Among patients without recorded heart failure (HF), starting atenolol after a myocardial infarction (MI) was associated with a lower two-year risk of major adverse cardiovascular events (MACE), but not all-cause mortality, compared with bisoprolol, according to an observational cohort study published Sept. 22 in NEJM Evidence.

Using data from the French National Health Data System, Thomas Laurenceau, MD, et al., identified adults hospitalized in the Paris area with a new MI between January 1, 2008, and December 31, 2018, who were prescribed atenolol or bisoprolol within two days of discharge. Outcomes were followed for up to two years. The average treatment effects (ATEs) of atenolol vs. bisoprolol were evaluated using targeted likelihood estimation.

The primary outcome was MACE, a composite of cardiac arrest, all-cause mortality, reinfarction, stroke or hospitalization for HF. The secondary outcome was all-cause mortality. Patients had a mean age of 58 years, and 79% were male.

Of the 11,558 patients, 13% started atenolol and 87% started bisoprolol within two days of discharge. Compared with bisoprolol, atenolol was associated with ATEs of 2.9% for MACE and 0.6% for all-cause mortality. Weighted MACE rates were 11% with atenolol and 14% with bisoprolol; corresponding all-cause mortality rates were 1% and 2%.

Results were consistent across per-protocol, subgroup and sensitivity analyses.

Laurenceau and colleagues note that the study "was restricted to the two most frequently prescribed [beta]-blockers in France, and whether similar comparative effectiveness would be observed for other [beta]-blockers remains unknown." They add that "a randomized head-to-head trial would be required to confirm these findings."

In an accompanying editorial, Jose-Angel Perez-Rivera, MD, PhD, and Fabian Blanco-Fernandez, MD, PhD, write, "These findings challenge the traditional assumption that all beta-selective beta-blockers exert equivalent clinical effects after MI and generate the hypothesis that individual agents within the class may differ in effectiveness." They add, "...the real-world nature of the study adds further value, providing insights into the effectiveness of beta-blocker therapy in routine clinical practice."