abstract：:Statistical methods for testing and interval estimation of the ratio of marginal probabilities in the matched-pair setting are considered in this paper. We are especially interested in the situation where the null value is not one, as in one-sided equivalence trials. We propose a Fieller-type statistic based on constr...

journal_title：Statistics in medicine

authors： Nam JM,Blackwelder WC

更新日期：2002-03-15 00:00:00

abstract：:The use of both sequential designs and adaptive treatment allocation are effective in reducing the number of patients receiving an inferior treatment in a clinical trial. In large samples, when the asymptotic normality of test statistics can be utilized, a standard sequential design can be combined with adaptive alloc...

journal_title：Statistics in medicine

authors： Stallard N,Rosenberger WF

更新日期：2002-02-28 00:00:00

abstract：:Recurrent event data are commonly encountered in health-related longitudinal studies. In this paper time-to-events models for recurrent event data are studied with non-informative and informative censorings. In statistical literature, the risk set methods have been confirmed to serve as an appropriate and efficient ap...

journal_title：Statistics in medicine

authors： Wang MC,Chiang CT

更新日期：2002-02-15 00:00:00

abstract：:Longitudinal studies with repeated measures are often subject to non-response. Methods currently employed to alleviate the difficulties caused by missing data are typically unsatisfactory, especially when the cause of the missingness is related to the outcomes. We present an approach for incomplete categorical data in...

journal_title：Statistics in medicine

authors： West CP,Dawson JD

更新日期：2002-01-30 00:00:00

abstract：:The primary goal of a phase I trial is to find the maximally tolerated dose (MTD) of a treatment. The MTD is usually defined in terms of a tolerable probability, q(*), of toxicity. Our objective is to find the highest dose with toxicity risk that does not exceed q(*), a criterion that is often desired in designing pha...

journal_title：Statistics in medicine

authors： Leung DH,Wang YG

更新日期：2002-01-15 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

abstract：:For the meta-analysis of controlled clinical trials with binary outcome a test statistic for testing an overall treatment effect is proposed, which is based on a refined estimator for the variance of the treatment effect estimator usually used in the random-effects model of meta-analysis. In simulation studies it is s...

journal_title：Statistics in medicine

authors： Hartung J,Knapp G

更新日期：2001-12-30 00:00:00

abstract：:For the analysis of time to event data in contraceptive studies when individuals are subject to competing causes for discontinuation, some authors have recently advocated the use of the cumulative incidence rate as a more appropriate measure to summarize data than the complement of the Kaplan-Meier estimate of discont...

journal_title：Statistics in medicine

authors： Farley TM,Ali MM,Slaymaker E

更新日期：2001-12-15 00:00:00

abstract：:A method is proposed to infer the randomized treatment effect on survival after an adjustment for a post-randomization variable. The post-randomization variable is made independent of the treatment assignment and is considered a surrogate for baseline prognostic factors. The relationship between the post-randomization...

journal_title：Statistics in medicine

authors： Heller G

更新日期：2001-11-30 00:00:00

abstract：:Some clinical trials aim to demonstrate therapeutic equivalence on multiple primary endpoints. For example, therapeutic equivalence studies of agents for the treatment of osteoarthritis use several primary endpoints including investigator's global assessment of disease activity, patient's global assessment of response...

journal_title：Statistics in medicine

authors： Quan H,Bolognese J,Yuan W

更新日期：2001-11-15 00:00:00

abstract：:This paper considers the regression analysis of CD4 cell counts, a commonly used indicator and prognostic factor of AIDS progression. For this purpose, a number of methods have been proposed and most of them are based on random effects models. We present an alternative that is based on a mean function regression model...

journal_title：Statistics in medicine

authors： Sun J

更新日期：2001-11-15 00:00:00

abstract：:A statistical definition of surrogate endpoints as well as validation criteria was first presented by Prentice. Freedman et al. supplemented these criteria with the so-called proportion explained. Buyse and Molenberghs pointed to inadequacies of these criteria and suggested a new definition of surrogacy based on (i) t...

journal_title：Statistics in medicine

authors： Molenberghs G,Geys H,Buyse M

更新日期：2001-10-30 00:00:00

abstract：:Correlated response data arise often in biomedical studies. The generalized estimation equation (GEE) approach is widely used in regression analysis for such data. However, there are few methods available to check the adequacy of regression models in GEE. In this paper, a graphical method is proposed based on Cook and...

