用ROC曲线确定最佳临界点和可疑值范围

目的：使用ROC曲线法，评价某试剂盒对冠心病的诊断价值，明确针对本试剂盒的诊断临界点，并探讨用ROC曲线法确定可疑值范围。方法：根据冠脉造影结合临床确定的正常组508例和冠心病组176例测定的某血浆指标含量，绘制ROC曲线。结果：ROC曲线下面积为0．9723，并有统计学意义，说明该试剂盒有较高的诊断价值。通过ROC曲线，确定诊断临界点为40．70U／L，并具有较高的灵敏度和特异度，可疑值范围为(36．90，47．80)U／L，一致性检验结果较好。结论：使用ROC曲线评价具有简单有效，并可用来确定诊断试验的敏感度及可疑值范围。     

列联表资料的对数线性模型与Logistic回归模型分析对比

目的: 对处理列联表资料的对数线性模型的Logistic回归模型进行了分析对比。方法: 对两模型的特色、理论联系、及某些不同之处进行了讨论。结果: 采用两种模型对同一组资料分析结果一致。结论: 对数线性模型与Logistic回归模型理论联系密切。虽然对同组资料分析结果一致, 但在有些情况下, 如针对不同资料, 不同的分析目的需选择与之相适合的模型分析     

INTERVAL CENSORED SURVIVAL DATA: A GENERALIZED LINEAR MODELLING APPROACH

A method is described for weak parametric modelling of arbitrarily interval censored survival data using generalized linear models. The method makes use of an associated Bernoulli model, with standard errors based on the observed information matrix. Three types of models are discussed: additive and multiplicative hazard models with piecewise constant baseline hazard, and a proportional hazards model with discrete baseline survivor function. These models may be fitted in the statistical package GLIM.     

混合线性模型在临床试验中重复测量资料的应用

目的：探讨混合线性模型在临床试验重复测量资料分析中的应用。方法：利用混合线性模型分析结果指标为定量资料的重复测量资料，通过参数和标准误的估计得出统计学结论。结果：对于临床试验重复测量资料，混合线性模型能有效的考虑数据相关性，处理有缺失值的资料，可以获得组别、时间及有无交互作用的结论。结论：采用混合线性模型对临床试验重复测量资料进行统计分析，可以更客观的进行药物疗效评价。     

ROBUST PROCEDURES FOR ANALYSING A TWO-PERIOD CROSS-OVER DESIGN WITH BASELINE MEASUREMENTS

Patel analysed a two-period cross-over design with baseline measurements assuming bivariate normality for the joint distribution of the period responses. In this paper, we propose non-parametric methods for analysing this design, including the use of the Wilcoxon rank sum test to derive the preliminary tests from the baseline measurements. We fit a robust regression line of the treatment response on baseline for each period and compute residuals. We also fit a robust locally weighted regression as an alternative method for computing residuals. Then, following Koch's procedure, we analyse the residuals for testing the significance of the treatment × period interaction and the treatment difference. We provide a numerical example to illustrate the methods.     

A COMPARATIVE STUDY OF FOUR METHODS FOR ANALYSING REPEATED MEASURES DATA

This paper compares four alternative statistical methods for the analysis of repeated measures data. The data set involves fatty acid composition of red blood cell membrane examined after acute MI and is characterized by a moderate sample size, unbalanced repeated measures and high within-individual correlations. Two methods are based on individual curve fitting and two on the random effects model. Results yielded by the four methods differed. The advantages and disadvantages of the methods are discussed. Assumptions required for the valid application of these methods are tested.     

A SIMPLE METHOD FOR COMPARING CORRELATED ROC CURVES USING INCOMPLETE DATA

Comparative studies of the accuracy of diagnostic procedures often use a paired design to gain in efficiency. Standard methods for analysing data from paired designs require complete observations. In many studies, however, one of the test results may be missing for some patients. In this paper, we propose a simple correction to the existing complete data methods to compare areas under ROC curves derived from paired designs. The approach makes it possible to use the entire available data set in carrying out the comparison, provided that the probability of having both tests does not depend on the test results. As an illustration, we apply our method to the analysis of data from prospective comparison of MRI and ultrasound in detecting periprostatic invasion.     

A COMPARISON OF DIFFERENT APRROACHES FOR FITTING CENTILE CURVES TO BIRTHWEIGHT DATA

Centile charts, plotted by week of gestational age, are widely used clinically to decide whether a child is ‘small-for-dates’, indicating that there may have been some cause of intra-uterine growth retardation. A variety of different statistical techniques have been proposed for constructing centile charts. Some methods are distribution free and work on the basis of obtaining and then smoothing the empirical centiles. In others the centiles are calculated assuming a Normal distribution either of the raw data or of transformed data. In Scotland the details of each maternity admission are entered onto an SMR2 form and these records are stored centrally by the Scottish Health Service. A data set consisting of all live births occurring in Scottish hospitals between 1980 and 1992 is used to compare different approaches to constructing centile charts.     

