A semi-parametric Bayesian approach to average bioequivalence.

abstract：:In a phase I clinical trial in cancer patients, the drug involved had one known main adverse effect, which also occurs spontaneously in cancer patients with a fairly high frequency. Experiments in rats have shown marked effects of the drug on tumour growth in high doses, but also dose-dependent toxicity. Consequently,...

journal_title：Statistics in medicine

authors： Møller S

更新日期：1995-05-15 00:00:00

abstract：:A few large multi-centre male-only heart trials done in the 1970s and 1980s have been seen as ill-conceived because they did not include females. The purpose here is to revisit two of those trials and to consider consequences in terms of cost and power had they been designed to include females. ...

journal_title：Statistics in medicine

authors： Meinert CL

更新日期：1999-02-15 00:00:00

abstract：:Confounding is a major concern in observational studies. To adjust for confounding bias, the potential confounder(s) for a study must first be identified and measured. But this is not always possible. The unmeasured factors may also exhibit effect modification, and this further complicates the situation. In this paper...

journal_title：Statistics in medicine

authors： Lee WC

更新日期：2011-04-30 00:00:00

abstract：:Biomedical studies often measure variables with error. Examples in the literature include investigation of the association between the change in some outcome variable (blood pressure, cholesterol level etc.) and a set of explanatory variables (age, smoking status etc.). Typically, one fits linear regression models to ...

journal_title：Statistics in medicine

authors： Yanez ND 3rd,Kronmal RA,Shemanski LR

更新日期：1998-11-30 00:00:00

abstract：:Assessing and comparing the performance of correlated predictive scores are of current interest in precision medicine. Given the limitations of available theoretical approaches for assessing and comparing the predictive accuracy, numerical methods are highly desired which, however, have not been systematically develop...

journal_title：Statistics in medicine

authors： Zhang Y,Shao Y

更新日期：2020-09-10 00:00:00

abstract：:The statistical analysis of panel count data has recently attracted a great deal of attention, and a number of approaches have been developed. However, most of these approaches are for situations where the observation and follow-up processes are independent of the underlying recurrent event process unconditional or co...

journal_title：Statistics in medicine

authors： Li N,Zhao H,Sun J

更新日期：2013-07-30 00:00:00

abstract：:Tree-based methods have become popular for analyzing complex data structures where the primary goal is risk stratification of patients. Ensemble techniques improve the accuracy in prediction and address the instability in a single tree by growing an ensemble of trees and aggregating. However, in the process, individua...

journal_title：Statistics in medicine

authors： Banerjee M,Ding Y,Noone AM

更新日期：2012-07-10 00:00:00

abstract：:Case-control studies are usually defined to investigate risk factors for a single disease of interest. However, subsequent to data collection, investigators may wish to examine as an 'outcome' a variable that was an exposure in the original study. A naive analysis that disregards the sampling strategy that gave rise t...

journal_title：Statistics in medicine

authors： Reilly M,Torrång A,Klint A

更新日期：2005-12-30 00:00:00

abstract：:We study prevalence-dependent diagnostic accuracy measures, specifically, positive and negative predictive values. These measures permit an assessment of the clinical utility of diagnostic tests across populations with different disease prevalences. In many cases, prevalence may not be known with certainty and the eva...

journal_title：Statistics in medicine

authors： Li J,Fine JP,Safdar N

更新日期：2007-07-30 00:00:00

abstract：:Subjective judgements of complex variables are commonly recorded as ordered categorical data. The rank-invariant properties of such data are well known, and there are various statistical approaches to the analysis and modelling of ordinal data. This paper focuses on the non-additive property of ordered categorical dat...

journal_title：Statistics in medicine

authors： Svensson E

更新日期：1998-12-30 00:00:00

abstract：:Interval-censored survival data often occur in medical studies, especially in clinical trials. In this case, many authors have considered estimation of a survival function. There is, however, relatively little discussion on estimating the variance of estimated survival functions. For right-censored data, a special cas...

journal_title：Statistics in medicine

authors： Sun J

更新日期：2001-04-30 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

authors： Taylor JM,Kim DK

更新日期：1994-10-15 00:00:00

abstract：:In this paper the following problem of clinical research is explored. Several potential new treatments are available for use against a certain disease. These are evaluated in a series of pilot studies which will constitute phase II clinical trials. The most promising will then be compared with a standard treatment in ...

journal_title：Statistics in medicine

authors： Whitehead J

更新日期：1986-09-01 00:00:00

abstract：:Among subjects who have experienced a biological event, such as menarche, menopause or a delivery, one cannot distinguish the effects of time since the event from age at the event due to the linear dependency among these time variables and age at study ('current age'). This is a well-known problem that also exists in ...

journal_title：Statistics in medicine

authors： Hsieh CC,Lan SJ

更新日期：1996-07-30 00:00:00

abstract：:This paper discusses and compares several estimators of mean rate of change in unbalanced longitudinal data based on a model with randomly distributed regression coefficients across individuals. The estimators are unweighted and weighted means of these coefficients. The paper also evaluates commonly used variance esti...

journal_title：Statistics in medicine

authors： Palta M,Cook T

更新日期：1987-07-01 00:00:00

abstract：:In analysis of longitudinal data, the variance matrix of the parameter estimates is usually estimated by the 'sandwich' method, in which the variance for each subject is estimated by its residual products. We propose smooth bootstrap methods by perturbing the estimating functions to obtain 'bootstrapped' realizations ...

