HPS Statin

Published

Heart Protection Study Collaborative Group Writers. "MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial". The Lancet. 2002. 360(9326):7-22.
PubMed • Full text

Clinical Question

In patients with high risk for CVD, does simvastatin reduce cardiovascular morbidity and mortality, as compared to placebo?

Bottom Line

In patients with high risk for CVD, simvastatin is safe and cholesterol lowering is associated with reduction in all-cause mortality and major vascular event risk, as compared to placebo. The benefit of cholesterol lowering was neither limited by a threshold LDL-C level nor dependent on the pretreatment cholesterol level.

Major Points

HMG-CoA reductase inhibitors (statins) have been shown to reduce cardiovascular (CV) mortality and morbidity in certain high risk patient groups. For example, 4S (1994) and LIPID (1998) found statins to reduce all-cause mortality among patients with prior MI. Similarly, study reported the benefit of Pravastatin in patients with coronary artery disease (CAD) and different cholesterol levels. The AFCAPS showed that Lovastatin is effective in patients without atherosclerotic CAD with average total cholesterol, LDL-C, and below-average HDL-C levels.

The Heart Protection Study (HPS) was published in 2002 and described the impact of simvastatin 40 mg PO qday vs. placebo among a mixed population of secondary and high-risk primary prevention for CVD events. Current guidelines consider this dose to be "moderate intensity". Specifically, HPS enrolled adults 20,536 patients with diabetes, CAD, peripheral artery disease (PAD), stroke, or men aged ≥65 years with hypertension. (This study was a 2x2 factorial design and also randomized to antioxidant medications, the findings of which are published elsewhere.) Simvastatin was associated with an approximately 2% absolute risk reduction in all-cause mortality (NNT=55), which was primarily driven by fewer CVD deaths (NNT=67), including CHD deaths (NNT=83). There were also benefits for CHD events and strokes. There was no LDL-C threshold evident below which no benefit would be obtained. Additionally, the reduction in risk associated with cholesterol lowering did not differ according to pretreatment cholesterol levels. Simvastatin demonstrated good safety profile. The trial was included in a meta-analysis which concluded that intensive LDL-C lowering with statins is safe. Reduction by 1.0 mmol/L is associated with a reduction of major vascular events risk by 20% approximately without any evidence of a threshold level. In addition, a Cochrane review concluded that statins are effective for the primary prevention of CVD.

Guidelines

ACC/AHA Cholesterol Guidelines (2013, adapted)

• Secondary prevention with high-intensity statin therapy for patients ≤75 years in age with clinical ASCVD (i.e. stable CAD) unless contraindicated (grade A, class I, level A)
• Moderate-intensity therapy for above group if contraindication to high-intensity statin therapy or risk for statin-associated adverse events (grade A, class I, level A)
• For patients ≥75 years with clinical ASCVD, evaluate risks and benefits when initiating high- or moderate-intensity statin therapy (grade E, class IIa, level B)
• No recommendation for specific targets for LDL- and non-HDL-cholesterol for primary or secondary prevention of ASCVD.
• Definition of intensity of statin therapy as:
  • High-intensity (LDL reduction ≥50%): Atorvastatin 40-80 mg, rosuvastatin 20-40 mg
  • Moderate-intensity (LDL reduction 30-<50%): Atorvastatin 10-20 mg, rosuvastatin 5-10 mg, simvastatin 20-40 mg, pravastatin 40-80 mg, lovastatin 40 mg, fluvastatin XL 80 mg, fluvastatin 40 mg BID, pitavastatin 2-4 mg
  • Lower-intensity (LDL reduction <30%): Simvastatin 10 mg, pravastatin 10-20 mg, lovastatin 20 mg, fluvastatin 20-40 mg, pitavastatin 1 mg

ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Stable Ischemic Heart Disease (2012)

• Recommend physical activity and weight management for all patients with stable ischemic heart disease (class I, level B)
• Recommend moderate or high dose of a statin should be prescribed for patients with stable ischemic heart disease unless contraindicated (class I, level A)

Design

• Double-blind, randomized, placebo-controlled, multicenter study
• N=20,536
  • Simvastatin 40 mg daily (n=10,269)
  • Placebo (n=10,267)
• Setting: 69 centers in the UK
• Enrollment: 1994-1997
• Mean follow-up: 5 years
• Analysis: intention to treat
• Primary outcome: all-cause mortality, fatal or non-fatal vascular events

Population

Inclusion Criteria

Described elsewhere

• Aged 40-80 years
• Non-fasting total cholesterol ≥3.5 mmol/L (135 mg/dL)
• ≥1 of the following potent risk factors for CHD mortality within 5 years:
  • Type 1 or 2 diabetes mellitus
  • Prior CHD (MI, unstable or stable angina, CABG, or PCI)
  • Non-coronary atherosclerotic disease (TIA/stroke, PAD with claudication, prior CEA, prior atherosclerotic disease-related surgery)
  • Treated hypertension in men aged ≥65 years

