Analyzing sequentially randomized trials based on causal effect models for realistic individualized treatment rules.

abstract：:Frailty models are encountered in many medical applications, yet little research has been devoted to develop measures that quantify the predictive ability of these models. In this paper, we elaborate on the concept of the concordance probability to clustered data, resulting in an 'Overall Conditional C-index' or bfC(O...

journal_title：Statistics in medicine

authors： Van Oirbeek R,Lesaffre E

更新日期：2010-12-30 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

authors： Chu H,Nie L,Kensler TW

更新日期：2008-06-15 00:00:00

abstract：:The log-rank test is the most powerful non-parametric test for detecting a proportional hazards alternative and thus is the most commonly used testing procedure for comparing time-to-event distributions between different treatments in clinical trials. When the log-rank test is used for the primary data analysis, the s...

journal_title：Statistics in medicine

authors： Zhang D,Quan H

更新日期：2009-02-28 00:00:00

abstract：:The analysis of repeated measures data can be conducted efficiently using a two-level random coefficients model. A standard assumption is that the within-individual (level 1) residuals are uncorrelated. In some cases, especially where measurements are made close together in time, this may not be reasonable and this ad...

journal_title：Statistics in medicine

authors： Goldstein H,Healy MJ,Rasbash J

更新日期：1994-08-30 00:00:00

abstract：:Determination of the equation that relates an ordered dependent variable to ordered independent variables is sought. One solution, non-parametric discriminant analysis (NPD), involves obtaining the best monotonic step function by means of a computer search procedure. Although one can use alternative selection criteria...

journal_title：Statistics in medicine

authors： Johnston B,Seshia SS

更新日期：1992-06-15 00:00:00

abstract：:The principles and historical development of clinical trials are outlined briefly. Some issues that extend the basic philosophy first put forward by Sir Austin Bradford Hill 40 years ago and that will need consideration in the future application of clinical trials are discussed. ...

journal_title：Statistics in medicine

authors： Holland WW,Breeze E,Swan AV

更新日期：1982-10-01 00:00:00

abstract：:Exploring the possible reasons for heterogeneity between studies is an important aspect of conducting a meta-analysis. This paper compares a number of methods which can be used to investigate whether a particular covariate, with a value defined for each study in the meta-analysis, explains any heterogeneity. The main ...

journal_title：Statistics in medicine

authors： Thompson SG,Sharp SJ

更新日期：1999-10-30 00:00:00

abstract：:In many community-based studies on the incidence of dementia, a target population is screened and a subsample is clinically evaluated at baseline and follow-up. Incidence rates are affected by missed cases at both exams and this complicates the estimation of these rates. Recent work proposes a regression-based techniq...

journal_title：Statistics in medicine

authors： Izmirlian G,Brock D,White L

更新日期：2000-06-15 00:00:00

abstract：:Although transportation safety has greatly improved over the past 2 decades, motor vehicle crash injuries remain a leading cause of morbidity and mortality, particularly among young drivers. Driver errors and behaviors such as speeding and distraction contribute disproportionately to crashes among inexperienced novice...

journal_title：Statistics in medicine

authors： Simons-Morton B

更新日期：2017-10-30 00:00:00

abstract：:We consider the analysis of serial biomarkers to screen and monitor individuals in a given population for onset of a specific disease of interest. The biomarker readings are subject to error. We survey some of the existing literature and concentrate on two recently proposed models. The first is a fully Bayesian hierar...

journal_title：Statistics in medicine

authors： Slate EH,Turnbull BW

更新日期：2000-02-29 00:00:00

abstract：:We consider counting process methods for analysing time-to-event data with multiple or recurrent outcomes, using the models developed by Anderson and Gill, Wei, Lin and Weissfeld and Prentice, Williams and Peterson. We compare the methods, and show how to implement them using popular statistical software programs. By ...

journal_title：Statistics in medicine

authors： Therneau TM,Hamilton SA

更新日期：1997-09-30 00:00:00

abstract：:Although radical changes in drug regulation are rare (e.g., the Federal Food, Drug and Cosmetic Act of 1938 and the 1962 amendment to the Act creating an effectiveness requirement), regulations and guidance do evolve significantly in the face of new problems and accumulating experience. Recent changes have been driven...

journal_title：Statistics in medicine

authors： Temple R

更新日期：2002-10-15 00:00:00

abstract：:In this paper statistical methods are proposed to estimate the distribution of a CD4 T-cell number at the time of a clinical AIDS endpoint from serial measurements of CD4 T-cell values in a cohort study. The statistical formulation of the problem is that of survival analysis with interval censored data, but in which t...

journal_title：Statistics in medicine

authors： Taylor JM,Kim DK

更新日期：1994-10-15 00:00:00

abstract：:In this paper, we discuss family-based association test (FBATs) relating genetic data to survival and time-to-onset data. We show how the standard logrank and Wilcoxon statistics can be used with family data to develop tests of association. We prove that the FBAT-logrank approach can be identical to the proportional h...

journal_title：Statistics in medicine

authors： Lange C,Blacker D,Laird NM

更新日期：2004-01-30 00:00:00

abstract：:We propose a two-step procedure to personalize drug dosage over time under the framework of a log-linear mixed-effect model. We model patients' heterogeneity using subject-specific random effects, which are treated as the realizations of an unspecified stochastic process. We extend the conditional quadratic inference ...

journal_title：Statistics in medicine

authors： Zhu X,Qu A

更新日期：2016-10-30 00:00:00

abstract：:We develop analysis methods for clinical trials with time-to-event outcomes which correct for treatment changes during follow-up, yet are based on comparisons of randomized groups and not of selected groups. A causal model relating observed event times to event times that would have been observed under other treatment...

