Individualizing drug dosage with longitudinal data.

abstract：:In designed longitudinal studies, information from the same set of subjects are collected repeatedly over time. The longitudinal measurements are often subject to missing data which impose an analytic challenge. We propose a functional multiple imputation approach modeling longitudinal response profiles as smooth curv...

journal_title：Statistics in medicine

authors： He Y,Yucel R,Raghunathan TE

更新日期：2011-05-10 00:00:00

abstract：:The most popular model used for survival analysis is the proportional hazards regression model proposed by Cox. This is mainly due to its exceptional simplicity. Nevertheless the fundamental assumption of the Cox model is the proportionality of the hazards. For many applications, however, this assumption is doubtful. ...

journal_title：Statistics in medicine

authors： Berger U,Schäfer J,Ulm K

更新日期：2003-04-15 00:00:00

abstract：:We present a new method of detection and inference for spatial clusters of a disease. To avoid ad hoc procedures to test for clustering, we have a clearly defined alternative hypothesis and our test statistic is based on the likelihood ratio. The proposed test can detect clusters of any size, located anywhere in the s...

journal_title：Statistics in medicine

authors： Kulldorff M,Nagarwalla N

更新日期：1995-04-30 00:00:00

abstract：:Between-community variance or community-by-time variance is one of the key factors driving the cost of conducting group randomized trials, which are often very expensive. We investigated empirically whether between-community variance could be reduced by controlling individual- and/or community-level covariates and ide...

journal_title：Statistics in medicine

authors： Feng Z,Diehr P,Yasui Y,Evans B,Beresford S,Koepsell TD

更新日期：1999-03-15 00:00:00

abstract：:For clinical trials with multiple treatment arms or endpoints a variety of sequentially rejective, weighted Bonferroni-type tests have been proposed, such as gatekeeping procedures, fixed sequence tests, and fallback procedures. They allow to map the difference in importance as well as the relationship between the var...

journal_title：Statistics in medicine

authors： Bretz F,Maurer W,Brannath W,Posch M

更新日期：2009-02-15 00:00:00

abstract：:Testing the equality of 2 proportions for a control group versus a treatment group is a well-researched statistical problem. In some settings, there may be strong historical data that allow one to reliably expect that the control proportion is one, or nearly so. While one-sample tests or comparisons to historical cont...

journal_title：Statistics in medicine

authors： Gabriel EE,Nason M,Fay MP,Follmann DA

更新日期：2018-03-30 00:00:00

abstract：:This paper presents a simple method for estimation of population vaccination effectiveness, which is the fraction of disease cases prevented by a vaccination programme. The method is based on the susceptible-infectious-recovered (SIR) model for the spread of an epidemic in a heterogeneous population under non-homogene...

journal_title：Statistics in medicine

authors： Haber M

更新日期：1997-03-30 00:00:00

abstract：:The Jimma Infant Survival Differential Longitudinal Study is an Ethiopian study, set up to establish risk factors affecting infant survival and to investigate socio-economic, maternal and infant-rearing factors that contribute most to the child's early survival. Here, a subgroup of about 1500 children born in Jimma to...

journal_title：Statistics in medicine

authors： Lesaffre E,Asefa M,Verbeke G

更新日期：1999-04-15 00:00:00

abstract：:We give up-to-date methods for estimating the age-specific incidence of a disease and for estimating the effect of risk factors. We recommend taking age as the basic time scale of the analysis; then, the hazard function can be interpreted as the age-specific incidence of the disease. This choice raises a delayed entry...

journal_title：Statistics in medicine

authors： Commenges D,Letenneur L,Joly P,Alioum A,Dartigues JF

更新日期：1998-09-15 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：:Assessing the QT prolongation potential of a drug is typically done based on pivotal safety studies called thorough QT studies. Model-based estimation of the drug-induced QT prolongation at the estimated mean maximum drug concentration could increase efficiency over the currently used intersection-union test. However,...

journal_title：Statistics in medicine

authors： Dosne AG,Bergstrand M,Karlsson MO,Renard D,Heimann G

更新日期：2017-10-30 00:00:00

abstract：:The one-step (Peto) method for obtaining pooled effect estimates can yield extremely biased results when applied to unbalanced data. Even for balanced studies, the one-step estimate may incorporate an unacceptable degree of bias. In place of the one-step estimate, we recommend use of ordinary Mantel-Haenszel, weighted...

journal_title：Statistics in medicine

authors： Greenland S,Salvan A

更新日期：1990-03-01 00:00:00

abstract：:Phase II trials often test the null hypothesis H(0): p or=p(1), where p is the true unknown proportion responding to the new treatment, p(0) is the greatest response proportion which is deemed clinically ineffective, and p(1) is the smallest response proportion which is deemed clinically effe...

journal_title：Statistics in medicine

authors： Ayanlowo AO,Redden DT

更新日期：2007-03-30 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：:Population heterogeneity is frequently observed among patients' treatment responses in clinical trials because of various factors such as clinical background, environmental, and genetic factors. Different subpopulations defined by those baseline factors can lead to differences in the benefit or safety profile of a the...

