Longitudinal quantile regression in the presence of informative dropout through longitudinal-survival joint modeling.

abstract：:We compared eight nominal 95 per cent confidence intervals for the ratio of two Poisson parameters, both assumed small, on their true coverage (the probability that the interval includes the ratio of Poisson parameters) and median width. The commonly used log-linear interval, justified by asymptotic considerations, pr...

journal_title：Statistics in medicine

authors： Barker L,Cadwell BL

更新日期：2008-09-10 00:00:00

abstract：:The FDA Guidance, while highly appropriate for industry sponsored trials, need not be imposed on publicly (e.g. NIH) financed clinical trials. While the potential for conflicts of interest exist in the latter, they are in general manageable and pose an acceptable low risk of threatening the integrity of a study. Howev...

journal_title：Statistics in medicine

authors： Lachin JM

更新日期：2004-05-30 00:00:00

abstract：:We discuss some of the statistical approaches to the design and analysis of phase I clinical trials in cancer. An attempt is made to identify the issues, particular to this type of trial, that should be addressed by an appropriate methodology. A brief review of schemes currently in use is provided together with our vi...

journal_title：Statistics in medicine

authors： O'Quigley J,Chevret S

更新日期：1991-11-01 00:00:00

abstract：:In time-to-event analysis, the traditional summary measures have been based on the hazard function, survival function, quantile event time, restricted mean event time, and residual lifetime. Under competing risks, furthermore, typical summary measures have been the cause-specific hazard function and cumulative inciden...

journal_title：Statistics in medicine

authors： Jia Y,Jeong JH

更新日期：2021-01-06 00:00:00

abstract：:Cancer immunotherapy trials have two special features: a delayed treatment effect and a cure rate. Both features violate the proportional hazard model assumption and ignoring either one of the two features in an immunotherapy trial design will result in substantial loss of statistical power. To properly design immunot...

journal_title：Statistics in medicine

authors： Wei J,Wu J

更新日期：2020-03-15 00:00:00

abstract：:Appropriate methods for meta-regression applied to a set of clinical trials, and the limitations and pitfalls in interpretation, are insufficiently recognized. Here we summarize recent research focusing on these issues, and consider three published examples of meta-regression in the light of this work. One principal m...

journal_title：Statistics in medicine

authors： Thompson SG,Higgins JP

更新日期：2002-06-15 00:00:00

abstract：:Estimating the causal effect of quitting smoking on time to death or first myocardial infarction requires that one control for the differences in risk factors between individuals who elect to quite at each time t versus those who elect to continue smoking at time t. In this paper we examine the limitations of standard...

journal_title：Statistics in medicine

authors： Mark SD,Robins JM

更新日期：1993-09-15 00:00:00

abstract：:The back-calculation method has been used to estimate the number of HIV infections from AIDS incidence data in a particular population. We present an extension of back calculation that provides estimates of the numbers of HIV infectives in different stages of infection. We model the staging process with a time-depende...

journal_title：Statistics in medicine

authors： Longini IM Jr,Byers RH,Hessol NA,Tan WY

更新日期：1992-04-01 00:00:00

abstract：:Although all clinical trials are designed and monitored using more than one endpoint, methods are needed to assure that decision criteria are chosen to reflect the clinically relevant tradeoffs that assure the trial's scientific integrity. This article presents a framework for the design and monitoring clinical trials...

journal_title：Statistics in medicine

authors： Hu J,Blatchford PJ,Goldenberg NA,Kittelson JM

更新日期：2020-11-20 00:00:00

abstract：:Reference ranges which take time (such as age) into account are often required in medicine, but simple, systematic and efficient statistical methods for constructing them are lacking. A method is described which is based on low order polynomial curves (linear, quadratic or occasionally cubic), together with guidelines...

journal_title：Statistics in medicine

authors： Royston P

更新日期：1991-05-01 00:00:00

abstract：:We consider the estimation of parameters in a particular segmented generalized linear model with additive measurement error in predictors, with a focus on linear and logistic regression. In epidemiologic studies segmented regression models often occur as threshold models, where it is assumed that the exposure has no i...

journal_title：Statistics in medicine

authors： Küchenhoff H,Carroll RJ

更新日期：1997-01-15 00:00:00

abstract：:A good measure of field vaccine efficacy should evaluate the direct protective effect of vaccination on the person who receives the vaccine. The conventional estimator for vaccine efficacy depends on population level factors that are either unrelated or indirectly related to the direct biological action of the vaccine...

journal_title：Statistics in medicine

authors： Longini IM Jr,Halloran ME,Haber M,Chen RT

更新日期：1993-02-01 00:00:00

abstract：:Spatial scan statistics are widely used for count data to detect geographical disease clusters of high or low incidence, mortality or prevalence and to evaluate their statistical significance. Some data are ordinal or continuous in nature, however, so that it is necessary to dichotomize the data to use a traditional s...

journal_title：Statistics in medicine

authors： Jung I,Kulldorff M,Klassen AC

更新日期：2007-03-30 00:00:00

abstract：:The use of the last observation carried forward (LOCF) method for imputing missing outcome data in randomized clinical trials has been much criticized and its shortcomings are well understood. However, only recently have published studies widely started using more appropriate imputation methods. Consequently, meta-ana...

journal_title：Statistics in medicine

authors： Mavridis D,Salanti G,Furukawa TA,Cipriani A,Chaimani A,White IR

更新日期：2019-02-28 00:00:00

abstract：:Risk prediction procedures can be quite useful for the patient's treatment selection, prevention strategy, or disease management in evidence-based medicine. Often, potentially important new predictors are available in addition to the conventional markers. The question is how to quantify the improvement from the new ma...