journal_title：Statistics in medicine

authors： Pan W,Connett JE,Porzio GC,Weisberg S

更新日期：2001-10-15 00:00:00

abstract：:Data monitoring committees (DMCs) have become an increasingly common component of randomized clinical trials in recent years. As experience has accumulated, and more individuals and organizations have become involved in such activities, a variety of approaches to the operation of such committees has inevitably arisen....

journal_title：Statistics in medicine

authors： Ellenberg SS

更新日期：2001-09-15 00:00:00

abstract：:Longitudinal studies are commonly used to study processes of change. Because data are collected over time, missing data are pervasive in longitudinal studies, and complete ascertainment of all variables is rare. In this paper a new imputation strategy for completing longitudinal data sets is proposed. The proposed met...

journal_title：Statistics in medicine

authors： Landrum MB,Becker MP

更新日期：2001-09-15 00:00:00

abstract：:Both traditional phase I designs and the increasingly popular continual reassessment method (CRM) designs select an estimate of maximum tolerable dose (MTD) from among a set of prespecified dose levels. Although CRM designs use an implied dose-response model to select the next dose level, in general it is neither assu...

journal_title：Statistics in medicine

authors： Storer BE

更新日期：2001-08-30 00:00:00

abstract：:Randomized clinical trial designs commonly include one or more planned interim analyses. At these times an external monitoring committee reviews the accumulated data and determines whether it is scientifically and ethically appropriate for the study to continue. With failure-time endpoints, it is common to schedule an...

journal_title：Statistics in medicine

authors： Bagiella E,Heitjan DF

更新日期：2001-07-30 00:00:00

abstract：:Typical analyses of lifetime data treat the time to death or failure as the response variable and use a variety of modelling strategies such as proportional hazards or fully parametric, to investigate the relationship between the response and covariates. In certain circumstances it may be more natural to view the dist...

journal_title：Statistics in medicine

authors： Ghahramani M,Dean CB,Spinelli JJ

更新日期：2001-07-15 00:00:00

abstract：:For the meta-analysis of controlled clinical trials or epidemiological studies, in which the responses are at least approximately normally distributed, a refined test for the hypothesis of no overall treatment effect is proposed. The test statistic is based on a direct estimation function for the variance of the overa...

journal_title：Statistics in medicine

authors： Hartung J,Knapp G

更新日期：2001-06-30 00:00:00

abstract：:A mixture model incorporating long-term survivors has been adopted in the field of biostatistics where some individuals may never experience the failure event under study. The surviving fractions may be considered as cured. In most applications, the survival times are assumed to be independent. However, when the survi...

journal_title：Statistics in medicine

authors： Yau KK,Ng AS

更新日期：2001-06-15 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：: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：:Interpretation of the Mantoux test for tuberculous infection can be complicated by cross-reactions caused by infection with non-specific mycobacteria. Thus, the distribution of positive indurations is a mixture of two distributions. To estimate tuberculous infection prevalence, the marginal distribution of indurations...

journal_title：Statistics in medicine

authors： Nagelkerke NJ,Borgdorff MW,Kim SJ

更新日期：2001-04-15 00:00:00

abstract：:New combination regimens evaluated in phase II cancer clinical trials often show promising results compared to the standard therapy for a disease system. Selection of patients with a better prognosis can be a prominent factor for this optimism. For most disease systems, prognostic variables that are related to the out...

journal_title：Statistics in medicine

authors： Mazumdar M,Fazzari M,Panageas KS

更新日期：2001-03-30 00:00:00

abstract：:In failure time studies involving a chronic disease such as cancer, several competing causes of mortality may be operating. Commonly, the conventional statistical technique of Kaplan-Meier, which is only meaningfully interpreted by assuming independence of failure types and the censoring mechanism, is employed in clin...

journal_title：Statistics in medicine

authors： Tai BC,Machin D,White I,Gebski V,EOI (The European Osteosarcoma Intergroup).

更新日期：2001-03-15 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：:The World Health Organization and collaborating institutions in four developing countries have conducted a multi-centre randomized controlled trial, in which clinics were allocated at random to two antenatal care (ANC) models. These were the standard 'Western' ANC model and a 'new' ANC model consisting of tests, clini...

journal_title：Statistics in medicine

authors： Piaggio G,Carroli G,Villar J,Pinol A,Bakketeig L,Lumbiganon P,Bergsjø P,Al-Mazrou Y,Ba'aqeel H,Belizán JM,Farnot U,Berendes H,WHO Antenatal Care Trial Research Group.

