Beta-blockers associated with worse outcomes in non-cardiac perioperative settings

1. Amongst Danish patients with uncomplicated hypertension, using beta-blockers as part of a two-drug anti-hypertensive regimen led to greater major adverse cardiac events (MACEs) and mortality in the perioperative setting of non-cardiac surgery compared to regimens with renin-angiotensin system (RAS) inhibitors, calcium channel blockers, or thiazide diuretics.

2. However, the higher risk of MACEs was not present if beta-blockers were a part of a three-drug anti-hypertensive regimen.

Evidence Rating Level: 2 (Good)

Study Rundown: The use of perioperative beta-blockers has been a source of debate for many years. While guidelines currently state to continue beta-blockers in the perioperative period amongst patients already on them, this recommendation is not necessarily based on strong data. Beta-blockers are also not standard first or second-line therapy for uncomplicated hypertension, yet their use for this is still present. This retrospective study was conducted to help determine risks of using beta-blockers for hypertension in the setting of non-cardiac surgery. Patients had known hypertension, but not other high-risk features (i.e., recent cardiac events, heart failure). The results showed that using beta-blockers as part of a two-drug anti-hypertensive regimen for uncomplicated hypertension led to greater MACEs and death in the perioperative setting of non-cardiac surgery compared to regimens with RAS inhibitors, calcium channel blockers, and thiazide diuretics. MACEs were defined as nonfatal acute myocardial infarction, nonfatal ischemic stroke, and cardiovascular death. However, the higher risk of MACEs was not present if beta-blockers were a part of a three-drug anti-hypertensive regimen.

The major strength of the study was the relative size of the population included and the confidence in the Danish national registry with regards to accuracy of the medical records. The weaknesses of the study include the inability to prove causation with this observational design, and the relative homogeneity of the population that was studied.

Click to read the study, published today in JAMA Internal Medicine

Relevant Reading: Meta-analysis of secure randomised controlled trials of β-blockade to prevent perioperative death in non-cardiac surgery.

In-Depth [retrospective cohort]: This study population was derived from the Danish registry from 2005 to 2011. The inclusion criteria were patients undergoing non-cardiac surgery who were on beta-blockers for a diagnosis of uncomplicated hypertension and on at least two anti-hypertensive medications. The exclusion criteria included any secondary cardiovascular conditions, renal disease, or liver disease. Patients on sotalol were also excluded. The primary outcomes were major adverse cardiac events (MACEs) and all-cause mortality. MACEs were a composite of nonfatal acute myocardial infarction, nonfatal ischemic stroke, and cardiovascular death.

In total, 55 320 patients with hypertension underwent non-cardiac surgery in the aforementioned time period. Of these, 14 644 were being treated with beta-blockers and 40 676 were being treated with other anti-hypertensive medications. Amongst patients on beta-blockers as part of their anti-hypertensive regimen, the non-cardiac perioperative risk of 30-day MACEs was 1.32% and risk of 30-day all-cause mortality was 1.93%. By comparison, patients on a regimen containing RAS inhibitors, calcium channel blockers, or thiazide diuretics had a 30-day MACE risk of 0.84% and 30-day all-cause mortality risk of 1.32% (p < 0.001). The risk of 30-day MACEs was not significant if the anti-hypertensive regimen with three drugs included a beta-blocker (OR 1.22; 95%CI 0.90-1.64).

Image: PD

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