Author + information
- Christopher B. Granger, MD, FACC⁎ ( and )
- John J.V. McMurray, MD, FACC
- ↵⁎Duke University Medical Center, Box 3409, Durham, North Carolina 27710-0001
We were pleased to see that Dr. Cohn (1) accepts the need to examine the effect of treatment on mortality, although he chooses to see this as a measure of safety rather than efficacy. We do not know how to decide which surrogate measure “tracks with disease progression.” Dr. Cohn currently favors a structural marker—a few years ago, norepinephrine or ejection fraction might have been the popular choice. Who is to say that in a few more years structural changes will go the same way as those previous favorites? Moreover, some highly effective treatments (like implantable cardioverter-defibrillators) do not affect structure or the disease process but do reduce mortality, underscoring the limitations of predicting treatment effect with disease markers.
Dr. Cohn’s vision is, of course, utopian. If only we could do what he wanted—but we have not yet managed to do so and have failed miserably when we have tried. In the end, however, we agree with Dr. Cohn’s call to design trials to better understand disease process and individual response to therapy. He rightly points out that our ultimate goal of individualized medicine will require much better understanding of patient response and safety. In doing so, however, even larger trials will be necessary, and ultimately measuring important clinical outcomes will always be necessary to determine the net effect that defines what matters in clinical care.
In the meantime, as long as Dr. Cohn accepts the need for assessment of “safety,” the debate is more of a philosophical than practical one—the same large trials with the same clinical outcomes will be needed.
- American College of Cardiology Foundation