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Exact inference on meta-analysis with generalized fixed-effects and random-effects models 广义固定效应和随机效应模型meta分析的精确推断
Q3 Medicine Pub Date : 2018-01-01 DOI: 10.1080/24709360.2017.1400714
Sifan Liu, L. Tian, Steve Lee, Min‐ge Xie
ABSTRACT Meta-analysis with fixed-effects and random-effects models provides a general framework for quantitatively summarizing multiple comparative studies. However, a majority of the conventional methods rely on large-sample approximations to justify their inference, which may be invalid and lead to erroneous conclusions, especially when the number of studies is not large, or sample sizes of the individual studies are small. In this article, we propose a set of ‘exact’ confidence intervals for the overall effect, where the coverage probabilities of the intervals can always be achieved. We start with conventional parametric fixed-effects and random-effects models, and then extend the exact methods beyond the commonly postulated Gaussian assumptions. Efficient numerical algorithms for implementing the proposed methods are developed. We also conduct simulation studies to compare the performance of our proposal to existing methods, indicating our proposed procedures are better in terms of coverage level and robustness. The new proposals are then illustrated with the data from meta-analyses for estimating the efficacy of statins and BCG vaccination.
固定效应和随机效应模型的荟萃分析为定量总结多个比较研究提供了一个总体框架。然而,大多数传统方法依赖于大样本近似来证明其推断,这可能是无效的,并导致错误的结论,特别是当研究数量不多或单个研究的样本量较小时。在本文中,我们为整体效果提出了一组“精确”置信区间,其中区间的覆盖概率总是可以实现的。我们从传统的参数固定效应和随机效应模型开始,然后将精确方法扩展到通常假设的高斯假设之外。开发了有效的数值算法来实现所提出的方法。我们还进行了模拟研究,将我们的建议与现有方法的性能进行比较,表明我们提出的程序在覆盖水平和鲁棒性方面更好。这些新建议随后用估计他汀类药物和卡介苗接种效果的荟萃分析数据加以说明。
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引用次数: 10
Identifying associated risk factors for severity of diabetic retinopathy from ordinal logistic regression models 从有序logistic回归模型中识别糖尿病视网膜病变严重程度的相关危险因素
Q3 Medicine Pub Date : 2018-01-01 DOI: 10.1080/24709360.2017.1406040
V. Kulothungan, M. Subbiah, R. Ramakrishnan, R. Raman
ABSTRACT The realm of medical statistics or epidemiology encourages the repeated application of few variants of generalized linear model. This work has identified a situation in understanding the risk factor modelling for diabetic retinopathy, major source for blindness in adults and associated with Type II diabetes. Main objective of this study is to retain the ordinal nature of the response variable, one of the main concerns in ordinal regression procedures; and to emphasize the need for applying stereotype regression for bio medical data. Analysis plan envisaged in this study has shown the relevance and scope to extend the use of ordinal regression models.
医学统计或流行病学领域鼓励重复应用广义线性模型的少数变体。这项工作已经确定了了解糖尿病视网膜病变风险因素建模的情况,糖尿病视网膜病变是成人失明的主要来源,并与II型糖尿病相关。本研究的主要目的是保留响应变量的序数性质,这是序数回归过程中主要关注的问题之一;并强调了将刻板印象回归应用于生物医学数据的必要性。本研究设想的分析计划显示了扩展有序回归模型使用的相关性和范围。
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引用次数: 2
Tree-based ensemble methods for individualized treatment rules 基于树的个性化治疗规则集成方法
Q3 Medicine Pub Date : 2018-01-01 DOI: 10.1080/24709360.2018.1435608
Kehao Zhu, Ying Huang, Xiao‐Hua Zhou
ABSTRACT There is a growing interest in the development of statistical methods for personalized medicine or precision medicine, especially for deriving optimal individualized treatment rules (ITRs). An ITR recommends a patient to a treatment based on the patient's characteristics. The common parametric methods for deriving an optimal ITR, which model the clinical endpoint as a function of the patient's characteristics, can have suboptimal performance when the conditional mean model is misspecified. Recent methodology development has cast the problem of deriving optimal ITR under a weighted classification framework. Under this weighted classification framework, we develop a weighted random forests (W-RF) algorithm that derives an optimal ITR nonparametrically. In addition, with the W-RF algorithm, we propose the variable importance measures for quantifying relative relevance of the patient's characteristics to treatment selection, and the out-of-bag estimator for the population average outcome under the estimated optimal ITR. Our proposed methods are evaluated through intensive simulation studies. We illustrate the application of our methods using data from Clinical Antipsychotic Trials of Intervention Effectiveness Alzheimer's Disease Study.