A MODEL FOR INTERVAL-CENSORED TUBERCULOSIS OUTBREAK DATA

As the incidence of tuberculosis (TB) has increased in the United States, occupationally acquired TB has increased among the health care workers (HCWs). This paper describes a model developed in response to the needs of an outbreak of multidrug-resistant TB. One of the goals of the outbreak investigation was to estimate the risk of tuberculin skin test (TST) conversion as a function of HCW job type and the period during which persons were employed over the study period. TST conversions were evaluated at periodic examinations and data are interval-censored. We present a generalized linear model that extends Efron's survival model for censored survival data to the case of interval-censored data. © 1997 by John Wiley & Sons, Ltd. © 1997 by John Wiley & Sons, Ltd.     

A MODEL FOR CROSS-OVER TRIALS EVALUATING THERAPEUTIC PREFERENCES

A preference trial is a special form of cross-over trial where clinical conditions determine when patients change treatment, in a prescribed order. This can be modelled using a geometric distribution. The model can be simply fitted using standard logistic regression methodology. The procedure is applied to a trial studying the effects of bronchodilators in the treatment of chronic asthma.     

以导师为中心的OEC模式在手术室新护士培训中的应用

目的探讨以导师为中心的OEC模式在手术室新护士培训效果,为手术室新护士的入职培训教育提供依据。方法将2008～2010年新毕业的手术室护士分为实验组和对照组,对照组给予常规＂三基＂培训模式,实验组给予以导师为中心的OEC培训模式,保证手术室护理工作的有效性和适宜性,通过基础理论考核、操作考核和业务能力考核进行比较分析。结果实施以导师为中心的OEC模式后,实验组的手术室新护士在基础理论考核、操作考核和业务能力考核方面明显高于对照组（p〈0.05）。结论以导师为中心的OEC模式在手术室新护士培训中能明显提高手术室新护士的理论、操作和业务水平及术科医生的满意度,同时也提高了导师的管理能力和带教的责任心值得临床推广应用。在手术室新护士入职培训教育中值得进一步推广。     

A FUNCTIONAL DECLINE MODEL FOR PREVALENT COHORT DATA

Longitudinal designs are often used for studying the natural history of diseases. Data sets typically consist of short series of repeated measures on prevalent cases. We propose a growth model approach to the analysis of follow-up data to describe functional decline and associated risk factors in disease progression. We illustrate the model with an application to longitudinal data that describe the time-evolution of cognitive decline in a cohort of patients with Alzheimer's disease.     

USE OF A STOCHASTIC MODEL FOR REPEATED BINARY ASSESSMENT

We discuss a stochastic model appropriate for binary data in clinical studies where assessments are made at various nominal times during a treatment phase. The model is then applied to data on headache relief, nausea and photophobia/phonophobia in a migraine study. The transition rates and probabilities during the initial 240 minutes after treatment administration are derived using the method of maximum likelihood. The results are then compared with analysis at each nominal time point. Stochastic modelling is considered more appropriate for the analysis of repeated binary assessments than analysis at each nominal time since each patient's assessments are modelled simultaneously.     

CYCLOLEUCINE, A NEW MODEL FOR AMINO ACID TRANSFER

1-Aminocyclopentane-1-carboxylic acid is essentially nonmetabolizable in the animal body but appears to reflect closely transfer processes for the common neutral amino acids.     

黄酮类化合物抗氧化活性的Free-Wilson模型

目的建立18种黄酮类化合物抗氧化活性(lgTEAC)和分子结构的定量构效关系模型。方法采用Free-Wilson法产生黄酮类化合物分子的结构参数(Xij),运用最佳变量子集回归法建立抗氧化活性的4参数(X2,X4,X5,X6)的Free-Wilson模型。结果所建QSAR模型的相关系数(R)及估计误差(S)依次为0.952、0.071,通过Fischer和VIF检验,具有良好的稳健性和预测能力。结论根据进入模型的4个参数可知,A环、B环上羟基是影响黄酮类衍生物抗氧化活性的主要因素。[营养学报,2012,34(4):392-394,399]     

分析季节性波动的新模型（1）

现有的各种季节性统计方法几乎都以正弦曲线作模型，只适应于对称单峰分布且波幅较小的特殊资料，对客观存在的大量不服从这种分布的资料，虽有人作过尝试，但尚未找到合适的统计分析方法。本文提出用混合ｖｏｎ Ｍｉｓｅｓ分布作季节性分析，并推导出估计极大似然参数的搜索迭代法，统计推断采用似然比统计量。模型分析和实验验证都表明：本文方法不仅能用于单峰偏态分布、一般双峰分布的季节性分析，而且对单峰对称分布资料也可