marker of the thoroughness of the conduct of the systematic review.Several approaches have been developed to conduct systematic reviews on a broader array of questions.For example,systematicreviews are now conducted to investigate cost-effectiveness [31],diagnostic [32]or prognostic questions [33],genetic associations [34],and policy making [35].The general concepts and topics covered by PRISMA are all relevant to any systematic review,not just those whose objective is to summarize the benefits and harms of a health care intervention.However,some modifications of the checklist items or flow diagram will be necessary in particular circumstances.For example,assessing the risk of bias is a key concept,but the items used to assess this in a diagnostic review are likely to focus on issues such as the spectrum of patients and the verification of disease status,which differ from reviews of interventions.The flow diagram will also need adjustments when reporting individual patient data meta-analysis [36].We have developed an explanatory document [18]to increase the usefulness of PRISMA.For each checklist item,this document contains an example of good reporting,a rationale for its inclusion,and supporting evidence,including references,whenever possible.We believe this document will also serve as a useful resource for those teaching systematic review methodology.We encourage journals to include reference to the explanatory document in their Instructions to Authors.Like any evidence-based endeavor,PRISMA is a living document.To this end we invite readers to comment on the revised version,particularly the new checklist and flow diagram,through the PRISMA Web site.We will use such information to inform PRISMA’s continueddevelopment.Figure 1.Flow of information through the different phases of a systematic review.doi:10.1371/journal.pmed.1000097.g001Table1.Checklist of items to include when reporting a systematic review or meta-analysis.Section/Topic#Checklist Item Reported on Page#TITLETitle1Identify the report as a systematic review,meta-analysis,or both.ABSTRACTStructured summary2Provide a structured summary including,as applicable:background;objectives;data sources;study eligibilitycriteria,participants,and interventions;study appraisal and synthesis methods;results;limitations;conclusionsand implications of key findings;systematic review registration number.INTRODUCTIONRationale3Describe the rationale for the review in the context of what is already known.Objectives4Provide an explicit statement of questions being addressed with reference to participants,interventions,comparisons,outcomes,and study design(PICOS).METHODSProtocol and registration5Indicate if a review protocol exists,if and where it can be accessed(e.g.,Web address),and,if available,provideregistration information including registration number.Eligibility criteria6Specify study characteristics(e.g.,PICOS,length of follow-up)and report characteristics(e.g.,years considered,language,publication status)used as criteria for eligibility,giving rationale.Information sources7Describe all information sources(e.g.,databases with dates of coverage,contact with study authors to identifyadditional studies)in the search and date last searched.Search8Present full electronic search strategy for at least one database,including any limits used,such that it could berepeated.Study selection9State the process for selecting studies(i.e.,screening,eligibility,included in systematic review,and,if applicable,included in the meta-analysis).Data collection process10Describe method of data extraction from reports(e.g.,piloted forms,independently,in duplicate)and anyprocesses for obtaining and confirming data from investigators.Data items11List and define all variables for which data were sought(e.g.,PICOS,funding sources)and any assumptions andsimplifications made.Risk of bias in individual studies 12Describe methods used for assessing risk of bias of individual studies(including specification of whether this was done at the study or outcome level),and how this information is to be used in