Effect of beta-blocker dose on mortality after acute coronary syndrome.

INTRODUCTION: Beta-blocker doses that have been shown to be effective in randomized clinical trials are not commonly used in daily clinical practice. The aim of this study was to analyze whether there is a prognostic benefit of high rather than low doses of beta-blockers after an acute coronary syndrome (ACS).

METHODS: In this retrospective cohort study, 2092 ACS patients discharged from hospital between June 2013 and January 2016 were classified according to the beta-blocker dose prescribed: high dose (≥50% of the target dose tested in clinical trials) and low dose (<50%). Two groups of 501 matched patients were obtained through propensity score matching according to treatment with high or low doses of beta-blockers. The prognostic impact (mortality) during follow-up of high vs. low dose was analyzed by Cox regression and represented by Kaplan-Meier curves.

RESULTS: Of the 2092 patients, 80.5% were discharged under beta-blockers, with lower mortality during follow-up (18.6±9.7 months). Of the 1685 patients discharged under beta-blockers, only 31.4% received high doses. There were no differences in mortality during follow-up between patients under high-dose vs. low-dose beta-blockers (HR 0.935, 95% CI 0.628-1.392, p=0.740), and the equivalence between the two doses remained after propensity score matching (HR 1.183, 95% CI 0.715-1.958, p=0.513).

CONCLUSION: No prognostic benefit was found in terms of mortality for high-dose vs. low-dose beta-blockers after an ACS.