The main findings of this study were as follows:
• The incidence of 30-day MACE was 1.32% in patients treated with β-blockers compared with 0.84% in patients treated with other drugs only (P<0.001). • 30-day mortality was 1.93% and 1.32%, respectively (p<0.001)• β-Blocker use was associated with increased risks of MACEs in 2-drug combinations with RAS inhibitors (OR 2.16), calcium antagonists (OR 2.17) and thiazides (OR 1.56), compared with the reference combination of RAS inhibitors and thiazides. • The increased risk for MACE was particularly pronounced for those aged ≥70 years (number needed to harm [NNH] of 140), in men (NNH 142) and in patients undergoing acute surgery (NNH 9).
The authors discuss the possible limitations of their study, including misclassification of some patients, use of beta-blockers for other reasons (e.g. renal or liver disease), possible undetected use of nitrates (sold over the counter in Denmark), lack of information on drug titration or withdrawal around the time of surgery, and on variables such as heart rate and blood pressure, and the fact that some of the subgroups had a small number of events (with wide confidence intervals).
Based on their findings, they suggest that the perioperative management of patients with hypertension should receive specific attention in clinical practice and future guidelines; additional clinical trials may however be warranted.