Evidence for caution: Women and statin use
By Harriet G. Rosenberg and Danielle Allard From Women and Health Protection Maryann Napoli Center for Medical Consumers www.medicalconsumers.org
Statins are a class of prescription drugs designed to lower cholesterol. The leading statin drugs are Lipitor (generic name atorvastatin), Crestor (rosuvastatin), Mevacor (lovastatin), Pravacol (pravastatin), Zocor (simvastatin) and Lescol (fluvastatin).
The rationale for prescribing these drugs is based on the cholesterol hypothesis which argues that drugs that can lower total cholesterol (TC) or LDL cholesterol (often called “bad” cholesterol) or raise HDL (“good” cholesterol) will prevent heart disease. The measurement of cholesterol lowering is called a surrogate endpoint, which is different from the measurement of the hard endpoints of decreased heart disease or death. Having cholesterol is often thought of as a virtual disease state. However, cholesterol performs many vital functions in the body: it maintains cell wall structure, is crucial for hormone and Vitamin D synthesis, bile salt production and digestion, brain and neuron function. It is critical in fetal development and is an essential component of breast milk.
In the last 20 years, a class of cholesterol-lowering drugs called statins have achieved the status of being the most widely prescribed pharmaceuticals in the world. In Canada, women account for half of the three million people who take statins daily.
Researchers Harriet Rosenberg and Danielle Allard at Women and Health Protection recently reviewed the effectiveness and safety of statin medications for women in Canada. They were looking for the evidence base for use of this widely prescribed class of drugs. What they found was evidence for caution.
In 2006, 23.6 million prescriptions for statins were dispensed in Canada at a cost of $2 billion (CAN). Statin sales were predicted to increase, with projected earnings of $30 to $33 billion (US) worldwide in 2007. Lipitor is the top selling pharmaceutical in Canada. Worldwide sales reached $12.9 billion (US) in 2005.
In their report, Evidence for Caution: Women and Statin Use, Rosenberg and Allard look closely at the available evidence about statin use and discuss research information that challenges the cholesterol hypothesis (see box), in particular for women.
There are significant differences in the way heart disease manifests in men and women. Women have different symptoms; their symptoms are less likely to be recognized and, as a result, women may not receive timely emergency treatment and usually have a higher risk of death after a heart attack. This is especially true for younger women. Heart disease is often described as the leading cause of death for women. This is true only for women in their 80s: women between the ages of 30 and 79 are most likely to die of cancer. For men, on the other hand, heart disease and stroke are much more likely to occur at a younger age. The death rate due to heart disease among women is currently only about half that for men.
In the recent past, these differences were explained by theories of hormonal differences between men and women—theories that led to the widespread prescription of hormone therapy (HT) for menopausal women to protect against heart disease. However, in 2002, the groundbreaking Women’s Health Initiative tested this hypothesis and found the opposite to be true; and, most recently, additional evidence has linked HT with an increased risk of developing breast cancer.