Abstract:
:In cancer clinical trials, patients often experience a recurrence of disease prior to the outcome of interest, overall survival. Additionally, for many cancers, there is a cured fraction of the population who will never experience a recurrence. There is often interest in how different covariates affect the probability of being cured of disease and the time to recurrence, time to death, and time to death after recurrence. We propose a multi-state Markov model with an incorporated cured fraction to jointly model recurrence and death in colon cancer. A Bayesian estimation strategy is used to obtain parameter estimates. The model can be used to assess how individual covariates affect the probability of being cured and each of the transition rates. Checks for the adequacy of the model fit and for the functional forms of covariates are explored. The methods are applied to data from 12 randomized trials in colon cancer, where we show common effects of specific covariates across the trials.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Conlon AS,Taylor JM,Sargent DJdoi
10.1002/sim.6056subject
Has Abstractpub_date
2014-05-10 00:00:00pages
1750-66issue
10eissn
0277-6715issn
1097-0258journal_volume
33pub_type
杂志文章abstract::A considerable number of the clinical reports which are presented to the Dutch Board for the Evaluation of Drugs, have deficiencies and/or shortcomings. A number of these, including loose description of the target population and sampling method, methodological flaws, incorrect treatment of withdrawals, confounding of ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780020209
更新日期:1983-04-01 00:00:00
abstract::In comparing two treatments under a typical sequential clinical trial setting, a 50-50 randomization design generates reliable data for making efficient inferences about the treatment difference for the benefit of patients in the general population. However, if the treatment difference is large and the endpoint of the...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19961130)15:22<2413::aid-s
更新日期:1996-11-15 00:00:00
abstract::R2 has been criticized as a measure of model performance when predicting a dichotomous outcome, both because its value is often low and because it is sensitive to the prevalence of the event of interest. The C statistic is more widely used to measure model performance in a 0/1 setting. We use a simple parametric famil...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19990228)18:4<375::aid-sim
更新日期:1999-02-28 00:00:00
abstract::In medical and health studies, heterogeneities in clustered count data have been traditionally modeled by positive random effects in Poisson mixed models; however, excessive zeros often occur in clustered medical and health count data. In this paper, we consider a three-level random effects zero-inflated Poisson model...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3619
更新日期:2009-08-15 00:00:00
abstract::For each of 211 arteriosclerosis obliterans patients, the degree of stenosis of arteries at four sites were examined at Hiroshima University Hospital to analyse the relationship between the degree of stenosis and age, sex and site. The generalized estimating equations using a proportional odds model for the stenosis p...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1363
更新日期:2003-07-15 00:00:00
abstract::Quality of life (QOL) assessment is a key component of many clinical studies and frequently requires the use of single global summary measures that capture the overall balance of findings from a potentially wide-ranging assessment of QOL issues. We propose and evaluate an irregular multilevel latent variable model sui...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4455
更新日期:2012-05-20 00:00:00
abstract::A number of variance formulae for the attributable fraction have been presented, but none is consistent in sparse data, such as found in individually matched case-control studies. This paper employs Mantel-Haenszel estimation to derive variance estimators for attributable fractions that are dually consistent, that is,...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780060607
更新日期:1987-09-01 00:00:00
abstract::During phase III clinical trials in life-threatening disease settings, it is important to ensure that the Data Monitoring Committee (DMC) has exclusive access to the interim efficacy and safety data generated by the data analysis centre, in order to minimize the risk of widespread prejudgement of unreliable trial resu...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1288
更新日期:2002-10-15 00:00:00
abstract::In the field of cluster detection, a weighted normal model-based scan statistic was recently developed to analyze regional continuous data and to evaluate the clustering pattern of pre-defined cells (such as state, county, tract, school, hospital) that include many individuals. The continuous measures of interest are,...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3990
更新日期:2010-10-15 00:00:00
abstract::The Spearman (rho(s)) and Kendall (tau) rank correlation coefficient are routinely used as measures of association between non-normally distributed random variables. However, confidence limits for rho(s) are only available under the assumption of bivariate normality and for tau under the assumption of asymptotic norma...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2547
更新日期:2007-02-10 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::Instrumental variable is an essential tool for addressing unmeasured confounding in observational studies. Two-stage predictor substitution (2SPS) estimator and two-stage residual inclusion (2SRI) are two commonly used approaches in applying instrumental variables. Recently, 2SPS was studied under the additive hazards...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8071
更新日期:2019-05-10 00:00:00
