摘要:

AbstractClinical trials played a dominant and expanding role in the evaluation of new treatments during the decade of the 1980s. There were major improvements in the quality of clinical trials in many medical fields. There were also important developments in the methodology of designing, monitoring, conducting, analysing, reporting and interpreting clinical trials. This paper attempts to review some of these developments. A comprehensive review is beyond the abilities of any one individual. Consequently, this paper attempts to offer a broad stroke description of this area and to highlight specific topics of importance based on my particular experience. An extensive, but non‐comprehensive bibliography is included to provide entry points to the literature of methodologic developments for clinical trials in the 1980

ISSN:0277-6715    

DOI:10.1002/sim.4780101203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper reviews developments in statistical modelling in epidemiology in the 1980's, with emphasis on cohort and case‐control studies. The central roles of the logistic and proportional hazard models are highlighted, and it is shown how these models lead to a deeper understanding of classical designs and methods of analysis as well as to efficient new designs and analytical procedures. The important area of model misspecification is discussed, including the problems of omitted latent structure, mis‐modelling of available measurements, missing data and errors in measurements. Various designs motivated by the logistic model are illustrated numerically, and designs based on the proportional hazards model are discussed, as are papers on sample size determination. There are brief introductions to the literature on other topics, including attributable risk, disease clustering, family studies and genetics, analysis of disease incidence data, infectious disease, longitudinal data, screening and miscellaneous related topics in statistics. An extensive bibliography is indexed according to the outline of the pa

ISSN:0277-6715    

DOI:10.1002/sim.4780101204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractResearch on diagnostic medicine has been directed at a number of topics in the past decade. Issues which have received a lot of attention are ROC analysis and the identification and correction of various analytic biases. Other topics of widespread interest include the use of expert systems, the relationship of such systems to statistical data‐based systems, and the evaluation of tests using cost‐effectiveness analysis. Increasingly there is a sentiment that well‐designed, prospective trials are required to provide credible information on the accuracy of diagnostic technologies, and so a consensus on methodological standards is needed, paralleling the earlier development of such standards in clinical trials and epidemi

ISSN:0277-6715    

DOI:10.1002/sim.4780101205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper reviews changes in the use of statistics in medical journals during the 1980s. Aspects considered are research design, statistical analysis, the presentation of results, medical journal policy (including statistical refereeing), and the misuse of statistics. Despite some notable successes, the misuse of statistics in medical papers remains common.

ISSN:0277-6715    

DOI:10.1002/sim.4780101206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper is intended as an overview of developments in the assessment of quality of life (QOL) in clinical trials over the last decade from the viewpoint of clinical biostatistics. In the first part we deal with aspects of obtaining adequate measurements of quality of life. A literature survey shows that a large number of quite heterogeneous measurement approaches for use in clinical trials exist, a substantial percentage of which cannot be regarded as sufficient for their actual measuring purpose. In the second part we review statistical methods applied to and adapted for the analysis of QOL data. Underlying the analysis should be the assumption of QOL as a stochastic process. Applied analysis procedures are again investigated in a literature survey. Finally, critical conclusions are outlined and suggestions for further research are given.

ISSN:0277-6715    

DOI:10.1002/sim.4780101207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA short review of the Cox regression model and its development from publication to 1982 is given. I discuss how the model is used and presented in medical journals and how improvement may be achieved. Finally, some extensions of the model are outlined.

ISSN:0277-6715    

DOI:10.1002/sim.4780101208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA technique is presented which provides guidance on the spacing of follow‐up waves in a multiwave study. Only information from the baseline wave is needed, as well as rough parameter estimates for the survival distribution. The computations use the expected Fisher information; a new method for its calculation is given. An analysis of the effects of simplifying assumptions, such as presuming that a distributional parameter is known, shows that gross discrepancies may result. Data from the Massachusetts Health Care Panel Study (MHCPS) are used for a demonstration. The MHCPS example shows that this technique can prevent large inefficiencies in multiwave experimental desig

ISSN:0277-6715    

DOI:10.1002/sim.4780101209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractTechniques applicable for the analysis of longitudinal data when the response variable is non‐normal are not nearly as comprehensive as for normally‐distributed outcomes. However, there have been several recent developments. Semi‐parametric and non‐parametric methodology for the analysis of repeated measurements is reviewed. The commonly encountered design in which, for each subject, one assesses a univariate response variable at multiple fixed time points, is considered. The types of outcomes considered include binary, ordered categorical, and continuous (but extremely non‐normal) response variables. All of the methods considered allow for incomplete data due to the occurrence of missing observations. In addition, discrete and/or continuous covariates, which may be time‐dependent, are accommodated by some of the approaches. The methods are demonstrated using data from three clin

ISSN:0277-6715    

DOI:10.1002/sim.4780101210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractMcNemar's one degree of freedom chi‐square test for the equality of proportions appears frequently in the analysis of pairs of matched, binary outcome data (Y1i,Y2i). An assumption underlying this test is that the responses from pair to pair are mutually independent. In certain applications, however, the pairs may represent repeated measurements on the same experimental unit, and hence this assumption is violated. In this paper we suggest an adjustment to the McNemar test to account for the repeated measures clustering effect and we report on a Monte Carlo simulation that evaluates the effectiveness of this approac

ISSN:0277-6715    

DOI:10.1002/sim.4780101211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractRecruitment of disease‐free subjects into cohort studies and measurement of their time from exposure/infection to disease selectively excludes individuals (the unseen sample) who had earlier exposure and who have shorter times to disease. The unseen and observed samples may differ in other characteristics in addition to incubation period and exposure/infection time. For data with known truncation times, we develop non‐parametric maximum likelihood estimates of the size, exposure/infection dates and distribution of incubation time in the unseen sample. We provide procedures to estimate and compensate for the biasing effects due to exclusion of the unseen sample in descriptive and survival analysis. We give consistency properties of these estimates and assess variability using bootstrap methods. One can use imputation to derive the above estimates from data with unknown truncation times that have been estimated parametrically. Application is made to an AIDS cohort study of over 5000 homosexual men. Important estimates obtained from this application are the annual seroconversion rates from 1978 to 1983, not otherwise obtainable in this study populat

ISSN:0277-6715    

DOI:10.1002/sim.4780101212

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY