Abstract:
:Screening for a disease such as cancer is often regarded as a beneficial and successful strategy for reducing mortality. However, as with any clinical treatment or intervention, benefit cannot be assumed, and screening can entail both costs and harms, so the screening as a 'treatment' must undergo evaluation. An evaluation requires a definition of the treatment 'benefit', design of studies to measure that benefit with as little bias and variance as possible, and the development of methods for estimating the potential benefit. In screening studies, the factors most central to the evaluation are unobservable (e.g. earliest point in time at which disease becomes detectable, or 'preclinical'; time at which disease might have been detected in the absence of screening; test sensitivity). Thus, screening programs should be evaluated on scenarios in which these factors are varied, to ensure the robustness of the estimated benefit under a variety of circumstances. This article describes the importance of computational methods and simulations to assess the benefit of screening programs, particularly for cancer, based on randomized screening trials, with special attention to benefit time, lead time, and bias due to length-biased sampling.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Kafadar K,Prorok PCdoi
10.1002/sim.2037subject
Has Abstractpub_date
2005-02-28 00:00:00pages
569-81issue
4eissn
0277-6715issn
1097-0258journal_volume
24pub_type
杂志文章abstract::Longitudinal studies are often concerned with estimating the recurrence rate of a non-fatal event. In many cases, only the total number of events occurring during successive time intervals is known. We compared a mixed Poisson-gamma regression method proposed by Thall and a quasi-likelihood method proposed by Zeger an...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1002/sim.4780121406
更新日期:1993-07-30 00:00:00
abstract::Generalized linear models may be extended in several ways. This paper describes five such extensions: (i) generalized additive models; (ii) the use of quasi-likelihood; (iii) joint modelling of mean and dispersion; (iv) introduction of extra random components to give hierarchical generalized linear models; (v) modelli...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19981215)17:23<2747::aid-s
更新日期:1998-12-15 00:00:00
abstract::Bioequivalence or interaction trials are commonly studied in crossover design and can be analysed by nonlinear mixed effects models as an alternative to noncompartmental approach. We propose an extension of the population Fisher information matrix in nonlinear mixed effects models to design crossover pharmacokinetic t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4390
更新日期:2012-05-20 00:00:00
abstract::It has been increasingly common to analyze simultaneously repeated measures and time to failure data. In this paper we propose a joint model when the repeated measures are semi-continuous, characterized by the presence of a large portion of zero values, as well as right skewness of non zero (positive) values. Examples...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3497
更新日期:2009-03-15 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
pub_type: 杂志文章
doi:10.1002/sim.4125
更新日期:2011-03-30 00:00:00
abstract::This paper considers the analysis of longitudinal data complicated by the fact that during follow-up patients can be in different disease states, such as remission, relapse or death. If both the response of interest (for example, quality of life (QOL)) and the amount of missing data depend on this disease state, ignor...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3755
更新日期:2009-12-30 00:00:00
abstract::Assessing the calibration of methods for estimating the probability of the occurrence of a binary outcome is an important aspect of validating the performance of risk-prediction algorithms. Calibration commonly refers to the agreement between predicted and observed probabilities of the outcome. Graphical methods are a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8281
更新日期:2019-09-20 00:00:00
abstract::The aim of this paper is to demonstrate the effect of excluding incomplete observations and competing events when calculating cross-sectional measures of NHS waiting times, and to obtain a more accurate estimate of the 'time-to-admission' of those listed on NHS waiting lists using life-table methods. The official 'tim...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20000815)19:15<2037::aid-sim606>
更新日期:2000-08-15 00:00:00
abstract::Longitudinal biomarker data are often collected in studies, providing important information regarding the probability of an outcome of interest occurring at a future time. With many new and evolving technologies for biomarker discovery, the number of biomarker measurements available for analysis of disease progression...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8687
更新日期:2020-11-20 00:00:00
abstract::In order for national statistical offices to maintain the trust of the public to collect data and publish statistics of importance to society and decision-making, it is imperative that respondents (persons or establishments) be guaranteed privacy and confidentiality in return for providing requested confidential data....
