β-blocker withdrawal among patients presenting for surgery from home

Objective: This study sought to measure the prevalence of perioperative β-blocker noncompliance by patients who were prescribed long-term β-blocker therapy and presented for surgery from home. The effect of patient noncompliance on the presenting heart rate on the day of surgery also was examined.

Design: Prospective observational study with outcome data obtained from reviews of medical records.

Setting: The preoperative clinic and operating rooms of a Veterans Administration hospital.

Participants: Patients on long-term β-blocker therapy who presented from home for surgery.

Interventions: None.

Measurements and main results: Demographic and comorbidity data and data on self-reported compliance to β-blocker therapy, vital signs on the initial day of surgery, and recent ambulatory vital signs were collected. Ten of 50 subjects (20%; 95% confidence interval, 9-31) reported not taking their β-blocker on the day of surgery. These self-reported nonadherers exhibited a higher presenting heart rate on the day of surgery than adherent subjects (median, 78 v 65 beats/min; p = 0.02 by Wilcoxon rank-sum test). The difference-in-difference analysis in heart rate between baseline primary care and the day of surgery also was statistically significant between compliant and noncompliant subjects (-7 v + 12.5 beats/min; p < 0.00001).

Conclusions: Patient self-report and physiologic data documented a failure to take β-blockers and possible β-blocker withdrawal in 20% of patients who presented for surgery from home. If these findings are confirmed in larger studies, improved patient understanding of and compliance with medication instructions during preoperative visits should be a focus of future quality improvement initiatives.