any data synthesis.Summary measures13State the principal summary measures(e.g.,risk ratio,difference in means).Synthesis of results14Describe the methods of handling data and combining results of studies,if done,including measures ofconsistency(e.g.,I2)for each meta-analysis.Risk of bias across studies15Specify any assessment of risk of bias that may affect the cumulative evidence(e.g.,publication bias,selectivereporting within studies).Additional analyses16Describe methods of additional analyses(e.g.,sensitivity or subgroup analyses,meta-regression),if done,indicating which were pre-specified.RESULTSStudy selection17Give numbers of studies screened,assessed for eligibility,and included in the review,with reasons for exclusionsat each stage,ideally with a flow diagram.Study characteristics18For each study,present characteristics for which data were extracted(e.g.,study size,PICOS,follow-up period)and provide the citations.Risk of bias within studies19Present data on risk of bias of each study and,if available,any outcome-level assessment(see Item12). Results of individual studies20For all outcomes considered(benefits or harms),present,for each study:(a)simple summary data for eachintervention group and(b)effect estimates and confidence intervals,ideally with a forest plot.Synthesis of results21Present results of each meta-analysis done,including confidence intervals and measures of consistency.Risk of bias across studies22Present results of any assessment of risk of bias across studies(see Item15).Additional analysis23Give results of additional analyses,if done(e.g.,sensitivity or subgroup analyses,meta-regression[see Item16]). DISCUSSIONSummary of evidence24Summarize the main findings including the strength of evidence for each main outcome;consider theirrelevance to key groups(e.g.,health care providers,users,and policy makers).Limitations25Discuss limitations at study and outcome level(e.g.,risk of bias),and at review level(e.g.,incomplete retrieval ofidentified research,reporting bias).Conclusions26Provide a general interpretation of the results in the context of other evidence,and implications for futureresearch.FUNDINGFunding27Describe sources of funding for the systematic review and other support(e.g.,supply of data);role of funders forthe systematic review.doi:10.1371/journal.pmed.1000097.t001Supporting InformationFigure S1Flow of information through the different phases of a systematic review(downloadable template document for researchers to re-use).Found at:doi:10.1371/journal.pmed.1000097.s001(0.08MB DOC)Text S1Checklist of items to include when reporting a systematic review or meta-analysis(downloadable tem-plate document for researchers to re-use).Found at:doi:10.1371/journal.pmed.1000097.s002(0.04MB DOC)AcknowledgmentsThe following people contributed to the PRISMA Statement:Doug Altman,DSc,Centre for Statistics in Medicine(Oxford,UK);Gerd Antes,PhD,University Hospital Freiburg(Freiburg,Germany);David Atkins,MD,MPH,Health Services Research and Development Service, Veterans Health Administration(Washington, D. C.,US);Virginia Barbour,MRCP,DPhil,PLoS Medicine(Cambridge,UK);Nick Barrow-man,PhD,Children’s Hospital of Eastern Ontario(Ottawa,Canada); Jesse A.Berlin,ScD,Johnson&Johnson Pharmaceutical Research and Development(Titusville,New Jersey,US);Jocalyn Clark,PhD,PLoS Medicine(at the time of writing,BMJ,London,UK);Mike Clarke,PhD, UK Cochrane Centre(Oxford,UK)and School of Nursing and Midwifery,Trinity College(Dublin,Ireland);Deborah Cook,MD, Departments of Medicine,Clinical Epidemiology and Biostatistics, McMaster University(Hamilton,Canada);Roberto D’Amico,PhD, Universita`di Modena e Reggio Emilia(Modena,Italy)and Centro Cochrane Italiano,Istituto Ricerche Farmacologiche Mario Negri (Milan,Italy);Jonathan J.Deeks,PhD,University of Birmingham (Birmingham,UK);P.J.Devereaux,MD,PhD,Departments of Medicine,Clinical Epidemiology and Biostatistics,McMaster University (Hamilton,Canada);Kay Dickersin,PhD,Johns Hopkins Bloomberg School of Public Health(Baltimore,Maryland,US);Matthias Egger, MD,Department of Social and