When the last set of US lipid-lowering guidelines was updated in 2004,1 placebo-controlled trials had proven statin therapy to be effective for the secondary prevention of cardiovascular disease. At that time, the ability of these agents to reduce rates of vascular events in primary prevention remained controversial, long-term safety with regard to cancer was unclear, and pharmacologic therapy was relatively expensive.
Ridker PM, Wilson PWF. A Trial-Based Approach to Statin Guidelines. JAMA. 2013;310(11):1123-1124. doi:10.1001/jama.2013.276529