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Is lower cholesterol better? - The SEARCH continues

The Clinical Trial Service Unit at the University of Oxford have announced the summary results (PDF) of the SEARCH study. Publication of the full results is expected in 2009.

The study aimed to assess the impact of intensive lipid lowering with simvastatin 80mg versus standard therapy with simvastatin 20mg and folic acid supplementation in patients who have had a heart attack.

The study recruited 12,000 participants with 6,000 being randomly assigned to treatment with intensive or standard statin therapy. The study ran for an average of 6.7 years. The intensive treatment produced a reduced level of low-density lipoprotein cholesterol (LDL-C) by 0.35mmol/L. This reduction was associated with a 6% reduction in heart attacks, stroke and revascularisation procedures although this was not statistically significant. The study also found that there was no benefit from folic acid or vitamin B12 supplementation in the prevention of heart attacks or strokes.

The press release states that the study results, although not statistically significant, are consistent with data from meta-analysis showing a 0.35mmol/L reduction in LDL-C is associated with a relative risk reduction of 6-7% and therefore supports the assertion at lower LDL-C is better.

However, it is also notable that during the study 3 patients treated with simvastatin 20mg developed myopathy while 53 developed this adverse drug reaction while taking simvastatin 80mg. This is a relative risk increase of 1667%.

Action: Clinicians should consider the absolute benefit that an individual patient could expect to achieve from additional cholesterol lowering before increasing statin therapy. This absolute benefit should be balanced against the increased risk of side effects and the potential benefits of other interventions (for example smoking cessation, lifestyle changes and blood pressure reduction).