journal_title：Statistics in medicine

authors： White IR,Babiker AG,Walker S,Darbyshire JH

更新日期：1999-10-15 00:00:00

abstract：:Generalized relative and absolute risk models, in which various functions of time and age modify the excess relative or absolute risk of radiation-induced cancer, are fitted to the Japanese atomic bomb survivor cancer incidence data set. Among generalized relative risk models, those in which a product of powers of tim...

journal_title：Statistics in medicine

authors： Little MP,Muirhead CR,Charles MW

更新日期：1999-01-15 00:00:00

abstract：:Longitudinal studies are often concerned with estimating the recurrence rate of a non-fatal event. In many cases, only the total number of events occurring during successive time intervals is known. We compared a mixed Poisson-gamma regression method proposed by Thall and a quasi-likelihood method proposed by Zeger an...

journal_title：Statistics in medicine

authors： Stukel TA

更新日期：1993-07-30 00:00:00

abstract：:Longitudinal studies are commonly used to study processes of change. Because data are collected over time, missing data are pervasive in longitudinal studies, and complete ascertainment of all variables is rare. In this paper a new imputation strategy for completing longitudinal data sets is proposed. The proposed met...

journal_title：Statistics in medicine

authors： Landrum MB,Becker MP

更新日期：2001-09-15 00:00:00

abstract：:Treatment effects for multiple outcomes can be meta-analyzed separately or jointly, but no systematic empirical comparison of the two approaches exists. From the Cochrane Library of Systematic Reviews, we identified 45 reviews, including 1473 trials and 258,675 patients, that contained two or three univariate meta-ana...

journal_title：Statistics in medicine

authors： Trikalinos TA,Hoaglin DC,Schmid CH

更新日期：2014-04-30 00:00:00

abstract：:Standard approaches to analysis of randomized controlled trials (RCTs) using Markov models make it difficult to generalize treatment effects to new patient groups and synthesize evidence across trials. This paper demonstrates how pair-wise and mixed treatment comparison meta-analysis can be applied to event history da...

journal_title：Statistics in medicine

authors： Price MJ,Welton NJ,Ades AE

更新日期：2011-01-30 00:00:00

abstract：:Having a surrogate for a definitive endpoint in a clinical trial can sometimes be useful when it is impractical, invasive or very time consuming to obtain the definitive endpoint. This paper discusses methods for assessing whether the surrogate-endpoint results of a trial can be used in place of definitive-endpoint re...

journal_title：Statistics in medicine

authors： Korn EL,Albert PS,McShane LM

更新日期：2005-01-30 00:00:00

abstract：:This article concerns construction of a confidence surface for tangential slopes of the dose-response surface of a combination therapy to identify where response increases as a function of drug dosage. This approach extends to the assessment of the effectiveness of the combination therapy. ...

journal_title：Statistics in medicine

authors： Hung HM

更新日期：1992-03-01 00:00:00

abstract：:In medical research, risk difference (RD) and number needed to treat (NNT) measures for survival times have been mainly proposed without consideration of covariates. In this paper, we develop adjusted RD and NNT measures for use in observational studies with survival time outcomes within the framework of the Cox propo...

journal_title：Statistics in medicine

authors： Laubender RP,Bender R

更新日期：2010-03-30 00:00:00

abstract：:Kappa coefficients are measures of correlation between categorical variables often used as reliability or validity coefficients. We recapitulate development and definitions of the K (categories) by M (ratings) kappas (K x M), discuss what they are well- or ill-designed to do, and summarize where kappas now stand with ...

journal_title：Statistics in medicine

authors： Chmura Kraemer H,Periyakoil VS,Noda A

更新日期：2002-07-30 00:00:00

abstract：:The recent revision of the Declaration of Helsinki and the existence of many new therapies that affect survival or serious morbidity, and that therefore cannot be denied patients, have generated increased interest in active-control trials, particularly those intended to show equivalence or non-inferiority to the activ...

journal_title：Statistics in medicine

authors： Rothmann M,Li N,Chen G,Chi GY,Temple R,Tsou HH

更新日期：2003-01-30 00:00:00

abstract：:One is often interested in the ratio of two variables, for example in genetics, assessing drug effectiveness, and in health economics. In this paper, we derive an explicit geometric solution to the general problem of identifying the two tangents from an arbitrary external point to an ellipse. This solution permits num...

journal_title：Statistics in medicine

authors： Walter SD,Gafni A,Birch S

更新日期：2008-12-10 00:00:00

abstract：:Clinical trials often assess efficacy by comparing treatments on the basis of two or more event-time outcomes. In the case of cancer clinical trials, progression-free survival (PFS), which is the minimum of the time from randomization to progression or to death, summarizes the comparison of treatments on the hazards f...

journal_title：Statistics in medicine

authors： Finkelstein DM,Schoenfeld DA

更新日期：2014-05-30 00:00:00

abstract：:We applied a computationally practical form of probit analysis for multiple response variables to data on early childhood development of four psychiatric disorders: disruptive disorders (DD-attention deficit disorders, oppositional defiant disorder, conduct disorder); adjustment disorders (ADJ); emotional disorders (E...

journal_title：Statistics in medicine

authors： Gibbons RD,Lavigne JV

更新日期：1998-11-15 00:00:00

abstract：:The goal of phase I cancer trials is to determine the highest dose of a treatment regimen with an acceptable toxicity rate. Traditional designs for phase I trials, such as the Continual Reassessment Method (CRM) and the 3 + 3 design, require each patient or a cohort of patients to be fully evaluated for the dose-limit...

journal_title：Statistics in medicine

authors： Polley MY

更新日期：2011-07-30 00:00:00