The EM algorithm in medical imaging.

abstract：:Nonlinear mixed-effects modeling is a popular approach to describe the temporal trajectory of repeated measurements of clinical endpoints collected over time in clinical trials, to distinguish the within-subject and the between-subject variabilities, and to investigate clinically important risk factors (covariates) th...

journal_title：Statistical methods in medical research

authors： Yuan M,Xu XS,Yang Y,Xu J,Huang X,Tao F,Zhao L,Zhang L,Pinheiro J

更新日期：2019-12-01 00:00:00

abstract：:Improving the quality of care that patients receive is a major focus of clinical research, particularly in the setting of cardiovascular hospitalization. Quality improvement studies seek to estimate and visualize the degree of variability in dichotomous treatment patterns and outcomes across different providers, where...

journal_title：Statistical methods in medical research

authors： Thomas LE,Schulte PJ

更新日期：2019-04-01 00:00:00

abstract：:This paper illustrates the use of multidimensional scaling methods (MDS) to examine space-time patterns in epidemic data. The paper begins by outlining the principles of MDS. The model is then formally specified and illustrated by application to two data sets. The first is partly a tutorial example. It uses monthly re...

journal_title：Statistical methods in medical research

authors： Cliff AD,Haggett P,Smallman-Raynor MR,Stroup DF,Williamson GD

更新日期：1995-06-01 00:00:00

abstract：:Most diagnostic accuracy measures and criteria for selecting optimal cut-points are only applicable to diseases with binary or three stages. Currently, there exist two diagnostic measures for diseases with general k stages: the hypervolume under the manifold and the generalized Youden index. While hypervolume under th...

journal_title：Statistical methods in medical research

authors： Dong T,Attwood K,Hutson A,Liu S,Tian L

更新日期：2017-12-01 00:00:00

abstract：:DNA methylation has been shown to play an important role in many complex diseases. The rapid development of high-throughput DNA methylation scan technologies provides great opportunities for genomewide DNA methylation-disease association studies. As methylation is a dynamic process involving time, it is quite plausibl...

journal_title：Statistical methods in medical research

authors： Wang C,Shen Q,Du L,Xu J,Zhang H

更新日期：2018-09-01 00:00:00

abstract：:Statistical models of breast cancer tumour progression have been used to further our knowledge of the natural history of breast cancer, to evaluate mammography screening in terms of mortality, to estimate overdiagnosis, and to estimate the impact of lead-time bias when comparing survival times between screen detected ...

journal_title：Statistical methods in medical research

authors： Isheden G,Humphreys K

更新日期：2019-03-01 00:00:00

abstract：:Censored data make survival analysis more complicated because exact event times are not observed. Statistical methodology developed to account for censored observations assumes that patients' withdrawal from a study is independent of the event of interest. However, in practice, some covariates might be associated to b...

journal_title：Statistical methods in medical research

authors： Willems S,Schat A,van Noorden MS,Fiocco M

更新日期：2018-02-01 00:00:00

abstract：:The estimation of population parameters using complex survey data requires careful statistical modelling to account for the design features. This is further complicated by unit and item nonresponse for which a number of methods have been developed in order to reduce estimation bias. In this paper, we address some issu...

journal_title：Statistical methods in medical research

authors： Geraci M

更新日期：2016-08-01 00:00:00

abstract：:Clustered data is not simply correlated data, but has its own unique aspects. In this paper, various methods for correlated receiver operating characteristic (ROC) curve data that have been extended specifically to clustered data are reviewed. For those methods that have not yet been extended, suggestions for their ap...

journal_title：Statistical methods in medical research

authors： Beam CA

更新日期：1998-12-01 00:00:00

abstract：:In the past two decades, it has become increasingly clear that genetic factors contribute to the aetiology of many common diseases including cancers, coronary disease, allergy and psychiatric disorders. While one goal of genetic epidemiological studies is to locate susceptibility genes for these complex diseases, it i...