人们对个性化医疗或精准医疗统计方法的发展越来越感兴趣,特别是对获得最佳个性化治疗规则(itr)的统计方法。ITR会根据患者的特点向患者推荐治疗方案。常用的参数化方法是将临床终点作为患者特征的函数来建模,当条件平均模型被错误指定时,用于推导最佳ITR的常用参数化方法可能具有次优性能。最近的方法发展将最优ITR的推导问题置于加权分类框架下。在此加权分类框架下,我们开发了一种加权随机森林(W-RF)算法,该算法非参数地推导出最优ITR。此外,通过W-RF算法,我们提出了用于量化患者特征与治疗选择的相对相关性的变量重要性度量,以及在估计的最优ITR下的总体平均结果的袋外估计。我们提出的方法是通过密集的模拟研究来评估的。我们使用阿尔茨海默病临床抗精神病药物干预有效性研究的数据来说明我们的方法的应用。
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引用次数: 2
Nonparametric estimation of medical cost quantiles in the presence of competing terminal events 存在竞争性终端事件时医疗费用分位数的非参数估计
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2017.1342185
Mei-Cheng Wang, Yifei Sun
ABSTRACT Medical care costs are commonly used by health policy-makers and decision-maker for evaluating health care service and decision on treatment plans. This type of data is commonly recorded in surveillance systems when inpatient or outpatient care service is provided. In this paper, we formulate medical cost data as a recurrent marker process, which is composed of recurrent events (inpatient or outpatient cares) and repeatedly measured marker measurements (medical charges). We consider nonparametric estimation of the quantiles of cost distribution among survivors in the absence or presence of competing terminal events. Statistical methods are developed for quantile estimation of the cost distribution for the purposes of evaluating cost performance in relation to recurrent events, marker measurements and time to the terminal event for different competing risk groups. The proposed approaches are illustrated by an analysis of data from the Surveillance, Epidemiology, and End Results (SEER) and Medicare linked database.
医疗费用是卫生政策制定者和决策者用于评估医疗服务和决定治疗计划的常用费用。当提供住院或门诊护理服务时,这种类型的数据通常记录在监控系统中。在本文中,我们将医疗成本数据公式化为一个重复标记过程,该过程由重复事件(住院或门诊护理)和重复测量的标记测量(医疗费用)组成。我们考虑在没有或存在竞争性终端事件的情况下,幸存者之间成本分布分位数的非参数估计。开发了用于成本分布分位数估计的统计方法,目的是评估与不同竞争风险组的复发事件、标志物测量和终点事件时间相关的成本效益。通过对监测、流行病学和最终结果(SEER)和医疗保险相关数据库的数据分析,说明了所提出的方法。
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引用次数: 0
Statistical considerations for assessing cognition and neuropathology associations in preclinical Alzheimer's disease 评估临床前阿尔茨海默病的认知和神经病理学关联的统计学考虑
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2017.1342186
M. Malek-Ahmadi, E. Mufson, S. Perez, Kewei Chen
ABSTRACT Analysis of the associations between the neuropathology of Alzheimer's disease (AD) and cognition has become a major area of investigation as both basic and clinical researchers have turned their attention toward identifying the factors underlying the onset of preclinical AD. Here we provide a conceptual overview of statistical approaches for analyzing associations between cognition and AD neuropathology in the context of the prodromal AD. The review will discuss a variety of statistical approaches, their application to various clinical pathological variables, and research questions, as well as the importance of accounting for and including interaction terms in statistical models. The overview presented here will introduce data analysts and statisticians to the nomenclature of AD neuropathology and provide relevant background information regarding the nature of cognitive and neuropathological data generated in the investigation of preclinical AD. In addition, we will introduce a number of statistical approaches that researchers who specialize in AD neuropathology may utilize in their studies. For both audiences, this review will provide an applied statistical framework to draw from for future research.
