WASHINGTON – Prescribing alpha-adrenergic blocking agents for treatment of benign prostatic hypertrophy in men with heart failure proved to be not only safe, but also was associated with significantly reduced rates of both heart failure readmission and all-cause mortality in a large retrospective cohort study.
“These findings are associative, not necessarily causative. But the novel association between alpha-blocker treatment and improved outcomes may warrant further study,” Alberta L. Warner, MD, said at the annual meeting of the American College of Cardiology.
Many men with heart failure also have benign prostatic hypertrophy (BPH), for which they receive treatment with an alpha-blocker. Yet little is known about the impact of this drug class on safety and outcomes in the setting of heart failure. Of note, the use of alpha-blockers for treatment of hypertension was associated with increased risk of new-onset heart failure in the ALLHAT study.
To shed light on the safety of alpha-blockers in patients with prevalent heart failure, Dr. Warner and her coinvestigators analyzed data on nearly 170,000 men with a primary diagnosis of heart failure discharged from Veterans Affairs hospitals in 2002-2015. They determined that fully 28% of them left the hospital on an alpha-blocker. From this pool of nearly 48,000 heart failure patients, they were able to propensity-score match 38,991 on the basis of 54 baseline clinical characteristics to an equal number of VA heart failure patients who weren’t on an alpha-blocker. The study outcomes were time to first readmission for heart failure or all-cause mortality during 2 years of follow-up.
Patients on an alpha-blocker had a 38% heart failure readmission rate at 2 years, compared with 40% in nonusers, for a modest, albeit statistically significant, 6% reduction in relative risk. The all-cause mortality rate also was significantly lower in patients on an alpha-blocker: 40% versus 44%, for a 9% relative risk reduction.
In a subanalysis restricted to the heart failure patients on an alpha-blocker, higher-dose therapy was associated with a significantly lower incidence of all-cause mortality than was a lower-dose alpha-blocker during 2 years of follow-up, with a 9% relative risk reduction. A high-dose alpha-blocker, however, wasn’t significantly more effective than lower-dose therapy in terms of reducing heart failure readmissions, said Dr. Warner, a cardiologist at the Veterans Affairs Greater Los Angeles Healthcare System and the University of California, Los Angeles.
Similarly, patients treated with a nonspecific, peripherally vasoactive alpha-blocker had a significantly lower mortality rate than those on an alpha-1a-adrenergic–specific agent, with a highly significant 15% reduction in relative risk. The type of alpha-blocker, however, didn’t make a significant difference in terms of heart failure readmissions, where both types of agents were similarly better than not being on an alpha-blocker at all, she said.
Eighty-five percent of study participants were on a beta-blocker. Heart failure readmissions and all-cause mortality were significantly lower with alpha-blocker therapy, regardless of whether patients were on background beta-blocker therapy.
One audience member, however, noting that the beta-blocker carvedilol possesses some alpha-blocking effects, asked if outcomes differed depending on whether a patient was on carvedilol or metoprolol.
Dr. Warner replied that those numbers are still being crunched, and that the final answer isn’t in yet, but her preliminary impression is that the benefits of alpha-blocker therapy in terms of both heart failure readmissions and all-cause mortality were attenuated in the patients on carvedilol, possibly due to that beta-blocker’s alpha-blocking properties.
She reported having no financial conflicts regarding the study.