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Evidence summaries

Benefit of Different Cholesterol-Lowering Interventions

Statins are the most effective cholesterol-lowering agents for reducing cardiovascular and all-cause mortality. The greater effect of statins is likely to be due to the large reduction in cholesterol. Statin treatments for hypercholesterolemia reduce the risk of death and major cardiovascular events by 20% to 30%. Level of evidence: "A"

A systematic review 1 including 66 RCTs with a total of 173 160 subjects was abstracted in DARE. Cholesterol reduction rates ranged from 22.86% for statins (range 12.8% to 32%) to 3.07% for n-3 long chain fatty acids and precursors. Coronary heart disease mortality according to intervention was as follows: HMG-CoA reductase inhibitors, RR 0.69 (95% CI 0.59 to 0.80, no heterogeneity); resins, RR 0.71 (95% CI 0.51 to 0.99, significant heterogeneity); all other interventions, no statistical significance. For overall mortality the RR for HMG-COA reductase inhibitors was 0.79 (95% CI 0.71 to 0.89) and (according to small trials) for n-3 fatty acids 0.68 (95% CI 0.53 to 0.88). Treatment with hormones was associated with borderline increase in overall mortality (RR 1.09, 95% CI 1.00 to 1.20).

A systematic review 2 including 17 studies with a total of 21 303 subjects was abstracted in DARE.

Patients who received statin treatment for hypercholesterolemia demonstrated a 20% to 30% reduction in death and major cardiovascular events compared with patients who received placebo. Studied treatments included (n=number of studies) lovastatin 20/40 mg (n=5), pravastatin 15/20/40 mg (n=10) and simvastatin 20 mg (n=3) versus placebo.

The results in different outcomes were as follows:

All-cause mortality (n = 14), the OR was 0.76 (95% CI: 0.67, 0.86) in favour of receiving statin treatment. NNT = 67.

Fatal MI (n = 14), the OR was 0.61 (95% CI: 0.48, 0.78) in favour of receiving statin treatment. NNT = 166.

Non-fatal MI (n = 13), the OR was 0.66 (95% CI: 0.57, 0.77) in favour of receiving statin treatment. NNT = 43.

Fatal stroke (n = 10), the OR was 0.77 (95% CI: 0.57, 1.04) that was not statistically significant. NNT = 500.

Non-fatal stroke (n = 7), the OR was 0.69 (95% CI: 0.54, 0.88) in favour of receiving statin treatment. NNT = 143.

Angina (n = 12), the OR was 0.70 (95% CI: 0.65, 0.76) in favour of receiving statin treatment. NNT = 24.

Withdrawals (n = 11), the OR was 0.80 (95% CI: 0.61, 1.04) which was not statistically significant. NNT not reported.

Sensitivity analyses revealed no significant differences in results. The advantage of statins was generally present across study types and statin treatment types and for patients with less severe dyslipidemias. The benefit in clinical outcomes was noticeable as early as 1 year.

    References

    • Bucher HC, Griffith LE, Guyatt GH. Systematic review on the risk and benefit of different cholesterol-lowering interventions. Arterioscler Thromb Vasc Biol 1999 Feb;19(2):187-95. [PubMed][DARE]
    • Ross SD, Allen IE, Connelly JE, Korenblat BM, Smith ME, Bishop D, Luo D. Clinical outcomes in statin treatment trials: a meta-analysis. Arch Intern Med 1999 Aug 9-23;159(15):1793-802. [PubMed][DARE]

Primary/Secondary Keywords