journal_title：Statistics in medicine

authors： Chiu YD,Koenig F,Posch M,Jaki T

更新日期：2018-12-20 00:00:00

abstract：:Log-linear models for capture-recapture type data are widely used for estimating sizes of populations. Log-linear methods model conditional interactions between the sources. Often, however, the marginal associations are more appropriate and easier for the practitioner to conceptualize. Analyses here of previously publ...

journal_title：Statistics in medicine

authors： Regal RR,Hook EB

更新日期：1998-01-15 00:00:00

abstract：:Determination of the equation that relates an ordered dependent variable to ordered independent variables is sought. One solution, non-parametric discriminant analysis (NPD), involves obtaining the best monotonic step function by means of a computer search procedure. Although one can use alternative selection criteria...

journal_title：Statistics in medicine

authors： Johnston B,Seshia SS

更新日期：1992-06-15 00:00:00

abstract：:This paper develops methods of analysis for active extension clinical trials. Under this design, patients are randomized to treatment or placebo for a period of time (period 1), and then all patients receive treatment for an additional period of time (period 2). We assume a continuous outcome is measured at baseline a...

journal_title：Statistics in medicine

authors： Hu Z,Follmann D

更新日期：2007-05-30 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：:In many studies, interest lies in determining whether members of the study population will undergo a particular event of interest. Such scenarios are often termed 'mover-stayer' scenarios, and interest lies in modelling two sub-populations of 'movers' (those who have a propensity to undergo the event of interest) and ...

journal_title：Statistics in medicine

authors： O'Keeffe AG,Tom BD,Farewell VT

更新日期：2013-02-20 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：:Cox proportional hazard regression model is a popular tool to analyze the relationship between a censored lifetime variable with other relevant factors. The semiparametric Cox model is widely used to study different types of data arising from applied disciplines such as medical science, biology, and reliability studie...

journal_title：Statistics in medicine

authors： Ghosh A,Basu A

更新日期：2019-11-30 00:00:00

abstract：:We consider bivariate survival times for heterogeneous populations, where heterogeneity induces deviations in an individual's risk of an event as well as associations between survival times. The heterogeneity is characterized by a bivariate frailty model. We measure the heterogeneity effects through deviations associa...

journal_title：Statistics in medicine

authors： Xue X,Ding Y

更新日期：1999-04-30 00:00:00

abstract：:We consider the problem of identifying subgroups of participants in a clinical trial that have enhanced treatment effect. Recursive partitioning methods that recursively partition the covariate space based on some measure of between groups treatment effect difference are popular for such subgroup identification. The m...

journal_title：Statistics in medicine

authors： Steingrimsson JA,Yang J

更新日期：2019-09-20 00:00:00

abstract：:Group sequential hypothesis testing is now widely used to analyze prospective data. If Monte Carlo simulation is used to construct the signaling threshold, the challenge is how to manage the type I error probability for each one of the multiple tests without losing control on the overall significance level. This paper...

journal_title：Statistics in medicine

authors： Silva IR

更新日期：2016-04-30 00:00:00

abstract：:Frailty models are encountered in many medical applications, yet little research has been devoted to develop measures that quantify the predictive ability of these models. In this paper, we elaborate on the concept of the concordance probability to clustered data, resulting in an 'Overall Conditional C-index' or bfC(O...

journal_title：Statistics in medicine

authors： Van Oirbeek R,Lesaffre E

更新日期：2010-12-30 00:00:00

abstract：:This paper presents tables analogous to T-tables for use in the 2 x 2 multinomial trial, where the continuity corrected Z-statistic is used to make exact unconditional inference. This is the first solution of a discrete exact unconditional inference problem involving a multivariate nuisance parameter for which no anci...

journal_title：Statistics in medicine

authors： Shuster JJ

更新日期：1992-05-01 00:00:00

abstract：:One may encounter the application of the two independent samples t-test to ordinal scaled data (for example, data that assume only the values 0, 1, 2, 3) from small samples. This situation clearly violates the underlying normality assumption for the t-test and one cannot appeal to large sample theory for validity. In ...

journal_title：Statistics in medicine

authors： Heeren T,D'Agostino R

更新日期：1987-01-01 00:00:00

abstract：:The identification of new adverse drug reactions is often tricky. For a given case, the relationship between drug exposure and symptom occurrence is usually questionable. It could be investigated statistically from a series of drug-event association cases with an independence test between the two variables. Analysing ...

journal_title：Statistics in medicine

authors： Tubert P,Begaud B

更新日期：1991-06-01 00:00:00

abstract：:We investigate a binary partitioning algorithm in the case of a continuous repeated measures outcome. The procedure is based on the use of the likelihood ratio statistic to evaluate the performance of individual splits. The procedure partitions a set of longitudinal data into two mutually exclusive groups based on an ...

journal_title：Statistics in medicine

authors： Abdolell M,LeBlanc M,Stephens D,Harrison RV

更新日期：2002-11-30 00:00:00