Uncomplicated Hypertension Undergoing Noncardiac Surgery: Another Subgroup to Avoid Beta-Blockade?
What is the risk of major adverse cardiovascular events (MACE) associated with long-term beta-blocker therapy in patients with uncomplicated hypertension undergoing noncardiac surgery?
This was a retrospective analysis of in-hospital records and out-of-hospital pharmacotherapy using a Danish nationwide cohort of patients with uncomplicated hypertension treated with at least two antihypertensive drugs (beta-blockers, thiazides, calcium channel antagonists, or renin-angiotensin [RAS] inhibitors) and undergoing noncardiac surgery between 2005 and 2011. Use of specific drugs was defined as at least one claimed prescription during the 120 days prior to surgery. The primary outcomes were MACE and all-cause mortality within 30 days of surgery (including events on the day of surgery). Eight possible combinations of the four study drugs were evaluated, with patients treated with RAS inhibitors and thiazides designated as the reference category.
A total of 55,320 hypertensive patients underwent noncardiac surgery (14,644 patients were treated with beta-blockers). The incidence of 30-day MACE and mortality was 1.32% and 1.93% in patients treated with beta-blockers compared with 0.84% and 1.32% in patients treated with other drugs only (both p < 0.001). Beta-blocker use was associated with increased risks of MACE in two-drug combinations with RAS inhibitors (odds ratio [OR], 2.16; 95% confidence interval [CI], 1.54-3.04), calcium antagonists (OR, 2.17; 95% CI, 1.48-3.17), and thiazides (OR, 1.56; 95% CI, 1.10-2.22), compared with the reference combination of RAS inhibitors and thiazides. The number needed to harm (NNH) was especially pronounced for patients at least 70 years old (NNH, 140; 95% CI, 86-364), men (NNH, 142; 95% CI, 93-195), and patients undergoing acute surgery (NNH, 97; 95% CI, 57-331).
Compared with other classes of antihypertensive drugs, treatment with an antihypertensive two-drug regimen including a beta-blocker was associated with a statistically significant increase in the rate of MACE and death within 30 days of noncardiac surgery.
This is a large nationwide study that adds to the controversy about perioperative beta-blockade therapy. While current guidelines recommend continuation of perioperative beta-blocker therapy in those who are taking such treatment chronically, this is based on limited literature and there is even greater uncertainty about the initiation of beta-blockade perioperatively in those not already taking this treatment. The current analysis adds to other recent studies that caution against the use of perioperative beta-blocker therapy in select patients and settings. Indeed, antihypertensive treatment with beta-blocker may be associated with increased adverse perioperative events. However, we need more studies before we can definitively say whether this relationship is causal or simply unmeasured selection bias.
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