High tierRandomized Controlled TrialCitation verified
Ezetimibe Added to Statin Therapy after Acute Coronary Syndromes
Christopher P Cannon, Michael A Blazing, Robert P Giugliano, Eugene Braunwald, IMPROVE-IT Investigators - New England Journal of Medicine, 2015
The first trial to show that adding a NON-statin LDL-lowering drug on top of a statin further reduces events. Ezetimibe (which blocks intestinal cholesterol absorption) lowered LDL from 69.5 to 53.7 mg/dL and modestly but significantly cut the composite endpoint (HR 0.936). Because ezetimibe works nothing like a statin, this is key evidence that LDL lowering itself - not a statin side effect - drives benefit.
Key findings
- Primary composite at 7 years (Kaplan-Meier): 32.7% vs 34.7%; HR 0.936 (95% CI 0.89-0.99, p=0.016).
- Time-weighted average LDL: 53.7 vs 69.5 mg/dL (1.4 vs 1.8 mmol/L, p<0.001).
- Benefit proportional to the additional LDL reduction, via a non-statin mechanism.
Effect measures
- Hazard Ratio: 0.936 (primary composite)95% CI 0.89-0.99
- Absolute Risk Reduction: 2.0 percentage points (34.7% vs 32.7%)
Why this evidence tier (High)
- Risk of bias:
- Large double-blind randomized placebo-controlled trial run to completion.
- Precision:
- Very large; precise estimate, though the effect is small and the upper CI approaches 1.0.
- Directness:
- Hard clinical composite; directly tests non-statin LDL lowering on top of a statin.
- Consistency:
- Concordant with statin and PCSK9 evidence - same direction per unit LDL.
- Funding / COI:
- Manufacturer-funded (Merck); several authors were Merck employees.
High certainty that adding non-statin LDL lowering reduces events, strongly supporting LDL as the operative factor; the absolute benefit is modest.
- Population:
- 18,144 patients stabilized after an acute coronary syndrome with LDL 50-100 mg/dL, randomized to simvastatin plus ezetimibe vs simvastatin plus placebo; median follow-up ~6 years.
- Conflicts of interest:
- Industry-funded by Merck, which manufactures ezetimibe. Several co-authors were Merck employees.
- Funding:
- Merck (manufacturer of ezetimibe); NCT00202878.
Limitations
- Small absolute benefit over ~6 years; upper confidence bound near 1.0.
- Secondary prevention (post-ACS); manufacturer-funded.