Background: Previous meta-analyses reported by Gould et al found significant decreases of 15% in the risk for coronary heart disease (CHD)-related mortality and 11 % in risk for all-cause mortality per decrease of 10% in total cholesterol (TC) level.
Objective: To evaluate the effects of reducing cholesterol on clinical events after including data from recent clinical trials.
Methods: Using a literature search (MeSH key terms, including: bezafibrate, coronary disease, efficacy, gemfibrozil, hydroxymethylglutaryl-CoA reductase inhibitors, hypercholesterolemia, niacin [nicotinic acids], randomized controlled trials, and treatment outcome; years: 1999-2005), we identified trials published in English that assessed the effects of lipid-modifying therapies on CHD end points, including CHD-related death, myocardial infarction, and angina pectoris. We also included all studies from the previously published meta-analysis. Using the same analytic approach as previously, we determined the effects of net absolute reductions (1 mmol/L [38.7 mg/dL]) in TC and low-density lipoprotein cholesterol (LDL-C) on the relative risks (RRs) for all-cause mortality, CHD-related mortality, any CHD event (mortality or nonfatal myocardial infarction), and non-CHD-related mortality.
Results: We included 62 studies involving 216,616 patients, including 126,474 from 24 randomized controlled trials the findings of which were published since the previous meta-analysis (1998). Among all patients, for every 1-mmol/L decrease in TC, there was a 17.5 reduction in RR for all-cause mortality; 24.5 %, for CHD-related mortality; and 29.5% for any CHD event. Corresponding reductions for every 1-mmol/L decrease in LDL-C were 15.6%, 28.0%, and 26.6%, respectively. Similar relationships were observed in patients without CHD. No significant relationship was found between lipid reduction and non-CHD-related mortality risk.
Conclusions: The results from the present analysis support conclusions from previous meta-analyses that cholesterol lowering is clinically beneficial in patients with CHD or at elevated CHD risk. These results also support the previous finding that non-CHD-related mortality is unrelated to lipid reductions.