Effects of controlled-release metoprolol on total mortality, hospitalizations, and well-being in patients with heart failure - The metoprolol CR/XL randomized intervention trial in congestive heart failure (MERIT-HF)

Context Results from recent studies on the effects of beta(1)-blockade in p atients with heart failure demonstrated a 34% reduction in total mortality. However, the effect of beta(1)-blockade on the frequency of hospitalizatio ns, symptoms, and quality of life in patients with heart failure has not be en fully explored. Objective To examine the effects of the beta(1)-blocker controlled-release/ extended-release metoprolol succinate (metoprolol CR/XL) on mortality, hosp italization, symptoms, and quality of life in patients with heart failure. Design Randomized, double-blind controlled trial, preceded by a 2-week sing le-blind placebo run-in period, conducted from February 14, 1997, to Octobe r 31, 1998, with a mean follow-up of 1 year. Setting Three hundred thirteen sites in 14 countries. Participants Patients (n = 3991) with chronic heart failure, New York Heart Association (NYHA) functional class II to IV, and election fraction of 0.4 0 or less who were stabilized with optimum standard therapy. Interventions Patients were randomized to metoprolol CR/XL, 25 mg once per day (NYHA class II), or 12.5 mg once per day (NYHA class III or IV), titrat ed for 6 to 8 weeks up to a target dosage of 200 mg once per day (n = 1990) ; or matching placebo (n = 2001). Main Outcome Measures Total mortality or any hospitalization (time to first event), number of hospitalizations for worsening heart failure, and change in NYHA class, by intervention group; quality of life was assessed in a su bstudy of 741 patients. Results The incidence of all predefined end points was lower in the metopro lol CR/XL group than in the placebo group, including total mortality or all -cause hospitalizations (the prespecified second primary end point; 641 vs 767 events; risk reduction, 19%; 95% confidence interval [CI], 10%-27%; P<. 001); total mortality or hospitalizations due to worsening heart failure (3 11 vs 439 events; risk reduction, 31%; 95% CI, 20%-40%; P<.001), number of hospitalizations due to worsening heart failure (317 vs 451; P<.001); and n umber of days in hospital due to worsening heart failure (3401 vs 5303 days ; P<.001). NYHA functional class, assessed by physicians, and McMaster Over all Treatment Evaluation score, assessed by patients, both improved in the metoprolol CR/XL group compared with the placebo group (P = .003 and P = .0 09, respectively). Conclusions In this study of patients with symptomatic heart failure, metop rolol CR/XL improved survival, reduced the need for hospitalizations due to worsening heart failure, improved NYHA functional class, and had beneficia l effects on patient well-being.