更新日期：2001-02-15 00:00:00

abstract：:Current methods for statistical analysis of twin studies focus on continuous and dichotomous data, while only limited methodology exists for analysing multinomial data. As a consequence, investigators are often tempted to collapse multinomial data into two categories simply to facilitate the analysis. We address this ...

journal_title：Statistics in medicine

authors： Bartfay E,Donner A

更新日期：2001-01-30 00:00:00

abstract：:Recently, Wu and Follmann developed summary measures to adjust for informative drop-out in longitudinal studies where drop-out depends on the underlying true value of the response. In this paper we evaluate these procedures in the common situation where drop-out depends on the observed responses. We also discuss vario...

journal_title：Statistics in medicine

authors： Wu MC,Albert PS,Wu BU

更新日期：2001-01-15 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：:A relationship between baseline risk and treatment effect is increasingly investigated as a possible explanation of between-study heterogeneity in clinical trial meta-analysis. An approach that is still often applied in the medical literature is to plot the estimated treatment effects against the estimated measures of...

journal_title：Statistics in medicine

authors： Arends LR,Hoes AW,Lubsen J,Grobbee DE,Stijnen T

更新日期：2000-12-30 00:00:00

abstract：:Austin Bradford Hill was once a friend to The Lancet, but, as occasionally happens, friends fall out. The great legacy of his association with the journal, however, was Principles of Medical Statistics. As each edition was succeeded by another--the first in 1937, the last in 1991--he seemed to shift his view about the...

journal_title：Statistics in medicine

authors： Horton R

更新日期：2000-12-15 00:00:00

abstract：:We review two recent trends: the emergence of evidence-based medicine and the growing use of Bayesian statistics in medical applications. Evidence-based medicine requires an integrated assessment of the available evidence, and associated uncertainty, but there is also an emphasis on decision-making, for individual pat...

journal_title：Statistics in medicine

authors： Ashby D,Smith AF

更新日期：2000-12-15 00:00:00

abstract：:Ewell and Ibrahim derived the large sample distribution of the logrank statistic under general local alternatives. Their asymptotic results enable us to extend several group sequential designs which allow for early stopping in favour of the null hypothesis to the setting in which the cure rate model is appropriate. In...

journal_title：Statistics in medicine

authors： Patricia Bernardo MV,Ibrahim JG

更新日期：2000-11-30 00:00:00

abstract：:The original article to which this Correction refers was published in Statistics in Medicine 2000 19(14): 1901-1914. ...

journal_title：Statistics in medicine

authors： Edwardes MD

更新日期：2000-11-15 00:00:00

abstract：:In a typical bioequivalence trial, summary measures of the plasma concentration versus time profile are used to compare two formulations of a drug product. Commonly used measures include area under the curve (AUC), maximum plasma concentration (C(max)) and time to maximum concentration (T(max)). Equivalence of these s...

journal_title：Statistics in medicine

authors： Mauger DT,Chinchilli VM

更新日期：2000-10-30 00:00:00

abstract：:The randomized clinical trial, LU19, conducted by the Medical Research Council Lung Cancer Working Party, was designed to compare ACE (doxorubicin, cyclophosphamide and etoposide) chemotherapy plus G-CSF (granulocyte colony-stimulating factor) at 2-week intervals versus ACE chemotherapy alone at standard 3-week interv...

journal_title：Statistics in medicine

authors： Qian W,Parmar MK,Sambrook RJ,Fayers PM,Girling DJ,Stephens RJ

更新日期：2000-10-15 00:00:00

abstract：:This paper describes a method for estimating the risk from a disease over a set of contiguous geographical regions, when data on a potentially important covariate, such as race, are not available. Conditions under which the extra margin can be recovered are suggested. An application to prostate cancer mortality among ...

journal_title：Statistics in medicine

authors： Byers S,Besag J

更新日期：2000-09-15 00:00:00

abstract：:Disease incidence or disease mortality rates for small areas are often displayed on maps. Maps of raw rates, disease counts divided by the total population at risk, have been criticized as unreliable due to non-constant variance associated with heterogeneity in base population size. This has led to the use of model-ba...

journal_title：Statistics in medicine

authors： Stern HS,Cressie N

更新日期：2000-09-15 00:00:00

abstract：:A Non-Parametric Maximum Likelihood approach to the estimation of relative risks in the context of disease mapping is discussed and a NPML approximation to conditional autoregressive models is proposed. NPML estimates have been compared to other proposed solutions (Maximum Likelihood via Monte Carlo Scoring, Hierarchi...

journal_title：Statistics in medicine

authors： Biggeri A,Marchi M,Lagazio C,Martuzzi M,Böhning D

更新日期：2000-09-15 00:00:00