Showing papers in "Controlled Clinical Trials in 1989"

TL;DR: An approach to elucidating the significance of changes in score in quality of life instruments by comparing them to global ratings of change is developed, and a plausible range within which the minimal clinically important difference (MCID) falls is established.

TL;DR: Two-stage designs that are optimal in the sense that the expected sample size is minimized if the regimen has low activity subject to constraints upon the size of the type 1 and type 2 errors are presented.

TL;DR: Important design aspects were decreasingly reported in NSAID trials over the years, whereas the quality of statistical analysis improved, and it is not obvious how a reliable meta-analysis could be done in these trials.

TL;DR: This article reviews a number of the central methodologic issues surrounding the development or selection of quality of life measures appropriate for use in clinical trials and focuses on research design and implementation issues in clinical trial-based quality oflife studies.

TL;DR: A Bayesian "shrinkage" method of analysis is proposed to help quantify the extent to which surprisingly large point and interval estimates of treatment difference in clinical trials that stop early should be moderated.

TL;DR: A critical review is provided of recent articles on two-treatment crossover trials that purport to provide solutions to the problems caused by the existence of differential carryover effects, and recommends the two-period crossover design only when prior experience suggests that its assumptions are likely to be satisfied.

TL;DR: 2.2.1 .

TL;DR: Some problems with applying methods based on classical sequential analysis to monitoring clinical trials and Bayesian methods are described, which provide the same desirable features as frequentist methods, without sacrificing flexibility and simplicity of interpretation.

TL;DR: With the aid of Canner's equation, using both formal analysis and simulation, the impact of covariate adjustment is further explored and it is shown that unless tight control over the analysis plans is established in advance, covariates can lead to seriously misleading inferences.

TL;DR: The database, maintained at the University of Minnesota's Nutrition Coordinating Center, has been used to calculate dietary intake data for a wide range of diet-disease related investigations including studies on cardiovascular disease, hypertension, cancer, gastroenterology, and osteoporosis.

TL;DR: The various ways in which prognostic information can be included in the analysis of treatment effect in clinical trials are discussed, which are an informative and needed complement to an analysis of overall treatment effect.

TL;DR: The randomized clinical trial (RCT) is the most powerful tool available to assess the effectiveness of a medical procedure but it is frustrated because doctors are not trained to weigh the evidence on treatment benefit-risk ratios, to read clinical research reports, or to select the appropriate information.

TL;DR: Key among the needs are improved means of identifying trials prior to publication via prospective registration of them and vocabulary and nomenclature for identifying reports of meta-analyses in the published literature.

TL;DR: The Trial of Antihypertensive Interventions and Management was a multicenter randomized, placebo-controlled trial designed to assess the effectiveness of various combinations of pharmacologic and dietary interventions in the treatment of mild hypertension.

TL;DR: It is argued in this paper that the log-likelihood ratio, as a measure of the "weight of evidence," can be a very useful tool in the meta-analysis.

TL;DR: The Hypertension Prevention Trial was a randomized, controlled, multicenter trial designed to test the feasibility of achieving and sustaining dietary changes in the intake of calories, sodium, and potassium and to assess the effect of those changes on blood pressure in a normotensive population.

TL;DR: There are some research questions that may warrant large and simple trials, but many clinically very relevant research questions require a more complex trial design.

TL;DR: In planning a study, five principal issues should be considered: design efficiency, completeness of follow-up, level of compliance, size of the probable risk reduction, and accumulation of sufficient numbers of outcome measures.

TL;DR: Dunnett's two-sided multiple comparison procedure may be proposed to perform the analysis to compare more than one experimental treatment to a control treatment to determine the appropriate sample size.

TL;DR: The "classification tree" technique is proposed, which combines the possible subgroup constellations to subgroup clusters with homogeneous response within the cluster and inferences about the interaction structure can be obtained.

TL;DR: This chapter describes HPT procedures for training and certifying clinic staff, for data entry checks and data audits of its distributed data entry system, and for inspecting clinical equipment.

TL;DR: A statistical test to compare the recurrence or tumor rates in two treatment groups, using the randomization distribution, is described, and confidence intervals for the rate ratio are determined from the bootstrap distribution.

TL;DR: A secondary goal of the study is to determine whether beta-carotene decreases the average number of new skin cancers per patient per year, and there are no established statistical methods for analysis of data in this situation.

TL;DR: The design and feasibility of a randomized controlled trial of the benefits of routine iron prophylaxis during pregnancy were reported and the use of existing health services and their personnel in evaluation of medical technology was encouraged.

TL;DR: These definitions will provide the opportunity to review and categorize existing clinical trial practices and procedures and clarify such issues as " when to look" and "when to pay a price" and characterize such issues in the context of pharmaceutical industry drug development.

TL;DR: Given the great complexity of statistical methodology and the anomalous nature of concepts of evidence, more sustained input into the interdisciplinary dialogue is needed from the statistical profession.

TL;DR: The Hypertension Prevention Trial (HPT) as mentioned in this paper was a randomized, controlled, multicenter (four clinics, four resource centers) trial designed to test the feasibility of achieving and sustaining dietary changes in the intake of calories, sodium, and potassium and to assess the effect of those changes on blood pressure in a normensive population.

TL;DR: It is found that group sequential designs based on a range rather than point of equivalence when averaged over the whole prior distribution seems to be most conservative in terms of probability of firm conclusion followed by the nonzero null hypothesis design.

TL;DR: The Southwest Oncology Group (SWOG) chose to use a relational database management system (RDBMS) for the management of data from multiple clinical trials because of the underlying relational model's inherent flexibility and the natural way multiple entity types can be accommodated.