The MERIT-HF trial: Addition of metoprolol reduces mortality in patients with symptomatic heart failure [Classics Series]

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1. In patients with symptomatic heart failure and reduced ejection fraction, the addition of metoprolol to standard therapy reduced all-cause mortality by 34% compared to placebo.

2. Similar findings were reported in the CIBIS-II trial.

Study Rundown: The findings of the MERIT-HF trial demonstrated that adding metoprolol controlled release/extended release to standard optimum therapy (i.e., a diuretic and ACE inhibitor) reduced all-cause mortality by 34% in patients with symptomatic heart failure compared to placebo. Another study published around the same time, the Cardiac Insufficiency Bisoprolol Study II (CIBIS-II), reported similar findings. Of note, the study was funded by grants from AstraZeneca.

In sum, adding metoprolol controlled release/extended release to optimum standard therapy in symptomatic heart failure (NYHA class II-IV) reduces all-cause mortality.

Please click to read study in The Lancet

In Depth [randomized controlled study]: Published in 1999 in The Lancet, the MERIT-HF trial was a randomized, double-blind, placebo-controlled study of patients with decreased ejection fraction and symptomatic heart failure to assess the effects of adding metoprolol to standard therapy. The inclusion criteria were as follows: 1) symptomatic heart failure (i.e., New York Heart Association functional class II-IV) for at least 3 months, 2) a left ventricular ejection fraction less than 0.40 in the 3 months before enrollment, 3) a stable clinical condition in the 2 week run-in phase for the study, and 4) taking optimum standard therapy (i.e., combination of diuretics and ACE inhibitor). A total of 3,991 patients were enrolled in the study and randomized to receive either metoprolol controlled release/extended release (12.5 mg for NYHA class III-IV, 25 mg for NYHA class II) once daily or placebo.

The study was conducted at 313 sites in 13 European countries and the United States. The trial was stopped early on the recommendation of the independent safety committee, as the predefined criterion for ending the study had been met. There was a significant reduction in all-cause mortality in the metoprolol group compared to the placebo group, with a relative risk of 0.66 (95% CI 0.53-0.81). Specifically, there were significantly fewer cardiovascular deaths, sudden deaths, and deaths from aggravated heart failure in the metoprolol group.

By Adrienne Cheung, Andrew Cheung, M.D.

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