In Reply: Drs Rifkin and Walerstein question
whether it might have been unethical to conduct the MERIT-HF study among patients
with previous MI because there was already sufficient evidence of benefit
of β-blockade in patients with CHF. However, when the MERIT-HF study
started in February 1997, there was no published randomized, double-blind,
placebo-controlled study of β-blockade in chronic CHF that was adequately
powered for a primary analysis of survival effects. In addition, CHF was a
relative contraindication for using β-blockade in patients with MI. The
results of the Cardiac Insufficiency Bisoprolol Study II (CIBIS-II) study,1 showing a survival benefit of bisoprolol, was published
in 1999, after the premature closure of the MERIT-HF study, which took place
in October 1998. The results regarding mortality outcome in the MERIT-HF study
were published in June 19992 and were followed
by our article in JAMA, presenting the effects on hospitalizations, symptoms,
and quality of life. Hence, the overwhelming documentation of the favorable
effect of β-blockade on mortality in CHF was obtained largely in parallel
from 2 studies, which were both published within a 12-month period.