The Scandinavian Simvastatin Survival Study (also known as the 4S study), was a multicentre, randomized, double-blind, placebo-controlled clinical trial, which provided the initial data that supported the use of the cholesterol-lowering drug, simvastatin, in people with a moderately raised cholesterol and coronary heart disease (CHD); that is people who had previously had a heart attack or angina.

[3] The study concluded that secondary prevention with simvastatin in a high risk group with CHD reduced overall mortality by 30%.

[2] The objective of the study was to assess the effect of a cholesterol-lowering drug called simvastatin on mortality and morbidity in people with a history of a previous heart attack or angina, who also had a moderately raised cholesterol; between 5.5 and 8.0 mmol/L.

[1][5][6] A second objective was to investigate whether the incidence of major coronary artery disease events (fatal and nonfatal myocardial infarction and sudden death) could be reduced with simvastatin.

[3][7] The study concluded that secondary prevention with simvastatin in a high risk group with CHD reduced overall mortality by 30%.