Six trials (n=10,183, range 97 to 8,351) were included; all had a quality of score of 5.
Compared with placebo, perioperative β-blocker use yielded a significant reduction in patients' likelihood of developing myocardial infarction (OR 0.74, 95% CI 0.61 to 0.89, NNT=72; five studies) whereas the odds of developing stroke (OR 1.98, 95% CI 1.23 to 3.20, NNH 200; five studies) were significantly increased; there was also a non-significant increase in mortality (OR 1.21, 95% CI 0.98 to 1.49, NNH=157; six studies). There was no significant heterogeneity for these comparisons. Control-rate meta-regression determined that patients with highest baseline odds of stroke had decreased relative odds of having a stroke with a β-blocker versus placebo (β coefficient -0.97, 95% credible interval -1.04 to -0.90).
The results were robust with respect to excluding studies with duration of follow-up of less than 30 days. Funnel plots suggested evidence of publication bias, but trim and fill analysis showed that the overall conclusions were unchanged.