Estimating the stage-specific numbers of HIV infection using a Markov model and back-calculation.

abstract：:We present an estimate of the kappa-coefficient of agreement between two methods of rating based on matched pairs of binary responses and show that the estimate depends on the common intraclass correlation coefficient between the pairs. Via Monte Carlo simulation, we investigate power of the test of significance on ka...

journal_title：Statistics in medicine

authors： Shoukri MM,Martin SW,Mian IU

更新日期：1995-01-15 00:00:00

abstract：:The mixed effect models for repeated measures (MMRM) analysis is sometimes used as a primary analysis in longitudinal randomized clinical trials. The SE for the treatment effect in the MMRM analysis is usually estimated by assuming the orthogonality of the fixed effect and variance-covariance parameters, which is the ...

journal_title：Statistics in medicine

authors： Maruo K,Ishii R,Yamaguchi Y,Doi M,Gosho M

更新日期：2020-04-30 00:00:00

abstract：:We examine the common clinical belief that there is an interaction between epilepsy type and the two standard anti-epileptic drugs, valproate and carbamazepine, using data from several randomized clinical trials. Epilepsy type is not always easy to define, and three possible reclassifications are investigated to see w...

journal_title：Statistics in medicine

authors： Williamson PR,Clough HE,Hutton JL,Marson AG,Chadwick DW

更新日期：2002-09-30 00:00:00

abstract：:This paper, arising out of an event to honour the statistical and scientific contributions of Professor Peter Armitage, is concerned with research strategies and needs for chronic disease prevention. A few highlights from recent intervention trials for the prevention of cancer, cardiovascular disease, fractures and di...

journal_title：Statistics in medicine

authors： Prentice RL

更新日期：2004-11-30 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：:In case-control studies, the Cochran-Armitage (CA) trend test is powerful for detection of an association between a risk allele and a marker. To apply this test, a score should be assigned to the genotypes based on the genetic model. When the underlying genetic model is unknown, the trend test statistic is a function ...

journal_title：Statistics in medicine

authors： Zheng G

更新日期：2003-08-30 00:00:00

abstract：:The cost and efficiency of training clinical centre staff and of duplicate data entry in clinical trials is reviewed. Training is an essential component of quality assurance programmes and it is usually carried out at regular intervals in long-term clinical trials. Initial training of staff and regular retraining is i...

journal_title：Statistics in medicine

authors： Neaton JD,Duchene AG,Svendsen KH,Wentworth D

更新日期：1990-01-01 00:00:00

abstract：:This paper introduces a new spatial scan statistic designed to adjust cluster detection for longitudinal confounding factors indexed in space. The functional-model-adjusted statistic was developed using generalized functional linear models in which longitudinal confounding factors were considered to be functional cova...

journal_title：Statistics in medicine

authors： Ahmed MS,Genin M

更新日期：2020-04-15 00:00:00

abstract：:When analyzing time to disease recurrence, we sometimes need to work with data where all the recurrences are recorded, but no information is available on the possible deaths. This may occur when studying diseases of benign nature where patients are only seen at disease recurrences or in poorly-designed registries of b...

journal_title：Statistics in medicine

authors： Štupnik T,Pohar Perme M

更新日期：2016-03-30 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：:A number of variance formulae for the attributable fraction have been presented, but none is consistent in sparse data, such as found in individually matched case-control studies. This paper employs Mantel-Haenszel estimation to derive variance estimators for attributable fractions that are dually consistent, that is,...

journal_title：Statistics in medicine

authors： Greenland S

更新日期：1987-09-01 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：:Ordinal data appear in a wide variety of scientific fields. These data are often analyzed using ordinal logistic regression models that assume proportional odds. When this assumption is not met, it may be possible to capture the lack of proportionality using a constrained structural relationship between the odds and t...

journal_title：Statistics in medicine

authors： Capuano AW,Dawson JD

更新日期：2013-06-15 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

abstract：:Identification of treatment selection biomarkers has become very important in cancer drug development. Adaptive enrichment designs have been developed for situations where a unique treatment selection biomarker is not apparent based on the mechanism of action of the drug. With such designs, the eligibility rules may b...

journal_title：Statistics in medicine

authors： Simon R,Simon N

更新日期：2017-11-20 00:00:00

abstract：:Conventional seamless phase 2/3 design with fixed sample size determination (SSD) has gained its popularity in oncology drug development due to attractive features such as significantly shortening the development timeline, minimizing sample size, as well as early decision making. However, this design is not immune to ...

journal_title：Statistics in medicine

authors： Teng Z,Tian Y,Liu Y,Liu G

更新日期：2020-08-15 00:00:00

abstract：:When designing a study to develop a new prediction model with binary or time-to-event outcomes, researchers should ensure their sample size is adequate in terms of the number of participants (n) and outcome events (E) relative to the number of predictor parameters (p) considered for inclusion. We propose that the mini...

