循证医学术语介绍（Ⅵ）

作为《循证医学术语介绍》的第6篇文章,我们主要回顾了研究综合、系统评价与Meta分析各自产生的背景、发展、步骤及未来的发展趋势,并对其概念进行了解析。     

应用Microsoft Excel软件Net Meta XL宏命令实现网状Meta分析

Net Meta XL是一款基于贝叶斯理论研发的在Microsot Excel框架下执行网状Meta分析的宏。该宏于2014年正式推出,将数据提取与输入、结果输出和图形绘制集于一体。当前,该宏可供选择的模型丰富,所有操作均为菜单式且操作简单,但其仅适用于二分类数据的网状Meta分析,仍有较大提升空间和需要完善之处。本文通过实例介绍应用Net Meta XL宏实现网状Meta分析的方法。     

R软件Metafor程序包在Meta分析中的应用

R软件是一款免费使用且功能强大的统计软件,常用的Meta分析程序包有Metafor、Meta、Rrneta等.Metafor程序包可以方便地进行Meta分析,包括二分类及连续性变量的Meta分析、Meta回归、累积Meta分析及对发表偏倚的Begg's检验和Egger's检验等,以及绘制森林图、漏斗图、星状图、拉贝图、Q-Q正态分位图等图形.此外,Metafor程序包是R软件Meta分析程序包中唯一可以进行混合效应模型(包括单个、多个分类或连续性变量)拟合运算的,还可以检验模型系数并获得可信区间.本文结合实例对应用Metafor程序包进行Meta分析的具体操作方法进行详细介绍.     

率的Meta分析及软件实现

目前对于效应量为率的同类研究进行Meta分析的研究很多,但相关方法的研究较少。因此,本文概括性介绍了率的Meta分析的适用条件、分析步骤及常用软件的实现过程,并通过应用实例中的数据比较常用的R软件、Comprehensive Meta-Analysis、Stata和MetaAnalyst的不同操作过程。率的Meta分析难点在于判断能否进行率的合并,对如何处理不同研究结果间异质性的问题尚需进一步探讨。     

我国糖尿病与阿尔茨海默病关联性的Meta分析

目的探讨糖尿病与阿尔茨海默病的关系。方法通过Medline、中国生物医学文献数据库和中国学术期刊全文数据库等数据库搜集资料,应用RevMan 4.2软件对所得资料进行Meta分析。结果有8篇文献进入Meta分析,共获得6 101例样本,其中病例组944例,对照组5 157例。经过Meta分析,采用固定效应模型,合并OR值和95%的可信区间为1.77（1.34-2.34）（P〈0.01）;敏感性分析结果提示,采用不同模型的Meta分析结果一致。结论糖尿病与阿尔茨海默病可能具有关联性,它是阿尔茨海默病发生的一个危险因素。     

冲突性Meta分析评价方法:Jadad法则简介

随着循证理念在国内的广泛传播,系统评价/Meta分析已逐渐成为指导医疗决策的重要工具。然而,伴随系统评价/Meta分析发表量急剧增加,出现了针对相同或相似临床问题的多篇系统评价/Meta分析。而这些已发表的系统评价/Meta分析的结果并不总是一致,这就使制定临床决策变得尤为困难。如何从诸多主题相近的系统评价/Meta分析中获取支持决策的证据是卫生保健研究者和决策者必须解决的问题。为此加拿大McMaster大学的Jadad等提出了用于评价冲突性Meta分析的Jadad法则。本文将对该方法进行介绍,并通过实例来展示该法则的具体应用。     

对系统评价/Meta分析报告规范的系统评价

目的全面收集系统评价/Meta分析的报告规范并对其进行评价,为系统评价/Meta分析的规范化发表及传播提供帮助。方法电子检索Ovid MEDLINE(1996～2010)及EMbase(截至2010年4月),纳入系统评价/Meta分析报告规范的文献,检索词包括guideline、report、systematic reviews、meta-analyses。通过阅读文题及摘要,排除无明显相关性的文献(针对具体疾病的系统评价,某一疾病的临床指南,以及仅讨论如何进行系统评价而未关注如何进行系统评价的报道等),而后进一步阅读全文,从纳入文献中提取如何报告系统评价/Meta分析的部分,并据其纳入原始研究设计的类型如随机对照试验、观察性研究、诊断性试验进行分类。结果初检获得285篇文献,最终纳入26篇文献。其中随机对照试验的系统评价/Meta分析报告规范有8篇,非随机对照试验(观察性研究)的系统评价/Meta分析报告规范2篇,诊断性试验的系统评价/Meta分析报告规范0篇,动物实验的系统评价/Meta分析报告规范1篇,针对系统评价/Meta分析的检索策略的报告规范2篇,评估系统评价/Meta分析质量的5篇,研究报告规范对系统评价/Meta分析质量影响的6篇。有2个指南更新。结论目前系统评价/Meta分析报告规范数量较多,其中QUOROM及其更新版本PRISMA被众多期刊广泛采纳。报告规范有利于提高系统评价和Meta分析的报告质量,尚需制定针对具体专业系统评价/Meta分析的报告规范。     