journal_title：Statistics in medicine

authors： Li Y,Wang YG

更新日期：2008-03-30 00:00:00

abstract：:In vaccine safety studies, subjects are considered at increased risk for adverse events for a period of time after vaccination known as risk window. To our knowledge, risk windows for vaccine safety studies have tended to be pre-defined and not to use information from the current study. Inaccurate specification of the...

journal_title：Statistics in medicine

authors： Xu S,Zhang L,Nelson JC,Zeng C,Mullooly J,McClure D,Glanz J

更新日期：2011-03-30 00:00:00

abstract：:We have used Monte Carlo methods to compare the type I error properties of the conditional and unconditional versions of the generalized t and the generalized rank-sum tests to those of the independent samples t and Wilcoxon rank-sum tests. Results showed inflated type I errors for the conditional generalized tests bu...

journal_title：Statistics in medicine

authors： Blair RC,Morel JG

更新日期：1992-02-28 00:00:00

abstract：:The recent revision of the Declaration of Helsinki and the existence of many new therapies that affect survival or serious morbidity, and that therefore cannot be denied patients, have generated increased interest in active-control trials, particularly those intended to show equivalence or non-inferiority to the activ...

journal_title：Statistics in medicine

authors： Rothmann M,Li N,Chen G,Chi GY,Temple R,Tsou HH

更新日期：2003-01-30 00:00:00

abstract：:We extend the shared frailty model of recurrent events and a dependent terminal event to allow for a nonparametric covariate function. We include a Gaussian random effect (frailty) in the intensity functions of both the recurrent and terminal events to capture correlation between the two processes. We employ the penal...

journal_title：Statistics in medicine

authors： Zhangsheng Y,Liu L

更新日期：2011-09-30 00:00:00

abstract：:Missing data arise in crossover trials, as they do in any form of clinical trial. Several papers have addressed the problems that missing data create, although almost all of these assume that the probability that a planned observation is missing does not depend on the value that would have been observed; that is, the ...

journal_title：Statistics in medicine

authors： Ho WK,Matthews JN,Henderson R,Farewell D,Rodgers LR

更新日期：2012-07-20 00:00:00

abstract：:This work is motivated by a longitudinal study of women and their ectopic pregnancy outcomes in Lund, Sweden. In this article, we review and apply the Liang-Zeger methodology to the Lund ectopic pregnancy data set. We further analyse the ectopic pregnancy data using conditional modelling approaches suggested by Rosner...

journal_title：Statistics in medicine

authors： Hadgu A,Koch G,Westrom L

更新日期：1997-11-15 00:00:00

abstract：:The stability-controlled quasi-experiment (SCQE) is an approach to study the effects of nonrandomized, newly adopted treatments. While covariate adjustment techniques rely on a "no unobserved confounding" assumption, SCQE imposes an assumption on the change in the average nontreatment outcome between successive cohort...

journal_title：Statistics in medicine

authors： Hazlett C,Maokola W,Wulf DA

更新日期：2020-12-10 00:00:00

abstract：:Correlation analysis is widely used in biomedical and psychosocial research for assessing rater reliability, precision of diagnosis and accuracy of proxy outcomes. The popularity of longitudinal study designs has propelled the proliferation in recent years of new methods for longitudinal and other multi-level clustere...

journal_title：Statistics in medicine

authors： Tu XM,Feng C,Kowalski J,Tang W,Wang H,Wan C,Ma Y

更新日期：2007-09-30 00:00:00

abstract：:Elevated plasma levels of apolipoproteins A1 (apoA1) and B (apoB) are important protective factors and risk factors, respectively, for atherosclerosis and coronary heart disease. It is well known that both apoA1 and apoB reveal strong familial aggregation. Our goal was to investigate whether exogenous variables influe...

journal_title：Statistics in medicine

authors： Ziegler A,Kastner C,Brunner D,Blettner M

更新日期：2000-12-30 00:00:00

abstract：:In this study, 401 cases of childhood cancer in four California counties in 1980-1988 were analysed with the innovative methodology of density equalizing map projections. The data were originally collected and analysed by the California State Department of Health Services (DHS). In addition to the new analytic techniq...

journal_title：Statistics in medicine

authors： Merrill DW

更新日期：2001-05-15 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

authors： Huang L,Tiwari RC,Pickle LW,Zou Z

更新日期：2010-10-15 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

authors： Schäfer H,Müller HH

更新日期：2004-05-15 00:00:00

abstract：:A new goodness-of-fit test for the logistic regression model is proposed. It exploits the property of this model that when it is correct, i.e. not misspecified, the parameter estimates are (asymptotically) invariant under reweighting the observations by weights wi that are a function of the binary (0/1) outcomes yi. M...

journal_title：Statistics in medicine

authors： Nagelkerke N,Smits J,le Cessie S,van Houwelingen H

更新日期：2005-01-15 00:00:00

abstract：:A method is presented which allows us to adapt the sample size as well as the number and time points of interim analyses to the treatment difference observed at an interim look during the course of a clinical trial with censored survival time as the endpoint. The method allows the inclusion of data inspections during ...

journal_title：Statistics in medicine

authors： Schäfer H,Müller HH

更新日期：2001-12-30 00:00:00