journal_title：Statistics in medicine

authors： Riley RD,Snell KI,Ensor J,Burke DL,Harrell FE Jr,Moons KG,Collins GS

更新日期：2019-03-30 00:00:00

abstract：:To study the spread of sexually transmitted diseases (STDs) using social/sexual mixing models, one must have quantitative information about sexual mixing. An unavoidable complication in gathering such information by survey is that members of the surveyed population will almost certainly have sexual contacts outside th...

journal_title：Statistics in medicine

authors： Rubin G,Umbach D,Shyu SF,Castillo-Chavez C

更新日期：1992-09-15 00:00:00

abstract：:Cross-sectional designs are often used to monitor the proportion of infections and other post-surgical complications acquired in hospitals. However, conventional methods for estimating incidence proportions when applied to cross-sectional data may provide estimators that are highly biased, as cross-sectional designs t...

journal_title：Statistics in medicine

authors： Fluss R,Mandel M,Freedman LS,Weiss IS,Zohar AE,Haklai Z,Gordon ES,Simchen E

更新日期：2013-06-30 00:00:00

abstract：:A new testing approach is described for improving statistical tests of independence in sets of tables stratified on one or more relevant factors in case of categorical (nominal or ordinal) variables. Common tests of independence that exploit the ordinality of one of the variables use a restricted-alternative approach....

journal_title：Statistics in medicine

authors： Iannario M,Lang JB

更新日期：2016-11-10 00:00:00

abstract：:The first randomized clinical trial at the National Cancer Institute (NCI), planned in 1954, commenced in 1955 for the treatment of patients with acute leukaemia. The programme in clinical trials at NCI had strong influence from the clinician and administrator, C. Gordon Zubrod, who introduced the randomized clinical ...

journal_title：Statistics in medicine

authors： Gehan EA,Schneiderman MA

更新日期：1990-08-01 00:00:00

abstract：:The risk that a drug newly introduced into medical use will occasionally cause adverse reactions is neither negligible nor totally avoidable. Only well organized systems of monitoring can bring early detection and appropriate action. These in turn require either detailed supervision or spontaneous reporting. The paper...

journal_title：Statistics in medicine

authors： Finney DJ

更新日期：1982-04-01 00:00:00

abstract：:In the pharmaceutical industry, some tests for quality assurance before, during and after the manufacture of a drug product involve a two-stage sampling technique. We propose statistical testing procedures in a two-stage sampling problem with large within-class sample sizes. We also derive a two-stage sampling plan by...

journal_title：Statistics in medicine

authors： Shao J,Chow SC

更新日期：1993-11-15 00:00:00

abstract：:Mesothelioma is a rare cancer caused by exposure to asbestos. Belgium has a known long history of asbestos production, resulting in one of the highest mesothelioma mortality rates worldwide. While the production of asbestos has stopped completely, the long latency period of mesothelioma, which can fluctuate between 20...

journal_title：Statistics in medicine

authors： Petrof O,Neyens T,Nuyts V,Nackaerts K,Nemery B,Faes C

更新日期：2020-11-20 00:00:00

abstract：:Kappa coefficients are measures of correlation between categorical variables often used as reliability or validity coefficients. We recapitulate development and definitions of the K (categories) by M (ratings) kappas (K x M), discuss what they are well- or ill-designed to do, and summarize where kappas now stand with ...

journal_title：Statistics in medicine

authors： Chmura Kraemer H,Periyakoil VS,Noda A

更新日期：2002-07-30 00:00:00

abstract：:Pattern-mixture models (PMM) and selection models (SM) are alternative approaches for statistical analysis when faced with incomplete data and a nonignorable missing-data mechanism. Both models make empirically unverifiable assumptions and need additional constraints to identify the parameters. Here, we first introduc...

journal_title：Statistics in medicine

authors： Kaciroti NA,Raghunathan T

更新日期：2014-11-30 00:00:00

abstract：:There is an increasing interest in the use of propensity score methods to estimate causal effects in observational studies. However, recent systematic reviews have demonstrated that propensity score methods are inconsistently used and frequently poorly applied in the medical literature. In this study, we compared the ...

journal_title：Statistics in medicine

authors： Austin PC,Mamdani MM

更新日期：2006-06-30 00:00:00

abstract：:Risk prediction models play an important role in prevention and treatment of several diseases. Models that are in clinical use are often refined and improved. In many instances, the most efficient way to improve a successful model is to identify subgroups for which there is a specific biological rationale for improvem...

journal_title：Statistics in medicine

authors： Biswas S,Arun B,Parmigiani G

更新日期：2014-05-20 00:00:00

abstract：:Blinded estimation of variance allows for changing the sample size without compromising the integrity of the trial. Some of the methods that estimate the variance in a blinded manner either make untenable assumptions or are only applicable to two-treatment trials. We propose a new method for continuous endpoints that ...

journal_title：Statistics in medicine

authors： Xing B,Ganju J

更新日期：2005-06-30 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

authors： Zhao L,Murray S,Mariani LH,Ju W

更新日期：2020-11-20 00:00:00