“A focus on beta-blocker continuation is a worthwhile quality improvement target and should improve patient outcomes,” they conclude.
Dr. David R. Flum, with the University of Washington, Seattle, and colleagues explain that continuation of beta-blocker therapy during and after surgery has become a quality improvement metric, but evidence to support this is very limited. Most relevant studies have been small and focused on cardiac or vascular surgery.
To assess broader-based evidence, the team examined information in a Washington state database, and identified 1976 patients who were taking beta-blockers before undergoing elective colorectal or bariatric surgery in 2008-2009. Beta-blockers were continued throughout the perioperative period in 1303 (65.9%) but discontinued on the day of surgery and/or postoperatively in 673 (34.1%).
The main outcome measure was a composite of mortality or adverse cardiac events at 90 days. The unadjusted rate was 2.8% in the continuation group compared with 4.8% (p=0.02) in the discontinuation group, the researchers found.
After adjustment for risk characteristics, discontinuation of beta-blockers conferred a two-fold increased risk of a 90-day combined adverse event (odds ratio of 1.97), the report indicates. Even if beta-blockers were discontinued only on the day of surgery and resumed postoperatively, the risk of an adverse event was still doubled (odds ratio 2.02).
The adverse effects of beta-blocker discontinuation appear to be long-lasting, as the odds ratio of the composite outcome at 1 year was 1.66, Dr. Flum and colleagues found.
Given these results, they conclude, “Our findings, based on the clinical records of patients from most hospitals in Washington across all types of medical centers and communities, suggest that beta-blocker continuation is critical to avoiding cardiac complications.”