解剖学和形态学
麻醉学
听力与言语-语言病理学
行为科学
心脏和心血管系统
细胞和组织工程学
临床神经病学
危重症监护医学
牙科,口腔外科和医学
皮肤病学
急诊医学
内分泌学和新陈代谢
肠胃学和肝脏学
老人病学和老年医学
卫生保健科学和服务
血液学
免疫学
传染病
综合和补充性医学
医学伦理学
医学信息学
医学实验室技术
医学,全科和内科
医学,法律
医学,研究和试验
神经系统科学
护理
营养学和饮食学
产科医学和妇科医学
肿瘤学
眼科学
整形外科学
耳鼻喉科学
病理学
儿科学
周围血管疾病
药理学和药剂学
生理学
基本医疗保健
精神病学
公共、环境和职业卫生
放射学,核医学和医学成像
康复学
生殖生物学
呼吸系统
风湿病学
运动科学
外科学
毒理学
热带医学
泌尿学和肾脏学
病毒学
老年医学
健康政策和服务
心理学,临床
abstract::This article deals with determination of a sample size that guarantees the success of a trial. We follow a Bayesian approach and we say an experiment is successful if it yields a large posterior probability that an unknown parameter of interest (an unknown treatment effect or an effects-difference) is greater than a c...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3175
更新日期:2008-06-15 00:00:00
abstract::Often in randomized clinical trials and observational studies in occupational and environmental health, a non-negative continuously distributed response variable denoting some metabolites of environmental toxicants is measured in treatment and control groups. When observations occur in both unexposed and exposed subje...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3170
更新日期:2008-06-15 00:00:00
abstract::Many critical questions in medicine require the analysis of complex multivariate data, often from large data sets describing numerous variables for numerous subjects. In this paper, we describe CoPlot, a tool for visualizing multivariate data in medicine. CoPlot is an adaptation of multidimensional scaling (MDS) that ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3078
更新日期:2008-05-30 00:00:00
abstract::Members of a cohort of workers in chemical industry (the so-called Boehringer cohort) exposed to 2, 3, 7, 8-tetrachlorodibenzo-para-dioxin (TCDD) from 1950 to 1984 were subject in the years 1985-1986 and 1992-1994 to an extensive biomonitoring programme on the TCDD levels of the individual workers. For establishing a ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3074
更新日期:2008-05-30 00:00:00
abstract::We consider Cox proportional hazards regression when the covariate vector includes error-prone discrete covariates along with error-free covariates, which may be discrete or continuous. The misclassification in the discrete error-prone covariates is allowed to be of any specified form. Building on the work of Nakamura...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3159
更新日期:2008-05-20 00:00:00
abstract::Parameters for latent transition analysis (LTA) are easily estimated by maximum likelihood (ML) or Bayesian method via Markov chain Monte Carlo (MCMC). However, unusual features in the likelihood can cause difficulties in ML and Bayesian inference and estimation, especially with small samples. In this study we explore...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3130
更新日期:2008-05-20 00:00:00
abstract::Adaptive designs have been proposed for clinical trials in which the nuisance parameters or alternative of interest are unknown or likely to be misspecified before the trial. Although most previous works on adaptive designs and mid-course sample size re-estimation have focused on two-stage or group-sequential designs ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3201
更新日期:2008-05-10 00:00:00
abstract::We consider evaluation and comparison of the diagnostic accuracy of biomarkers with continuous test outcomes, possibly correlated due to repeated measurements. We develop nonparametric group sequential testing procedures to evaluate and compare the area of biomarkers under their receiver operating characteristic curve...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3203
更新日期:2008-05-10 00:00:00
abstract::We consider a general model for anomaly detection in a longitudinal cohort mortality pattern based on logistic joinpoint regression with unknown joinpoints. We discuss backward and forward sequential procedures for selecting both the locations and the number of joinpoints. Estimation of the model parameters and the se...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3017
更新日期:2008-04-30 00:00:00
abstract::In analysis of longitudinal data, the variance matrix of the parameter estimates is usually estimated by the 'sandwich' method, in which the variance for each subject is estimated by its residual products. We propose smooth bootstrap methods by perturbing the estimating functions to obtain 'bootstrapped' realizations ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3027
更新日期:2008-03-30 00:00:00
abstract::Inference for randomized clinical trials is generally based on the assumption that outcomes are independently and identically distributed under the null hypothesis. In some trials, particularly in infectious disease, outcomes may be correlated. This may be known in advance (e.g. allowing randomization of family member...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2977
更新日期:2008-03-15 00:00:00
abstract::Identification of key factors associated with the risk of developing cardiovascular disease and quantification of this risk using multivariable prediction algorithms are among the major advances made in preventive cardiology and cardiovascular epidemiology in the 20th century. The ongoing discovery of new risk markers...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2929
更新日期:2008-01-30 00:00:00
abstract::During a course of human immunodeficiency virus (HIV-1) infection, the viral load usually increases sharply to a peak following infection and then drops rapidly to a steady state, where it remains until progression to AIDS. This steady state is often referred to as the viral set point. It is believed that the HIV vira...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3038
更新日期:2008-01-15 00:00:00
abstract::In clinical research, we are often interested in assessing how a biomarker changes with time, and whether it could be used as a surrogate marker when evaluating the efficacy of a new drug. However, when the longitudinal marker is correlated with survival, linear mixed models for longitudinal data may be inappropriate....
