Statistical Modeling最新文献_第2页

Handling dropout and clustering in longitudinal multicentre clinical trials 纵向多中心临床试验中退出和聚类的处理

Statistical Modeling Pub Date : 2006-07-01 DOI: 10.1191/1471082X06st113oa

P. Bianco, R. Borgoni

{"title":"Handling dropout and clustering in longitudinal multicentre clinical trials","authors":"P. Bianco, R. Borgoni","doi":"10.1191/1471082X06st113oa","DOIUrl":"https://doi.org/10.1191/1471082X06st113oa","url":null,"abstract":"Many clinical trials enrol patients from different medical centres. Multi-centre studies are particularly helpful in cancer research as they allow researchers to evaluate the efficacy of a therapy in a variety of patients and settings, making it possible to investigate the effect of treatments in those cases when it is difficult, or even impossible, for a single centre to recruit the required number of patients. It is often argued, however, that despite agreement among different centres to follow common standardized protocols, variation may occur in both baseline characteristics of the recruited patients and in treatment effects. This heterogeneity should be detected and, if present, accounted for in the data analysis. Furthermore, the longitudinal nature of these types of experimental studies raises the problem of attrition, that is, patients may dropout of the study for a number of reasons mainly death or disease progression. In this paper, we consider the health related quality of life of advanced melanoma patients in a longitudinal multi-centre randomized clinical trial comparing two different anti-tumoural treatments. We propose a Heckman type model to account for the possibility that patients dropout according to a non-ignorable mechanism. The model is extended to a multilevel setting to account both for the longitudinal nature and the multi-centre structure of the design. We found a strong variation across centres in the quality of life evaluation. The effect of centres on the dropout was not found to be relevant in the considered data although dropout does depend on patient′s characteristics.","PeriodicalId":354759,"journal":{"name":"Statistical Modeling","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125143988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Binomial thinning models for integer time series 整数时间序列的二项细化模型

Statistical Modeling Pub Date : 2006-07-01 DOI: 10.1191/1471082X06st114oa

Robert C. Jung, A. Tremayne

引用次数: 73

Space-cohort Bayesian models in ecological studies 生态学研究中的空间队列贝叶斯模型

Statistical Modeling Pub Date : 2006-07-01 DOI: 10.1191/1471082X06st111oa

D. Catelan, A. Biggeri, E. Dreassi, C. Lagazio

{"title":"Space-cohort Bayesian models in ecological studies","authors":"D. Catelan, A. Biggeri, E. Dreassi, C. Lagazio","doi":"10.1191/1471082X06st111oa","DOIUrl":"https://doi.org/10.1191/1471082X06st111oa","url":null,"abstract":"The ecological association between ‘low educational level′ and lung cancer mortality, both recorded at municipality level, is investigated. Six birth cohorts were retained from 1905 to 1940. Education data were derived from censuses of the period 1921-91. The education score was defined as prevalence of less educated people and was measured on a relative scale, defining a different threshold for ‘low educational level′ at each census. Four potentially relevant ages at first exposure were defined (20, 30, 40,50) to explore the temporal pattern of the disease. Thus, mortality in each cohort was matched to relative education at different periods corresponding to different ages at first exposure. The relevance of each age at first exposure and the degree of association between education and lung cancer mortality (males, Tuscany, 1971-99) were evaluated, defining a set of hierarchical Bayesian models, each corresponding to a different aetiologic hypothesis. Results show an inverse relationship between low education score and mortality for lung cancer, whose intensity decreases by cohort and becomes positive in the last one. This association was more evident for age at first exposure in the range 20-30 years. These results are consistent with the epidemiological transition of risk factors among socioeconomic classes and are coherent with the biological model of initiating carcinogen agents.","PeriodicalId":354759,"journal":{"name":"Statistical Modeling","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124561575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Comparing vocational training courses through a discrete-time multilevel hazard model 通过离散时间多层风险模型比较职业培训课程

Statistical Modeling Pub Date : 2006-07-01 DOI: 10.1191/1471082X06st115oa

O. Paccagnella

引用次数: 6

A hierarchical Bayesian model for a variability analysis of measurements of occupational n-hexane exposure in Italy 一个层次贝叶斯模型的可变性分析测量的职业正己烷暴露在意大利

Statistical Modeling Pub Date : 2006-07-01 DOI: 10.1191/1471082X06st110oa

S. Toti, A. Biggeri, A. Baldasseroni

引用次数: 1

Estimation and filtering by reversible jump MCMC for a doubly stochastic Poisson model for ultra-high-frequency financial data 超高频金融数据双随机泊松模型的可逆跳变MCMC估计与滤波

Statistical Modeling Pub Date : 2006-07-01 DOI: 10.1191/1471082X06st112oa

S. Centanni, M. Minozzo

引用次数: 24

Comment on the logistic-sinh distribution 论物流配送

Statistical Modeling Pub Date : 2006-04-01 DOI: 10.1191/1471082X06st109er

S. Nadarajah, S. Kotz

引用次数: 0

Bayesian semi-parametric accelerated failure time model for paired doubly interval-censored data 成对双间隔截尾数据的贝叶斯半参数加速失效时间模型

Statistical Modeling Pub Date : 2006-04-01 DOI: 10.1191/1471082X06st107oa

A. Komárek, E. Lesaffre

{"title":"Bayesian semi-parametric accelerated failure time model for paired doubly interval-censored data","authors":"A. Komárek, E. Lesaffre","doi":"10.1191/1471082X06st107oa","DOIUrl":"https://doi.org/10.1191/1471082X06st107oa","url":null,"abstract":"In this paper, we propose a methodology which a) evaluates the effect of covariates on doubly interval-censored paired responses, b) is based on minimal parametric assumptions concerning the distributional parts of the model and c) evaluates the association between the two responses of the pair. Our methodology tackles three research questions arising from the Signal Tandmobiel® project, a prospective Flemish (Belgian) longitudinal dental study. The research questions are 1) What is the effect of baseline covariates on the time-to-caries of the permanent right first molars? 2) Is the effect of the covariates the same for the upper and lower teeth? 3) What is the association between the times-to-caries on the upper and lower teeth? Time-to-caries is defined as the difference of two interval-censored observations, caries time and emergence time, and hence it is a doubly interval-censored response. We suggest using an accelerated failure time model with a bivariate smooth error distribution being a mixture of bivariate normal components defined on a fine fixed grid. To deal with the problem of doubly interval censoring, we use Bayesian methodology and Markov chain Monte Carlo sampling.","PeriodicalId":354759,"journal":{"name":"Statistical Modeling","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124967865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Assessment of variance components in elliptical linear mixed models 椭圆线性混合模型中方差成分的评估

Statistical Modeling Pub Date : 2006-04-01 DOI: 10.1191/1471082X06st104oa

C. Savalli, G. Paula, Francisco Ja Cysneiros

引用次数: 42

Regression models for covariance structures in longitudinal studies 纵向研究中协方差结构的回归模型

Statistical Modeling Pub Date : 2006-04-01 DOI: 10.1191/1471082X06st105oa

Jianxin Pan, G. MacKenzie

引用次数: 45