应用SAS软件宏命令实现Meta分析统计效能计算

SAS被誉为国际上数据处理和统计分析领域的标准软件,也是实现Meta分析的优秀软件之一,但其程序编写复杂且难度较大,要求使用者具备较强的编程功底。评价显著性检验的统计效能是Meta分析的重要步骤,为更好地使用SAS软件,美国南佛罗里达大学的Guy Cafri等共同研发了一款专用于实现Meta分析统计效能计算的SAS宏命令(%metapower)。该宏命令可实现Meta分析整体结果、异质性和亚组分析统计效能的计算,简洁易操作,本文结合实例对该宏命令进行介绍。     

Meta分析中的异质性及其处理方法

摘要介绍Meta分析中异质性研究,包括Meta分析中异质性的定义,并将异质性分为临床异质性、方法学异质性、统计学异质性三类,介绍减少纳入临床异质性和方法学异质性研究的措施,统计学异质性的五种检验方法（Q统计量、P统计量、H统计量、Galbraith图法、L＇Abbe图）、实例分析及适用情况。根据异质性的有无将Meta分析分为探索型Meta分析和分析型Meta分析,存在异质性时可采取的措施及其流程图。     

WinBUGS软件实现Meta分析的Doodle模型图的构建

WinBUGS软件实现Meta分析的关键在于构建贝叶斯统计模型,目前有手工编写代码和构建Doodle模型两种方法。手工编写代码具有灵活、方便的特点,但编写语言易错;Doodle模型的构建过程较为繁琐,但不易出错,且有利于加强对手工代码结构的理解。本文简要介绍使用WinBUGS软件行二分类和连续型数据的传统Meta分析、间接比较证据的Meta分析及网状Meta分析和有序变量的Meta分析时Doodle模型的构建。     

Standardization of terminology in meta-analysis: a proposal for working definitions

Summary— In this paper we present a brief overview of the growing concern to standardize definitions and terminology in meta-analysis. This tool has become inescapable in both drug research and therapeutic evaluation. The performed and published meta-analyses are increasing, as well as the variation in the meaning of the terms used in meta-analysis. In the second part of the paper we propose glossary of the most common terms used in reports of meta-analyses. The glossary has been written by only one group of scientists, the definitions are therefore proposed to the scientific community as working definitions , to be subject to reactions from leaders in meta-analysis.     

Meta‐analysis: the glass eye of evidence‐based practice?

Meta-analysis was developed as a technique for combining the results of many different quantitative studies: it is often used to produce quantitative estimates of causal relations and/or association between variables. Meta-analysis is sometimes regarded as a central component of evidence-based practice. We draw attention to an incompatibility in the epistemology and methods of reasoning in quantitative meta-analysis and the epistemology and reasoning implicit in expert practice. We argue that this may be because the common perception of meta-analysis appeals to truth as correspondence; we suggest that rejecting the naive realism that underpins truth as correspondence allows meta-analysis to be understood in terms of truth as coherence. We can then develop an account of meta-analysis that does not depend upon reduction to a mathematical procedure but is an attempt to maximise coherence in beliefs about what works that is consistent with clinical reasoning in expert practice.     

The Relationship Between Pacing and Avoidance in Chronic Pain: A Systematic Review and Meta-Analysis

Activity pacing is ubiquitous in chronic pain management and aims to reduce pain-contingent avoidance of activity to improve functioning. A meta-analysis, however, has linked pacing with higher levels of pain and disability. One potential explanation is an overlap between existing measures of pacing and avoidance, leading to links with poorer outcomes that are typically associated with avoidance. This study systematically reviews the evidence regarding the relationship between measures of pacing and avoidance. A search was conducted for studies measuring both constructs in adults with chronic pain. A meta-analysis of correlations between pacing and avoidance was conducted; 16 studies were included and a small positive correlation was found (r = .290, P < .001) overall. Single-item and multiple-item measures were also compared; a moderate positive correlation was found for multiple-item measures (r = .410, P < .001), which differed significantly from a small positive correlation found for single-item measures (r = .105, P < .001). Due to limited studies, independent analyses of individual subscales were not possible. Existing measures of pacing—particularly multiple-item measures—may partially confound pacing with avoidance. Further research is required to ensure that a reliable measure of pacing that distinguishes this construct from avoidance is available to adequately evaluate pacing instruction and the effect of pacing on key outcomes in chronic pain.

A multilevel meta-analysis of single-subject experimental design studies

A multilevel approach is proposed to synthesize the results of single-subject experimental research by combining either raw data or effect-size measures. A multilevel meta-analysis of single-subject data allows us to make inferences not only about the effects for the participants that are investigated, but also about the generality of the effects. It also permits a systematic exploration of the possible moderating effect of study and participant characteristics. We also discuss the possibility of combining single-subject experimental research and group-comparison research in one single meta-analysis, and the difficulties involved, especially in making effect-size measures comparable for both kinds of studies.     

