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 beta‐blocker (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.