Exclusion Criteria

• Clear indication or contraindication for statin therapy
• MI, stroke, severe heart failure or hospital admission for angina within the prior 6 months
• Chronic liver disease or abnormal liver function (eg, ALT>67 lU/L [1.5xULN])
• severe renal disease (creatinine >200 μmol/L)
• Inflammatory muscle disease or evidence of muscle problems (creatine kinase >750 IU/L [3XULN])
• Concurrent use of cyclosporin, fibrates, or high-dose niacin
• Child-bearing potential
• Life-threatening condition other than vascular disease or diabetes
• Conditions that might limit long-term compliance

Baseline Characteristics

From all patients

• Demographics: 28% aged ≥70 years; 75% males
• Qualifying event specifics: diabetes 19%; MI 41%; other coronary disease 24%; cerebrovascular disease 16%; PAD 32.9% treated hypertension 41%
• LDL-C: 3.4±0.8 mmol/L; total cholesterol 5.9±1.0 mmol/L; HDL-C 1.06±0.33 mmol/L; triglyceride 2.1±1.4 mmol/L; apolipoprotein A₁ 1.20±0.22 g/L, and apolipoprotein B 1.14±0.23 g/L

Interventions

• Run-in period involved 4 weeks of placebo, followed by 4-6 weeks of simvastatin 40 mg fixed dose daily.
• Patients were randomized to receive placebo or simvastatin 40 mg daily
• Compliance was defined as having taken ≥80% of the study drug. The rate was 89% at the end of the 1first year of follow-up, and 82% at the end of the fifth year in the statin group.
• Using a 2X2 factorial design, participants were also randomized to receive 600 mg vitamin E, 250 mg vitamin C, and 20 mg β-carotene daily or placebo. The outcomes are described in another paper.

Outcomes

Comparisons are simvastatin vs. placebo

Primary Outcome

All-cause mortality

12.9% vs. 14.7% (RR 0.87; 95% CI 0.81-0.94; P=0.0003; NNT 55)

CVD mortality: 7.6% vs. 9.1% (RR 0.83; 95% CI 0.75-0.91; P<.0001; NNT 67)

CHD mortality: 5.7% vs. 6.9% (P=0.0005; NNT 83)

Other vascular mortality: 1.9% vs. 2.2% (P=0.07)

Non-vascular mortality

5.3% vs. 5.6% (RR 0.95; 95% CI 0.85-1.07; P=0.40)

Secondary Outcomes

Any major vascular event

19.8% vs. 25.2% patients (RR 0.76; 95% CI 0.72-0.81; P<0.0001; NNT 18)

Fatal or nonfatal CHD event: 8.7% vs. 11.8% (RR 0.73; 95% CI 0.67-0.79; P<0.0001; NNT 32)

Fatal or nonfatal stroke: 4.3% vs. 5.7% (RR 0.75; 95% CI 0.66-0.85; P<0.0001; NNT 71)

Coronary or non-coronary revascularisation: 9.1% vs. 11.7% (RR 0.76; 95% CI 0.70-0.83; P<0.0001; NNT 38)

Additional Outcomes

LDL-C reduction

1.0±0.02 mmol/L (P value not reported)

Total cholesterol reduction

1.2±0.02 mmol/L (P value not reported)

HDL-C increase

0.03±0.01 mmol/L (P value not reported)

Triglyceride reduction

0.3±0.03 mmol/L (P value not reported)

Apo-A₁ increase

0.01±0.007 mmol/L (P value not reported)

Apo-B reduction

0.28±0.01 mmol/L(P value not reported)

Subgroup analysis

There was no clinically-meaningful heterogeneity in the efficacy of simvastatin across major subgroups, including age, sex, treated hypertension, medication use at baseline, smoking status, pre-randomisation cholesterol levels or prior history of vascular disease.

Adverse Events

Discontinuation of treatment due to adverse events

4.8% vs. 5.1% (P=NS)

ALT elevation >4x ULN

0.42% vs. 0.31% (P not given)

Persistent elevation: 0.09% vs. 0.04% (P=0.30)

Leading to discontinuation: 0.5% vs. 0.3% (P=NS)

Myalgia

32.9% vs. 33.2% (P=NS)

Myopathy without rhabdomyolysis: 0.05% vs. 0.01%

Myopathy with rhabdomyolysis: 0.05% vs. 0.03%

leading to discontinuation: 0.5% vs. 0.5% (P=NS)

Criticisms

• Only 32% of all screened patients were randomized to receive simvastatin in the trial. It is important to take this into account when interpreting the low adverse event rate in the study and when applying the data to an unselected population.

Funding

• UK Medical Research Council, the British Heart Foundation
• Merck & Co (manufacturers of simvastatin).
• Roche Vitamins Ltd (manufacturers of the vitamins).