β blockers and mortality after myocardial infarction in patients without heart failure: multicentre prospective cohort study

OBJECTIVE To assess the association between early and prolonged beta blocker treatment and mortality after acute myocardial infarction. DESIGN Multicentre prospective cohort study. SETTING Nationwide French registry of Acute ST- and non-STelevation Myocardial Infarction (FAST-MI) (at 223 centres) at the end of 2005. PARTICIPANTS 2679 consecutive patients with acute myocardial infarction and without heart failure or left ventricular dysfunction. MAIN OUTCOME MEASURES Mortality was assessed at 30 days in relation to early use of beta blockers (<= 48 hours of admission), at one year in relation to discharge prescription, and at five years in relation to one year use. RESULTS beta blockers were used early in 77% (2050/2679) of patients, were prescribed at discharge in 80% (1783/2217), and were still being used in 89% (1230/1383) of those alive at one year. Thirty day mortality was lower in patients taking early beta blockers (adjusted hazard ratio 0.46, 95% confidence interval 0.26 to 0.82), whereas the hazard ratio for one year mortality associated with beta blockers at discharge was 0.77 (0.46 to 1.30). Persistence of beta blockers at one year was not associated with lower five year mortality (hazard ratio 1.19, 0.65 to 2.18). In contrast, five year mortality was lower in patients continuing statins at one year (hazard ratio 0.42, 0.25 to 0.72) compared with those discontinuing statins. Propensity score and sensitivity analyses showed consistent results. CONCLUSIONS Early beta blocker use was associated with reduced 30 day mortality in patients with acute myocardial infarction, and discontinuation of beta blockers at one year was not associated with higher five year mortality. These findings question the utility of prolonged beta blocker treatment after acute myocardial infarction in patients without heart failure or left ventricular dysfunction.