Preventive Medicine,University of Bern (Bern,Switzerland);Edzard Ernst,MD,PhD,FRCP,FRCP(Edin), Peninsula Medical School(Exeter,UK);Peter C.Gøtzsche,MD,MSc, The Nordic Cochrane Centre(Copenhagen,Denmark);Jeremy Grim-shaw,MBChB,PhD,FRCFP,Ottawa Hospital Research Institute (Ottawa,Canada);Gordon Guyatt,MD,Departments of Medicine, Clinical Epidemiology and Biostatistics,McMaster University(Hamilton, Canada);Julian Higgins,PhD,MRC Biostatistics Unit(Cambridge,UK); John P.A.Ioannidis,MD,University of Ioannina Campus(Ioannina, Greece);Jos Kleijnen,MD,PhD,Kleijnen Systematic Reviews Ltd (York,UK)and School for Public Health and Primary Care(CAPHRI), University of Maastricht(Maastricht,Netherlands);Tom Lang,MA, Tom Lang Communications and Training(Davis,California,US); Alessandro Liberati,MD,Universita`di Modena e Reggio Emilia (Modena,Italy)and Centro Cochrane Italiano,Istituto Ricerche Farmacologiche Mario Negri(Milan,Italy);Nicola Magrini,MD,NHS Centre for the Evaluation of the Effectiveness of Health Care–CeVEAS (Modena,Italy);David McNamee,PhD,The Lancet(London,UK); Lorenzo Moja,MD,MSc,Centro Cochrane Italiano,Istituto Ricerche Farmacologiche Mario Negri(Milan,Italy);David Moher,PhD,Ottawa Methods Centre,Ottawa Hospital Research Institute(Ottawa,Canada); Cynthia Mulrow,MD,MSc,Annals of Internal Medicine(Philadelphia, Pennsylvania,US);Maryann Napoli,Center for Medical Consumers (New York,New York,US);Andy Oxman,MD,Norwegian Health Services Research Centre(Oslo,Norway);Ba’Pham,MMath,Toronto Health Economics and Technology Assessment Collaborative(Toronto, Canada)(at the time of the first meeting of the group,GlaxoSmithKline Canada,Mississauga,Canada);Drummond Rennie,MD,FRCP,FACP, University of California San Francisco(San Francisco,California,US); Margaret Sampson,MLIS,Children’s Hospital of Eastern Ontario (Ottawa,Canada);Kenneth F.Schulz,PhD,MBA,Family Health International(Durham,North Carolina,US);Paul G.Shekelle,MD, PhD,Southern California Evidence Based Practice Center(Santa Monica,California,US);Jennifer Tetzlaff,BSc,Ottawa Methods Centre,Ottawa Hospital Research Institute(Ottawa,Canada);David Tovey,FRCGP,The Cochrane Library,Cochrane CollaborationTable2.Substantive specific changes between the QUOROM checklist and the PRISMA checklist(a tick indicates the presence of the topic in QUOROM or PRISMA).Section/Topic Item QUOROM PRISMA CommentAbstract!!QUOROM and PRISMA ask authors to report an abstract.However,PRISMA is notspecific about format.Introduction Objective!This new item(4)addresses the explicit question the review addresses using the PICOreporting system(which describes the participants,interventions,comparisons,andoutcome(s)of the systematic review),together with the specification of the type ofstudy design(PICOS);the item is linked to Items6,11,and18of the checklist. Methods Protocol!This new item(5)asks authors to report whether the review has a protocol and if sohow it can be accessed.Methods Search!!Although reporting the search is present in both QUOROM and PRISMA checklists,PRISMA asks authors to provide a full description of at least one electronic searchstrategy(Item8).Without such information it is impossible to repeat the authors’search.Methods Assessment ofrisk of bias inincluded studies !!Renamed from‘‘quality assessment’’in QUOROM.This item(12)is linked withreporting this information in the results(Item19).The new concept of‘‘outcome-level’’assessment has been introduced.Methods Assessment ofrisk of bias acrossstudies !This new item(15)asks authors to describe any assessments of risk of bias in the review,such as selective reporting within the included studies.This item is linkedwith reporting this information in the results(Item22).Discussion!!Although both QUOROM and PRISMA checklists address the discussion section,PRISMA devotes three items(24–26)to the discussion.In PRISMA the main types oflimitations are explicitly stated and their discussion required.Funding!This new item(27)asks authors to provide information on any sources of funding forthe systematic review.doi:10.1371/journal.pmed.1000097.t002(Oxford,UK)(at