Variations in coronary artery disease secondary prevention prescriptions among outpatient cardiology practices: insights from the NCDR (National Cardiovascular Data Registry)

Objectives: This study assessed practice variations in secondary prevention medication prescriptions among coronary artery disease (CAD) patients treated in outpatient practices participating in the National Cardiovascular Data Registry (NCDR) Practice Innovation and Clinical Excellence (PINNACLE) registry.

Background: Among patients with CAD, secondary prevention with a combination of beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and statins reduces cardiac mortality and myocardial infarction (MI). Accordingly, every CAD patient should receive the combination of these medications for which they are eligible. However, little is known about current prescription patterns of these medications and the variation in use among outpatient cardiology clinics.

Methods: Using data from NCDR PINNACLE registry, a national outpatient cardiology practice registry, we assessed medication prescription patterns among eligible CAD patients, between July 2008 and December 2010. Overall rates of prescription and variation by practice were calculated, adjusting for patient characteristics.

Results: Among 156,145 CAD patients in 58 practices, 103,830 (66.5%) patients were prescribed the optimal combination of medications for which they were eligible. The median rate of optimal combined prescription by practice was 73.5% and varied from 28.8% to 100%. After adjustment for patient factors, the practice median rate ratio for prescription was 1.25 (95% confidence interval: 1.20 to 1.32), indicating a 25% likelihood that 2 random practices would differ in treating identical CAD patients.

Conclusions: Among a national registry of CAD patients treated in outpatient cardiology practices, over one-third of patients failed to receive their optimal combination of secondary prevention medications. Significant variation was observed across practices, even after adjusting for patient characteristics, suggesting that quality improvement efforts may be needed to support more uniform practice.