To the Editor:
Rothwell needs to be complimented for highlighting the problems surrounding the terms “prevention” and “reduction in mortality.”1 Trialists, as Tan points out elsewhere,2 often concentrate mainly on the changes in the number of events (y axis) and ignore the changes on the time scale (x axis) in the analysis of survival curves. Malkin and Channer3 have also dealt with this highly relevant topic giving tips on how to derive the extension of life figure from survival curves. Furthermore, they point out, I am sure to the surprise of many of us, that ACE inhibitors, which have the most robust evidence in heart failure, extend life only by 9 months.
I agree with Rothwell that choosing the right term is not about being merely semantically correct but about addressing the patients’ expectations as accurately as possible. However, I am less convinced about using the term “delay” when referring to the outcome measures like stroke. Unlike death, events like stroke are not inevitable. The term “delay” has an element of inevitability, and its usage carries the risk of encouraging pessimism. On the other hand, “prevention” implies, strictly speaking, that the event will not happen which is clearly incorrect.
Hence, I suggest that clinicians should avoid using the term “prevent strokes” and use the term “reduce the risk of strokes” when referring to events other than death like stroke and the term “delay” while referring to death.