β-blocker withdrawal among patients presenting for surgery from home

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.

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

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

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

None.

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).

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.