Cholesterol in patients with coronary heart disease: how low should we go?

CLINICAL PROBLEM: To examine the evidence supporting the recent National Cholesterol Education Program (NCEP) recommendation that low to moderate levels of cholesterol should be aggressively managed in patients with coronary heart disease (CHD).
METHODS: Cohort studies and clinical trials with angiographic or clinical endpoints, that included CHD patients with low to moderate levels of cholesterol, were systematically identified through a MEDLINE search and critically reviewed. SYNOPSIS: None of the cohort studies show that a moderate level of cholesterol confers significantly increased risk of CHD death, although a pooled relative risk of 1.14 (95% CI 1.08 to 1.4) suggests that there may be a slight excess risk. Of five angiographic trials of CHD patients with moderate levels of cholesterol, two demonstrated no improvement in angiographic endpoints with intensive lipid-lowering therapy and the other three are difficult to interpret since they included other interventions in addition to the cholesterol-lowering regimen. No large clinical trial with clinical endpoints has been reported for CHD patients with low to moderate levels of cholesterol. RECOMMENDATIONS: The recommendation to treat CHD patients who have low to moderate levels of cholesterol with diet or drugs is not based on convincing evidence of efficacy. This is in clear contrast to the recommendation for CHD patients with high levels of cholesterol, for whom there is definitive clinical trial evidence of benefit from cholesterol-lowering therapy. While we await clinical trial results for CHD patients with low to moderate levels of cholesterol, clinicians and patients must consider the possible disadvantages of therapy in relation to the uncertain benefit.