Underuse of Statins in Patients with Coronary Artery Disease
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco.
Source: Arnold SV, et al. Statin use in outpatients with obstructive coronary artery disease. Circulation 2011;124:2405-2410.
The benefits of statin use in patients with proven coronary artery disease (CAD) are well established. Current guidelines recommend that this patient group, which is at high risk for recurrent events, be treated to LDL cholesterol levels < 100 mg/dL. Clinical trials have shown that similar reduction in risk for future cardiac events is achieved with statin therapy, despite the LDL level at initiation. Even patients whose LDL is < 100 mg/dL at initiation of statin therapy derive clinical benefits from statins. Whether there is general adherence to the secondary prevention guidelines in ambulatory clinical practice is not known. Accordingly, Arnold and colleagues used the American College of Cardiology's Practice INNovation And CLinical Excellence (PINNACLE) registry. This registry study includes data on ambulatory cardiac outpatients collected from 24 practices in 111 practice locations in 18 states.
Patients with obstructive CAD were defined as those with diagnoses of prior myocardial infarction (MI), prior percutaneous coronary intervention (PCI), or prior coronary artery bypass graft surgery (CABG). After excluding those with contraindications to statin therapy, 38,775 patients with obstructive CAD were identified. Statin therapy was prescribed for 77.8%, 17% were untreated, 16.6% received both a statin and a non-statin lipid-lowering medication, and 5.3% received only a non-statin lipid-lowering medication.
Patients without medical insurance were less likely to receive a statin (risk ratio [RR] 0.94; P = 0.039). Patients were more likely to receive a statin if they were male (RR 1.10; P < 0.001), hypertensive (RR 1.07; P = 0.003), had prior CABG (RR 1.09; P < 0.001), or had prior PCI (RR 1.11; P < 0.001). A history of diabetes and prior MI were weakly associated with a greater likelihood of receiving statin therapy. Among the patients who did not receive any lipid-lowering therapy, 46.7% had LDL levels > 100 mg/dL. The authors conclude that despite robust clinical trial evidence, a substantial number of patients with obstructive CAD remain untreated with statins. A small proportion were treated with non-statin therapy and one in six patients was simply untreated; only half of the untreated patients had LDL < 100 mg/dL. These findings illustrate important opportunities to improve lipid management in outpatients with obstructive CAD.
Commentary
The benefits of stain therapy in those with obstructive CAD are clear. This study is an important wake-up call to clinicians to be vigilant about aggressive secondary prevention measures in this high-risk patient group. Unfortunately, this study is unable to provide the reasons for nonprescription of statins. We are left to ponder if this represents intolerance of statins that was not documented, physician oversight, patient unwillingness to adhere to a statin regimen, or other reasons. Prior small studies have also suggested low adherence rates to statin therapy, which is congruent with the data presented here. However, this study provides a more contemporary look at statin usage in secondary prevention with a larger sample size. Furthermore, we are not told how the data are logged for the PINNACLE registry. Prior MI may have represented a demand ischemia event, rather than a ruptured plaque with atherothrombotic occlusion of a coronary artery.
Lipid levels were available in approximately half of the patients who were not receiving lipid-lowering therapy. Nearly 50% had elevated LDL levels > 100 mg/dL. The authors postulate that the group with LDL < 100 mg/dL were not treated because physicians thought their LDL was at goal and they would not benefit from statin therapy. In fact, the opposite is true. Even those who begin with a low LDL derive clinical benefit from statins. Thus, both those with a high LDL and those with a low LDL should have been treated with lipid lowering, preferably a statin, and this represents a significant treatment gap. This study reminds us that we should all be vigilant that our patients are receiving guideline-based secondary prevention measures.
The benefits of statin use in patients with proven coronary artery disease (CAD) are well established. Current guidelines recommend that this patient group, which is at high risk for recurrent events, be treated to LDL cholesterol levels < 100 mg/dL.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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