We've known about cholesterol since 1769, when a French chemist first identified the substance in gall stones. While it makes up about 30 percent of your cell membranes and is essential to your organs functioning properly, it is also a risk factor coronary heart disease. By 1910, doctors discovered the connection.
With more than a century of investigation under their belts, scientists have been able to add to a body of evidence that confirms that curious connection between blood cholesterol and coronary heart disease. Did you know there have been 13 Nobel Prizes awarded for research breakthroughs in the scrutiny of cholesterol?
Building on that experience, the pharmaceutical industry has developed a very effective class of drugs, called statins, which do a good job of lowering cholesterol levels in blood, reducing the frequency of heart attacks and strokes. About 28 percent of Americans over 40 take a cholesterol-lowering drug and more than 90 percent of those take a statin. Late last year, the U.S. Preventive Services Task Force issued new guidance for the use of cholesterol-busting statin drugs. The task force greatly expanded the subset for those who should be screened, and those who should be prescribed statins to everyone over age 40 with risk factors -- whether they have a history of cardiovascular disease or not.
Not everyone who needs statins is able to take advantage of them. It's not a cost, or availability issue; some patients just don't tolerate statins. A significant number of people complain of muscle pain, weakness and cramping so severe that they quit taking the medication -- even at the risk of heart attack or stroke. This statin intolerance has been controversial, as there are typically no biomarkers (indicators of some biological problem or condition) for the muscle problems these individuals describe. There are other reasons patients may not benefit from statins, including pregnant or breast-feeding women and those with elevated liver enzymes, active liver disease or allergic reactions.
In the past year, a new class of lipid-lowering medications, PCSK9 inhibitors have shown promise in treating high cholesterol in patients who don't tolerate statins. PCSK9 functions as a binding protein. By blocking PCSK9, these drugs increased the body's ability to remove LDL cholesterol (the bad one) from circulation. Clinical trials showed patients treated with the PCSK9 inhibitor, in addition to standard lipid-lowering therapy, saw a 61 percent reduction in LDL-C compared to those treated with standard therapy alone.
With PCSK9 inhibitors, cost is a major issue. These drugs cost more than $13,000 annually. They are delivered through injections and unlike the very costly but generally one-time-use hepatitis C treatment, PCSK9 inhibitors must be taken for a lifetime. Although they were not developed to treat the average range of patients with elevated LDL-C, concerns remain about the cost to patients. Insurance companies require a great deal of documentation of patients and their providers. The determination of an inability to tolerate statin therapy is complex and requires assessing whether symptoms are real or perceived, as well as whether alternative therapies such as prescribing a different statin, alternative dose, or even use of non-statin medication can effectively treat the patient's elevated cholesterol.
What is needed is data from large clinical trials investigating whether PCSK9 inhibitors are safe and actually prevent deaths from heart disease and stroke. The study furthest along is the known as the FOURIER trial, which enrolled more than 27,500 patients and expects results later this year.
The FDA also requested that neurocognitive effects and cognitive function be monitored and assessed in ongoing long-term studies of PCSK9 inhibitors, in addition to possible development of antidrug antibodies.
During Heart Month, I hope you'll take time to consider your cholesterol levels. According to the Centers for Disease Control:
• Having high blood cholesterol puts you at risk of heart disease, the leading cause of death in the United States.
• Less than half of adults with high LDL cholesterol get treatment.
• Lowering your cholesterol can reduce your risk of having a heart attack, needing heart bypass surgery or angioplasty, and dying of heart disease.
Don't forget, lifestyle choices affect cholesterol levels. A diet rich in fruits and vegetables, and regular exercise can not only lower "bad" cholesterol--it can raise the level of the "good" cholesterol.
-- Dr. David R. Blick, MD FACC, practices at St. Mary's Medical Center.