BMJ  2005;330:594-596 (12 March), doi:10.1136/bmj.330.7491.594

Education and debate

Validity of composite end points in clinical trials

¹ Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA, ² Cardiology Service, Epidemiology Unit, Hospital General Vall d'Hebron, Barcelona 08035, Spain, ³ Department de Medicina, Universitat Autònoma de Barcelona, Hospital General Vall d'Hebron, ⁴ Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON L8N 3Z5, Canada, ⁵ Department of Medicine, McMaster University, ⁶ Primary Care Centre Turó, EAP Vilapicina, Institut Català de la Salut, Barcelona, Spain, ⁷ Health Services Research Unit, Institut Municipal d'Investigació Mèdica, Barcelona, Spain, ⁸ Department of Medicine and of Social and Preventive Medicine, University at Buffalo, Buffalo, NY 14214, USA, ⁹ Department of Research, Canadian College of Naturopathic Medicine, Toronto, Canada M2K 1E2

Use of composite end points as the main outcome in randomised trials can hide wide differences in the individual measures. How should you apply the results to clinical practice?

The first 150 words of the full text of this article appear below.

Introduction

Improvements in medical care over the past two decades have decreased the frequency with which patients with common conditions such as myocardial infarction develop subsequent adverse events. Although welcome for patients, low event rates provide challenges for clinical investigators, who consequently require large sample sizes and long follow up to test the incremental benefits of new treatments. Clinical trialists have responded to these challenges by relying increasingly on composite end points, which capture the number of patients experiencing any one of several adverse events—for example, death, myocardial infarction, or hospital admission.¹

Use of composite end points is usually justified by the assumption that the effect on each of the components will be similar and that patients will attach similar importance to each component.¹ But this is not always the case. In this article we provide a strategy to interpret the results of clinical trials when investigators measure the effect of . . . [Full text of this article]

Example case

Evaluating composite end points

Importance of individual components to patients
Frequency of component end points
Treatment effects on component end points

Applying the questions

Conclusions

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