journal_title：Statistics in medicine

authors： Uno H,Tian L,Cai T,Kohane IS,Wei LJ

更新日期：2013-06-30 00:00:00

abstract：:With reference to a real data on cataract surgery, we discuss the problem of zero-inflated circular-circular regression when both covariate and response are circular random variables and a large proportion of the responses are zeros. The regression model is proposed, and the estimation procedure for the parameters is ...

journal_title：Statistics in medicine

authors： Jha J,Biswas A

更新日期：2018-01-15 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：:The standard analysis of clinical trials stratified by centre is to include centres as fixed effects, but if many centres contribute small numbers of patients, this approach results in a loss of power. Assuming no treatment by centre interaction, we used simulation to examine power and coverage of confidence intervals...

journal_title：Statistics in medicine

authors： Pickering RM,Weatherall M

更新日期：2007-12-30 00:00:00

abstract：:When interpreting screening mammograms radiologists decide whether suspicious abnormalities exist that warrant the recall of the patient for further testing. Previous work has found significant differences in interpretation among radiologists; their false-positive and false-negative rates have been shown to vary widel...

journal_title：Statistics in medicine

authors： Woodard DB,Gelfand AE,Barlow WE,Elmore JG

更新日期：2007-03-30 00:00:00

abstract：:Performance of a diagnostic test is ideally evaluated by a comparison of the test results to a gold standard for all the patients in a study. In practice, however, it is common for a subset of study patients to have the gold standard not verified (missing) due to ethical or expense considerations. Sensitivity and spec...

journal_title：Statistics in medicine

authors： Kosinski AS,Chen Y,Lyles RH

更新日期：2010-07-10 00:00:00

abstract：:The incremental life expectancy, defined as the difference in mean survival times between two treatment groups, is a crucial quantity of interest in cost-effectiveness analyses. Usually, this quantity is very difficult to estimate from censored survival data with a limited follow-up period. The paper develops estimati...

journal_title：Statistics in medicine

authors： Titman AC

更新日期：2016-09-10 00:00:00

abstract：:The additional time to complete a three-period two-treatment (3P2T) cross-over trial may cause a greater number of patient dropouts than with a two-period trial. This paper develops maximum likelihood (ML), single imputation and multiple imputation missing data analysis methods for the 3P2T cross-over designs. We use ...

journal_title：Statistics in medicine

authors： Richardson BA,Flack VF

更新日期：1996-01-30 00:00:00

abstract：:In many medical and health studies, high-dimensional data are often encountered. Principal component analysis (PCA) is a commonly used technique to reduce such data to a few components that includes most of the information provided by the original data. However, PCA is known to be very sensitive to some abnormal obser...

journal_title：Statistics in medicine

authors： Fung WK,Gu H,Xiang L,Yau KK

更新日期：2007-06-15 00:00:00

abstract：:Binary matched-pairs data occur commonly in longitudinal studies, such as in cross-over experiments. Many analyses for comparing the matched probabilities of a particular outcome do not utilize pairs having the same outcome for each observation. An example is McNemar's test. Some methodologists find this to be counter...

journal_title：Statistics in medicine

authors： Agresti A,Min Y

更新日期：2004-01-15 00:00:00

abstract：:Both the variation of positive responses (negative responses) among individuals and the internal correlation among responses for the same individual affect the precision of the estimate of sensitivity (specificity). To estimate the sensitivity (specificity) of a medical diagnostic test, this paper proposes a Bayesian ...

journal_title：Statistics in medicine

authors： Lui KJ

更新日期：1989-10-01 00:00:00

abstract：:The semi-Markov assumption emphasizes the importance of time spent in a state. In order to compute this type of multistate model, most transition times are always considered to be exactly identified or right censored. However, in the longitudinal analysis of chronic diseases, investigators are often confronted with in...

journal_title：Statistics in medicine

authors： Foucher Y,Giral M,Soulillou JP,Daures JP

更新日期：2007-12-30 00:00:00

abstract：:In randomised trials, continuous endpoints are often measured with some degree of error. This study explores the impact of ignoring measurement error and proposes methods to improve statistical inference in the presence of measurement error. Three main types of measurement error in continuous endpoints are considered:...

journal_title：Statistics in medicine

authors： Nab L,Groenwold RHH,Welsing PMJ,van Smeden M

更新日期：2019-11-30 00:00:00

abstract：:A frequent objective in medical research is the investigation of differences in patient survival between several experimental treatments and one standard treatment. In order to assess these differences statistically, we have to apply adjustments for multiple comparisons to prevent an increased number of false-positive...

journal_title：Statistics in medicine

authors： Herberich E,Hothorn T

更新日期：2012-01-13 00:00:00

abstract：:Logistic regression analysis may well be used to develop a prognostic model for a dichotomous outcome. Especially when limited data are available, it is difficult to determine an appropriate selection of covariables for inclusion in such models. Also, predictions may be improved by applying some sort of shrinkage in t...

journal_title：Statistics in medicine

authors： Steyerberg EW,Eijkemans MJ,Harrell FE Jr,Habbema JD

更新日期：2000-04-30 00:00:00

abstract：:Modelling disease clustering over space and time can be helpful in providing indications of possible exposures and planning corresponding public health practices. Though a considerable number of studies focus on modelling spatio-temporal patterns of disease, most of them do not directly model a spatio-temporal cluster...

journal_title：Statistics in medicine

authors： Yan P,Clayton MK

更新日期：2006-03-15 00:00:00