Abstract:
:Clustered grouped survival data arise naturally in clinical medicine and biological research. For example, in a randomized clinical trial, the variable of interest is the time to occurrence of a certain event with or without a new treatment and the data are collected from possibly correlated subjects from independent clusters. However it is sometimes impossible or too expensive to monitor the experimental subjects continuously. The subjects are examined regularly and the continuous survival data are thus grouped into a discrete time scale. With such a design, researchers are mainly interested in the effectiveness of the new treatment as well as the correlation among subjects from the same cluster, namely the intracluster correlation. This paper suggests a random effects approach to the estimation of the regression parameter with various choices of regression model and also the dependence parameter which characterizes the intracluster correlation. Time dependent covariates can be accommodated in the proposed model, and the estimation procedure will not be further complicated with large cluster sizes. The proposed method is applied to the data from the Diabetic Retinopathy Study, the objective of which is to evaluate the effectiveness of laser photocoagulation in delaying or preventing the onset of blindness in the left and right eyes of individuals with diabetes-associated retinopathy. The intracluster correlation using a grouped proportional hazards regression model can be estimated and the relationship between the regression parameter estimates based on the random effects approach and the marginal approach using a dynamic logistic regression model are discussed. Results from a simulation study of the proposed method are also presented.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Lam KF,Ip Ddoi
10.1002/sim.1323subject
Has Abstractpub_date
2003-06-30 00:00:00pages
2025-34issue
12eissn
0277-6715issn
1097-0258journal_volume
22pub_type
杂志文章abstract::The sample size required for a cluster randomised trial is inflated compared with an individually randomised trial because outcomes of participants from the same cluster are correlated. Sample size calculations for longitudinal cluster randomised trials (including stepped wedge trials) need to take account of at least...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7028
更新日期:2016-11-20 00:00:00
abstract::We investigate population-averaged (PA) and cluster-specific (CS) associations for clustered binary logistic regression in the context of a longitudinal clinical trial that investigated the association between tooth-specific visual elastase kit results and periodontal disease progression within 26 weeks of follow-up. ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780140407
更新日期:1995-02-28 00:00:00
abstract::This paper describes statistical procedures for use in an experiment that compares two handwashing protocols. The evaluation of a handwashing protocol entails collection of the wash effluent. Colony counts for the effluent reflect the number of flora removed by the wash protocol. The analysis aims to formulate and est...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1002/sim.4780050412
更新日期:1986-07-01 00:00:00
abstract::In this paper, we construct a partial additive regression (PAR) model to predict the survival times of cancer patients based on microarray gene expression data with right censoring. The area under time-dependent receiver operating characteristic curve is used as a model evaluation criterion. We conduct a simulation st...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3412
更新日期:2009-01-30 00:00:00
abstract::Health surveillance involves collecting public health data on chronic and infectious diseases to detect changes in disease incidence rates in order to improve public health. Timely detection of disease clusters is essential in prospective public health surveillance. Most existing health surveillance research is based ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3877
更新日期:2011-02-28 00:00:00
abstract::Meta-analysis has generally been accepted as a fundamental tool for combining effect estimates from several studies. For binary studies with rare events, the Peto odds ratio (POR) method has become the relative effect estimator of choice. However, the POR leads to biased estimates for the OR when treatment effects are...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6301
更新日期:2014-12-10 00:00:00
abstract::Estimation of genetic and environmental contributions to cancers falls in the framework of generalized linear mixed modelling with several random effect components. Computational challenges remain, however, in dealing with binary or survival phenotypes. In this paper, we consider the analysis of melanoma onset in a po...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2266
更新日期:2006-09-30 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
pub_type: 杂志文章
doi:10.1002/sim.4780131915
更新日期:1994-10-15 00:00:00
abstract::Propensity score analysis is widely used in observational studies to adjust for confounding and estimate the causal effect of a treatment on the outcome. When the outcome is survival time, there are special considerations on the definition of the causal estimand, point, and variance estimation that have not been thoro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7839
更新日期:2018-11-20 00:00:00
abstract::Ordinal data appear in a wide variety of scientific fields. These data are often analyzed using ordinal logistic regression models that assume proportional odds. When this assumption is not met, it may be possible to capture the lack of proportionality using a constrained structural relationship between the odds and t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5689
更新日期:2013-06-15 00:00:00
abstract::In this paper, we develop a method for the simultaneous estimation of spectral density functions (SDFs) for a collection of stationary time series that share some common features. Due to the similarities among the SDFs, the log-SDF can be represented using a common set of basis functions. The basis shared by the colle...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7972
更新日期:2018-12-30 00:00:00
abstract::When estimating causal effects, unmeasured confounding and model misspecification are both potential sources of bias. We propose a method to simultaneously address both issues in the form of a semi-parametric sensitivity analysis. In particular, our approach incorporates Bayesian Additive Regression Trees into a two-p...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6973
更新日期:2016-09-10 00:00:00
