Common Cholesterol Testing Faulty, What You Should Do
It appears that common cholesterol testing may be missing the majority of people with high triglyceride levels who are at risk of heart disease. If you are wondering how that could happen and what you should do about it, the authors of a new major study offer explanations.
What do your cholesterol levels mean?
The common cholesterol test, also referred to as a basic lipid panel, is a simple blood test that is used for more than 85 percent of cholesterol testing in the United States each year. But what if that test isn’t as useful as it should be and is letting millions of people at risk for heart disease slip through the cracks?
According to the findings of a major study that evaluated more than 1.3 million adults in the United States, the standard cholesterol test (a 40-plus year old formula called Friedewald) may be faulty when it comes to measuring LDL (low-density lipoprotein) cholesterol, a major risk factor for heart disease that is also referred to as “bad” cholesterol.
As way of reference, here are the standards for both LDL and triglyceride levels so you can better understand what the study findings mean. Keep in mind that generally, the lower your LDL cholesterol level is, the better off you are, and that the main focus of cholesterol-lowering treatment is your LDL.
- 100-129 mg/dL is near ideal
- 130-159 mg/dL is borderline high
- 160-189 mg/dL is high
- 190 mg/dL or greater is very high
- 150-199 mg/dL is borderline high
- 200-499 mg/dL is high
- 500 mg/dL and greater is very high
What the investigators found
Steven R. Jones, MD, of the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease and the study’s senior investigator, explained that while clinicians routinely depend on the calculation of LDL using the Friedewald equation, this method is less accurate than desirable in patients at greatest risk of heart disease: those with “LDL cholesterol levels in the high-risk treatment target range and elevated triglycerides.”
The investigative team compared LDL cholesterol levels using the Friedewald method with another test, the Vertical Auto Profile (VAP) lipid panel in 1,310,440 patients from 2009 to 2011. The VAP Lipid Panel can be ordered for individuals who are at high risk for heart disease and those with elevated triglyceride levels, and the cost is comparable to the common cholesterol test.
The authors found that use of the common cholesterol test underestimated the risk of heart disease in 23 to 59 percent of patients with Friedewald LDL levels less than 70 mg/dL and triglyceride levels greater than 150. Specifically, use of Friedewald commonly classifies LDL cholesterol as less than 70 mg/dL “despite directly measured levels” of 70 mg/dL or greater.
This could result in undertreatment of people at high risk for heart disease. Anyone who has LDL or triglyceride levels that place them at risk for heart disease should talk to their doctor about the type of cholesterol testing they are using and ask about the more accurate VAP Lipid Profile.
At the same time, there are lifestyle changes people can make to help improve their LDL and triglyceride levels.
- Routine moderate exercise, such as brisk walking, dancing, bicycling, or swimming, five or more days a week
- Achieve and maintain a healthy weight
- Limit alcohol consumption to one (women) to two (men) drinks daily, as alcohol raises triglyceride levels
- Include lots of omega-3 fatty acids in your diet and/or take fish oil supplements
- Maintain a diet high in foods rich in fiber, such as fruits, vegetables, legumes, and whole grains
- Limit your intake of saturated and trans fats which are found mainly in meats, poultry, dairy foods, and processed foods
- Don’t smoke
- Practice stress management to help lower blood pressure, which also has an impact on heart disease risk
Everyone needs to be aware of their cholesterol and triglyceride levels to better appreciate their risk of heart disease. Accurate cholesterol testing is a critical tool for understanding that risk, and so healthcare consumers should be sure they are being tested properly.
Martin SS et al. Friedewald estimated versus directly measured low-density lipoprotein cholesterol and treatment implications. Journal of the American College of Cardiology 2013; in press. DOI:10.1016/j.jacc.2013.01.079