Stochastically curtailed phase II clinical trials.

abstract：:Linear mixed effects (LME) models are increasingly used for analyses of biological and biomedical data. When the multivariate normal assumption is not adequate for an LME model, then a robust estimation approach is preferable to the maximum likelihood one. M-estimators were considered before for robust estimation of t...

journal_title：Statistics in medicine

authors： Chervoneva I,Vishnyakov M

更新日期：2011-06-30 00:00:00

abstract：:In some randomized controlled trials, subjects with a better prognosis may be diverted into the treatment group. This subverting of randomization results in an unobserved non-compliance with the originally intended treatment assignment. Consequently, the estimate of treatment effect from these trials may be biased. Th...

journal_title：Statistics in medicine

authors： Marcus SM

更新日期：2001-02-28 00:00:00

abstract：:In observational studies, many continuous or categorical covariates may be related to an outcome. Various spline-based procedures or the multivariable fractional polynomial (MFP) procedure can be used to identify important variables and functional forms for continuous covariates. This is the main aim of an explanatory...

journal_title：Statistics in medicine

authors： Binder H,Sauerbrei W,Royston P

更新日期：2013-06-15 00:00:00

abstract：:This paper introduces a dynamic clustering methodology based on multi-valued descriptors of dermoscopic images. The main idea is to support medical diagnosis to decide if pigmented skin lesions belonging to an uncertain set are nearer to malignant melanoma or to benign nevi. Melanoma is the most deadly skin cancer, an...

journal_title：Statistics in medicine

authors： Cozza V,Guarracino MR,Maddalena L,Baroni A

更新日期：2011-09-10 00:00:00

abstract：:Arming the immune system against cancer has emerged as a powerful tool in oncology during recent years. Instead of poisoning a tumor or destroying it with radiation, therapeutic cancer vaccine, a type of cancer immunotherapy, unleashes the immune system to combat cancer. This indirect mechanism-of-action of vaccines p...

journal_title：Statistics in medicine

authors： Xu Z,Zhen B,Park Y,Zhu B

更新日期：2017-02-20 00:00:00

abstract：:In the study of multiple failure times for the same subjects, for example, recurrent infections for patients with a given disease, there are often subject effects, that is, subjects have different risks that cannot be explained by known covariates. Standard methods, which ignore subject effects, lead to overestimation...

journal_title：Statistics in medicine

authors： Yau KK,McGilchrist CA

更新日期：1998-06-15 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 matched case-control designs are commonly used to control for potential confounding factors in genetic epidemiology studies especially epigenetic studies with DNA methylation. Compared with unmatched case-control studies with high-dimensional genomic or epigenetic data, there have been few variable selection metho...

journal_title：Statistics in medicine

authors： Sun H,Wang S

更新日期：2013-05-30 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

authors： Taylor JM,Shen J,Kennedy EH,Wang L,Schaubel DE

更新日期：2014-01-30 00:00:00

abstract：:Girardeau, Ravaud and Donner in 2008 presented a formula for sample size calculations for cluster randomised crossover trials, when the intracluster correlation coefficient, interperiod correlation coefficient and mean cluster size are specified in advance. However, in many randomised trials, the number of clusters is...

journal_title：Statistics in medicine

authors： Kelly TL,Pratt N

更新日期：2019-08-15 00:00:00

abstract：BACKGROUND:It has been recommended that onset of antidepressant action be assessed using survival analyses with assessments taken at least twice per week. However, such an assessment schedule is problematic to implement. The present study assessed the feasibility of comparing onset of action between treatments using a ...

journal_title：Statistics in medicine

authors： Mallinckrodt CH,Detke MJ,Kaiser CJ,Watkin JG,Molenberghs G,Carroll RJ

更新日期：2006-07-30 00:00:00

abstract：:Weak measurement of epidemiologic exposures is an impediment to appreciation of the effects of those exposures. This paper discusses two strategies to assess the true effects of weakly measured exposure. The first is to use external information about the extent of mismeasurement to adjust estimates of the effects of e...

journal_title：Statistics in medicine

authors： Marshall JR

更新日期：1989-09-01 00:00:00

abstract：:A new method is proposed for the surveillance of Down's syndrome among newborn. Despite the strong dependence of overall risk of Down's syndrome on maternal age, it has been suggested that an environmentally induced increase in risk may be additive over all maternal ages. The surveillance method introduced here is spe...

journal_title：Statistics in medicine

authors： Lie RT,Heuch I,Irgens LM

更新日期：1993-01-15 00:00:00

abstract：:Researchers in clinical science and bioinformatics frequently aim to learn which of a set of candidate biomarkers is important in determining a given outcome, and to rank the contributions of the candidates accordingly. This article introduces a new approach to research questions of this type, based on targeted maximu...

journal_title：Statistics in medicine

authors： Bembom O,Petersen ML,Rhee SY,Fessel WJ,Sinisi SE,Shafer RW,van der Laan MJ

更新日期：2009-01-15 00:00:00

abstract：:The problem of testing symmetry about zero has a long and rich history in the statistical literature. We introduce a new test that sequentially discards observations whose absolute value is below increasing thresholds defined by the data. McNemar's statistic is obtained at each threshold and the largest is used as the...

