Impact of beta-blocker initiation timing on mortality risk in patients with diabetes mellitus undergoing noncardiac surgery: A nationwide population-based cohort study

Background--Relevant clinical studies have been small and have not convincingly demonstrated whether the perioperative initiation of beta-blockers should be considered in patients with diabetes mellitus undergoing noncardiac surgery. Methods and Results--In this nationwide propensity score-matched study, we included patients with diabetes mellitus undergoing noncardiac surgery between 2000 and 2011 from Taiwan's National Health Insurance Research Database. Patients were classified as beta-blocker and non-beta-blocker cohorts. We further stratified beta-blocker users into cardioprotective betablocker (atenolol, bisoprolol, metoprolol, or carvedilol) and other beta-blocker users. To investigate time of initiation of beta-blocker use, initiation time was stratified into 2 periods (>30 and ≤30 days preoperatively). The outcomes of interest were in-hospital and 30-day mortality. After propensity score matching, we identified 50 952 beta-blocker users and 50 952 matched controls. Compared with non-beta-blocker users, cardioprotective beta-blocker users were associated with lower risks of in-hospital (odds ratio 0.75, 95% CI 0.68-0.82) and 30-day (odds ratio 0.75, 95% CI 0.70-0.81) mortality. Among initiation times, only the use of cardioprotective beta-blockers for >30 days was associated with decreased risk of in-hospital (odds ratio 0.72, 95% CI 0.65-0.78) and 30-day (odds ratio 0.72, 95% CI 0.66-0.78) mortality. Of note, use of other beta-blockers for ≤30 days before surgery was associated with increased risk of both in-hospital and 30-day mortality. Conclusions--The use of cardioprotective beta-blockers for >30 days before surgery was associated with reduced mortality risk, whereas short-term use of beta-blockers was not associated with differences in mortality in patients with diabetes mellitus.