Scandinavian Simvastatin Survival Study

The Scandinavian Simvastatin Survival Study (also known under the abbreviation 4S) is a multicenter clinical trial that was performed in 1990s in Scandinavia.

The objective of the study was to assess effect of a cholesterol-lowering drug called simvastatin on mortality and morbidity in a group of 4444 patients with coronary heart disease, aged between 35 and 70 years.

The patients exhibited moderate hypercholesterolemia, between 5.5 and 8.0 mmol/l.

The trial showed that treatment of patients suffering from coronary heart disease with simvastatin had a lowering effect on mortality and morbidity.

2223 patients were assigned placebo and 2221 were assigned simvastatin treatment for a mean period of 5.4 years. There was a 30% relative reduction in the risk of death with simvastatin treatment. The absolute CHD-mortality was reduced from 8.5% to 5.0%, making the number needed to treat around 30 (thirty patients would need to be treated to prevent one death). Additionally there was no excess morbidity of non-cardiac deaths from causes like cancer or suicide, a concern that has occasionally arisen in respect to the statins.

The treatment of 100 patients for six years would prevent four deaths of the disease and seven non-fatal myocardial infarcts.

The 4S study turned out to be a milestone in cardiology and evidence-based medicine - it was clearly proven that treatment with statins saved lives of patients with coronary heart disease. A host of other large multicenter clinical trials followed that paved way to widespread use of this class of pharmaceuticals.

However, it should be noted that no trial of statin in primary prevention (people without symptomatic coronary artery disease or diabetes) has shown an overall health benefit.