journal_title：Statistics in medicine

authors： Laska E,Meisner M,Wanderling J

更新日期：2012-11-20 00:00:00

abstract：:The mutation and natural selection phenomenon can and often does cause the failure of antimicrobial, herbicidal, pesticide and cancer treatments selection pressures. This phenomenon operates in a mathematically predictable behavior, which when understood leads to approaches to reduce and prevent the failure of the use...

journal_title：Statistics in medicine

authors： Kleinman A

更新日期：2014-12-20 00:00:00

abstract：:A new, intuitive method has recently been proposed to explore treatment-covariate interactions in survival data arising from two treatment arms of a clinical trial. The method is based on constructing overlapping subpopulations of patients with respect to one (or more) covariates of interest and in observing the patte...

journal_title：Statistics in medicine

authors： Bonetti M,Zahrieh D,Cole BF,Gelber RD

更新日期：2009-04-15 00:00:00

abstract：:In the last decade or so, pharmaceutical drug development activities in the area of new antibacterial drugs for treating serious bacterial diseases have declined, and at the same time, there are worries that the increased prevalence of antibiotic-resistant bacterial infections, especially the increase in drug-resistan...

journal_title：Statistics in medicine

authors： Huque MF,Valappil T,Soon GG

更新日期：2014-11-10 00:00:00

abstract：:Lower urinary tract symptoms can indicate the presence of urinary tract infection (UTI), a condition that if it becomes chronic requires expensive and time consuming care as well as leading to reduced quality of life. Detecting the presence and gravity of an infection from the earliest symptoms is then highly valuable...

journal_title：Statistics in medicine

authors： Barcella W,Iorio MD,Baio G,Malone-Lee J

更新日期：2016-04-15 00:00:00

abstract：:We propose a semiparametric method for estimating ROC surfaces for continuous diagnostic tests based on two test measurements. Such a three-class diagnostic problem based on two test measurements arises naturally from some DNA amplification-related diagnostic scenarios. Simulation results show that our proposed semipa...

journal_title：Statistics in medicine

authors： Wan S,Zhang B

更新日期：2009-08-15 00:00:00

abstract：:We applied a two-stage random effects model to pulmonary function data from 31 sarcoidosis patients to illustrate its usefulness in analysing unbalanced longitudinal data. For the first stage, repeated measurements of percentage of predicted forced vital capacity (FVC%) from an individual were modelled as a function o...

journal_title：Statistics in medicine

authors： Vacek PM,Mickey RM,Bell DY

更新日期：1989-02-01 00:00:00

abstract：:Meta-analyses of clinical trials are increasingly seeking to go beyond estimating the effect of a treatment and may also aim to investigate the effect of other covariates and how they alter treatment effectiveness. This requires the estimation of treatment-covariate interactions. Meta-regression can be used to estimat...

journal_title：Statistics in medicine

authors： Simmonds MC,Higgins JP

更新日期：2007-07-10 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：:Machine learning techniques such as classification and regression trees (CART) have been suggested as promising alternatives to logistic regression for the estimation of propensity scores. The authors examined the performance of various CART-based propensity score models using simulated data. Hypothetical studies of v...

journal_title：Statistics in medicine

authors： Lee BK,Lessler J,Stuart EA

更新日期：2010-02-10 00:00:00

abstract：:This paper describes compliance with the completion of a quality of life questionnaire in the Breast Cancer Prevention Trial, a large multi-centre randomized trial that is studying the efficacy of Tamoxifen in preventing breast cancer. In the first 4875 women enrolled in the control arm of the study, there was a very ...

journal_title：Statistics in medicine

authors： Ganz PA,Day R,Costantino J

更新日期：1998-03-15 00:00:00

abstract：:Multivariate finite mixture models have been applied to the identification of dietary patterns. These models are known to have many parameters, and consequently large samples are usually required. We present a special case of a multivariate mixture model that reduces the number of parameters to be estimated and seems ...

journal_title：Statistics in medicine

authors： Rita Gaio A,Costa JP,Santos AC,Ramos E,Lopes C

更新日期：2012-08-30 00:00:00

abstract：:We propose a new design for dose finding for cytotoxic agents in two ordered groups of patients. By ordered groups, we mean that prior to the study there is clinical information that would indicate that for a given dose one group would be more susceptible to toxicities than patients in the other group. The designs are...

journal_title：Statistics in medicine

authors： Conaway MR,Wages NA

更新日期：2017-01-30 00:00:00

abstract：:Conditional power (CP) is the probability that the final study result will be statistically significant, given the data observed thus far and a specific assumption about the pattern of the data to be observed in the remainder of the study, such as assuming the original design effect, or the effect estimated from the c...

journal_title：Statistics in medicine

authors： Lachin JM

更新日期：2005-09-30 00:00:00

abstract：:It is often assumed that randomisation will prevent bias in estimation of treatment effects from clinical trials, but this is not true of the semiparametric Proportional Hazards model for survival data when there is underlying risk heterogeneity. Here, a new formula is proposed for estimation of this bias, improving o...

journal_title：Statistics in medicine

authors： McNamee R

更新日期：2017-09-20 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