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2043
更新日期:2005-02-28 00:00:00
abstract::There is a rich literature that considers whether an observed relation between treatment and response is due to an unobserved covariate. In order to quantify this unmeasured bias, an assumption is made about the distribution of this unobserved covariate; typically that it is either binary or at least confined to the u...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2344
更新日期:2006-07-15 00:00:00
abstract::Multilevel and longitudinal studies are frequently subject to missing data. For example, biomarker studies for oral cancer may involve multiple assays for each participant. Assays may fail, resulting in missing data values that can be assumed to be missing completely at random. Catellier and Muller proposed a data ana...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6811
更新日期:2016-07-30 00:00:00
abstract::Sexually transmitted infections (STIs) with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis are among the most common infectious diseases in the United States, disproportionately affecting young women. Because a significant portion of the infections present no symptoms, infection control relies...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6515
更新日期:2015-09-10 00:00:00
abstract::This paper presents a statistical analysis of treatment effects in 24-hour ambulatory blood pressure recordings. The statistical models account for circadian rhythms, subject effects, and the effects of treatment with drugs or relaxation therapy. In view of the heterogeneity of the subjects, we fit a separate linear m...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780070608
更新日期:1988-06-01 00:00:00
abstract::We consider the use of the assurance method in clinical trial planning. In the assurance method, which is an alternative to a power calculation, we calculate the probability of a clinical trial resulting in a successful outcome, via eliciting a prior probability distribution about the relevant treatment effect. This i...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5916
更新日期:2014-01-15 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
pub_type: 临床试验,杂志文章
doi:10.1002/1097-0258(20001015)19:19<2657::aid-sim557>
更新日期:2000-10-15 00:00:00
abstract::We propose a goodness-of-fit test statistic for linear regression with heterogeneous variance, which is asymptotically chi-square if the given model is correct. The test statistic is computed as a quadratic form of observed minus predicted responses. We apply the method to a linear regression for an ordinal categorica...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780130205
更新日期:1994-01-30 00:00:00
abstract::Conditional power and predictive power provide estimates of the probability of success at the end of the trial based on the information from the interim analysis. The observed value of the time to event endpoint at the interim analysis could be biased for the true treatment effect due to early censoring, leading to a ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7673
更新日期:2018-08-15 00:00:00
abstract::Clinical trials of treatments for rare or fatal diseases must often use historical rather than randomized concurrent controls. Randomized trials may not be possible if (1) the number of patients available is quite small, (2) ethical considerations discourage the assignment of patients to control treatments known to be...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780030305
更新日期:1984-07-01 00:00:00
abstract::Increasing numbers of economic evaluations are conducted alongside randomised controlled trials. Such studies include factorial trials, which randomise patients to different levels of two or more factors and can therefore evaluate the effect of multiple treatments alone and in combination. Factorial trials can provide...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7322
更新日期:2017-08-15 00:00:00
abstract::Relative survival provides a measure of the proportion of patients dying from the disease under study without requiring the knowledge of the cause of death. We propose an overall strategy based on regression models to estimate the relative survival and model the effects of potential prognostic factors. The baseline ha...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2656
更新日期:2007-05-10 00:00:00
abstract::Health questionnaires are often built up from sets of questions that are totaled to obtain a sum score. An important consideration in designing questionnaires is to minimize respondent burden. An increasingly popular method for efficient measurement is computerized adaptive testing; unfortunately, many health question...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5936
更新日期:2014-02-10 00:00:00
abstract::The statistical analysis of spatially correlated data has become an important scientific research topic lately. The analysis of the mortality or morbidity rates observed at different areas may help to decide if people living in certain locations are considered at higher risk than others. Once the statistical model for...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20000730)19:14<1915::aid-sim503>
更新日期:2000-07-30 00:00:00
abstract::Slow recruitment in clinical trials leads to increased costs and resource utilization, which includes both the clinic staff and patient volunteers. Careful planning and monitoring of the accrual process can prevent the unnecessary loss of these resources. We propose two hierarchical extensions to the existing Bayesian...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6359
更新日期:2015-02-20 00:00:00
abstract::We survey models for analysing repeated observations on an ordered categorical response variable. The models presented are univariate models that permit correlation among repeated measurements. The models describe simultaneously the dependence of marginal response distributions on values of explanatory variables and o...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780081005
更新日期:1989-10-01 00:00:00
abstract::We examine different methods to pool binary outcomes used both in parallel and cross-over trials. Odds ratio (OR) estimators obtained from joint conditional probabilities in cross-over trials, such as the Mantel-Haenszel and Peto methods, are compared to an OR estimator using marginal results of cross-over trials. Whe...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1206
更新日期:2002-08-15 00:00:00
abstract::Although statistical methodology is well-developed for comparing diagnostic tests in terms of their sensitivity and specificity, comparative inference about predictive values is not. In this paper, we consider the analysis of studies comparing operating characteristics of two diagnostic tests that are measured on all ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6485
更新日期:2015-07-10 00:00:00
abstract::Equivalence trials aim to show that two treatments have equivalent therapeutic effects. The approach is to define, in advance, a range of equivalence -d to +d for the treatment difference such that any value in the range is clinically unimportant. If the confidence interval for the difference, calculated after the tri...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19980815/30)17:15/16<1691:
更新日期:1998-08-15 00:00:00
abstract::There has been substantial statistical literature in the last several decades on assessing agreement, and coverage probability approach was selected as a preferred index for assessing and improving measurement agreement in a core laboratory setting. With this approach, a satisfactory agreement is based on pre-specifie...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6903
更新日期:2016-08-15 00:00:00
abstract::For each of 211 arteriosclerosis obliterans patients, the degree of stenosis of arteries at four sites were examined at Hiroshima University Hospital to analyse the relationship between the degree of stenosis and age, sex and site. The generalized estimating equations using a proportional odds model for the stenosis p...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1363
更新日期:2003-07-15 00:00:00