Methods for Improving Clinical Trials
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Ton J. Cleophas
Abstract
Over the past decades, the randomized controlled trial has entered an era of continuous improvement and has gradually become accepted as the most effective way of determining the relative efficacy and toxicity of new therapies because it controls for placebo and time effects. However, even sensitive and properly designed and executed trials do not always confirm hypotheses to be tested, and conclusions are not always confirmed by subsequent trials. Although the former may be due to wrong hypotheses, the latter is likely to be due to the presence of certain imperfections within the design and execution of the trial itself.
In this opinion paper, while focusing on such imperfections, the author searched for methods for further improvement of controlled trials, particularly clinical trials. The examples used in this paper are obtained from literature search as well as recent studies performed by the Netherlands Working Group on Cardiovascular Research (WCN).
Methods for improvement could include: 1. making every effort to avoid asymmetries in the treatment groups; 2. emphasis on statistical power rather than just null-hypothesis testing; 3. adjusting for asymmetries not only of patient characteristics but also of outcome variables; 4. accounting routinely for type III errors; 5. routinely weighing benefits of a new drug against risks.
Copyright © 1999 by Walter de Gruyter GmbH & Co. KG
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- Author Index
- Contents
- Subject Index
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- Statistical Techniques for Evaluating the Diagnostic Utility of Laboratory Tests
- Magnesium in Disease: a Review with Special Emphasis on the Serum Ionized Magnesium
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- Accurate Platelet Counting in an Insidious Case of Pseudothrombocytopenia
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- The Specificity of Biochemical Markers of Cardiac Damage: a Problem Solved
- Biochemical Factors Influencing Measurement of Cardiac Troponin I in Serum
- The Sensitivity of Cardiac Markers: an Evidence-based Approach
- Risk Stratification and Therapeutic Decision Making in Patients with Acute Coronary Syndromes the Role of Cardiac Troponin T
- Cardiac Markers: Centralized or Decentralized Testing?
- EC4 European Syllabus for Post-Graduate Training in Clinical Chemistry. Version 2 – 1999
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- Lipoprotein Protocols. By J.M. Ordovas, editor
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Articles in the same Issue
- Author Index
- Contents
- Subject Index
- Strategies for Cardiac Marker Measurement
- Statistical Techniques for Evaluating the Diagnostic Utility of Laboratory Tests
- Magnesium in Disease: a Review with Special Emphasis on the Serum Ionized Magnesium
- Methods for Improving Clinical Trials
- Infrared Analysis of Urinary Stones: a Trial of Automated Identification
- Evaluation of a Direct α-Amylase Assay Using 2-Chloro-4-nitrophenyl-α-D-maltotrioside
- Accurate Platelet Counting in an Insidious Case of Pseudothrombocytopenia
- A New Liquid Homogeneous Assay for HDL Cholesterol Determination Evaluated in Seven Laboratories in Europe and the United States
- Tissue Release of Cardiac Markers: from Physiology to Clinical Applications
- The Specificity of Biochemical Markers of Cardiac Damage: a Problem Solved
- Biochemical Factors Influencing Measurement of Cardiac Troponin I in Serum
- The Sensitivity of Cardiac Markers: an Evidence-based Approach
- Risk Stratification and Therapeutic Decision Making in Patients with Acute Coronary Syndromes the Role of Cardiac Troponin T
- Cardiac Markers: Centralized or Decentralized Testing?
- EC4 European Syllabus for Post-Graduate Training in Clinical Chemistry. Version 2 – 1999
- Plasma Malondialdehyde and Obesity: Is there a Relationship?
- Reference Intervals: Are Interlaboratory Differences Appropriate?
- Lipoprotein Protocols. By J.M. Ordovas, editor
- Tietz Textbook of Clinical Chemistry. By C.A. Burtis and E.R. Ashwood, editors