abstract::With considerable current interest in longitudinal epidemiologic studies, little is available regarding sample size requirements. This paper considers a method for analysis of longitudinal data, where one compares the mean rates of change for two or more groups, and proposes a statistic for use in determining sample s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780090414
更新日期:1990-04-01 00:00:00
abstract::Recently, there has been much work on early phase cancer designs that incorporate both toxicity and efficacy data, called phase I-II designs because they combine elements of both phases. However, they do not explicitly address the phase II hypothesis test of H0 : p ≤ p0 , where p is the probability of efficacy at the ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6124
更新日期:2014-07-20 00:00:00
abstract::Providing personalized treatments designed to maximize benefits and minimizing harms is of tremendous current medical interest. One problem in this area is the evaluation of the interaction between the treatment and other predictor variables. Treatment effects in subgroups having the same direction but different magni...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5429
更新日期:2012-12-10 00:00:00
abstract::To benefit Alzheimer's disease research, a central data co-ordinating centre (CDCC) is planned that will systematically collect data from 27 Alzheimer's disease centres (ADCs) located nationwide. This CDCC will combine, analyse and disseminate epidemiologic, demographic, clinical and neuropathological data to research...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(20000615/30)19:11/12<1453:
更新日期:2000-06-15 00:00:00
abstract::A method is proposed to infer the randomized treatment effect on survival after an adjustment for a post-randomization variable. The post-randomization variable is made independent of the treatment assignment and is considered a surrogate for baseline prognostic factors. The relationship between the post-randomization...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.968
更新日期:2001-11-30 00:00:00
abstract::Meta-analysis to investigate the joint effect of multiple factors in the aetiology of a disease is of increasing importance in epidemiology. This task is often challenging in practice, because studies typically concentrate on studying the effect of only one exposure, sometimes may report the interaction between two ex...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2689
更新日期:2006-12-30 00:00:00
abstract::The FDA permits marketing of a generic formulation of a drug G for the same indications as a standard preparation S if one can show that G is bioequivalent to S. Present implementation requires convincing evidence that the population mean difference in bioavailability (drug exposure) between the two preparations lies ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780111311
更新日期:1992-09-30 00:00:00
abstract::The treatment effect sizes that can be detected with sufficient power up to the different interim analyses constitute a clinically meaningful criterion for the selection of a group sequential test for a clinical trial. For any pre-specified sequence of effect sizes, it is possible to construct group sequential boundar...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1751
更新日期:2004-05-15 00:00:00
abstract::A new testing approach is described for improving statistical tests of independence in sets of tables stratified on one or more relevant factors in case of categorical (nominal or ordinal) variables. Common tests of independence that exploit the ordinality of one of the variables use a restricted-alternative approach....
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7006
更新日期:2016-11-10 00:00:00
abstract::In observational studies, many continuous or categorical covariates may be related to an outcome. Various spline-based procedures or the multivariable fractional polynomial (MFP) procedure can be used to identify important variables and functional forms for continuous covariates. This is the main aim of an explanatory...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5639
更新日期:2013-06-15 00:00:00
abstract::In this paper, we consider pooling schemes in which samples are to be tested in two-stages. We show that when batch size is limited as well as pool size, selection schemes tend to be more efficient and flexible. Formulae for the efficiencies of square arrays in all dimensions and for all selection schemes are given in...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3965
更新日期:2010-09-20 00:00:00
abstract::Recurrent event data are commonly encountered in health-related longitudinal studies. In this paper time-to-events models for recurrent event data are studied with non-informative and informative censorings. In statistical literature, the risk set methods have been confirmed to serve as an appropriate and efficient ap...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1029
更新日期:2002-02-15 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::Growth trends in children are often based on cross-sectional studies, in which a sample of the population is investigated at one given point in time. Estimating age-related percentiles in such studies involves fitting data distributions, each of which is specific for one age group, and a subsequent smoothing of the pe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(20000315)19:5<697::aid-sim
更新日期:2000-03-15 00:00:00
abstract::The application of Bayesian hierarchical models to measure spatial effects in time to event data has not been widely reported. This case study aims to estimate the effect of area of residence on waiting times to coronary artery bypass graft (CABG) and to assess the role of important individual specific covariates (age...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1535
更新日期:2003-09-30 00:00:00
abstract::In contrast to other models for ordinal data, the continuation ratio model can be fitted with standard statistical software. This makes it particularly appropriate for large clinical trials with ordinal response variables. In addition, when the trials are longitudinal, this model can be applied to individual responses...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1002/(sici)1097-0258(19971230)16:24<2873::aid-s
更新日期:1997-12-30 00:00:00
abstract::This paper describes the Stoke Index which has been designed to give a global measure of disease activity in rheumatoid arthritis. The index is based on two objective laboratory measurements, one subjective and two semi-objective clinical measurements, chosen from 13 measurements using clinical judgement. Variable sel...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780121206
更新日期:1993-06-30 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