journal_title：Statistical methods in medical research

authors： Liang KY,Beaty TH

更新日期：2000-12-01 00:00:00

abstract：:Excessive zeros are common in practice and may cause overdispersion and invalidate inference when fitting Poisson regression models. There is a large body of literature on zero-inflated Poisson models. However, methods for testing whether there are excessive zeros are less well developed. The Vuong test comparing a Po...

journal_title：Statistical methods in medical research

authors： He H,Zhang H,Ye P,Tang W

更新日期：2019-04-01 00:00:00

abstract：:Joint modelling of longitudinal biomarker and event-time processes has gained its popularity in recent years as they yield more accurate and precise estimates. Considering this modelling framework, a new methodology for evaluating the time-dependent efficacy of a longitudinal biomarker for clinical endpoint is propose...

journal_title：Statistical methods in medical research

authors： Kolamunnage-Dona R,Williamson PR

更新日期：2018-06-01 00:00:00

abstract：:Previous work has shown that individual randomized "proof-of-concept" (PoC) studies may be designed to maximize cost-effectiveness, subject to an overall PoC budget constraint. Maximizing cost-effectiveness has also been considered for arrays of simultaneously executed PoC studies. Defining Type III error as the oppor...

journal_title：Statistical methods in medical research

authors： He L,Du L,Antonijevic Z,Posch M,Korostyshevskiy VR,Beckman RA

更新日期：2020-09-21 00:00:00

abstract：:Cancer survival trend analyses are essential to describe accurately the way medical practices impact patients' survival according to the year of diagnosis. To this end, survival models should be able to account simultaneously for non-linear and non-proportional effects and for complex interactions between continuous v...

journal_title：Statistical methods in medical research

authors： Remontet L,Uhry Z,Bossard N,Iwaz J,Belot A,Danieli C,Charvat H,Roche L,CENSUR Working Survival Group.

更新日期：2019-08-01 00:00:00

abstract：:Surveys are key means of obtaining policy-relevant information not available from routine sources. Bias arising from non-participation is typically handled by applying weights derived from limited socio-demographic characteristics. This approach neither captures nor adjusts for differences in health and related behavi...

journal_title：Statistical methods in medical research

authors： Gray L,Gorman E,White IR,Katikireddi SV,McCartney G,Rutherford L,Leyland AH

更新日期：2020-04-01 00:00:00

abstract：:Spatial resolution plays an important role in functional magnetic resonance imaging studies as the signal-to-noise ratio increases linearly with voxel volume. In scientific studies, where functional magnetic resonance imaging is widely used, the standard spatial resolution typically used is relatively low which ensure...

journal_title：Statistical methods in medical research

authors： Liu Z,Bartsch AJ,Berrocal VJ,Johnson TD

更新日期：2019-04-01 00:00:00

abstract：:The analysis of health care costs is complicated by the skewed and heteroscedastic nature of their distribution with possibly additional zero values. Statistical methods that do not adjust for these features can lead to incorrect conclusions. This paper reviews recent developments in statistical methods for the analys...

journal_title：Statistical methods in medical research

authors： Zhou XH

更新日期：2002-08-01 00:00:00

abstract：:One of the main advantages of Bayesian analyses of clinical trials is their ability to formally incorporate skepticism about large treatment effects through the use of informative priors. We conducted a simulation study to assess the performance of informative normal, Student- t, and beta distributions in estimating r...

journal_title：Statistical methods in medical research

authors： Pedroza C,Han W,Truong VTT,Green C,Tyson JE

更新日期：2018-01-01 00:00:00

abstract：:In this paper, we develop a simple diagnostic test for the random-effects distribution in mixed models. The test is based on the gradient function, a graphical tool proposed by Verbeke and Molenberghs to check the impact of assumptions about the random-effects distribution in mixed models on inferences. Inference is c...

journal_title：Statistical methods in medical research

authors： Efendi A,Drikvandi R,Verbeke G,Molenberghs G

更新日期：2017-04-01 00:00:00

abstract：:In this article, we present an overview and tutorial of statistical methods for meta-analysis of diagnostic tests under two scenarios: (1) when the reference test can be considered a gold standard and (2) when the reference test cannot be considered a gold standard. In the first scenario, we first review the conventio...

