Abstract:
:The mixed effects model for repeated measures has been widely used for the analysis of longitudinal clinical data collected at a number of fixed time points. We propose a robust extension of the mixed effects model for repeated measures for skewed and heavy-tailed data on basis of the multivariate skew-t distribution, and it includes the multivariate normal, t, and skew-normal distributions as special cases. An efficient Markov chain Monte Carlo algorithm is developed using the monotone data augmentation and parameter expansion techniques. We employ the algorithm to perform controlled pattern imputations for sensitivity analyses of longitudinal clinical trials with nonignorable dropouts. The proposed methods are illustrated by real data analyses. Sample SAS programs for the analyses are provided in the online supplementary material.
journal_name
Stat Methods Med Resjournal_title
Statistical methods in medical researchauthors
Tang Ydoi
10.1177/0962280219865579subject
Has Abstractpub_date
2020-06-01 00:00:00pages
1542-1562issue
6eissn
0962-2802issn
1477-0334journal_volume
29pub_type
杂志文章abstract::Multilevel models were originally developed to allow linear regression or ANOVA models to be applied to observations that are not mutually independent. This lack of independence commonly arises due to clustering of the units of observations into 'higher level units' such as patients in hospitals. In linear mixed model...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/096228020101000604
更新日期:2001-12-01 00:00:00
abstract::This paper reviews recent developments by the Washington/Brown groups for the study of anatomical shape in the emerging new discipline of computational anatomy. Parametric representations of anatomical variation for computational anatomy are reviewed, restricted to the assumption of small deformations. The generation ...
journal_title:Statistical methods in medical research
pub_type: 杂志文章,评审
doi:10.1177/096228029700600305
更新日期:1997-09-01 00:00:00
abstract:BACKGROUND:Recent literature on the comparison of machine learning methods has raised questions about the neutrality, unbiasedness and utility of many comparative studies. Reporting of results on favourable datasets and sampling error in the estimated performance measures based on single samples are thought to be the m...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280213502437
更新日期:2016-10-01 00:00:00
abstract::This study proposes semiparametric models for analysis of hierarchical count data containing excess zeros and overdispersion simultaneously. The methods discussed in this paper handle nonlinear covariate effects through flexible semiparametric multilevel regression techniques. This is performed by providing a comprehe...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280216657376
更新日期:2018-04-01 00:00:00
abstract::Clinical trials investigating the efficacy of two or more doses of an experimental treatment compared to a single reference arm are not uncommon. In such situations, if each dose is compared to the reference arm using an un-adjusted significance level, consideration of the Type I familywise error is likely to be requi...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280210378943
更新日期:2011-12-01 00:00:00
abstract::Immunotherapy, gene therapy or adoptive cell therapies, such as the chimeric antigen receptor+ T-cell therapies, have demonstrated promising therapeutic effects in oncology patients. We consider statistical designs for dose-finding adoptive cell therapy trials, in which the monotonic dose-response relationship assumed...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280220977009
更新日期:2020-12-16 00:00:00
abstract::The statistical analysis of genome-wide association studies (GWASs) with multiple diseases and shared controls (SCs) is discussed. The usual method for analyzing data from these studies is to compare each individual disease with either the SCs or the pooled controls which include other diseases. We observed that apply...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280212474061
更新日期:2016-04-01 00:00:00
abstract::When comparing two different kinds of group therapy or two individual treatments where patients within each arm are nested within care providers, clustering of observations may occur in both arms. The arms may differ in terms of (a) the intraclass correlation, (b) the outcome variance, (c) the cluster size, and (d) th...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280214563100
更新日期:2015-10-01 00:00:00
abstract::This paper presents and compares several methods of measuring continuous baseline covariate imbalance in clinical trial data. Simulations illustrate that though the t-test is an inappropriate method of assessing continuous baseline covariate imbalance, the test statistic itself is a robust measure in capturing imbalan...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280211416038
更新日期:2015-04-01 00:00:00
abstract::The change-point model has drawn much attention over the past few decades. It can accommodate the jump process, which allows for changes of the effects before and after the change point. Intellectual disability is a long-term disability that impacts performance in cognitive aspects of life and usually has its onset pr...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280212463415
更新日期:2016-04-01 00:00:00
abstract::Early phase trials of complex interventions currently focus on assessing the feasibility of a large randomised control trial and on conducting pilot work. Assessing the efficacy of the proposed intervention is generally discouraged, due to concerns of underpowered hypothesis testing. In contrast, early assessment of e...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280215589507
更新日期:2016-06-01 00:00:00
abstract::The threat of pandemics has made influenza surveillance systems a priority in epidemiology services around the world. The emergence of A-H1N1 influenza has required accurate surveillance systems in order to undertake specific actions only when and where they are necessary. In that sense, the main goal of this article ...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280210370265
更新日期:2011-04-01 00:00:00
