## Featured Research

from universities, journals, and other organizations

# Researchers develop formula to more accurately calculate 'bad' cholesterol

Date:
November 17, 2013
Source:
Johns Hopkins Medicine
Summary:
Researchers have developed a more accurate way to calculate low-density lipoprotein (LDL) cholesterol, the so-called “bad” form of blood fat that can lead to hardening of the arteries and increase the risk of heart attack and stroke. If confirmed and adopted by medical laboratories that routinely calculate blood cholesterol for patients, the researchers say their formula would give patients and their doctors a much more accurate assessment of LDL cholesterol.

Johns Hopkins researchers have developed a more accurate way to calculate low-density lipoprotein (LDL) cholesterol, the so-called "bad" form of blood fat that can lead to hardening of the arteries and increase the risk of heart attack and stroke. If confirmed and adopted by medical laboratories that routinely calculate blood cholesterol for patients, the researchers say their formula would give patients and their doctors a much more accurate assessment of LDL cholesterol.

"The standard formula that has been used for decades to calculate LDL cholesterol often underestimates LDL where accuracy matters most -- in the range considered desirable for patients at high risk for heart attack and stroke," says Seth S. Martin, M.D., a cardiology fellow at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease. Martin is first author of the study detailed in a Nov. 19, 2013 article in the Journal of the American Medical Association.

Many studies have shown that higher levels of LDL cholesterol signal greater risk of plaque accumulating in heart arteries. Since 1972, a formula called the Friedewald equation has been used to gauge LDL cholesterol. It is an estimate rather than a direct measurement. However, physicians use the number to assess their patients' risk and determine the best course of treatment.

The Friedewald equation estimates LDL cholesterol with the following formula: total cholesterol minus HDL cholesterol minus triglycerides divided by five. The result is expressed in milligrams per deciliter. That equation, the researchers say, applies a one-size-fits-all factor of five to everyone; a more accurate formula would take specific details about a person's cholesterol and triglyceride levels into account.

Using a database of blood lipid samples from more than 1.3 million Americans that were directly measured with a traditional and widely accepted technique known as ultracentrifugation, the researchers developed an entirely different system and created a chart that uses 180 different factors to more accurately calculate LDL cholesterol and individualize the assessment for patients.

"We believe that this new system would provide a more accurate basis for decisions about treatment to prevent heart attack and stroke," says Martin.

Results of the new study are built on research by the same authors from the Johns Hopkins University School of Medicine and published in the Journal of the American College of Cardiology. In that study, the researchers compared samples assessed using the Friedewald equation with a direct calculation of the LDL cholesterol.

They found that in nearly one out of four samples in the "desirable" range for people with a higher heart disease risk, the Friedewald equation was not accurate.

"As a result, many people -- especially those with high triglyceride levels -- may have a false sense of assurance that their LDL cholesterol is at an ideal level. Instead, they may need more aggressive treatment to reduce their heart disease risk," says Steven Jones, M.D., director of inpatient cardiology at The Johns Hopkins Hospital and a faculty member at the Ciccarone Center who is the senior author of the study.

The lipid profiles used for the study were from a laboratory in Birmingham, Ala., which provides a detailed analysis of samples sent in by doctors across the country. Except for the age of people on whom the samples were based (59 years on average) and the gender (52 percent of the samples were from women), the patients were not identifiable to the researchers. That database was almost 3,000 times larger than the sample used to devise the Friedewald equation 43 years ago.

Story Source:

The above story is based on materials provided by Johns Hopkins Medicine. Note: Materials may be edited for content and length.

Journal Reference:

1. Seth S. Martin, Michael J. Blaha, Mohamed B. Elshazly, Peter P. Toth, Peter O. Kwiterovich, Roger S. Blumenthal, Steven R. Jones. Comparison of a Novel Method vs the Friedewald Equation for Estimating Low-Density Lipoprotein Cholesterol Levels From the Standard Lipid Profile. JAMA, 2013; 310 (19): 2061 DOI: 10.1001/jama.2013.280532

Johns Hopkins Medicine. "Researchers develop formula to more accurately calculate 'bad' cholesterol." ScienceDaily. ScienceDaily, 17 November 2013. <www.sciencedaily.com/releases/2013/11/131117155408.htm>.
Johns Hopkins Medicine. (2013, November 17). Researchers develop formula to more accurately calculate 'bad' cholesterol. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2013/11/131117155408.htm
Johns Hopkins Medicine. "Researchers develop formula to more accurately calculate 'bad' cholesterol." ScienceDaily. www.sciencedaily.com/releases/2013/11/131117155408.htm (accessed July 22, 2014).

## More Health & Medicine News

Tuesday, July 22, 2014

### Featured Research

from universities, journals, and other organizations

### Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's \$1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

### Gilead's \$1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) — New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
\$23.6 Billion Awarded To Widow In Smoking Lawsuit

### \$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) — Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Tooth Plaque Provides Insight Into Diets Of Ancient People

### Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) — Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Contaminated Water Kills 3 Babies in South African Town

### Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) — Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP

## Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):

Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

## In Other News

... from NewsDaily.com

Save/Print:
Share:

## Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

## Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

## Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web