Perioperative beta-blocker therapy has been associated with increased risk of stroke. However, the association between beta-blocker initiation prior to the day of surgery and the risk of stroke is unknown. We hypothesized there would be no association between preoperative beta-blocker initiation within 60 days of surgery or chronic beta blockade (> 60 days) and the risk of stroke in patients undergoing major abdominal surgery.
Data on elective major abdominal surgery was obtained from the Truven Health MarketScan® 2005 to 2015 Commercial and Medicare Supplemental Databases. Patients were stratified by beta-blocker dispensing exposure: 1. beta-blocker naïve, 2. preoperative beta-blocker initiation within 60 days of surgery, 3. chronic beta-blocker dispensing (> 60 days). We compared in-hospital stroke and major adverse cardiac events between the different beta-blocker therapy exposures.
There were 204,981 patients who underwent major abdominal surgery. Beta-blocker exposure was: perioperative initiation within 60 days of surgery for 4,026 (2.0%) patients, chronic beta-blocker therapy for 45,424 (22.2%) patients, and beta blocker naïve for 155,531 (75.9%) patients. The unadjusted frequency of stroke for patients with beta-blocker initiation (0.4%, 17/4,026) and chronic beta-blocker therapy (0.4%, 171/45,424) was greater than beta-blocker naïve patients (0.2%, 235/155,531) (P <0.001). After propensity score weighting, patients initiated on a beta-blocker within 60 days of surgery (OR: 0.90, 95% CI: 0.31 – 2.04; P = 0.757) or on chronic beta-blocker therapy (OR: 0.86, 95% CI: 0.65 – 1.15; P = 0.901) demonstrated similar stroke risk compared to beta blocker naïve patients. Patients on chronic beta blocker therapy demonstrated lower adjusted risk of major adverse cardiac events compared to beta blocker naïve patients (OR: 0.81, 95% CI: 0.72 – 0.91; P = 0.007), despite higher unadjusted absolute event rate [2.6%, (1,173/45,424) vs 0.6%, (872/155,531)].
Among patients undergoing elective major abdominal surgery, we observed no association between preoperative beta-blocker initiation within 60 days of surgery or chronic beta-blocker therapy and stroke.