abstract::Genetic networks for gene expression data are often built by graphical models, which in turn are built from pair-wise correlations of gene expression levels. A key feature of building graphical models is the evaluation of conditional independence of two traits, given other traits. When conditional independence can be ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3274
更新日期:2008-08-30 00:00:00
abstract::Studies in health research are commonly carried out in clustered settings, where the individual response data are correlated within clusters. Estimation and modelling of the extent of between-cluster variation contributes to understanding of the current study and to design of future studies. It is common to express be...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2304
更新日期:2006-05-15 00:00:00
abstract::For patients who were previously treated for prostate cancer, salvage hormone therapy is frequently given when the longitudinal marker prostate-specific antigen begins to rise during follow-up. Because the treatment is given by indication, estimating the effect of the hormone therapy is challenging. In a previous pape...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5890
更新日期:2014-01-30 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::In case-control studies, the Cochran-Armitage (CA) trend test is powerful for detection of an association between a risk allele and a marker. To apply this test, a score should be assigned to the genotypes based on the genetic model. When the underlying genetic model is unknown, the trend test statistic is a function ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1474
更新日期:2003-08-30 00:00:00
abstract::Generalized linear models may be extended in several ways. This paper describes five such extensions: (i) generalized additive models; (ii) the use of quasi-likelihood; (iii) joint modelling of mean and dispersion; (iv) introduction of extra random components to give hierarchical generalized linear models; (v) modelli...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19981215)17:23<2747::aid-s
更新日期:1998-12-15 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
pub_type: 杂志文章
doi:10.1002/sim.4780131605
更新日期:1994-08-30 00:00:00
abstract::The identification of new adverse drug reactions is often tricky. For a given case, the relationship between drug exposure and symptom occurrence is usually questionable. It could be investigated statistically from a series of drug-event association cases with an independence test between the two variables. Analysing ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780100621
更新日期:1991-06-01 00:00:00
abstract::In this paper, we investigate the impact of time-invariant covariates when fitting transition mixed models. This is carried out by emphasizing on the role of baseline responses on the estimation process. Transition models are allowed for two cases of exogenous and endogenous baseline responses. We illustrate these con...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6270
更新日期:2014-11-30 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::A statistical definition of surrogate endpoints as well as validation criteria was first presented by Prentice. Freedman et al. supplemented these criteria with the so-called proportion explained. Buyse and Molenberghs pointed to inadequacies of these criteria and suggested a new definition of surrogacy based on (i) t...
journal_title:Statistics in medicine
pub_type: 评论,杂志文章
doi:10.1002/sim.923
更新日期:2001-10-30 00:00:00
abstract::Although the frequentist paradigm has been the predominant approach to clinical trial design since the 1940s, it has several notable limitations. Advancements in computational algorithms and computer hardware have greatly enhanced the alternative Bayesian paradigm. Compared with its frequentist counterpart, the Bayesi...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.5404
更新日期:2012-11-10 00:00:00
abstract::This article introduces a global hypothesis test intended for studies with multiple endpoints. Our test makes use of a priori predictions about the direction of the result of each endpoint and we weight these predictions using the sample correlation matrix. The global alternative hypothesis concerns a parameter, ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8724
更新日期:2020-12-10 00:00:00
abstract::The purpose of this research was to develop appropriate methods for analysing repeated ordinal categorical data that arose in an intervention trial to prevent oesophageal cancer. The measured response was the degree of oesophageal dysplasia at 2.5 and 6 years after randomization. An important feature was that some res...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780130511
更新日期:1994-03-15 00:00:00
abstract::In phase 3 clinical trials, ethical and financial concerns motivate sequential analyses in which the data are analyzed prior to completion of the entire planned study. Existing group sequential software accounts for the effects of these interim analyses on the sampling density by assuming that the contribution of subs...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6306
更新日期:2014-12-20 00:00:00
abstract::For genome-wide association studies, we propose a new method for identifying significant biological pathways. In this approach, we aggregate data across single-nucleotide polymorphisms to obtain summary measures at the gene level. We then use a hierarchical Bayesian model, which takes the gene-level summary measures a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4477
更新日期:2012-05-10 00:00:00
abstract::Motivated by a previously published study of HIV treatment, we simulated data subject to time-varying confounding affected by prior treatment to examine some finite-sample properties of marginal structural Cox proportional hazards models. We compared (a) unadjusted, (b) regression-adjusted, (c) unstabilized, and (d) s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5317
更新日期:2012-08-30 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