journal_title：Statistical methods in medical research

authors： Ma X,Nie L,Cole SR,Chu H

更新日期：2016-08-01 00:00:00

abstract：:Accelerated failure time model is a popular model to analyze censored time-to-event data. Analysis of this model without assuming any parametric distribution for the model error is challenging, and the model complexity is enhanced in the presence of large number of covariates. We developed a nonparametric Bayesian met...

journal_title：Statistical methods in medical research

authors： Zhang Z,Sinha S,Maiti T,Shipp E

更新日期：2018-04-01 00:00:00

abstract：:This article is motivated by the need for discovering patterns of patients' health based on their daily settings of care to aid the health policy-makers to improve the effectiveness of distributing funding for health services. The hidden process of one's health status is assumed to be a continuous smooth function, cal...

journal_title：Statistical methods in medical research

authors： Wang S,Nie Y,Sutherland JM,Wang L

更新日期：2020-09-25 00:00:00

abstract：:We propose a fully parametric model for the analysis of competing risks data where the types of failure may not be independent. We show how the dependence between the cause-specific survival times can be modelled with a copula function. Features include: identifiability of the problem; accessible understanding of the ...

journal_title：Statistical methods in medical research

authors： Escarela G,Carrière JF

更新日期：2003-08-01 00:00:00

abstract：:We consider two exact unconditional procedures to test the difference between two multinomials with ordered categorical data. Exact unconditional procedures are compared to other approaches based on the Wilcoxon mid-rank test and the proportional odds model. We use a real example from an arthritis pain study to illust...

journal_title：Statistical methods in medical research

authors： Shan G,Ma C

更新日期：2016-02-01 00:00:00

abstract：:There is debate whether clinical trials with suboptimal power are justified and whether results from large studies are more reliable than the (combined) results of smaller trials. We quantified the error rates for evaluations based on single conventionally powered trials (80% or 90% power) versus evaluations based on ...

journal_title：Statistical methods in medical research

authors： IntHout J,Ioannidis JP,Borm GF

更新日期：2016-04-01 00:00:00

abstract：:This work presents a brief overview of Markov models in cancer screening evaluation and focuses on two specific models. A three-state model was first proposed to estimate jointly the sensitivity of the screening procedure and the average duration in the preclinical phase, i.e. the period when the cancer is asymptomati...

journal_title：Statistical methods in medical research

authors： Uhry Z,Hédelin G,Colonna M,Asselain B,Arveux P,Rogel A,Exbrayat C,Guldenfels C,Courtial I,Soler-Michel P,Molinié F,Eilstein D,Duffy SW

更新日期：2010-10-01 00:00:00

abstract：:To evaluate the antiretroviral activity of antiretroviral agents and to compare the effects of two different antiretroviral agents, we propose a non-parametric mixed-effects model to investigate change of CD4+ counts. The proposed model and methods are applied to analyse the data from PACTG345 study. Population and in...

journal_title：Statistical methods in medical research

authors： Liang H

更新日期：2008-04-01 00:00:00

abstract：:Appropriate handling of aggregate missing outcome data is necessary to minimise bias in the conclusions of systematic reviews. The two-stage pattern-mixture model has been already proposed to address aggregate missing continuous outcome data. While this approach is more proper compared with the exclusion of missing co...

journal_title：Statistical methods in medical research

authors： Spineli LM,Kalyvas C,Papadimitropoulou K

更新日期：2021-01-06 00:00:00

abstract：:Publication bias frequently appears in meta-analyses when the included studies' results (e.g., p-values) influence the studies' publication processes. Some unfavorable studies may be suppressed from publication, so the meta-analytic results may be biased toward an artificially favorable direction. Many statistical tes...

journal_title：Statistical methods in medical research

authors： Lin L

更新日期：2020-10-01 00:00:00

abstract：:In multi-regional trials, the underlying overall and region-specific accrual rates often do not hold constant over time and different regions could have different start-up times, which combined with initial jump in accrual within each region often leads to a discontinuous overall accrual rate, and these issues associa...

journal_title：Statistical methods in medical research

authors： Deng Y,Zhang X,Long Q

更新日期：2017-04-01 00:00:00