Principles From Clinical Trials Relevant to Clinical Practice: Part I
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
The first 2 parts of this review discussed lessons learned from cardiovascular clinical trials about the design and interpretation of clinical trials. In the next 2 parts, we will attempt to apply these lessons to decision-making in clinical practice. We undertake this effort with trepidation, recognizing that translating research findings into the care of an individual patient is a frontier that has not been adequately explored. Yet the potential for an empirical-based medical practice that would improve on the intuitive-based practice of the past, when combined with traditional clinical skills and patient preferences, demands that we move forward to apply what we have learned in populations to the care of individual patients.
Principle 1: Treatment Effects Are Modest
The benefit of most cardiovascular therapies is much smaller than was anticipated before the first large-scale outcome trials. Relative risk reductions of 25% are rarely exceeded, as demonstrated in Figure 1, for post–myocardial infarction (MI) patients. This means that the patient’s outcome is determined more by the natural history of the disease than by the treatments we deliver, and that multiple combined treatments will be needed in most cases to achieve the best possible outcome.
At the other extreme, from chronic therapies designed to prevent events, Guyatt and Sackett popularized the concept of the n=1 clinical trial, which is oriented toward symptomatic treatments.1,2⇓ This approach engages the clinician and the patient in an experiment in which the treatment, or placebo, is randomly allocated and symptoms are measured …