As Dr Stello points out in his letter, the baseline risk of death among patients included in the trials of vasodilating β-blockers was lower (8.7%) than that of those treated with nonvasodilating agents (19.4%). However, comparisons of the magnitude of effects measured in populations with different baseline risks can only be made on the basis of the relative effect, rather than on the basis of the absolute effect. According to our results, the relative reduction in mortality was greater with vasodilating agents (45%) than with nonvasodilating agents (27%), and the difference between these estimates was significant (P= .007). This suggests that vasodilating β-blockers have a greater effect on overall mortality. The higher baseline risk in patients included in trials with nonvasodilating agents may reflect a more advanced condition, with different or additional underlying pathophysiological processes. These might respond differently to any kind of β-blocker. Unfortunately, the small sample size of the majority of trials does not allow an analysis of the magnitude of the effect of vasodilating and nonvasodilating agents according to the patients' baseline risk. We agree with Dr Stello that the results of some ongoing clinical trials will bring a more definitive answer to this question.
Bonet S, Agustí A, Arnau JM, Vidal X, Diogène E, Galve E, Laporte J. β-Blockers in Congestive Heart Failure: Is There a Difference Between Classes?—Reply. Arch Intern Med. 2000;160(19):3005-3006. doi: