Observational results show benefit of beta-blockers at discharge after PCI

Patients who underwent primary PCI for STEMI and received beta-blockers at discharge experienced approximately 50% lower mortality than those who did not receive beta-blockers at discharge, according to results of a recent analysis.

Researchers of the prospective, multicenter registry study noted the paucity of data for beta-blockers as secondary prevention in this patient population and examined whether beta-blocker therapy at discharge was associated with improved outcomes in patients who underwent primary PCI for STEMI between Nov. 1, 2005 and Sept. 30, 2010.

The analysis included 20,344 patients, 8,510 of whom were discharged alive. There were 6,873 patients in the beta-blocker group and 1,637 in the non-beta-blocker group. The researchers performed a propensity-score matching analysis in 1,325 patient triplets.

All-cause mortality served as the primary outcome measure.

Clinicians followed patients for a median of 367 days (interquartile range, 157-440 days).

All-cause mortality was 2.1% among patients receiving beta-blockers at discharge and 3.6% among those not receiving beta-blockers (P<.001).

Results of the 2:1 propensity-score matched analysis indicated that all-cause mortality was 2.8% in the beta-blocker group and 4.1% in the non-beta-blocker group (adjusted HR=0.46; 95% CI, 0.27-0.78). This association persisted across patient sub-populations, including those with relatively low-risk profiles, such as single-vessel disease or ejection fraction >40%.

“Our results support the current American College of Cardiology/American Heart Association guidelines, which recommend long-term beta-blocker therapy in all patients with STEMI regardless of reperfusion therapy or risk profile,” the researchers concluded.

Christopher B. Granger, MD, and Meena P. Rao, MD, MPH, from the Duke Clinical Research Institute in Durham, N.C., suggested in an accompanying editorial that the current results are consistent with previous findings. “Interestingly, the subgroup analysis of this study showed a consistent association with lower mortality among low-risk patients defined as those with a preserved [ejection fraction] and single-vessel coronary disease,” they wrote, adding that the data support the conclusion that beta-blockers at discharge results in better outcomes in primary PCI.

“The 50% lower mortality in this study is substantially more than the 20% estimate from randomized trials and therefore raises some question regarding the degree of benefit seen in this study,” Granger and Rao wrote. “As with all observational data, inference of treatment effect in this study is hazardous. This and related studies have selection bias for the use of beta-blockers that is related to measured and unmeasured factors. Whereas propensity scoring can control confounding, it cannot account for unmeasured confounders.”

Granger and Rao noted that propensity scoring may not always be the most reliable way to adjust for confounding factors to determine a treatment effect. They also wrote that the findings fail to provide information about whether beta-blockers were continued, and how they were continued, after discharge.

“Despite these limitations, however, this observational study provides some evidence that the well-established benefits of beta-blockers are likely consistent for patients treated with primary PCI, including patients at lower risk,” they wrote.

For more information:

Granger CB. J Am Coll Cardiol Intv. 2014;7:602-603

Yang JH. J Am Coll Cardiol Intv. 2014;7:592-601.

Disclosure The researchers report no relevant financial disclosures. Granger and Rao report associations with companies including AstraZeneca, Bayer HealthCare, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi Sankyo, Eli Lilly, GlaxoSmithKline, Hoffmann-LaRoche, Janssen Pharmaceuticals, Medtronic Foundation, Merck and Company, Pfizer, Ross Medical Corporation, Salix Pharmaceuticals, Sanofi Aventis, Takeda and The Medicines Company.