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3142
更新日期:2007-12-30 00:00:00
abstract::The semi-Markov assumption emphasizes the importance of time spent in a state. In order to compute this type of multistate model, most transition times are always considered to be exactly identified or right censored. However, in the longitudinal analysis of chronic diseases, investigators are often confronted with in...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3100
更新日期:2007-12-30 00:00:00
abstract::The standard analysis of clinical trials stratified by centre is to include centres as fixed effects, but if many centres contribute small numbers of patients, this approach results in a loss of power. Assuming no treatment by centre interaction, we used simulation to examine power and coverage of confidence intervals...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3068
更新日期:2007-12-30 00:00:00
abstract::A popular method to control multiplicity in confirmatory clinical trials is to use a so-called hierarchical, or fixed sequence, test procedure. This requires that the null hypotheses are ordered a priori, for example, in order of clinical importance. The procedure tests the hypotheses in this order using alpha-level t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2905
更新日期:2007-12-10 00:00:00
abstract::Non-linear mixed-effects models (NLMEMs) are used to improve information gathering from longitudinal studies and are applied to treatment evaluation in disease-evolution studies, such as human immunodeficiency virus (HIV) infection. The estimation of parameters and the statistical tests are critical issues in NLMEMs s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2950
更新日期:2007-11-30 00:00:00
abstract::It has been well known that ignoring measurement error may result in substantially biased estimates in many contexts including linear and nonlinear regressions. For survival data with measurement error in covariates there has been extensive discussion in the literature with the focus being on the Cox proportional haza...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2892
更新日期:2007-11-20 00:00:00
abstract::A common problem encountered in many medical applications is the comparison of survival curves. Often, rather than comparison of the entire survival curves, interest is focused on the comparison at a fixed point in time. In most cases, the naive test based on a difference in the estimates of survival is used for this ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2864
更新日期:2007-10-30 00:00:00
abstract::Pearson's chi-squared, the likelihood-ratio, and Fisher-Freeman-Halton's test statistics are often used to test the association of unordered r x c tables. Asymptotical, exact conditional, or exact conditional with mid-p adjustment methods are commonly used to compute the p-value. We have compared test power and signif...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2839
更新日期:2007-10-15 00:00:00
abstract::Teaching statistics to medical students is a challenging and often unrewarding task. However, few would argue the need for statistics in the medical school curriculum. In recent years, there has been a growing call for teaching only statistical concepts in medical schools. We strongly oppose this opinion and offer an ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2906
更新日期:2007-10-15 00:00:00
abstract::Correlation analysis is widely used in biomedical and psychosocial research for assessing rater reliability, precision of diagnosis and accuracy of proxy outcomes. The popularity of longitudinal study designs has propelled the proliferation in recent years of new methods for longitudinal and other multi-level clustere...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2857
更新日期:2007-09-30 00:00:00
abstract::For robust detection performance, traditional control chart monitoring for biosurveillance is based on input data free of trends, day-of-week effects, and other systematic behaviour. Time series forecasting methods may be used to remove this behaviour by subtracting forecasts from observations to form residuals for al...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2835
更新日期:2007-09-30 00:00:00
abstract::The problem of evaluating an averaged functional magnetic resonance imaging (fMRI) response for repeated block design experiments was considered within a semiparametric regression model with autocorrelated residuals. We applied functional data analysis (FDA) techniques that use a least-squares fitting of B-spline expa...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2981
更新日期:2007-09-20 00:00:00
abstract::In drug-drug interaction (DDI) research, a two drug interaction is usually predicted by individual drug pharmacokinetics (PK). Although subject-specific drug concentration data from clinical PK studies on inhibitor/inducer or substrate's PK are not usually published, sample mean plasma drug concentrations and their st...