abstract::Pattern-mixture model (PMM)-based controlled imputations have become a popular tool to assess the sensitivity of primary analysis inference to different post-dropout assumptions or to estimate treatment effectiveness. The methodology is well established for continuous responses but less well established for binary res...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280220941880
更新日期:2020-12-01 00:00:00
abstract::In biomedical research, various longitudinal markers measuring different quantities are often collected over time. For example, repeated measures of psychometric scores are very informative about the degradation process toward dementia. These trajectories are generally nonlinear with an acceleration of the decline a f...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280219898719
更新日期:2020-09-01 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
pub_type: 杂志文章
doi:10.1177/0962280220951834
更新日期:2020-09-25 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
pub_type: 杂志文章
doi:10.1177/0962280219854482
更新日期:2020-04-01 00:00:00
abstract::The semiparametric Cox regression model is often fitted in the modeling of survival data. One of its main advantages is the ease of interpretation, as long as the hazards rates for two individuals do not vary over time. In practice the proportionality assumption of the hazards may not be true in some situations. In ad...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280219883905
更新日期:2020-08-01 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
pub_type: 杂志文章
doi:10.1177/0962280212450957
更新日期:2016-02-01 00:00:00
abstract::Many statistical studies report p-values for inferential purposes. In several scenarios, the stochastic aspect of p-values is neglected, which may contribute to drawing wrong conclusions in real data experiments. The stochastic nature of p-values makes their use to examine the performance of given testing procedures o...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280217704451
更新日期:2018-12-01 00:00:00
abstract::Evaluation of medical imaging devices often involves clinical studies where multiple readers (MR) read images of multiple cases (MC) for a clinical task, which are often called MRMC studies. In addition to sizing patient cases as is required in most clinical trials, MRMC studies also require sizing readers, since both...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280219869370
更新日期:2020-06-01 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
pub_type: 杂志文章
doi:10.1177/096228029500400202
更新日期:1995-06-01 00:00:00
abstract::Estimating the long-term health impact of air pollution using an ecological spatio-temporal study design is a challenging task, due to the presence of residual spatio-temporal autocorrelation in the health counts after adjusting for the covariate effects. This autocorrelation is commonly modelled by a set of random ef...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280214527384
更新日期:2014-12-01 00:00:00
abstract::Pediatric cardiac surgery may lead to poor outcomes such as acute kidney injury (AKI) and prolonged hospital length of stay (LOS). Plasma and urine biomarkers may help with early identification and prediction of these adverse clinical outcomes. In a recent multi-center study, 311 children undergoing cardiac surgery we...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280214530608
更新日期:2016-12-01 00:00:00
abstract::Cluster-level dynamic treatment regimens can be used to guide sequential treatment decision-making at the cluster level in order to improve outcomes at the individual or patient-level. In a cluster-level dynamic treatment regimen, the treatment is potentially adapted and re-adapted over time based on changes in the cl...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280217708654
更新日期:2017-08-01 00:00:00
abstract::Within paediatric populations, there may be distinct age groups characterised by different exposure-response relationships. Several regulatory guidance documents have suggested general age groupings. However, it is not clear whether these categorisations will be suitable for all new medicines and in all disease areas....
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280220903751
更新日期:2020-09-01 00:00:00
abstract::Tree-based methods are very powerful and popular tools for analysing survival data with right-censoring. The existing methods assume that the true time-to-event and the censoring times are independent given the covariates. We propose different ways to build survival forests when dependent censoring is suspected, by us...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280217727314
更新日期:2019-02-01 00:00:00
abstract::Age-period-cohort models are a popular tool for studying population-level rates; for example, trends in cancer incidence and mortality. Age-period-cohort models decompose observed trends into age effects that correlate with natural history, period effects that reveal factors impacting all ages simultaneously (e.g. inn...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280217713033
更新日期:2019-01-01 00:00:00
abstract::Methods for the analysis of reliability of ordered categorical scales are discussed, focussing on the limitation of the single summary-weighted kappa coefficients. A symmetric matrix of kappa-type coefficients is suggested as an alternative. The method is proposed as being suitable for ordinal scale where there is no ...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1191/0962280205sm413oa
更新日期:2005-10-01 00:00:00
abstract::It is now widely accepted that multiple imputation (MI) methods properly handle the uncertainty of missing data over single imputation methods. Several standard statistical software packages, such as SAS, R and STATA, have standard procedures or user-written programs to perform MI. The performance of these packages is...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280206074464
更新日期:2007-06-01 00:00:00
abstract::This article aims to develop a probability-based model involving the use of direct likelihood formulation and generalised linear modelling (GLM) approaches useful in estimating important disease parameters from longitudinal or repeated measurement data. The current application is based on infection with respiratory sy...
journal_title:Statistical methods in medical research
pub_type: 杂志文章
doi:10.1177/0962280210385749
更新日期:2011-10-01 00:00:00