单个大样本随机对照试验与小样本随机对照试验Meta分析的比较

在缺乏针对临床干预措施的大样本、决定性的随机对照试验的情况下,基于小样本随机对照试验的Meta分析是否能够替代大样本随机对照试验,为临床实践提供最佳证据,是值得探讨的。本文对大样本随机对照试验和Meta分析的原始文献质量、方法学质量进行分析和讨论,并比较单个大样本随机对照试验(RCT)和Meta分析优缺点,以供循证医学研究者参考。     

The Association Between Preoperative Frailty and Postoperative Delirium: A Systematic Review and Meta-analysis

PurposeIdentifying factors that place patients at high risk for developing postoperative delirium is an important first step to reduce incidence. Frailty is associated with poor postoperative outcomes. This meta-analysis aims to determine the association between preoperative frailty and postoperative delirium.DesignThis is a systematic review and meta-analysis.MethodsWe used PubMed, Scopus, Embase, CINAHL, Cochrane, and Web of Science as databases for the search up to April 23, 2020. We included cohort studies that assessed postoperative delirium as the outcome and described the prevalence of delirium among participants during the postoperative period. Odds ratio and 95% confidence interval were calculated to examine the association.FindingsTwenty cohort studies met our inclusion criteria, which included a total of 4,568 patients. We found that preoperative frailty was significantly associated with an increased risk of postoperative delirium (crude odds ratio: 3.28; 95% confidence interval: 2.51 to 4.28; I² = 46.7%) (adjusted odds ratio: 2.45; 95% confidence interval: 1.58 to 3.81; I² = 88.6%).ConclusionsThis meta-analysis showed that preoperative frailty is an independent risk factor for postoperative delirium. In patients undergoing cardiovascular surgery, there is a lower association between frailty and postoperative delirium. In patients with other types of surgery, preoperative frailty is closely related to postoperative delirium.     

Differences in post-operative infection rates between patients receiving autologous and allogeneic blood transfusion: a meta-analysis of published randomized and nonrandomized studies

Summary. We have undertaken a meta-analysis of the post-operative infection rates in patients who received autologous blood compared with allogeneic blood. Nine studies published after 1989 were identified, of which seven had sufficient data on transfusion given in the paper to be included, giving a total of 1060 patients. The risk of post-operative infection was greater in the allogeneic group, odds ratio 2.37 (95% confidence interval (CI) 1.6-3.6, P < 0.0001) compared with the autologous group. Allogeneic and autologous blood transfusion should be compared in a large multicentre randomized control trial.     

Chapter 2. Surge capacity and infrastructure considerations for mass critical care

Meta-analysis is a technique for combining evidence from multiple trials. However, meta-analyses of studies with substantial heterogeneity among patients within trials—common in intensive care—can lead to incorrect conclusions if performed using aggregate data. Use of individual patient data (IPD) can avoid this concern, increase the power of a meta-analysis, and is useful for exploring subgroup effects. Barriers exist to IPD meta-analysis, most of which are overcome if clinical trials are designed to prospectively facilitate the incorporation of their results with other trials. We review the features of prospective IPD meta-analysis and identify those of relevance to intensive care research. We identify three clinical questions, which are the subject of recent or planned randomised controlled trials where IPD MA offers advantages over approaches using aggregate data.     

试验序贯分析简介

试验序贯分析（trial equential nalysis,TSA）作为累积Meta分析的一种,其主要是将序贯分析方法引入传统的Meta分析,以解决传统Meta分析在反复更新中出现的随机误差（假阳性／假阴性的结果）问题,同时也能计算得出某一个确切的结论所需要的样本量。本文通过参阅世界范围内已发表的文献,着重总结介绍TSA方法的提出、基本原理、应用软件以及当前的局限,同时依据具体的实例来说明TSA的优势,以期吸引更多研究者关注,进而促进我国Meta分析方法学的发展。     

Psychometric evaluation of the Demands of Immigration Scale with Taiwanese-Chinese immigrants: a pilot study

AIMS: This paper highlights the lack of consideration that is given to power in the health and social sciences, which is a continuing problem with both single study research and more importantly for meta-analysis. BACKGROUND: The power of a study is the probability that it will lead to a statistically significant result. By ignoring power the single study researcher makes it difficult to get negative results published and therefore affects meta-analysis through publication bias. Researchers using meta-analysis, who also ignore power, then compound the problem by including studies with low power that are more likely to show significant effects. METHOD: A simple means of calculating an easily understood measure of effect size from a contingency table is demonstrated in this paper. A computer programme for determining the power of a study is recommended and a method of reflecting the adequacy of the power of the studies in a meta-analysis is suggested. An example of this calculation from a meta-analytic study on intravenous magnesium, which produced inaccurate results, is provided. CONCLUSION: It is demonstrated that incorporating power analysis into this meta-analysis would have prevented misleading conclusions being reached. Some suggestions are made for changes in the protocol of meta-analytic studies, which highlight the importance of power analysis.