journal_title:Statistics in medicine
pub_type: 杂志文章,meta分析
doi:10.1002/sim.2837
更新日期:2007-09-10 00:00:00
abstract::The proposed guidelines for the assessment of the effect of new pharmaceutical agents on the QT interval (beginning of QRS complex to end of T wave on the electrocardiogram) are based on the maximum of a series over time of simple one-sided 95 per cent upper confidence bounds. This procedure is typically very conserva...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2826
更新日期:2007-09-10 00:00:00
abstract::In this paper we study the problem of variable selection for the proportional odds model, which is a useful alternative to the proportional hazards model and might be appropriate when the proportional hazards assumption is not satisfied. We propose to fit the proportional odds model by maximizing the marginal likeliho...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2833
更新日期:2007-09-10 00:00:00
abstract::In this article we develop flexible regression models in two respects to evaluate the influence of the covariate variables on the mixed Poisson and continuous responses and to evaluate how the correlation between Poisson response and continuous response changes over time. A scenario for dealing with regression models ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2776
更新日期:2007-09-10 00:00:00
abstract::In monitoring a clinical trial or other observational study with a survival endpoint, sometimes the numbers of patients entering and dying at each time point are presented, but the connections between them are kept confidential. Hence, the exact time to failure or censoring for each individual is missing. We refer to ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2819
更新日期:2007-08-30 00:00:00
abstract::A mediator acts as a third variable in the causal pathway between a risk factor and an outcome. In this paper, we consider the estimation of the mediation effect when the mediator is a binary variable. We give a precise definition of the mediation effect and examine asymptotic properties of five different estimators o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2730
更新日期:2007-08-15 00:00:00
abstract::Many split-mouth trials are characterized by the pairing of site-specific outcome and baseline data within each segment of a subject's mouth. However when the response variable of interest is binary, methods of statistical analysis for this design are not well developed. In this paper we present several analytic appro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2782
更新日期:2007-08-15 00:00:00
abstract::In an individually matched case-control study, effects of potential risk factors are ascertained through conditional logistic regression (CLR). Extension of CLR to situations with multiple disease or reference categories has been made through polychotomous CLR and is shown to be more efficient than carrying out separa...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2790
更新日期:2007-07-30 00:00:00
abstract::We study prevalence-dependent diagnostic accuracy measures, specifically, positive and negative predictive values. These measures permit an assessment of the clinical utility of diagnostic tests across populations with different disease prevalences. In many cases, prevalence may not be known with certainty and the eva...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2812
更新日期:2007-07-30 00:00:00
abstract::Meta-analyses of clinical trials are increasingly seeking to go beyond estimating the effect of a treatment and may also aim to investigate the effect of other covariates and how they alter treatment effectiveness. This requires the estimation of treatment-covariate interactions. Meta-regression can be used to estimat...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2768
更新日期:2007-07-10 00:00:00
abstract::Existing methods for power analysis for longitudinal study designs are limited in that they do not adequately address random missing data patterns. Although the pattern of missing data can be assessed during data analysis, it is unknown during the design phase of a study. The random nature of the missing data pattern ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2773
更新日期:2007-07-10 00:00:00
abstract::Confidence intervals for a standardized effect are derived after stabilizing the variance of the Welch t-statistic. Simulation studies demonstrate the viability of the resulting intervals for a wide range of parameter values and sample sizes as small as five. The methodology is extended to the combination of results f...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2751
更新日期:2007-06-30 00:00:00
abstract::In many medical and health studies, high-dimensional data are often encountered. Principal component analysis (PCA) is a commonly used technique to reduce such data to a few components that includes most of the information provided by the original data. However, PCA is known to be very sensitive to some abnormal obser...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2747
更新日期:2007-06-15 00:00:00
abstract::Models for infant growth have usually been based on parametric forms, commonly an exponential or similar model, which have been shown to fit poorly especially during the first year of life. An alternative approach is to use a non-parametric model, based on a shape invariant model (SIM), where a single function is tran...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2718
更新日期:2007-05-30 00:00:00
abstract::This paper develops methods of analysis for active extension clinical trials. Under this design, patients are randomized to treatment or placebo for a period of time (period 1), and then all patients receive treatment for an additional period of time (period 2). We assume a continuous outcome is measured at baseline a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2720
更新日期:2007-05-30 00:00:00