ISSN:0277-6715    

DOI:10.1002/sim.4780081102

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

年代:1989

数据来源: WILEY

ISSN:0277-6715    

DOI:10.1002/sim.4780081103

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

年代:1989

数据来源: WILEY

摘要:

AbstractOrdered logistic regression is an extension of binary logistic regression, and is particularly well suited to the analysis of many psychiatric scores. Its use is demonstrated in a pair of linked cross‐sectional surveys of dementia in residents of old people's homes, first to model the association of dementia with demographic characteristics, and then to explore possible reasons for a rise in the prevalence of dementia in the homes over a four‐year per

ISSN:0277-6715    

DOI:10.1002/sim.4780081104

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

年代:1989

数据来源: WILEY

摘要:

AbstractA statistical model is proposed for predicting the range of plasma carbamazepine concentrations after administration of a controlled‐release formulation at steady state. The model is based on previous clinical studies in patients with epilepsy. The predicted range may be used to monitor and adjust treatment in a patien

ISSN:0277-6715    

DOI:10.1002/sim.4780081105

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

年代:1989

数据来源: WILEY

摘要:

AbstractTwo important qualities of controlled clinical trials are that they reduce dependence on historical standards for evaluating therapy and separate the effect of treatment from the confounding influence of time. Whatever the theory of the clinical trial, however, time has not easily been banished from the analysis of medical experiments in practice, and many doctors still prefer to evaluate treatments by comparingnowwiththenrather than treatment with control. This is especially so in trials of bronchodilators in the treatment of asthma where, it is shown, baselines are used in ways which can increase the variability of measurement and even bias the results.

ISSN:0277-6715    

DOI:10.1002/sim.4780081106

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

年代:1989

数据来源: WILEY

摘要:

AbstractIn clinical diagnosis, a patient's symptoms are observed and the probabilities of various diseases are assessed. A widely used method of formalizing this approach is independent Bayes in which symptoms are assumed to be independent conditional on the disease category. Correspondence analysis provides a method for examining the dependence between symptoms and assists in the selection of a reduced set of symptoms for the application of the independent Bayes method. This approach is illustrated on two data sets concerned with patients attending Accident and Emergency departments with chest pain and acute abdominal pain, respectively.

ISSN:0277-6715    

DOI:10.1002/sim.4780081107

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

年代:1989

数据来源: WILEY

摘要:

AbstractRegression models with mixture (random) components are proposed for the statistical analysis of recurrent events when waiting times between successive events are unknown. These models allow adjustment of parameter estimates for unobserved heterogeneity in the population (due for example to missing covariates) or overdispersion resulting from inexact distributional assumptions. The models are illustrated by a study of recurrence rates of superficial bladder cancer in men.

ISSN:0277-6715    

DOI:10.1002/sim.4780081108

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

年代:1989

数据来源: WILEY

摘要:

AbstractCancer chemotherapy has been remarkably successful in the treatment of several types of malignancies, but has also been demonstrated to cause leukaemia and perhaps other cancer in long‐term survivors. Radiotherapy also carries a carcinogenic risk. A large case‐control study of second cancer has been carried out, with the aim of quantifying the risk due to chemotherapy and radiotherapy. One of the most important goals of this study is the estimation of the temporal pattern of risk following chemotherapy. Methods are presented for modelling risk as a function of type of treatment and the interval since reatment. The methods are applications of generally available linear regression programs for epidemiological data, and could be equally well applied to studies of occupationally induced can

ISSN:0277-6715    

DOI:10.1002/sim.4780081109

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

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper is concerned with the problem of constructing a suitable cut‐off point for a quantitative diagnostic test from a sample of diseased and non‐diseased individuals, when the specificity and/or sensitivity required for the resulting diagnostic classification rule are specified. Statistical procedures are discussed which yield an explicit cut‐off point, together with the necessary confidence limits on the true specificity and sensitivity of the test operating at this point (by contrast to confidence limits referring to an unknown optimal choice of the cut‐off point). Sample size formulae are derived, showing a relative efficiency of up to 1.5 for a new procedure introduced in this paper over the usual procedure based on tolerance

ISSN:0277-6715    

DOI:10.1002/sim.4780081110

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe spontaneous variability of ventricular arrhythmias is the major problem in assessing antiarrhythmic drug efficacy. Efficacy is usually assessed on one form of ventricular premature beats, namely either single beats (VPC) or more complex forms like couplets or salvos. The reduction rates required to assume efficacy with a confidence of 95 per cent are 63 per cent for VPCs, 92 per cent for couplets or 96 per cent for salvos. These rates are valid for two Holter electrocardiogram recordings within one week; otherwise the rates are higher and close to 100 per cent. In this paper we extend our ratio method for calculating these criteria to consider two or all three forms of ventricular premature beats simultaneously. The method is based on the first principal component. For use in practice we decided to calculate fixed criteria for each form of ventricular premature beats. For the combination of VPCs and couplets and a confidence level of 95 per cent, reduction rates of 42 per cent for VPC and 87 per cent for couplets are required. Both criteria must be fulfilled to assume the efficacy of a drug. These criteria are lower than those for each form alone. For all three forms together, reduction rates of 28, 72 and 88 per cent for VPC, couplets and salvos respectively are required.

ISSN:0277-6715    

DOI:10.1002/sim.4780081111

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

年代:1989

数据来源: WILEY