摘要分析阿尔茨海默病(AD)的神经病理学与认知之间的关系已成为一个主要的研究领域,因为基础和临床研究人员都将注意力转向了识别临床前AD发病的潜在因素。在这里,我们对在前驱AD的背景下分析认知和AD神经病理学之间关系的统计方法进行了概念概述。这篇综述将讨论各种统计方法,它们在各种临床病理变量中的应用,以及研究问题,以及在统计模型中考虑和包括相互作用项的重要性。本文概述将向数据分析师和统计学家介绍AD神经病理学的命名,并提供有关临床前AD研究中产生的认知和神经病理学数据性质的相关背景信息。此外,我们将介绍一些专门研究AD神经病理学的研究人员可能在研究中使用的统计方法。对于这两个受众来说,这篇综述将为未来的研究提供一个实用的统计框架。
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引用次数: 5
Joint modeling of longitudinal cholesterol measurements and time to onset of dementia in an elderly African American Cohort 纵向胆固醇测量和老年非裔美国人痴呆发病时间的联合建模
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2017.1381300
Shanshan Li, Mengjie Zheng, Sujuan Gao
ABSTRACT This paper presents a statistical method for analyzing the association between longitudinal cholesterol measurements and the timing of onset of dementia. The proposed approach jointly models the longitudinal and survival processes for each individual on the basis of a shared random effect, where a linear mixed effects model is assumed for the longitudinal component and an extended Cox regression model is employed for the survival component. A dynamic prediction model is built based on the joint model, which provides prediction of the conditional survival probabilities at different time points using available longitudinal measurements as well as baseline characteristics. We apply our method to the Indianapolis-Ibadan Dementia project, a 20-year study of dementia in elderly African Americans living in Indianapolis, Indiana. We find that with baseline covariates and comorbidities adjusted, the risk of dementia decreases by 1% per one mg/dl increase in total cholesterol. Therefore we conclude that, in a healthy cohort of African Americans aged 65 years or more, high late-life cholesterol level is associated with lower incidence of dementia.
摘要本文提出了一种统计方法来分析纵向胆固醇测量与痴呆发病时间之间的关系。所提出的方法在共享随机效应的基础上联合建模每个个体的纵向和生存过程,其中假设纵向分量采用线性混合效应模型,生存分量采用扩展的Cox回归模型。基于联合模型建立了动态预测模型,该模型使用可用的纵向测量以及基线特征来预测不同时间点的条件生存概率。我们将我们的方法应用于印第安纳波利斯-伊巴丹痴呆症项目,这是一项对居住在印第安纳州印第安纳波利斯的老年非裔美国人痴呆症的20年研究。我们发现,调整基线协变量和合并症后,总胆固醇每增加1 mg/dl,患痴呆症的风险就会降低1%。因此,我们得出结论,在65岁或65岁以上的非裔美国人的健康队列中,晚年胆固醇水平高与痴呆症的发病率低有关。
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引用次数: 2
Using time-varying quantile regression approaches to model the influence of prenatal and infant exposures on childhood growth 使用时变分位数回归方法模拟产前和婴儿暴露对儿童生长的影响
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2017.1358137
Ying Wei, Xinran Ma, Xinhua Liu, M. Terry
ABSTRACT For many applications, it is valuable to assess whether the effects of exposures over time vary by quantiles of the outcome. We have previously shown that quantile methods complement the traditional mean-based analyses, and are useful for studies of body size. Here, we extended previous work to time-varying quantile associations. Using data from over 18,000 children in the U.S. Collaborative Perinatal Project, we investigated the impact of maternal pre-pregnancy body mass index (BMI), maternal pregnancy weight gain, placental weight, and birth weight on childhood body size measured 4 times between 3 months and 7 years, using both parametric and non-parametric time-varying quantile regressions. Using our proposed model assessment tool, we found that non-parametric models fit the childhood growth data better than the parametric approaches. We also observed that quantile analysis resulted in difference inferences than the conditional mean models in three of the four constructs (maternal per-pregancy BMI, maternal weight gain, and placental weight). Overall, these results suggest the utility of applying time-varying quantile models for longitudinal outcome data. They also suggest that in the studies of body size, merely modelling the conditional mean may lead to incomplete summary of the data.
摘要在许多应用中,评估暴露的影响是否随时间的推移而随结果的分位数而变化是很有价值的。我们之前已经表明,分位数方法补充了传统的基于均值的分析,对体型研究很有用。在这里,我们将先前的工作扩展到时变分位数关联。利用来自美国围产期合作项目18000多名儿童的数据,我们使用参数和非参数时变分位数回归,研究了母亲孕前体重指数(BMI)、母亲妊娠体重增加、胎盘重量和出生体重对儿童体型的影响,这些影响在3个月至7岁之间测量了4次。使用我们提出的模型评估工具,我们发现非参数模型比参数方法更适合儿童成长数据。我们还观察到,分位数分析在四种结构中的三种结构(母体每孕体重指数、母体体重增加和胎盘重量)中产生了与条件平均值模型不同的推断。总的来说,这些结果表明了将时变分位数模型应用于纵向结果数据的效用。他们还表示,在体型研究中,仅仅对条件平均值进行建模可能会导致数据汇总不完整。
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引用次数: 2
Editorial 社论
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2016.1198464
Xiaohong Zhou
Dear Readers, We are delighted to announce the launch of Biostatistics & Epidemiology as the official journal of the International Biometric Society Chinese region. The International Biometric Society Chinese Region was founded in 2012, with the support of the International Biometric Society, and has grown strongly since then, becoming a focus of biostatistical and epidemiological research in China and beyond. The growth of this community has reached the point where the launch of a dedicated and top-quality peerreviewed research journal is necessary and warranted. Below, we outline the mission and scope of the Journal, along with the review process. The Journal aims to provide a platform for the dissemination of new statistical methods and the promotion of good analytical practices in biomedical investigation and epidemiology. The Journal has four main sections:
亲爱的读者们,我们很高兴地宣布《生物统计学与流行病学》作为国际生物识别学会中文区的官方期刊正式出版。国际生物识别学会中国区成立于2012年,在国际生物识别协会的支持下,自那时以来发展迅速,成为中国及其他地区生物统计学和流行病学研究的焦点。这个社区的发展已经到了推出一本专门的、高质量的同行评审研究期刊的必要性和必要性的地步。下面,我们概述了《日刊》的使命和范围,以及审查过程。该杂志旨在为传播新的统计方法和促进生物医学调查和流行病学方面的良好分析做法提供一个平台。《华尔街日报》有四个主要部分:
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引用次数: 0
A tutorial on kernel density estimation and recent advances 一个关于核密度估计和最新进展的教程
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2017.1396742
Yen-Chi Chen
ABSTRACT This tutorial provides a gentle introduction to kernel density estimation (KDE) and recent advances regarding confidence bands and geometric/topological features. We begin with a discussion of basic properties of KDE: the convergence rate under various metrics, density derivative estimation, and bandwidth selection. Then, we introduce common approaches to the construction of confidence intervals/bands, and we discuss how to handle bias. Next, we talk about recent advances in the inference of geometric and topological features of a density function using KDE. Finally, we illustrate how one can use KDE to estimate a cumulative distribution function and a receiver operating characteristic curve. We provide R implementations related to this tutorial at the end.
本教程简要介绍了核密度估计(KDE)以及有关置信带和几何/拓扑特征的最新进展。我们首先讨论KDE的基本性质:在各种度量下的收敛速率、密度导数估计和带宽选择。然后,我们介绍了构建置信区间/频带的常用方法,并讨论了如何处理偏差。接下来,我们将讨论使用KDE推断密度函数的几何和拓扑特征方面的最新进展。最后,我们说明了如何使用KDE来估计累积分布函数和接收者工作特性曲线。我们在最后提供与本教程相关的R实现。
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引用次数: 281
Analysis of progressive multi-state models with misclassified states: likelihood and pairwise likelihood methods 状态分类错误的渐进式多状态模型分析:似然与两两似然方法
Q3 Medicine Pub Date : 2017-01-01 DOI: 10.1080/24709360.2017.1359356
G. Yi, Wenqing He, Feng He
ABSTRACT Multi-state models are commonly used in studies of disease progression. Methods developed under this framework, however, are often challenged by misclassification in states. In this article, we investigate issues concerning continuous-time progressive multi-state models with state misclassification. We develop inference methods using both the likelihood and pairwise likelihood methods that are based on joint modelling of the progressive and misclassification processes. We assess the performance of the proposed methods by simulation studies, and illustrate their use by the application to the data arising from a coronary allograft vasculopathy study.
多状态模型常用于疾病进展的研究。然而,在这一框架下开发的方法经常受到各州分类错误的挑战。本文研究了具有状态误分类的连续时间渐进多状态模型问题。我们使用基于渐进和错误分类过程的联合建模的似然和成对似然方法开发推理方法。我们通过模拟研究评估所提出的方法的性能,并通过应用于冠状动脉异体移植血管病变研究的数据来说明它们的使用。
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引用次数: 0
期刊
Biostatistics and Epidemiology
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