Clinical question
Does ezetimibe modify clinical outcomes?
Bottom line
Only the IMPROVE-IT trial provides meaningful data on ezetimibe. In patients with acute coronary syndrome, adding ezetimibe to moderate-intensity statin therapy prevents 1 cardiovascular event for every 50 people treated for 7 years. Baseline low-density lipoprotein (LDL) level does not influence this benefit. There are no data for ezetimibe in primary prevention, but the benefit is likely lower proportional to baseline cardiovascular disease (CVD) risk.
Evidence
Several RCTs examine outcomes for 10 mg of ezetimibe or placebo added to statin therapy.
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IMPROVE-IT1–3: In 18 144 patients with acute coronary syndrome (within 10 days) and LDL levels of 1.3 to 3.2 mmol/L, ezetimibe lowered LDL levels by 0.43 mmol/L (24%) at 1 year.
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-Clinical outcomes at 7 years included no difference in mortality (15.4% vs 15.3%) and significantly reduced CVD (32.7% vs 34.7%, NNT = 50, P = .016), myocardial infarction (NNT = 59, P = .002), and ischemic stroke (NNT = 167, P = .008).
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—Benefits were seen regardless of baseline LDL level.
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—There were no differences in adverse events.
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ENHANCE4: In 720 patients with familial hypercholesterolemia, there was no difference in events at 2 years.
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Vascular surgery patients5: In 262 patients there was no difference in events at 1 year.
One RCT (N = 363) comparing ezetimibe and niacin (only other active comparator trial)6 found significantly increased CVD events with ezetimibe (5% vs 1%, P = .04) at 14 months.
Context
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Two RCTs examine statin therapy plus ezetimibe versus placebo in which the effects of ezetimibe and statin therapy cannot be separated.
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There are no primary prevention data for ezetimibe. If the relative effects are generalizable (as they are for statins9), for patients receiving low or moderate intensity statin therapy (eg, 20–40 mg of simvastatin or 10 mg of atorvastatin) the following would be expected:
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-Adding ezetimibe would prevent 1 CVD event in approximately 100 high-risk patients (20% baseline 10-year CVD risk) and approximately 200 low-risk patients (10% baseline 10-year CVD risk).1–3
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-Increasing to a high-intensity statin (eg, 80 mg of atorvastatin) would prevent 1 CVD event in approximately 43 high-risk and approximately 85 low-risk patients.9
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Implementation
In patients with CVD who tolerate a low- to moderate-dose statin, 2 evidence-based lipid-lowering interventions further decrease CVD events: increasing to a high-dose statin or adding ezetimibe. Increasing to a high-dose statin is more than twice as effective as adding ezetimibe. High-dose statins cause intolerable adverse effects for 1 in about 50 patients and diabetes in 1 in about 125 patients over 5 years10,11; adding ezetimibe does not increase adverse effects.1–3 Finally, 10 mg of atorvastatin plus ezetimibe costs $240 every 90 days versus $50 for 80 mg of atorvastatin.12
Notes
Tools for Practice articles in Canadian Family Physician (CFP) are adapted from articles published on the Alberta College of Family Physicians (ACFP) website, summarizing medical evidence with a focus on topical issues and practice-modifying information. The ACFP summaries and the series in CFP are coordinated by Dr G. Michael Allan, and the summaries are co-authored by at least 1 practising family physician and are peer reviewed. Feedback is welcome and can be sent to toolsforpractice{at}cfpc.ca. Archived articles are available on the ACFP website: www.acfp.ca.
Footnotes
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The opinions expressed in Tools for Practice articles are those of the authors and do not necessarily mirror the perspective and policy of the Alberta College of Family Physicians.
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