the time of the first meeting of the group,BMJ, London,UK);Peter Tugwell,MD,MSc,FRCPC,Institute of Population Health,University of Ottawa(Ottawa,Canada).Author ContributionsICMJE criteria for authorship read and met:DM AL JT DGA.Wrote the first draft of the paper:DM AL DGA.Contributed to the writing of the paper:DM AL JT DGA.Participated in regular conference calls,identified the participants,secured funds,planned the meeting,participated in the meeting,and drafted the manuscript:DM AL DGA.Participated in identifying the evidence base for PRISMA,refining the checklist,and drafting the manuscript:JT.Agree with the recommendations:DM AL JT DGA.References1.Oxman AD,Cook DJ,Guyatt GH(1994)Users’guides to 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系统评价Meta分析详细介绍
系统评价Meta分析详细介绍目录一、系统评价Meta分析的基本概念 (2)1.1 系统评价的定义 (3)1.2 Meta分析的定义 (4)二、系统评价Meta分析的目的和意义 (4)三、系统评价Meta分析的流程 (5)3.1 明确研究问题 (6)3.2 检索文献 (7)3.3 筛选文献 (8)3.4 数据提取 (9)3.5 整理数据 (10)3.6 进行Meta分析 (11)3.7 结果解释 (12)3.8 评估偏倚风险 (13)3.9 结果的综合评价 (14)四、系统评价Meta分析中的统计方法 (15)4.1 基本统计方法 (16)4.2 元分析统计方法 (17)五、系统评价Meta分析的质量评价 (19)5.1 文献质量评价 (20)5.2 结果的一致性评价 (21)5.3 可靠性评价 (22)六、系统评价Meta分析的结果解释和应用 (24)6.1 结果的解释 (25)6.2 结果的应用 (26)6.3 对未来研究的启示 (27)七、系统评价Meta分析的局限性 (28)7.1 样本选择偏差 (29)7.2 数据质量问题 (31)7.3 不同研究结果间的异质性 (32)八、系统评价Meta分析的伦理问题 (33)8.1 保护受试者隐私 (35)8.2 避免学术不端行为 (36)九、系统评价Meta分析的未来发展趋势 (37)9.1 技术的发展 (38)9.2 方法学的创新 (39)一、系统评价Meta分析的基本概念系统评价(Systematic Review,简称SR)是一种多学科研究方法，旨在通过收集、整理和分析大量关于某一主题的独立研究结果，以便得出全面、准确和可靠的结论。
Meta分析(Metaanalysis)是系统评价的一种扩展和深化，它通过对多个独立研究的统计分析，对原始研究结果进行加权汇总，以提高研究结果的可靠性和推广性。
系统评价的目的是对现有的研究进行全面、客观和公正的评估，从而为实践提供有价值的指导。
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Canadian Cochrane Network & Centre
CC built on 10 Principles
• collaboration • building on the enthusiasm of individuals • avoiding duplication • minimizing bias • keeping up to date • striving for relevance • promoting access • ensuring quality • continuity • enabling wide participation
Davidoff F et al. (1995) EBM; A new journal to help doctors identify the information they need. BMJ 310:1085-86.
Hale Waihona Puke Statistical Quality of Medical Research gets low marks!
The Cochrane Collaboration - origins
• Archie Cochrane – “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.”
Most studies are too small
Inconclusive, often conflicting results
Traditional reviews are unstructured &
subjective
Biased conclusions
WHO CAN KEEP UP?
Over 345,000 trials published to date
Why Systematic Reviews?
Help to deal with the volume of literature Help resolve conflicting results Scientific rather than subjective summarization of literature Can reveal new evidence Identify knowledge gaps More reliable evidence with which to aid decision making Guide clinical research by providing new hypotheses
organization that aims to help people make wellinformed decisions about healthcare by preparing, maintaining and promoting the accessibility of systematic reviews of the effects of healthcare interventions”
Over 20,000 new trials
published annually Help!
For General Physicians to keep current:
Read 19 new articles per day which appear in medical journals
19 x 2 hrs (Critical Appraisal) = 38 hrs per day
RESULTS???
Problems with Standard Reviews
Lack of scientific purpose (question) Undocumented methods of literature search Unstated criteria for selecting studies No methodological assessment of selected studies Inadequate assessment of inter-study differences in results No attempt at quantitative synthesis (pooling) to take advantage of increased power
1996 G. WELCH, S. GABBE Review of Statistics Usage in the Amer J Obstet Gynecol 175;1138-41
All clinical papers: Jan - June 1994 (Vol. 170, No. 1 to 6) 31.7% (46/145) had inappropriate statistics 27 of 46 papers had serious flaws
• Pregnancy and childbirth work - 1980s
Canadian Cochrane Network & Centre
Aims and objectives of the CC
“The Cochrane Collaboration is an international
Systematic Reviews and Meta-Analyses
Ritz Kakuma, MSc (PhD Candidate) Department of Epidemiology & Biostatistics McGill University
Problems with Today's Medical Literature