The medical community was shaken last week by news that raising HDL (good) cholesterol with drugs did nothing to protect against heart attacks, strokes, and death. Since high HDL levels have been linked to better heart health, it seemed a given that raising HDL would help prevent heart attacks. But the new study found that t’aint necessarily so.
The study, from the National Institute of Health with backing from the drug makers Abbott and Merck, was halted after 32 months of a planned 6-year clinical trial. The study included 3,414 people with a history of cardiovascular disease who were all on a cholesterol-lowering statin to lower their LDL (bad) cholesterol level. Roughly half were also put on high-dose niacin (Niaspan) to raise their HDL and lower their triglycerides. Niacin did improve those levels. But the researchers saw no reduction in the number of cardiovascular events and deaths compared with those on a statin alone, and so the trial suffered an early demise.
This study points out at least two shortcoming in medical research: The first is the frequent focus on markers of disease, such as HDL levels, instead of the important stuff: how many lives are saved or heart attacks prevented. That doesn’t just apply to HDL. For example, improving bone density with drugs doesn’t always prevent fractures. And tightly controlling blood sugar levels doesn’t reduce deaths from cardiovascular disease in people with type 2 diabetes.
The second is that we should almost never rely on the results of observational studies, which can only suggest associations with disease but not prove them. Randomized controlled clinical trials, such as the recent HDL study, remain the gold standard. Without it we would still be treating post-menopausal women with estrogens and guessing about the effectiveness of many forms of treatment.
Of course, the hardest question, is what should patients do now? Is it still important to know your HDL level? Probably. Even if raising a low HDL with drugs doesn’t prevent heart attacks, lifestyle changes that have that effect might still be helpful. Moreover, and perhaps more important, knowing your HDL level can help you assess your overall coronary risk. In fact, the main function of knowing your HDL has long been simply to know how aggressively you need to lower your LDL.
Use our calculator to assess your risk of heart attack and stroke. And see our advice on the lifestyle changes that can raise HDL and lower LDL, as well as our Best Buy Drugs recommendations for statins.
—Marvin M. Lipman, MD